Review Reports - The Effects of Aromatherapy on Sleep Quality in Menopausal Women: A Systematic Review and Meta-Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This systematic review and meta-analysis by Tangkeeratichai et al. investigates the efficacy of aromatherapy in improving sleep quality among postmenopausal women. The authors analyze six randomized controlled trials (RCTs), three of which are included in a meta-analysis involving 301 participants. The main finding is that while aromatherapy does not significantly improve overall sleep quality (as measured by global PSQI scores), it has significant positive effects on sleep latency and daytime drowsiness. The study's strengths include its focused population, clear methodology aligned with PRISMA guidelines, and an evidence-based approach to an increasingly relevant non-pharmacological intervention.

1. Clarify whether high heterogeneity was anticipated and how it was addressed beyond subgroup analysis.

2. The wide variability in dosage, duration, and administration modality should be further discussed in the limitations.

3. Given the variability in essential oil type, route of administration, and dosage across studies, how do you propose future trials be standardized to improve comparability?

4. Several studies were rated as having "some concerns." Could you provide more detail on which domains were most problematic and how that may have influenced overall conclusions?

5. For the studies excluded from meta-analysis due to incomplete data, were the corresponding authors contacted for missing values? If so, how many responded?

6. The conclusion suggests aromatherapy is "promising" for menopausal sleep issues, but the global PSQI did not show significant improvement. Could this be reframed more cautiously?

7. None of the included studies appear to have long-term follow-up. How might this limit the interpretation of sustained effects of aromatherapy on sleep?

8. Were any of the included studies controlled for common confounders like caffeine intake, exercise, or concurrent use of sleep aids? If not, could this have biased the outcomes?

9. Several studies also measured menopausal symptoms beyond sleep. Would incorporating this information into the discussion provide a more holistic view of aromatherapy’s benefits?

10. While the neurophysiological mechanisms are discussed, would you consider adding a diagram or summary table linking essential oil components to their proposed actions on sleep physiology?

Author Response

Response to Reviewers and Academic Editor

Manuscript Title: The Effects of Aromatherapy on Sleep Quality in Menopausal Women: A Systematic Review and Meta-analysis

Manuscript ID: women-3678483

Reviewer 1:

General Comments
Thank you for your insightful comments. We have carefully revised the Discussion section to address all concerns and clarify our findings. Key updates include:

1. Clarify whether high heterogeneity was anticipated and how it was addressed beyond subgroup analysis.

We appreciate the reviewer’s insightful comment regarding the high heterogeneity (I² = 98%) observed in the global PSQI outcome. This variability was anticipated due to differences in essential oil types, administration routes, and intervention durations across studies.

To address this concern, we have elaborated on the issue in the sixth paragraph of the Discussion section, clarifying that we applied a random-effects model to account for between-study variance and performed subgroup analyses for individual PSQI domains. We also acknowledged that further methods such as sensitivity analysis or meta-regression were not feasible due to the limited number of studies. This has been highlighted as a key limitation of the present meta-analysis.

The wide variability in dosage, duration, and administration modality should be further discussed in the limitations.

Thank you for your helpful suggestion. We agree that the considerable variability in the dosage, duration, and administration methods of aromatherapy across the included studies presents a limitation in interpreting pooled results.

Accordingly, we have added a statement in the seventh paragraph of the Discussion section to acknowledge this heterogeneity in intervention protocols. We also emphasized that these differences may have contributed to the observed inconsistencies in outcomes and reduced the generalizability of the findings. We believe this addition strengthens the transparency of the study's limitations.

Given the variability in essential oil type, route of administration, and dosage across studies, how do you propose future trials be standardized to improve comparability?

We agree that the variability in essential oil type, route of administration, and dosage limits comparability across studies. To address this, we have revised the Discussion (paragraph 12) to propose specific recommendations for future RCTs. These include the use of a single, well-characterized essential oil (e.g., Lavandula angustifolia), consistent administration route (preferably inhalation), fixed dosage (e.g., 2–4 drops per session), and defined treatment duration (e.g., 4–8 weeks). We also suggest standardizing outcome measurements (e.g., PSQI at fixed time points) to enhance the validity and comparability of future pooled analyses.
4. Several studies were rated as having "some concerns." Could you provide more detail on which domains were most problematic and how that may have influenced overall conclusions?

We have clarified this point in the final paragraph of the Discussion (paragraph 15). Specifically, several included studies were rated as having "some concerns" in the Cochrane Risk of Bias assessment, primarily due to issues in the randomization process and incomplete outcome reporting. These methodological weaknesses may have introduced potential bias and were considered when interpreting the overall findings of this meta-analysis.

For the studies excluded from meta-analysis due to incomplete data, were the corresponding authors contacted for missing values? If so, how many responded?

Thank you for your thoughtful question. Among the six included RCTs, three were excluded from the meta-analysis due to incomplete or non-comparable outcome data (e.g., lack of means, standard deviations, or inconsistent reporting formats).

We attempted to contact the corresponding authors of all three studies via the email addresses provided in their publications. However, no responses were received during the data collection period.

This limitation has now been explicitly addressed in the seventh paragraph of the Discussion section, where we note that the exclusion of these studies may have reduced the comprehensiveness of the pooled analysis.

The conclusion suggests aromatherapy is "promising" for menopausal sleep issues, but the global PSQI did not show significant improvement. Could this be reframed more cautiously?

Thank you for your thoughtful comment. We agree that the term “promising” may overstate the strength of the evidence, given that the global PSQI did not reach statistical significance.

In response, we have revised both the final sentence of the Abstract and the Conclusions section to reflect a more cautious interpretation. The phrase “promising” has been replaced with “potentially beneficial,” and the language has been modified to emphasize that the significant findings pertain to specific PSQI subdomains (sleep latency and daytime drowsiness), rather than overall sleep quality.

These revisions aim to provide a more balanced summary that aligns with the actual findings of the study.

None of the included studies appear to have long-term follow-up. How might this limit the interpretation of sustained effects of aromatherapy on sleep?

We agree that the absence of long-term follow-up in the included studies limits the ability to assess the durability of aromatherapy’s effects on sleep outcomes.

In response, we have added a statement in the Discussion section (paragraph 13) to acknowledge this limitation. Specifically, we note that none of the included RCTs reported post-intervention follow-up beyond the immediate treatment period, which restricts our understanding of whether improvements in sleep latency or daytime functioning are sustained over time.

We recommend that future trials incorporate longer follow-up durations (e.g., 3 to 6 months post-intervention) to evaluate the persistence of treatment effects and potential relapse in sleep disturbances.

Were any of the included studies controlled for common confounders like caffeine intake, exercise, or concurrent use of sleep aids? If not, could this have biased the outcomes?

We agree that control for potential confounders is essential in sleep research. Upon reviewing the included studies, we found that most did not explicitly report whether they accounted for common confounding factors such as caffeine intake, physical activity, or concurrent use of sleep aids. We acknowledge that this limitation may have introduced bias and affected the internal validity of the results. To address this concern, we have added a statement in the Discussion (paragraph 8) noting the absence of control for these variables and recommending that future studies include protocols to monitor or control for such confounders.

Several studies also measured menopausal symptoms beyond sleep. Would incorporating this information into the discussion provide a more holistic view of aromatherapy’s benefits?
We agree that considering menopausal symptoms beyond sleep would provide a more comprehensive perspective on the benefits of aromatherapy. While our study focused primarily on sleep outcomes, we have reviewed the included studies and noted that some also assessed symptoms such as anxiety, hot flashes, and mood disturbances. To acknowledge this broader context, we have added a statement in the Discussion (paragraph 9) highlighting these additional outcomes and suggesting their inclusion in future trials to capture the full therapeutic potential of aromatherapy in menopausal populations.
While the neurophysiological mechanisms are discussed, would you consider adding a diagram or summary table linking essential oil components to their proposed actions on sleep physiology?

In response, we have added Table 3 to summarize the key essential oils used in the included studies, their major active constituents, and the proposed neurophysiological mechanisms by which they may influence sleep quality. This table helps to clarify the biological plausibility of aromatherapy as a sleep-promoting intervention by linking phytochemical components (e.g., linalool, limonene) to effects such as enhanced GABAergic activity, reduced sympathetic arousal, and modulation of serotonin pathways. The addition of this table aims to provide a clearer understanding of the mechanistic basis for the observed clinical effects and supports the rationale for aromatherapy use in menopausal insomnia. Reference to Table 3 has also been incorporated into the second paragraph of the Discussion section.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Please find the comments:

Adding more keywords (up to 10) would be beneficial.
The introduction is concise and in general nice. Potential mechanisms related to aromatherapy and sleep quality are described. However, please elaborate on precautions which should be taken into account when using aromatherapy ("aromatherapy is a safe, accessible, and potentially effective adjunctive approach that can be integrated into holistic sleep care for menopausal women" sounds too strong). Not all essential oils are helpful in individual cases. Aromatherapy is a very individual therapy, which can be applied not in all circumstances. These pieces of information should be addressed in the introduction and discussion sections.
Table 2. Characteristics of Aromatherapy in included studies: The authors should justify the use of aromatherapy in a form of massage. This is a combination of not just two different methods of administration, these are in fact two different methods. I do not believe that Darsareh et al., 2012 [36] study should be included in this review.
Also, oral vs inhalation aromatherapy should be described in detail. Are mechanism during oral vs inhalation different? if yes, please consider how this can impact the results.
The image quality of forest plots is low. Please reconsider.
The funnel plot was not presented. Please reconsider.
Limitations of the study should be elaborated. Please elaborate on limitations of included studies. Please consider discussion their methodological and statistical issues, and provide recommendation for future studies.
Future directions should be definitely extended.

Author Response

Response to Reviewers and Academic Editor

Manuscript Title: The Effects of Aromatherapy on Sleep Quality in Menopausal Women: A Systematic Review and Meta-analysis

Manuscript ID: women-3678483

Reviewer 2:

General Comments

Thank you for your insightful comments. We have carefully revised the Discussion section to address all concerns and clarify our findings. Key updates include:

Adding more keywords (up to 10) would be beneficial.

Thank you for your suggestion. In response, we have expanded the list of keywords to enhance searchability and indexing of the manuscript. The revised keywords now include: aromatherapy; menopause; sleep quality; essential oils; sleep latency; daytime dysfunction; lavender oil; complementary therapies; non-pharmacological interventions; postmenopausal insomnia

The introduction is concise and in general nice. Potential mechanisms related to aromatherapy and sleep quality are described. However, please elaborate on precautions which should be taken into account when using aromatherapy ("aromatherapy is a safe, accessible, and potentially effective adjunctive approach that can be integrated into holistic sleep care for menopausal women" sounds too strong). Not all essential oils are helpful in individual cases. Aromatherapy is a very individual therapy, which can be applied not in all circumstances. These pieces of information should be addressed in the introduction and discussion sections.

We acknowledge that while aromatherapy is generally considered safe and accessible, individual responses may vary, and certain precautions should be taken into account. Not all essential oils are suitable for every individual, and contraindications (e.g., allergies, asthma, pregnancy) or inappropriate use (e.g., excessive dosage, ingestion without supervision) may pose potential risks.

To address this concern, we have made the following revisions:

In the Introduction (paragraph 2): We have added a sentence acknowledging the individualized nature of aromatherapy and the need for caution.
In the Discussion (paragraph 11): We have elaborated on potential precautions and emphasized that aromatherapy should be applied under appropriate guidance, considering individual variability and contraindications.

Table 2. Characteristics of Aromatherapy in included studies: The authors should justify the use of aromatherapy in a form of massage. This is a combination of not just two different methods of administration, these are in fact two different methods. I do not believe that Darsareh et al., 2012 [36] study should be included in this review.

We appreciate your insightful comment. We acknowledge that aromatherapy via massage combines both the pharmacological effects of essential oils and the therapeutic benefits of tactile stimulation. However, Darsareh et al. (2012) explicitly reported aromatherapy massage as the intervention of interest, using standardized essential oils (lavender) in controlled protocols, which aligns with our predefined inclusion criteria. Furthermore, previous meta-analyses and clinical guidelines also consider aromatherapy massage as a legitimate form of aromatherapy intervention. Given the limited number of RCTs focusing exclusively on menopausal women, we chose to include this study to enrich the analysis and reflect real-world clinical application. Nevertheless, we have clarified this rationale in the Methods and Discussion sections and added a sensitivity note regarding potential differences in effect due to administration modality.

Also, oral vs inhalation aromatherapy should be described in detail. Are mechanism during oral vs inhalation different? if yes, please consider how this can impact the results.

Thank you for highlighting this important point. Yes, the mechanisms of action differ between oral and inhalation routes of aromatherapy. Inhalation primarily stimulates the olfactory system and limbic pathways, directly influencing neurophysiological responses such as parasympathetic activation, GABAergic modulation, and stress hormone regulation. In contrast, oral administration may involve systemic absorption and metabolism through the gastrointestinal and hepatic systems, with potentially slower onset and different bioavailability.

These differences in pharmacodynamics and delivery pathways may contribute to heterogeneity in treatment effects. We have elaborated on this distinction and its possible implications for interpretation in the Discussion section (paragraph 6), and added a note in Table 2 to clarify administration routes.

The image quality of forest plots is low. Please reconsider.

We acknowledge the issue regarding the low resolution of the forest plots. We will revise and replace all forest plot images with higher-quality versions to ensure clarity and improve readability in the final submission.

The funnel plot was not presented. Please reconsider.

We appreciate your comment. While a funnel plot was generated for internal assessment, we chose not to include it in the manuscript due to the limited number of studies (n = 3), With such a small sample, visual inspection may be misleading. This limitation has been acknowledged in the Discussion section.

Limitations of the study should be elaborated. Please elaborate on limitations of included studies. Please consider discussion their methodological and statistical issues, and provide recommendation for future studies.

We have elaborated on the methodological and statistical limitations of the included studies in the Discussion section, and provided specific recommendations for improving the rigor and comparability of future trials.

Future directions should be definitely extended.

We have expanded the ‘Future Directions’ section in the Discussion (paragraphs 9, 13, and 14), outlining the need for standardized aromatherapy protocols, confounder control, multidimensional outcomes, and long-term follow-up to strengthen future research.