Implications for Self-Management among African Caribbean Adults with Noncommunicable Diseases and Mental Health Disorders: A Systematic Review

Mental health problems are common among individuals suffering from chronic noncommunicable diseases (NCDs) such as type 2 diabetes mellitus and hypertension. Self-management is essential in preventing NCD progression. Mental health problems can impede the ability to self-manage one’s NCDs. The African Caribbean population in the United States suffers from a high burden of NCDs and has unique societal factors that alter disease management. This systematic review aimed to better understand the burden of mental health problems among African Caribbean adults with one or more NCDs and explore the association between mental health disorders and the level of control of NCDs. A literature search was conducted for original research documenting the prevalence of mental illnesses in individuals with NCDs. Data were descriptively summarized. Fourteen studies met inclusion criteria. Three themes emerged: (1) prevalence of comorbid mental health problems and chronic NCDs; (2) factors that mitigate or mediate the association between mental health problems and chronic NCDs—(a) factors influencing self-management; (b) association between mental health and NCD outcome studies focused on (b1) risk factors and (b2) protective factors; and (3) varied results. Chronic disease self-management and disease outcomes are influenced by mental problems and the association is mitigated by complex factors in the African Caribbean population.


Introduction
The Caribbean population has the highest mortality rate of chronic noncommunicable diseases (NCDs) in the Americas, where chronic diseases account for 75% of deaths [1,2]. This population is disproportionately affected by diabetes, with a prevalence ranging between 11 and 18% [1,2]. In the North American and Caribbean regions, diabetes accounts for 13.8% of deaths [3]. This mortality rate is expected to increase over time [3]. NCDs require adequate management to prevent adverse outcomes, including mortality. Such management methods are important for African Caribbean individuals, a population with elevated incidence and mortality rate of hypertension and type 2 diabetes [2,4]. African Caribbeans also have elevated rates of hypertension compared with people of European and West African descent, and these rates have been associated with increased stroke incidence [4,5]. The high mortality rate associated with chronic diseases in the African Caribbean population underscores the need for further research on NCD management to create workable strategies for promoting better health.
Chronic disease self-management is the application of knowledge and skills required to complete daily disease management. Self-management strategies are essential to successful chronic disease treatments, as they are positively correlated with improved glycemic and hypertensive targets, reduction in complications, and quality of life improvements [6][7][8]. Exercise, healthy eating, and medication adherence are considered effective self-management strategies for hypertension and type 2 diabetes [7][8][9].
Engaging in effective self-management behaviors is often difficult when individuals living with NCDs have a comorbid mental health problem. African Caribbean adults have a higher prevalence and severity of major depressive disorder than their white counterparts [10,11]. However, in the United States (US), they are less likely to receive assistance for major depressive disorder than European Americans and African Americans [12]. It is worth noting that depressive disorders are the most significant contributor to years lived with disability in the Caribbean [10]. Moreover, African Caribbeans are more likely to report severe cases of anxiety than their African American and European American counterparts [13].
The relationship between control of mental health problems and control of NCDs is bidirectional. Poorly controlled mental health is associated with worse NCD outcomes, and NCDs and their management is associated with worsening mental health problems. Furthermore, poorly controlled mental health problems put individuals at higher risk of type 2 diabetes-related complications (e.g., retinopathy, nephropathy, neuropathy) and reduced quality of life [14,15]. Poor mental health is also associated with unsuccessful type 2 diabetes self-management behaviors, resulting in poor glycemic targets [14,16]. Individuals with heart disease have been found to have high rates of mood and anxiety disorders [17]. Comorbid depression, anxiety, and elevated stress among people with hypertension, is reported to reduce hypertensive medication adherence [16,18].
While there is substantial evidence to support these associations, there is a gap in the literature on how poorly controlled mental health problems are associated with the self-management of chronic diseases such as diabetes, hypertensiofxfn, hyperlipidemia, and cardiovascular disease in the African Caribbean population. Evidence is needed to inform interventions and practices that can address comorbid mental health and NCD management to improve the health and wellbeing of the African Caribbean population. Accordingly, the purpose of this study is to better understand the burden of mental health problems among African Caribbean adults with one or more NCDs. A secondary aim was to explore the association between mental health disorders and the level of control of NCDs.

Materials and Methods
A systematic review of the literature was conducted and registered in PROSPERO: CRD42021269666. The Population, Intervention, Comparator, and Outcomes (PICO) model was applied to refine the research question [19]. The following terms were defined using the PICO framework: All retrieved articles were assessed using the inclusion and exclusion criteria in Covidence. The inclusion criteria were studies of African Caribbean adults published in English with data collected on NCD outcomes based on objectively measured data and mental health outcomes assessed through self-reported questionnaires. The exclusion criteria included the following: other chronic health conditions (e.g., cancer) and all experimental studies on participants under 18 years of age, animal studies, and gestational diabetes. Two reviewers independently assessed each study in Covidence to determine if the inclusion criteria were met.

Data Extraction
The selected articles were summarized systematically using a data extraction table. Relevant details from each study, including author, purpose, design, location, samples, age, ethnicity, measures, and key findings, were extracted, and inputted in Table 1. The studied population was not categorized by gender, age, or other groups. Data analysis continued, comparing study results while focused on the purpose of the review. After data were independently extracted from each study by one of the authors (Catrina Longhurst, Cherlie Magny-Normilus, Julie Sanders), another author reviewed the analysis and critiqued the results to reach a consensus. This process was repeated for quality control and consistency.   Men were more likely to be diagnosed with schizophrenia and related psychotic disorders compared to their female counterparts (x 2 (2) = 6.03). [26] To examine the associations between positive optimistic orientation and LS7 among African Americans

Quality Appraisal/Risk of Bias
To assess risk of bias, the Cochrane Collaboration tool was used for a quality appraisal of experimental studies. Risk of bias was evaluated by three authors using the National Institutes of Health (NIH) Quality Assessment Tool [34] for observational and cross-sectional studies. All studies were assigned a yes, no, not applicable, or not reported to each of the 14 criteria, as outlined in the appraisal tool. Conversely, the Consolidated Criteria for Reporting Qualitative Research (COREQ) was used to determine the quality of qualitative studies [20]. Two reviewers independently labeled each article as good, fair, or poor, and answered questions from each of the COREQ's three domains. Most of the selected articles were rated "good", but one was rated "fair" due to the population sample. Any differences were deliberated in a group discussion until a consensus was reached.

Data Synthesis
Based on the inclusion and exclusion criteria, studies were selected. These studies were rated fair or good in the risk of bias assessment. Themes were identified and all members of the research team agreed on the final themes. This synthesis method was chosen due to the wide variety of measures and variables reported by the studies.

Results
The search strategy yielded 14,530 potentially relevant reports, of which 4329 were duplicates, leaving a remainder of 10,201 studies. Initial screening using the inclusion and exclusion criteria led to the removal of 10,186 articles. Ineligible papers were most often eliminated for not focusing on the African Caribbean population. An additional study was added after the initial search due to its later publication, and inclusion and exclusion criteria were applied to this study manually to confirm eligibility. The final sample included 14 articles between 2006 and 2021 ( Figure 1).   The included studies were observational, cross-sectional, and one qualitative. The number of study participants ranged from 57 to 6082. Most of the studies were conducted in the US and focused on a variety of NCDs (e.g., diabetes, hypertension, cardiovascular disease). Study characteristics and key findings are described in Table 1. None of the selected studies were rated as being poor in quality. The findings of the quality assessment are summarized in Tables 2 and 3. Was the research question or objective in this paper clearly stated?
Was the study population clearly specified and defined?
Was the participation rate of eligible persons at least 50%?
Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants?
Was a sample size justification, power description, or variance and effect estimates provided?
For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured?
Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed?
For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)?
Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?
Was the exposure(s) assessed more than once over time?
Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?
Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)?   Clinical, anthropometric, psychological, and biometric measures were studied in most articles. Clinical variables included blood pressure, height, weight, waist circumference, and body mass index; laboratory variables included low-density lipoprotein, total cholesterol, hemoglobin A1c (HbA1c); self-reported variables included medication adherence, anxiety, stress, depression, history of stroke, hypertension, and/or diabetes. Instruments used included the Perceived Stress Scale (stress), Beck Depression Inventory Scale (depression), Morisky Medication Adherence Scale (medication adherence), level of antidepressant use (medication utilization), and World Health Organization's Composite International Diagnostic Instrument (mental disorder). Additional addressed variables included physical activity, education, language preference, social support, socioeconomic status, smoking status, and education level.

Comorbid Mental Health Problems and Chronic NCDs
Comorbid poor mental health and chronic NCDs were reported throughout the literature, with 7 out of 14 studies reporting a statistically significant association between mental health problems (e.g., depression) and comorbid NCDs in African Caribbeans [21][22][23][24][25][26]30]. Stewart et al. reported a strong association between depression and physical illness and subsequent disability (e.g., stroke) in the African Caribbean population (OR = 2.48) [20]. These results were mirrored by Watkins et al., as they revealed that the odds of having more than one comorbid chronic NCD were greater for African Caribbeans with major depressive disorder when compared to those without (OR = 3.66) [21]. Similarly, Seecheran et al. outlined how the number of comorbid conditions in African Caribbean populations was positively correlated with major depressive disorder symptoms (OR = 1.125) [22]. Frederick and Maharajah explored the relationship between mental health measures and type 2 diabetes [23]. They found African Caribbeans with coexisting medical complications and type 2 diabetes reported more incidents of severe depression, with a Zung Depression Scale average score of 6.27 higher than those with type 2 diabetes alone [23]. Additionally, Frederick and Maharajh highlighted a correlation between coexisting medical conditions and depression (r = −0.32) [23].
Comparably, Huffman and associates [24] identified that African Caribbeans with type 2 diabetes had a depression score 3.2 points higher than those without type 2 diabetes. de Caluwé et al. showed diabetes prevalence to be 7.6% higher in patients with significant mental illness than in the general population [25]. Among patients with diabetes and depression, 11% had a heart condition and 15% had hypertension [23]. de Caluwé et al. reported that the prevalence of hypertension was statistically significantly higher (37.4%) in all patients with significant mental illness compared to the general African Caribbean population (19.9%) [25]. In a large study of African Caribbeans (n = 1203), 80% had comorbid depressive symptoms, with 25% having severe depressive symptoms [22]. The same study found that cardiovascular disease, hypertension, chronic kidney disease, and chronic obstructive pulmonary disease were statistically significantly associated with depressive symptoms (OR = 1.988) [22]. Conversely, Sims and colleagues associated optimism with ideal blood pressure (p > 0.05), depression, and major life events contributing to obesity prevalence and CVD conditions [26]. The same study found that mental health measures, including cynicism, negative affect, stress, and major life events, were associated with obesity prevalence (p < 0.05) [26]. Stewart et al. identified an association between depression and previous stroke history in the United Kingdom (UK) population born in the Caribbean (OR = 4.93) [20]. Assari and Lankarani, observed an association between heart disease and depressive symptoms in African Caribbeans, unlike other Blacks or non-Hispanic Whites living in the US (OR = 18.174) [28]. Collins-McNeil calculated 10% of the variance in cardiovascular risk to be accounted for by anxiety, depression, and perceived social support scores (R 2 = 0.095) [29]. Overall, the included studies imply a statistically significant association between mental health disorders, particularly depression, and chronic NCDs, among African Caribbeans.

Factors That Mitigate or Mediate the Association between Mental Health Problems and Chronic NCDs Factors Influencing Self-Management
Self-management of NCDs in African Caribbeans was influenced by several factors, including cultural health beliefs and environment. Sims et al. reported that mental health measures such as high anger and stress reduced diabetes control (p > 0.05) [27]. Three studies clarified the relationship between social support or isolation and self-management of diabetes and mental health disorders, including depression and anxiety [26,29,30]. Collins-McNeil identified social support to be negatively correlated with the trait (r = −0.505) and state anxiety (r = −0.511) as well as depressive symptoms (r = −0.479) [29]. In a 2021 qualitative study, Magny-Normilus and colleagues highlighted social isolation as a contributing factor inhibiting the ability of older African Caribbeans to manage their type 2 diabetes [30].

Risk Factors
Social determinants of health were found to influence the level of care for NCDs. Magny-Normilus et al. identified diabetes as "not a poor man's disease" due to the selfmanagement requirements of food, insulin, and doctor visits [30]. They highlighted the lack of resources as a barrier to self-management. Substance use has been tied to mental illness in the literature. Seecheran et al. found African Caribbean individuals to have elevated levels of substance use disorder (SUD) when significant mental illness was present [22]. The same study revealed an association between metabolic syndrome and SUD (p < 0.001) [22]. Frederick and Maharajh showed a positive correlation between the number of substances used and having major depressive disorder (OR = 1.062) and NCDs, where hypertension and type 2 diabetes were the two most common coexisting medical conditions [23]. Sex was reported as a possible factor affecting the association between NCDs and mental health. For example, many physical health comorbidities were more prevalent in African Caribbean women than men [25,27,31]. De Caluwé found that female patients with significant mental health illnesses had a higher prevalence of diabetes (28.2%), obesity (50.0%), and increased waist circumference (88%) when compared to men [25]. Frederick and Maharajh outlined that African-Caribbean women with type 2 diabetes had a 10.4% increased likelihood of depression compared to their male counterparts [23]. Sex differences also affected self-management. Sims et al. strongly associated psychosocial factors in women with lower NCD control, but this was not found in men. The same study identified that women with high cynicism had a 38% lower prevalence of hypertension control [27].
Protective Factors-Some biological measures were proposed to aid NCD management [24,31,33]. Overall, Fuster's team reported Haitian-born residents in Chile to be generally healthy, with a lower prevalence of obesity and cardiovascular risk than other residents of Chile [31]. Young et al. determined that African Caribbeans had average problem areas, in a diabetes score that was 10 points lower when compared to European American and Asian Indian participants [33]. It was common among studies to report reduced substance rates among African Caribbeans. Fuster and colleagues found African Caribbeans to have low levels of alcohol use, with 7.3% of individuals drinking more than once a week and 4.2% of individuals smoking [31]. Huffman et al. reported African Americans to have a 40% prevalence of smoking, while African Caribbeans had a 6% prevalence [24].

Varied Results
Three studies reported results that differed from the majority of the data [27,28,31]. Assari and Lankarani associated hypertension with a lack of depressive symptoms [28]. Sims et al. reported the influence of cumulative stress and negative affect on hypertension control among men and the consequence of significant life events on hypertension control in men and women [27]. Fuster et al. described African Caribbeans as having high sedentarism levels (87.9%). Although these studies showed differing results, they were rated good in the quality assessment [31].

Discussion
This review aimed to further our understanding of the prevalence of mental health problems among African Caribbean adults with chronic NCDs and explore the association between mental health disorders and the self-management of their diseases. This review revealed a strong association between depression and chronic NCDs in the African Caribbean population [20,21,23]. Diabetes and hypertension were associated with the presence of depression and depression severity, stress measures, and significant life events; hypertension alone was also associated with severe mental illness and a high negative affect [23][24][25][26]28,29,32]. Other NCDs, including obesity, stroke, cardiovascular disease, heart disease, and atherosclerosis, were also associated with mental health measures such as cynicism, negative affect, stress, major life events, anger, and depressive symptoms [20,27,28]. Ahmed and Conway found that American Indians and Hispanics were more likely to suffer comorbid mental health and NCDs than their White counterparts [11]. These results align with the literature that describes the comorbidity between mental health and chronic NCDs and the variance in comorbidity between ethnic groups [11,35,36].
While the majority of included studies identified an association between NCDs and mental health in the African Caribbean population, three studies reported a lack of association between depression and hypertension, as well as depression and diabetes [22,28,32]. Mental health measures were reported to improve hypertension control in one study (Sims et al., 2020) [27]. These variances are similarly reflected in the broader literature, as a 2015 study by Lankarani and Assari found statistically significant comorbidity between NCDs and depression for European Americans and African Americans, but not African Caribbeans [28]. While most of this study's results report comorbidity between chronic NCDs and mental health, this variance must still be considered. It may highlight a need for future research to quantify the relationship between chronic NCDs and mental health in populations with varying racial and ethnic backgrounds.
Comorbidity between NCDs and mental health problems is important to recognize because it influences hypertension and diabetes control in the African Caribbean population [22,27]. Mental health challenges have also been shown to reduce the practice and success of self-management behaviors in other populations [16,37]. Axon et al. found an association between medication adherence and depression in patients with type 2 diabetes for non-Hispanic Blacks, Hispanics, non-Hispanic Whites, and people of other racial/ethnic groups [16]. Nanayakkara et al. supported these results in an Australian population [38].
Social determinants of health and substance use were found to negatively impact the self-management of chronic NCDs in the African Caribbean population [21,24,30]. The results of this review are supported by Walker et al. and their findings of a direct relationship between glycemic management in subjects with type 2 diabetes and psychosocial determinants of health [39]. While, overall, African Caribbean individuals had reduced substance use [24,31], those with severe mental illness were found to have elevated substance use disorder [24].
Within the African Caribbean population, sex played a role in self-management, mental health, and physical health measures. Biological sex, rather than gender, was analyzed for this review, as it reflects the previous body of research. Further research is needed on the relationship between gender and self-management, mental health, and physical health measures in the African Caribbean population. African Caribbean women were found to have more poorly controlled NCDs than men, with a higher rate of metabolic syndrome, type 2 diabetes, body mass index, obesity, and waist circumference [25,31]. The increase in weight and associated conditions for African Caribbean women may stem from ingrained cultural preferences and practices that shapely framed Black women are more attractive in their communities. A 2019 study found that African Caribbean women had an aversion to being "too thin" rather than "too thick," which paralleled the beliefs of African American women [40].
This study reveals women have higher rates of depression, the stress of all categories, and diagnosis of affective disorders [22][23][24][25]27,32]. On the other hand, men were more likely to be diagnosed with schizophrenia, psychotic disorders, low optimism, cynicism, and substance use disorder [25,27]. The difference in diagnosis and increased substance use in men may be attributed to cultural views of mental health. Smith et al. summarized the stigma against men's mental health in 2018, and they highlighted that men were less likely to seek help for mental health problems, less likely to report symptoms, and more likely to experience substance use that significantly affects their lives as women [26]. These findings may negatively impact chronic disease management and could be associated with the higher rates of cardiovascular conditions in African Caribbeans. Aside from factors that reduce self-management outcomes, family and general social support were found to improve self-management for diabetes and mental health conditions [29,30]. The African Caribbean population reported better self-management strategies generally, consuming fewer calories, following dietary advice, practicing healthier eating, and having fewer problem areas in diabetes management than other populations [30,33]. The study by Fuster et al. varied in its results on self-management and reported high levels of sedentary lifestyles in the African Caribbean population [31]. The protective social factors and self-management practices may result in improved biological measures in the African Caribbean population, such as decreased waist circumference, decreased lowdensity lipoprotein, decreased instances of obesity, and lower body mass indexes [30,31,41].

Limitations
Only English language publications were analyzed. Restricting the review to one language may have omitted other relevant studies unique to this ethnic group. Our focus was on the African Caribbean population. Immigration status was not considered in this review. Broader populations were considered applicable in this study because of the limited number of studies specifically focusing on African Caribbeans. This is especially true for African Americans, a demographic that African Caribbeans are often included in but not often differentiated from. As a result, this review is a global representation of African Caribbeans deriving from various unique backgrounds and environments.

Conclusions
The African Caribbean population is at elevated risk of NCDs, mental health disorders, and comorbid conditions. This population has unique factors that influence selfmanagement and health outcomes, including social determinants of health, high substance use in those with significant mental illness, sex differences, social support, and reported high levels of self-management adherence. Despite the wealth of knowledge surrounding the high prevalence and comorbidity of NCDs and mental health in the African Caribbean population, there is limited research on how mental health influences self-management of NCDs in the African Caribbean population specifically. Additionally, despite, the abundance of evidence on the prevalence of mental health disorders and NCDs, this analysis indicates a paucity of intervention research to improve mental health and management of NCDs. Thus, future research should quantify and qualify the relationship between mental health and NCD self-management in the African Caribbean population. This research is needed to inform strategies to effectively address comorbid mental health problems and NCDs in the African Caribbean population in the US.