Review Reports

Response to Reviewer 1 Comments

1. Summary

Dear Reviewer, thank you very much for taking the time to review this manuscript. Your valuable insights have greatly contributed to its improvement. Please find our detailed responses below, with the corresponding revisions/corrections highlighted in the re-submitted files

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Can be improved

We have carefully considered the reviewer’s comment and clarified in manuscript rationale for our design choices, including the sampling strategy.

Are all the cited references relevant to the research?

Yes

Is the research design appropriate?

Can be improved

Are the methods adequately described?

Can be improved

Are the results clearly presented?

Yes

Are the conclusions supported by the results?

Yes

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: This manuscript addresses an important and timely topic, successful aging and quality of life among older adults, with a specific focus on urban–rural disparities. The topic is highly relevant to public health, gerontology, and nursing research, particularly in the context of rapid global population aging. Overall, the study is methodologically sound, theoretically grounded, and clearly written. The use of validated instruments (PWI and SSAS), a relatively large sample size, and advanced statistical analyses (including moderation analysis) are notable strengths. However, several conceptual, methodological, and reporting issues should be addressed to further strengthen the manuscript prior to publication.

Response 1: Thank you for your positive and encouraging evaluation of our manuscript. We appreciate your recognition of the importance and timeliness of the topic, as well as the assessment of the study as methodologically sound, theoretically grounded, and clearly written. We are grateful for your acknowledgment of the use of validated instruments, the sample size, and the applied statistical analyses.

Comments 2: Study design and causal language

While the authors acknowledge the cross-sectional design as a limitation, causal language occasionally appears (e.g., “predictors of successful aging”).

Recommendation: Reframe causal phrasing throughout the manuscript (especially in the Discussion and Conclusion) to emphasize associations rather than causation.

Response 2: We thank the Reviewer for this important comment. We have carefully revised the manuscript to minimize causal wording and to ensure consistency with the cross-sectional study design. Specifically, we systematically reframed causal expressions to emphasize associations rather than causation, particularly in the Discussion and Conclusion sections. Although regression-based terminology (e.g., “predictors”) is retained in accordance with conventional statistical modeling language, we now explicitly clarify in the Methods section that these analyses are intended to examine associative and predictive relationships rather than causal effects. In addition, we have strengthened statements throughout the manuscript to avoid causal interpretation and have clearly acknowledged that the cross-sectional design precludes causal inference. We believe these revisions improve conceptual clarity and ensure that the interpretation of findings is fully aligned with the study design.

Line 274: 2.6. Data analysis: Although regression models were applied to examine the predictive relationships be-tween variables, the cross-sectional nature of the study precludes causal interpretation of the observed associations.

Line 606: 4.6. Study strengths, limitations, and recommendations

The cross-sectional design prevents causal inferences, and the regional focus on Eastern Croatia – Slavonia, with its specific socio-cultural and demographic characteristics, limits generalizability. Reliance on self-report questionnaires may introduce social desirability bias.

Line 388-624: 4. Discussion This study specifically examined differences and factors associated with successful aging, considering the contrasts between urban and rural areas and accounting for the presence of chronic illness, which are theoretically expected to negatively affect sucessful aging [19].

In particular, the study aimed to determine whether quality of life, as a subjective dimension that can typically be enhanced through psychosocial interventions and community-based public health programs [38], represents the factor most strongly associated with successful aging, potentially independent of comorbid conditions.

Regression analyses further showed that PWI was strongly associated with SSAS, while rural residence and the presence of chronic illness were independently associated with lower SSAS scores.

Comments 3: Sampling strategy and representativeness

The use of non-probability quota sampling combined with snowball sampling raises concerns regarding selection bias.

Recommendation: Expand the limitations section to more explicitly discuss how the sampling strategy may affect representativeness and external validity.

Response 3: We thank the Reviewer for this valuable comment. We have expanded the Limitations section to more explicitly address potential selection bias associated with the use of non-probability quota sampling combined with snowball sampling. Specifically, we now acknowledge that this sampling strategy may limit the representativeness of the sample and reduce generalizability of the findings beyond the studied population.

We further clarify that, although quota sampling was used to ensure balanced representation of urban and rural older adults, the non-random recruitment and reliance on participant referral may have further affected sample composition. These limitations are now clearly stated, and the findings are interpreted as context-specific rather than nationally representative.

We believe that this expanded discussion improves methodological transparency and appropriately contextualizes the study’s conclusions.

Line 610: 4.6 Study strengths, limitations, and recommendations

In addition, this study employed a non-probability quota sampling strategy combined with snowball sampling, which may limit the representativeness of the sample. Although quota sampling was used to ensure an equal distribution of participants across relevant subgroups, the non-random nature of participant selection and the use of snowball sampling may have introduced selection bias and reduced sample heterogeneity. Furthermore, other potentially influential but unmeasured factors may have further affected sample composition. Although the sample was adequate for detecting main effects, it is recommended to test moderation results with a larger sample to rule out the possibility of small interaction effects, which is important when interpreting non-significant findings. These methodological limitations highlight important considerations for interpretation and highlight the need for further investigation.

Future research should adopt longitudinal designs, include probability-based sampling methods, expand to other regions, integrate quantitative and qualitative methods, and incorporate comparative samples of older adults residing in institutional settings to gain a more comprehensive understanding of successful aging.

Comments 4: Urban–rural classification clarity

The manuscript would benefit from a clearer operational definition of “urban,” “suburban,” and “rural.”

Recommendation: Briefly describe the criteria used to classify residence (e.g., administrative definition, population size, infrastructure characteristics).

Response 4: We thank the Reviewer for this valuable comment. In response, we have clarified the operational definition of place of residence in the Methods section (Section 2.2, Participants). Participants’ residence was classified according to administrative boundaries, in line with European statistical approaches [30]. Urban and suburban areas included settlements within city administrative boundaries or administratively connected suburban settlements, whereas rural areas encompassed villages and settlements outside urban administrative units.

Line 1890: 2.2. Participants

Participants’ place of residence was classified according to administrative boundaries in line with European statistical approaches [30]. Urban and suburban areas included settlements within city administrative boundaries or administratively connected sub-urban settlements, while rural areas encompassed villages.

Comments 5: Moderation analysis interpretation

Although moderation effects were not significant, their inclusion is valuable.

Recommendation: Strengthen the interpretation by explaining why moderation may not have been observed (e.g., robustness of subjective well-being across contexts, measurement issues, or limited variability).

Response 5: We thank the Reviewer for this valuable comment. In response, we have strengthened the interpretation of the non-significant moderation effects in the Discussion section (Section 4.3). Specifically, we now emphasize that although rural residence and chronic illness were independently associated with lower SSAS and could theoretically attenuate the relationship between subjective well-being and successful aging, no significant moderation effects were observed. This finding is interpreted as indicating the relative robustness of subjective quality of life as a context-independent determinant of perceived successful aging across environmental and health contexts. We believe this addition provides a clearer and more theoretically grounded interpretation of the moderation results, in line with the Reviewer’s recommendation.

Line 546: 4.3 Urban–rural differences in successful aging and quality of life

Moderation analyses showed that PWI predicts SSAS regardless of residence or chron-ic illness, suggesting that well-being consistently predicts perceived successful aging across different environmental contexts and in the presence of illness. Although rural residence and the presence of chronic illness are independently associated with lower SSAS and could theoretically attenuate the effects of personal well-being, the observed lack of significant moderation highlights the robustness of subjective quality of life as a context-independent determinant of perceived successful aging. Overall, these find-ings suggest that interventions aimed at enhancing well-being could help promote successful aging and warrant further investigation.

Comments 6: Overlap with previously published work

The manuscript states that it is part of a larger research project with a previously published article.

Recommendation: More clearly differentiate the present study from prior publications to avoid concerns about redundancy or salami slicing.

Response 6: We thank the Reviewer for this important comment. To address concerns regarding potential overlap with previously published work, we have more clearly delineated the scope and contribution of the present study in the Study Design section (Section 2.1). Specifically, we now clarify that, although the study is part of a larger research project, the current manuscript presents new analyses focusing on urban–rural differences in self-rated successful aging (SSAS) and subjective quality of life (PWI), their associations with psychosocial factors (community involvement and regret), and the examination of predictors of successful aging, including potential moderating effects of place of residence and chronic illness. This clarification explicitly differentiates the aims and analytical focus of the present study from prior publications and reduces the risk of perceived redundancy.

Line 179: 2.1. Study Design

However, this study focuses on new analyses examining urban–rural differences in self-rated successful aging (SSAS) and subjective quality of life (PWI), their associa-tions with psychosocial factors (community involvement and regret), and predictors of successful aging, including potential moderating effects of place of residence and chronic illness.

4. Response to Comments on the Quality of English Language

Point 1: The English is fine and does not require any improvement.

Response 1: We have thoroughly reviewed the entire manuscript for spelling, grammar, and overall language quality. We have carefully revised the text to enhance clarity, readability, and fluency throughout, considering the other reviewer’s comments regarding language. We therefore believe that the manuscript is now clearly and accurately written in English and meets the high standards expected for publication.  

5. Additional clarifications

N/A

Response to Reviewer 2 Comments

1. Summary

Dear Reviewer, thank you very much for taking the time to review this manuscript. We greatly appreciate your positive and thorough evaluation, and we are encouraged by your recognition of the originality, methodological rigor, and relevance of our study. We note that you have no suggested changes, and we are pleased that the manuscript is considered suitable for publication in its current form.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes

Are all the cited references relevant to the research?

Yes

Is the research design appropriate?

Yes

Are the methods adequately described?

Yes

Are the results clearly presented?

Yes

Are the conclusions supported by the results?

Yes

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: In recent years there have been a number of studies and reports on the need to lessen the ill-effects of the international ageing of populations, to achieve ‘successful ageing’ or ‘active ageing’ rather than the decline stereotypically associated with ageing. Reports by the WHO and UN referenced in this article, and also from the EU, whose directives and reports drawing on ageing policies in member-states are not referenced, have defined successful, and unsuccessful, ageing and means to achieve it in terms adopted in this study. They define successful ageing as including good health, good access to support services including for health care, active involvement of older people in their communities while living independently in a supportive environment providing access to contact with others and to community activities facilitated by good transport to provide access to activities and services. These experiences are judged essential for achieving personal well-being and good quality of life in later life i.e. for successful ageing. This article is original in assessing the subjective views of older people on their quality of life and well-being, defined by these measures, rather than assessing it by quantitative methods. It takes a representative sample of people over age 60 who are living independently, not in care homes, in Croatia, where the issue has not been previously studied. The sample is evenly divided between rural and urban residents because it is known from previous studies that rural dwellers find it harder to achieve successful ageing due to poorer, less accessible services including for health care and transport, fewer opportunities for community involvement bringing greater isolation, and often poorer living standards than in urban areas. There was a small majority of female over male respondents, which is appropriate because in Croatia as in most countries women tend to outlive men, though not always in better health. The views of the respondents were achieved by interviews in their own homes by trained interviewers. The methods are sound, clearly described and good ethical standards were achieved. The findings bear out those of previous studies including that there are higher levels of successful ageing in urban areas, among those with higher levels of education and higher living standards, for all the reasons described above, while no significant specifically gendered differences were identified. One difference the study discovered in Croatia compared with other countries was that experience of successful ageing declined with age, which it attributes to the effects of older peoples’ experience of past insecurities in wartime. The authors rightly conclude that the study ‘provides novel insights into the psychosocial and environmental determinants of successful ageing’ in the region. They propose policies to improve levels of successful ageing, especially in rural areas, including integrated public health and social policies to improve psychological well-being, social participation and structural inequalities, including in health care. They also recognize the limitations of the study including that the focus upon Eastern Croatia – Slovenia with its specific characteristics limits the generalizability of the findings to other regions and nations, that the reliance solely on self-reporting interviews may introduce bias, and the design of the study prevents inferences of causality. These limitations do not undermine the value of the study, especially because they are described so clearly. The authors usefully recommend methods whereby future researchers can build upon their work to gain further, widely comparable, insights. The (American) English is good. Altogether I believe that the article merits publication unchanged. I have no significant criticisms.

Response 1: We thank the Reviewer for this comprehensive, thoughtful, and highly positive evaluation of our manuscript. We greatly appreciate the Reviewer’s careful reading and their recognition of the originality, methodological rigor, ethical standards, and relevance of the study, particularly in the context of population ageing and urban–rural disparities in Croatia. We are encouraged by the Reviewer’s assessment that the findings provide novel insights into the psychosocial and environmental determinants of successful ageing and by their acknowledgement of the clarity with which the study’s limitations are presented. We are especially grateful for the Reviewer’s conclusion that the manuscript merits publication unchanged.

4. Response to Comments on the Quality of English Language

Point 1: The English is fine and does not require any improvement.

Response 1: We have thoroughly reviewed the entire manuscript for spelling, grammar, and overall language quality. We have carefully revised the text to enhance clarity, readability, and fluency throughout, considering the other reviewer’s comments regarding language. We therefore believe that the manuscript is now clearly and accurately written in English and meets the high standards expected for publication.  

5. Additional clarifications

N/A

Response to Reviewer 3 Comments

1. Summary

Dear Reviewer, thank you very much for taking the time to review this manuscript. Your valuable insights have greatly contributed to its improvement. Please find our detailed responses below, with the corresponding revisions/corrections highlighted in the re-submitted files

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Can be improved

We have carefully considered the reviewer’s comment and made revisions in manuscript.

Are all the cited references relevant to the research?

Yes

Is the research design appropriate?

Yes

Are the methods adequately described?

Yes

Are the results clearly presented?

Can be improved

Are the conclusions supported by the results?

Can be improved

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: The article “Quality of Life as a Predictor of Successful Aging among Older Adults: A Cross-Sectional Study in Urban and Rural Settings” addresses a scientifically relevant theme, engaging with the contemporary debate on population aging, quality of life, and successful aging. The focus on differences between urban and rural contexts, applied to a structurally disadvantaged European region (Eastern Slavonia, Croatia), constitutes a pertinent contribution, primarily by providing empirical visibility to contexts that are underrepresented in international literature.

Overall, the article is well-structured as a scientific work. The organization follows the typical standards of international journals, and the writing is clear and consistent. The introduction provides a solid framework for aging, quality of life, and successful aging, culminating in clear and well-defined research objectives. The instruments used (PWI and SSAS) are appropriate, validated, and coherent with the theoretical constructs employed, and the methodology is presented in detail.

In general, there is consistency between the various sections of the paper. The empirical analyses address the proposed objectives and are well-organized into tables. The conclusions are derived from the results and reinforce the importance of subjective well-being as a central variable associated with successful aging.

Response 1: Dear Reviewer, We sincerely thank you for your careful and positive evaluation of our manuscript. We greatly appreciate your recognition of the scientific relevance of our study, particularly the focus on urban–rural differences in a structurally disadvantaged region and its contribution to the international literature on aging, quality of life, and successful aging. We are also grateful for your acknowledgment of the manuscript’s clear structure, rigorous methodology, appropriate use of validated instruments (PWI and SSAS), and coherent empirical analyses.

Comments 2:  The article does not formulate explicit research hypotheses, despite employing predictive models and moderation analyses. Although the objectives are clearly defined, the absence of hypotheses weakens the theoretical-analytical framework and makes it difficult to distinguish between confirmatory and exploratory analyses. For a study utilizing linear regression and moderation models, the inclusion of hypotheses is a fundamental requirement.

Response 2: We thank the Reviewer for their constructive and detailed comment. In response, explicit hypotheses were added in Section 1.3 to strengthen the theoretical-analytical framework, specifying expected differences and associations in subjective well-being (PWI), self-rated successful aging (SSAS), and potential moderation effects. We believe that the inclusion of these hypotheses clarifies the confirmatory and exploratory aspects of the analyses and provides a clearer foundation for interpreting the regression and moderation results.

Line 158: 1.3. Aims and hypotheses

To address these aims, the following hypotheses were formulated:

•          Hypothesis 1: There are significant differences in subjective quality of life, measured by the Personal Well-Being Index (PWI), and self-rated successful aging (SSAS) between older adults living in urban and rural areas.

•          Hypothesis 2: Higher subjective quality of life (PWI) is associated with higher levels of self-rated successful aging (SSAS).

•          Hypothesis 3: Subjective quality of life (PWI), place of residence (urban vs. rural), and the presence of chronic illness predict self-rated successful aging (SSAS).

•          Hypothesis 4: Place of residence (urban vs. rural) and the presence of chronic ill-ness moderate the relationship between subjective quality of life (PWI) and self-rated successful aging (SSAS).

Comments 3 - There is a recurrent use of predictive language (“predictor,” “explained variance”) that may suggest a causal interpretation of the results, despite the study’s cross-sectional design. While this limitation is acknowledged in the limitations section, the way results are interpreted in the discussion and conclusions tends to overstate the explanatory scope of the model. It is recommended that the analytical language be revised to align inferences with the actual possibilities of the methodological design.

Response 2:

We thank the Reviewer for this important comment. We have carefully revised the manuscript to minimize causal wording and to ensure consistency with the cross-sectional study design. Specifically, we systematically reframed causal expressions to emphasize associations rather than causation, particularly in the Discussion and Conclusion sections. Although regression-based terminology (e.g., “predictors”) is retained in accordance with conventional statistical modeling language, we now explicitly clarify in the Methods section that these analyses are intended to examine associative and predictive relationships rather than causal effects. In addition, we have strengthened statements throughout the manuscript to avoid causal interpretation and have clearly acknowledged that the cross-sectional design precludes causal inference. We believe these revisions improve conceptual clarity and ensure that the interpretation of findings is fully aligned with the study design.

Line 274: 2.6. Data analysis: Although regression models were applied to examine the predictive relationships be-tween variables, the cross-sectional nature of the study precludes causal interpretation of the observed associations.

Line 606: 4.6. Study strengths, limitations, and recommendations

The cross-sectional design prevents causal inferences, and the regional focus on Eastern Croatia – Slavonia, with its specific socio-cultural and demographic characteristics, limits generalizability. Reliance on self-report questionnaires may introduce social desirability bias.

Line 388-624: 4. Discussion This study specifically examined differences and factors associated with successful aging, considering the contrasts between urban and rural areas and accounting for the presence of chronic illness, which are theoretically expected to negatively affect sucessful aging [19].

In particular, the study aimed to determine whether quality of life, as a subjective dimension that can typically be enhanced through psychosocial interventions and community-based public health programs [38], represents the factor most strongly associated with successful aging, potentially independent of comorbid conditions.

Regression analyses further showed that PWI was strongly associated with SSAS, while rural residence and the presence of chronic illness were independently associated with lower SSAS scores.

Comments 3: The sampling strategy (quota sampling combined with snowball sampling) is correctly presented; however, the discussion of the implications of this choice for representativeness and generalizability is insufficient. The claim that the sample is representative should be more cautious or supported by comparisons with regional population data.

Response 3: We thank the Reviewer for this valuable comment. We have expanded the Limitations section to more explicitly address potential selection bias associated with the use of non-probability quota sampling combined with snowball sampling. Specifically, we now acknowledge that this sampling strategy may limit the representativeness of the sample and reduce generalizability of the findings beyond the studied population. We further clarify that, although quota sampling was used to ensure balanced representation of urban and rural older adults, the non-random recruitment and reliance on participant referral may have further affected sample composition. These limitations are now clearly stated, and the findings are interpreted as context-specific rather than nationally representative. We believe that this expanded discussion improves methodological transparency and appropriately contextualizes the study’s conclusions. Additionally, in the Methods section, the text regarding the sample size has been reformulated to avoid implying generalization, as generalizability is limited in the present study; the sample is considered context-specific and does not represent the entire population.

Line 610: 4.6 Study strengths, limitations, and recommendations

In addition, this study employed a non-probability quota sampling strategy combined with snowball sampling, which may limit the representativeness of the sample. Although quota sampling was used to ensure an equal distribution of participants across relevant subgroups, the non-random nature of participant selection and the use of snowball sampling may have introduced selection bias and reduced sample heterogeneity. Furthermore, other potentially influential but unmeasured factors may have further affected sample composition. Although the sample was adequate for detecting main effects, it is recommended to test moderation results with a larger sample to rule out the possibility of small interaction effects, which is important when interpreting non-significant findings. These methodological limitations highlight important considerations for interpretation and highlight the need for further investigation.

Future research should adopt longitudinal designs, include probability-based sampling methods, expand to other regions, integrate quantitative and qualitative methods, and incorporate comparative samples of older adults residing in institutional settings to gain a more comprehensive understanding of successful aging.

Line 184: 2.2. Participants

Based on these criteria, the minimum required sample size (n = 384) was calculated using an online Sample Size Calculator [31], assuming a 95% confidence level and a 5% margin of error for a population of 181,904 older adults aged 60 years and older in the Eastern region of Croatia (Slavonia). The final sample included 403 participants, exceeding the minimum required sample size

Comments 4: Although the moderation analyses were correctly conducted, the absence of moderating effects is not discussed substantively. It would be important to reflect on the theoretical implications of this lack of moderation, as well as on potential limitations regarding statistical power to detect interaction effects.

Response 4: We thank the Reviewer for this valuable comment. In response, we have strengthened the interpretation of the non-significant moderation effects in the Discussion section (Section 4.3). Specifically, we now emphasize that although rural residence and chronic illness were independently associated with lower SSAS and could theoretically attenuate the relationship between subjective well-being and successful aging, no significant moderation effects were observed. This finding is interpreted as indicating the relative robustness of subjective quality of life as a context-independent determinant of perceived successful aging across environmental and health contexts. We believe this addition provides a clearer and more theoretically grounded interpretation of the moderation results, in line with the Reviewer’s recommendation.

Line 546: 4.3 Urban–rural differences in successful aging and quality of life

Moderation analyses showed that PWI predicts SSAS regardless of residence or chronic illness, suggesting that well-being consistently predicts perceived successful aging across different environmental contexts and in the presence of illness. Although rural residence and the presence of chronic illness are independently associated with lower SSAS and could theoretically attenuate the effects of personal well-being, the observed lack of significant moderation highlights the robustness of subjective quality of life as a context-independent determinant of perceived successful aging. Overall, these findings suggest that interventions aimed at enhancing well-being could help promote successful aging and warrant further investigation.

Comments 5: From a theoretical perspective, the article relies on Rowe and Kahn’s classic model of successful aging without in-depth critical problematization. Given the vast literature questioning the normative and biomedical assumptions of this model, it would be desirable to integrate alternative or critical perspectives, thereby strengthening the article’s originality.

Response 5: We thank the Reviewer for this important comment. In response, the Discussion section (Line 402, Section 2.1) has been expanded to critically reflect on the theoretical grounding of the study in Rowe and Kahn’s classical model of successful aging. We now explicitly acknowledge the limitations of approaches that equate successful aging primarily with the absence of disease and high functional capacity. These considerations align the study with contemporary, person-centered perspectives on aging and strengthen its theoretical originality.

Line 402: 2.1. Discussion

Although the conceptualization of successful aging in this study is theoretically grounded in the classical model proposed by Rowe and Kahn [19], it is important to acknowledge the limitations inherent in approaches that equate successful aging pri-marily with the absence of disease and high levels of functional capacity [40–42]. The findings of the present study partially challenge this biomedical emphasis. Subjective quality of life was independently associated with self-rated successful aging, regard-less of the presence of chronic illness. This suggests that successful aging, as operation-alized in this study, should not be understood solely as an outcome of optimal health status, but rather as a subjective and contextually embedded process shaped by per-sonal well-being, adaptive capacities, and lived experience. These results align with contemporary shifts toward more inclusive and person-centered conceptualizations of aging well [40].

Comments 6: Finally, while the discussion is extensive and well-founded, it tends at times to reiterate results already presented rather than providing a stronger interpretive synthesis. A more assertive and objective style would strengthen the scientific impact of the text.

Response 6: We thank the Reviewer for this valuable comment. In response, the Discussion section has been revised to provide a more assertive and interpretive synthesis, while retaining the original text. These revisions aim to strengthen the interpretive depth and scientific impact of the Discussion without unnecessary repetition of results.

Line 402: 2.1. Discussion

Lower satisfaction with close relationships among older adults should be inter-preted in the context of urban–rural differences in social support networks.

In rural settings, participants reported lower levels of satisfaction with safety and future security, which may reflect limited quality and availability of services, includ-ing healthcare, as well as deteriorating environmental conditions and infrastructure [55].

Consistent with the findings of lower rated health among participants from rural areas, Jiang et al. [53] report that older adults in rural areas more frequently perceive their health as poor, experience higher rates of depressive symptoms, and encounter greater difficulties in functional abilities.

4. Response to Comments on the Quality of English Language

Point 1: The English is fine and does not require any improvement.

Response 1: We have thoroughly reviewed the entire manuscript for spelling, grammar, and overall language quality. We have carefully revised the text to enhance clarity, readability, and fluency throughout, considering the other reviewer’s comments regarding language. We therefore believe that the manuscript is now clearly and accurately written in English and meets the high standards expected for publication.  

5. Additional clarifications

N/A

Response to Reviewer 4 Comments

1. Summary

Dear Reviewer, thank you very much for taking the time to review this manuscript. Your valuable insights have greatly contributed to its improvement. Please find our detailed responses below, with the corresponding revisions/corrections highlighted in the re-submitted files

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Must be improved

We have carefully considered the reviewer’s comment and made revisions in manuscript.

Are all the cited references relevant to the research?

Can be improved

Is the research design appropriate?

Can be improved

Are the methods adequately described?

Must be improved

Are the results clearly presented?

Must be improved

Are the conclusions supported by the results?

Must be improved

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: I found the topic addressed not particularly novel and fairly well established in the literature; however, for a genuine international interpretation of the collected data, it requires substantial further investigation.

Response 1: Dear Reviewer, thank you. We acknowledge that the general concept of successful aging is well established in the literature. However, our study provides novel empirical insights by examining urban–rural differences in self-rated successful aging and subjective quality of life in a structurally disadvantaged Eastern European region (Slavonia, Croatia), a context that is underrepresented in international research. We agree that further investigation in additional international contexts would be valuable to enhance the generalizability and cross-cultural interpretation of these findings.

Comments 2:  Title: it should be made clearer in terms of the type of setting.

Response 2: We thank the Reviewer for this suggestion. In response, the title has been revised to more clearly indicate the study setting. The updated title is now: “Quality of Life as a Predictor of Successful Aging in Urban and Rural Older Adults: A Cross-Sectional Study in Eastern Croatia–Slavonia.”

Line 1-2: Title

Quality of Life as a Predictor of Successful Aging in Urban and Rural Older Adults: A Cross-Sectional Study in Eastern Croatia–Slavonia

Comments 3: While remaining within the standard format of a maximum of 200–250 words, I suggest giving greater attention to clinical and assistive practice in the conclusions (the same applies to the sections on “implications and main findings”). Keywords: I suggest including the type of study conducted and the setting, keeping to 4–5 keywords as per classical standards.

Response 3:

We thank the Reviewer for these valuable suggestions. In response, we have enhanced the Conclusions and Abstract conclusion to place greater emphasis on clinical and assistive practice, highlighting how the findings may inform interventions and support for older adults in both urban and rural settings. Additionally, the keywords have been revised to include the type of study and the study setting, in line with standard journal requirements.

Line 34: Abstract

Background: Population aging has increased attention on the quality of life and suc-cessful aging of older adults. Objective: To examine urban–rural differences in subjec-tive quality of life and self-rated successful aging, explore associations with psycho-social factors, and identify predictors of successful aging, including potential modera-ting effects of place of residence and chronic illness. Methods: A cross-sectional study was conducted among 403 adults aged ≥60 years in Eastern Croatia. Measures in-cluded a sociodemographic questionnaire, the Self-assessment of Successful Ageing Scale (SSAS), and the Personal Wellbeing Index (PWI). Data were analyzed using nonparametric tests (Mann–Whitney U, Spearman’s correlation), linear regression, and moderation analyses. Significance was set at p < 0.05. Ethical approval was obtai-ned (Class: 602-01/24-12/02; IRB: 2158/97-97-10-24-36). Results: Rural participants reported lower PWI scores (p = 0.005) and self-rated successful aging (p < 0.001) than urban participants. Active community involvement was positively associated with quality of life (Rho = 0.46; p < 0.001), whereas regret about missed opportunities and past actions was negatively associated (Rho = −0.20; p < 0.01). Regression analyses ex-plained 48.3% of the variance in SSAS, with higher PWI scores being strongly associa-ted with higher SSAS scores, and rural residence and chronic illness being associated with lower SSAS scores. Moderation analyses indicated that the association between PWI and SSAS was consistent across different environmental contexts and in the presence of illness. Conclusion: Older adults living in rural areas reported lower qua-lity of life and self-rated successful aging compared with those in urban and suburban areas, with subjective well-being emerging as a key predictor. Promoting social enga-gement and addressing psychosocial barriers may enhance successful aging, particu-larly in rural populations. Findings suggest that social engagement and psychosocial support are associated with higher level of perceived successful aging, indicating po-tential areas for future community-based or healthcare interventions.

Keywords: quality of life; successful aging; older adults; urban and rural settings; cross-sectional study; Slavonia, Eastern Croatiaa

Line 626: 5. Conclusion

This study provides evidence of significant urban–rural disparities in subjective quality of life and self-rated successful aging among older adults in Eastern Croatia–Slavonia. Older individuals residing in rural areas consistently reported lower levels of well-being across multiple life domains, as well as lower overall perceptions of suc-cessful aging. These findings suggest that successful aging is shaped not only by indi-vidual health status but also by broader environmental and social conditions associat-ed with place of residence. Subjective quality of life was strongly associated with self-rated successful aging, explaining a substantial proportion of its variance. Despite lower scores observed among rural residents and participants with chronic illness, moderation analyses indicated that the association between well-being and successful aging remained consistent across environmental and health contexts. These findings underscore the robustness of personal well-being as a context-independent correlate of successful aging. This underscores the robustness of subjective well-being as a core component of successful aging in later life. Importantly, psychosocial factors played a meaningful role in shaping both quality of life and successful aging. Active involve-ment in the community was positively associated with higher well-being across all domains, whereas regret related to missed opportunities and past actions was linked to poorer outcomes. These findings highlight the interplay of adaptive and maladaptive psychosocial processes in later life and underscore the association between social par-ticipation, psychological resources, and self-perceived successful aging. Taken togeth-er, the results point to the need for integrated public health and social policies that go beyond medical care and address social participation, psychological well-being, and structural inequalities, particularly in rural settings. Interventions aimed at enhancing community engagement, reducing social isolation, and supporting adaptive coping strategies may contribute substantially to improved quality of life and more successful aging among older adults, particularly in socioeconomically disadvantaged and rural contexts.

Line 60: Keywords: quality of life; successful aging; older adults; urban and rural settings; cross-sectional study; Slavonia, Eastern Croatia

Comments 4: Introduction: The social aspects are sufficiently explored, but the section needs improvement to reflect modern clinical practice (possibly by adding a specific sub-section), including strategic elements of integrated care such as clinical networks. These could also serve as a basis for academic discussion in relation to the relevant policy framework (see also the suggestions for the Discussion section). In this regard, I suggest expanding and completing this section—which in its current version is somewhat lacking in this key determinant—with appropriate and recent references on topics such as Achieving quadruple aim goals through clinical networks, and The effectiveness of clinical networks in improving quality of care and patient outcomes. This would certainly broaden the audience of potential readers/researchers interested in the collected data, which moreover have a strong impact on clinical practice in terms of qualitative and quantitative outcomes explored in the study. Regarding the objectives (currently not easy to follow, as they appear at the end of subsection 1.2, lines 121–124), I suggest adopting the classic format of clearly stating the primary objectives first, followed by the secondary ones, using the standard wording: “The primary objectives of the study were…, while the secondary objectives were…”. Given the overall structure of the section, I also recommend creating a specific sub-section entitled “Aims”.

Response 4: We thank the Reviewer for this insightful comment. In response, the Introduction has been expanded to include a new subsection entitled “Integrated and Community-Oriented Approaches to Supporting Subjective Quality of Life and Successful Aging”, emphasizing contemporary models of integrated care, clinical networks, and their relevance for supporting functional ability, independence, and quality of life among older adults. We have incorporated recent references on the effectiveness of integrated care interventions and patient-reported outcomes, highlighting their applicability to contexts with urban–rural disparities.

Additionally, the Aims and Hypotheses have been clearly restructured: primary objectives are now stated first, followed by secondary objectives, and corresponding hypotheses are explicitly formulated to align with the study’s analytical framework. These revisions improve clarity, strengthen the theoretical foundation, and connect the study to current clinical practice and policy-relevant frameworks.

Line 128: 1.3. Integrated and Community-Oriented Approaches to Supporting Subjective Quality of Life and Successful Aging

            Beyond individual biopsychosocial determinants, contemporary approaches to aging increasingly emphasize the role of integrated and community-oriented models of care and support [23] in supporting functional ability, independence, and quality of life among older adults. As aging is frequently accompanied by chronic conditions, multimorbidity, and complex care needs [6–9,18], older adults often interact with mul-tiple health and social care providers, which places them at heightened risk of frag-mented and poorly coordinated care. Fragmented care is associated with unmet needs, lower patient satisfaction, inefficient use of health services, and poorer health out-comes [24], highlighting the importance of integrated care models that ensure conti-nuity and coordination across sectors and levels of care. In response to these challeng-es, the World Health Organization has promoted the Integrated Care for Older People (ICOPE) approach, which focuses on maintaining and optimizing intrinsic capacity and functional ability through person-centred, coordinated health and social services, particularly within community settings [25]. Importantly, the effectiveness of inte-grated care models for older adults is increasingly evaluated not only through clinical or service-related indicators, but also through patient-reported outcomes, including subjective quality of life and functional performance in everyday life. Umbrella re-views and systematic evidence syntheses identify quality of life as an outcome in the assessment of integrated and community-based care interventions for older populations [23]. These considerations are particularly relevant in contexts characterized by urban–rural disparities in service availability, accessibility, and social infrastructure, including geographical remoteness and transport-related barriers [26,27]. Additional structural barriers to care, reduced access to specialized services, and more limited so-cial resources can shape older adults’ quality of life and opportunities for successful aging. Understanding how subjective quality of life and perceptions of successful aging vary across different living environments is therefore essential for informing the de-velopment and contextual adaptation of integrated, community-oriented approaches to supporting older adults.

1.3. Aims and hypoteses

The primary aims of this study were to examine urban–rural differences in subjec-tive quality of life and self-rated successful aging among older adults and to analyze their associations with psychosocial factors. The secondary aims were to identify pre-dictors of successful aging, including the potential moderating effects of place of resi-dence and chronic illness. To address these aims, the following hypotheses were for-mulated:

•          Hypothesis 1: There are significant differences in subjective quality of life, meas-ured by the Personal Well-Being Index (PWI), and self-rated successful aging (SSAS) between older adults living in urban and rural areas.

•          Hypothesis 2: Higher subjective quality of life (PWI) is associated with higher lev-els of self-rated successful aging (SSAS).

•          Hypothesis 3: Subjective quality of life (PWI), place of residence (urban vs. rural), and the presence of chronic illness predict self-rated successful aging (SSAS).

•          Hypothesis 4: Place of residence (urban vs. rural) and the presence of chronic ill-ness moderate the relationship between subjective quality of life (PWI) and self-rated successful aging (SSAS).

Comments 5: Methods: This section needs to be completely revised. In addition to clarifying inconsistencies in terms of objectives, transparency requires the application of the appropriate reporting guideline for the type of study conducted, together with the relevant checklist. This element is critically important, and failure to address it will not allow a true international interpretation of the manuscript.

Response 5: We thank the Reviewer for this valuable comment. In response, we have strengthened the interpretation of the non-significant moderation effects in the Discussion section (Section 4.3). Specifically, we now emphasize that although rural residence and chronic illness were independently associated with lower SSAS and could theoretically attenuate the relationship between subjective well-being and successful aging, no significant moderation effects were observed. This finding is interpreted as indicating the relative robustness of subjective quality of life as a context-independent determinant of perceived successful aging across environmental and health contexts. We believe this addition provides a clearer and more theoretically grounded interpretation of the moderation results, in line with the Reviewer’s recommendation.

Line 174:

2. Materials and Methods

2.1. Study Design

This quantitative cross-sectional study across urban and rural settings was con-ducted between January and June 2024 in the Eastern region of Croatia—Slavonia in participants’ homes. The study is part of a larger research project on successful aging, from which a previous article has been published [28]. However, this study focuses on new analyses examining urban–rural differences in self-rated successful aging (SSAS) and subjective quality of life (PWI), their associations with psychosocial factors (community involvement and regret), and predictors of successful aging, including potential moderating effects of place of residence and chronic illness.

2.2. Participants

The study population comprised community-dwelling older adults, defined ac-cording to the United Nations classification as individuals aged 60 years and above [29]. Eligibility criteria included: (1) chronological age ≥60 years, (2) ability to provide informed consent, and (3) residence in the community, excluding individuals living in institutionalized care facilities. Participants’ place of residence was classified accord-ing to administrative boundaries in line with European statistical approaches [30]. Urban and suburban areas included settlements within city administrative boundaries or administratively connected suburban settlements, while rural areas encompassed villages.

Based on these criteria, the minimum required sample size (n = 384) was calcu-lated using an online Sample Size Calculator [31], assuming a 95% confidence level and a 5% margin of error for a population of 181,904 older adults aged 60 years and older in the Eastern region of Croatia (Slavonia). The final sample included 403 par-ticipants, exceeding the minimum required sample size.

The final sample consisted of 175 men (43.4%) and 228 women (56.6%), with a median age of 70 years (range: 60–92). No participants identified as “Other” gender.

Power analysis confirmed that the achieved sample size provided sufficient sta-tistical power (≥0.80) for all analyses performed, including multivariate regression (observed power = 0.95) [32].

Line 202: 2.2. Participants

A non-probability quota sampling strategy was applied to ensure proportional representation of urban and rural participants, followed by snowball sampling. The response rate was 83%. The participant selection process is illustrated in Figure 1 in accordance with STROBE recommendations

Comments 6: Results: Overall, these could represent the strength of the manuscript and will certainly benefit from the previous and subsequent suggestions. However, they will require a realistic reassessment once the previously identified conflicts are resolved, as well as improved editing (acronym legends are missing in the proposed tables and figures). The addition of a study flow diagram could also facilitate a rapid assessment of the phenomenon under investigation.

Response 6: We thank the Reviewer for this constructive comment. In response, we have clarified all acronyms in tables and figures (SSAS – Self-Assessment of Successful Aging Scale; PWI – Personal Wellbeing Index). Additionally, a flow diagram of participant recruitment and selection has been added (Figure 1) in accordance with STROBE recommendations, facilitating a clearer and quicker understanding of the study sample and the phenomenon under investigation. These revisions improve clarity, readability, and the overall presentation of the results.

Line 311: Table 2. Differences in SSAS and PWI scores between urban/suburban and rural older adults

SSAS – Self-assessment of Successful Ageing Scale; PWI – Personal Wellbeing Index

Comments 7: Discussion: This section also needs to be revised from an integrated care and healthcare management perspective. Following the suggestions made for the Introduction and starting from the proposed topics, I recommend creating a specific section, for example entitled “Perspectives for Clinical and Assistive Practice,” which could serve as a concrete evidence-based reference for policy, linking organizational and assistive care elements with the collected data.

Response 7: We thank the Reviewer for this valuable comment. In response, a new subsection entitled “Perspectives for Clinical and Assistive Practice” has been added to the Discussion (Section 4.5). This section highlights the practical implications of the findings for integrated, person-centered care, particularly in rural settings, linking organizational and assistive care elements with empirical results. It emphasizes the role of personal well-being and self-rated successful aging as patient-relevant outcomes, the importance of coordinated care and clinical networks, and the integration of structured psychosocial interventions. Additionally, the discussion aligns with contemporary outcome-oriented frameworks, including the Quadruple Aim, to inform evidence-based practice and policy development.

Line 570: 2.1. 4.5 Perspectives for Clinical and Assistive Practice

The findings of this study have direct implications for the organization of inte-grated, person-centered care for older adults, particularly in rural settings. PWI was found to be strongly associated with SSAS across residence and chronic disease status. This suggests that interventions aimed at enhancing personal well-being and social in-clusion may yield broad and transferable benefits across contexts and healthcare pro-files. From a health management perspective, these findings support the integration of routine personal well-being screening into needs assessments for older adults within primary healthcare settings.

In rural areas, where subjective quality of life is generally lower, integrating healthcare, social services, and opportunities for community participation may better meet older adults’ needs. Personal well-being and self-rated successful aging can serve as patient-relevant, measurable outcomes for planning, monitoring, and evaluating integrated care models, aligning with outcome-oriented frameworks that prioritize domains most meaningful to older individuals, such as daily functioning and emotion-al well-being [70].

The high prevalence of chronic illness among older adults further underscores the need for coordinated care, as these individuals are more likely to utilize services from multiple providers across health and social care systems. Accordingly, the findings confirm the need for organizational mechanisms that reduce care fragmentation and strengthen collaboration through clinical networks.

The positive association between community involvement and personal well-being, alongside the negative impact of regret on quality-of-life domains, indi-cates that assistive practice should include structured psychosocial components, such as empowerment-oriented interventions, support for coping with losses, life-course evaluations, and the promotion of meaningful community roles. Evaluation of inte-grated care models would benefit from outcomes aligned with the Quadruple Aim framework, which emphasizes improving patient experience, population health, re-ducing costs, and supporting healthcare staff well-being [71].

Comments 8: The limitations require an in-depth discussion, given the type of study conducted, particularly with regard to data generalizability.

Response 8: We thank the Reviewer for this valuable comment. In response, the Discussion section has been expanded (Section 4.6) to provide a more in-depth discussion of the study’s limitations, with particular emphasis on the generalizability of the findings. We now explicitly address the cross-sectional design, the regional focus on Eastern Croatia – Slavonia, the use of self-report questionnaires, and the non-probability quota plus snowball sampling strategy. These revisions highlight how these methodological factors may affect representativeness and interpretation of results. Additionally, we provide recommendations for future research, including the adoption of longitudinal designs, probability-based sampling, expansion to other regions, and integration of quantitative and qualitative methods, to support broader understanding and applicability of findings.

Line 402: 2.1. Discussion

4.6 Study strengths, limitations, and recommendations

This study presents several strengths. It includes a sizable sample of older adults from both rural and urban areas, allowing robust comparisons across settings. The use of validated instruments to assess subjective well-being and self-rated successful aging enhances the reliability of the findings. Moreover, it provides novel insights into psy-chosocial and environmental determinants of successful aging within a region charac-terized by unique socio-cultural and demographic features.

Despite these strengths, several limitations should be acknowledged. The cross-sectional design prevents causal inferences, and the regional focus on Eastern Croatia – Slavonia, with its specific socio-cultural and demographic characteristics, limits generalizability. Reliance on self-report questionnaires may introduce social de-sirability bias.

In addition, this study employed a non-probability quota sampling strategy com-bined with snowball sampling, which may limit the representativeness of the sample. Although quota sampling was used to ensure an equal distribution of participants across relevant subgroups, the non-random nature of participant selection and the use of snowball sampling may have introduced selection bias and reduced sample hetero-geneity. Furthermore, other potentially influential but unmeasured factors may have further affected sample composition. Although the sample was adequate for detecting main effects, it is recommended to test moderation results with a larger sample to rule out the possibility of small interaction effects, which is important when interpreting non-significant findings. These methodological limitations highlight important con-siderations for interpretation and highlight the need for further investigation.

Future research should adopt longitudinal designs, include probability-based sampling methods, expand to other regions, integrate quantitative and qualitative methods, and incorporate comparative samples of older adults residing in institutional settings to gain a more comprehensive understanding of successful aging..

Comments 9: Conclusions: They are too lengthy and scientifically weak; they should be revised in line with the suggestions provided.

Response 9: Thank you. Based on the feedback from all Reviewers, the conclusions have been reviewed and refined to better reflect the key findings and their implications..

Line 627: 5. Conclusion

This study provides evidence of significant urban–rural disparities in subjective quality of life and self-rated successful aging among older adults in Eastern Croatia–Slavonia. Older individuals residing in rural areas consistently reported lower levels of well-being across multiple life domains, as well as lower overall perceptions of suc-cessful aging. These findings suggest that successful aging is shaped not only by indi-vidual health status but also by broader environmental and social conditions associat-ed with place of residence. Subjective quality of life was strongly associated with self-rated successful aging, explaining a substantial proportion of its variance. Despite lower scores observed among rural residents and participants with chronic illness, moderation analyses indicated that the association between well-being and successful aging remained consistent across environmental and health contexts. These findings underscore the robustness of personal well-being as a context-independent correlate of successful aging. This underscores the robustness of subjective well-being as a core component of successful aging in later life. Importantly, psychosocial factors played a meaningful role in shaping both quality of life and successful aging. Active involve-ment in the community was positively associated with higher well-being across all domains, whereas regret related to missed opportunities and past actions was linked to poorer outcomes. These findings highlight the interplay of adaptive and maladaptive psychosocial processes in later life and underscore the association between social par-ticipation, psychological resources, and self-perceived successful aging. Taken togeth-er, the results point to the need for integrated public health and social policies that go beyond medical care and address social participation, psychological well-being, and structural inequalities, particularly in rural settings. Interventions aimed at enhancing community engagement, reducing social isolation, and supporting adaptive coping strategies may contribute substantially to improved quality of life and more successful aging among older adults, particularly in socioeconomically disadvantaged and rural contexts.

Comments 10: References: These should be expanded according to the indications given, and references older than ten years should be updated unless they are methodological or of high evidence-based impact; some of the current references date back twenty years or more

Response 10: We thank the Reviewer for this valuable comment. References have been expanded in accordance with the Reviewers’ suggestions. Older references (over 10 years) have been retained only if they are of high methodological or evidence-based significance and remain relevant to the context of the study.

4. Response to Comments on the Quality of English Language

Point 1: The English could be improved to more clearly express the research..

Response 1: We have thoroughly reviewed the entire manuscript for spelling, grammar, and overall language quality. We have carefully revised the text to enhance clarity, readability, and fluency throughout. We therefore believe that the manuscript is now clearly and accurately written in English and meets the high standards expected for publication.  

5. Additional clarifications

N/A