Laura J. Samuel

Depression and oxidative stress: results from a meta-analysis of observational studies.

Objective To perform a systematic review and meta-analysis that quantitatively tests and summarizes the hypothesis that depression results in elevated oxidative stress and lower antioxidant levels. Methods We performed a meta-analysis of studies that reported an association between depression and oxidative stress and/or antioxidant status markers. PubMed and EMBASE databases were searched for articles published from January 1980 through December 2012. A random-effects model, weighted by inverse variance, was performed to pool standard deviation (Cohen’s d) effect size estimates across studies for oxidative stress and antioxidant status measures, separately. Results Twenty-three studies with 4980 participants were included in the meta-analysis. Depression was most commonly measured using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. A Cohen’s d effect size of 0.55 (95% confidence interval = 0.47–0.63) was found for the association between depression and oxidative stress, indicating a roughly 0.55 of 1-standard-deviation increase in oxidative stress among individuals with depression compared with those without depression. The results of the studies displayed significant heterogeneity (I2 = 80.0%, p < .001). A statistically significant effect was also observed for the association between depression and antioxidant status markers (Cohen’s d = −0.24, 95% confidence interval = −0.33 to −0.15). Conclusions This meta-analysis observed an association between depression and oxidative stress and antioxidant status across many different studies. Differences in measures of depression and markers of oxidative stress and antioxidant status markers could account for the observed heterogeneity. These findings suggest that well-established associations between depression and poor heath outcomes may be mediated by high oxidative stress.

Hypertension and overweight/obesity in Ghanaians and Nigerians living in West Africa and industrialized countries: a systematic review.

Context: There is a growing prevalence of cardiovascular disease (CVD) risk factors in West Africa and among its migrants to industrialized countries. Despite this, no study has reviewed CVD risk factor prevalence among West Africans in Africa and industrialized countries. Objective: To appraise studies on the prevalence of two CVD risk factors (hypertension and overweight/obesity) among two major West African populations (Ghanaians and Nigerians) in Africa and industrialized countries. Methods: A comprehensive literature search from 1996 to July 2012 was undertaken to identify quantitative studies on hypertension and overweight/obesity among adult Ghanaians and Nigerians in West Africa and industrialized countries. Results: Twenty studies were included with 10 conducted in Ghana, six conducted in Nigeria and four in industrialized countries. Studies in Ghana and Nigeria reported a hypertension prevalence of 19.3–54.6% with minimal differences between rural, urban, semi-urban, and mixed populations. Of the hypertensive patients, 14–73% were aware of their condition, 3–86% were on treatment, and 2–13% had controlled blood pressures. Overweight/obesity prevalence in Ghana and Nigeria ranged from 20 to 62% and 4 to 49%, respectively. The four studies in industrialized countries reported a hypertension prevalence of 8.4–55% and overweight/obesity prevalence of 65.7–90%. Conclusion: Hypertension and overweight/obesity are highly prevalent conditions in West Africa and in its migrants residing in industrialized countries. Urgent measures are needed to prevent CVD risk factors and halt the clinical sequelae.

Community Based Cardiovascular Health Interventions in Vulnerable Populations: A Systematic Review

Background:Although cardiovascular health has been improving for many Americans, this is not true of those in “vulnerable populations.” To address this growing disparity, communities and researchers have worked for decades, and as a result of their work, a growing body of literature supports the use of community engagement as a component of successful interventions. However, little literature synthesizes community-based interventions that address this disparity among a wide range of vulnerable populations. Objective:This article provides a critical review of community-based cardiovascular disease interventions to improve cardiovascular health behaviors and factors among vulnerable populations based on the American Heart Association’s 7 metrics of ideal cardiovascular health. Methods:In February 2011, 4 databases (PubMed, PsychInfo, CINAHL, and Scopus) were searched using the following keywords: vulnerable populations OR healthcare disparities AND cardiovascular disease AND clinical trials OR public health practice AND English. Results:This search strategy resulted in the retrieval of 7120 abstracts. Each abstract was reviewed by at least 2 authors, and eligibility for the systematic review was confirmed after reading the full article. Thirty-two studies met eligibility criteria. Education was the most common intervention (41%), followed by counseling or support (38%) and exercise classes (28%). Half of the interventions were multicomponent. Healthcare providers were the most frequent interventionists. Interventions aimed at decreasing blood pressure were the most promising, whereas behavior change interventions were the most challenging. Almost all of the interventions were at the individual level and were proof-of-concept or efficacy trials. Conclusions:This analysis provides a step toward understanding the current literature on cardiovascular interventions for vulnerable population. The next step should be integrating the identified successful interventions into larger health systems and/or social policies.

Developing Behavioral Theory With the Systematic Integration of Community Social Capital Concepts

Health behavior theories state that social environments influence health behaviors, but theories of how this occurs are relatively underdeveloped. This article systematically surveys community social capital concepts in health behavior literature and proposes a conceptual framework that integrates these concepts into existing behavioral theory. Fifty-three studies tested associations between community social capital concepts and physical activity (38 studies), smoking (19 studies), and diet (2 studies). Trustworthiness of community members was consistently associated with more health-promoting and less disease-promoting behaviors in 19 studies. Neighborly reciprocity showed mixed results in 10 studies. Reporting a good sense of community was associated with more physical activity in only 5 of 16 studies. Neighborhood collective efficacy, which includes social cohesion and informal social control, was inconsistently associated with behaviors in 22 studies. Behavioral social norms were associated with smoking and physical activity in 2 of 6 studies, and neighborhood modeling of physical activity was associated with increased activity in 12 of 17 studies, with 1 opposing result. This review identifies several community social capital–related concepts that are, at times, associated with both health-promoting and disease-promoting behaviors and often have no associations. Theory explains these findings by describing the relationships and interactions among these concepts. Using these findings, this article proposes a conceptual framework that integrates community social capital concepts into existing behavioral theory. Iterative empirically based theory development is needed to address these concepts, which affect behaviors. These results can also inform theoretically based community-based and socially tailored interventions.

Social engagement and chronic disease risk behaviors: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE Although engagement in social networks is important to health, multiple different dimensions exist. This study identifies which dimensions are associated with chronic disease risk behaviors. METHODS Cross-sectional data on social support, loneliness, and neighborhood social cohesion from 5381 participants, aged 45-84 from the Multi-Ethnic Study of Atherosclerosis was used. RESULTS After adjusting for individual characteristics and all social engagement variables, social support was associated with lower smoking prevalence (PR=0.88, 95% CI: 0.82, 0.94), higher probability of having quit (PR=1.03, 95% CI: 1.01, 1.06) and a slightly higher probability of achieving physical activity recommendations (PR=1.03, 95% CI: 1.01, 1.06). Neighborhood social cohesion was associated with very slightly higher probability of achieving recommended (PR=1.03, 95% CI: 1.01, 1.05) or any regular (PR=1.0, 95% CI: 1.01, 1.04) physical activity, and a higher probability of consuming at least five daily fruit and vegetable servings (PR=1.05, 95% CI: 1.01, 1.09). CONCLUSIONS Both social support and neighborhood social cohesion, a less commonly considered aspect of social engagement, appear to be important for chronic disease prevention interventions and likely act via separate pathways.

Financial Strain Is Associated with Malnutrition Risk in Community-Dwelling Older Women

This study examined the relationship between financial strain, or difficulty acquiring necessities, and malnutrition risk in a community dwelling sample of frail and nonfrail women aged 70-79 in the Womens Health and Aging Study (n = 679). Malnutrition risk was measured with a modified version of the Mini-Nutritional Assessment Short Form (MNA-SF) and defined as a score <11, financial strain was measured by (1) sufficiency of money on a monthly basis and (2) adequacy of income for food, and income was measured by ordinal categories. Mean (SD) modified MNA-SF score was 12.2 (1.80), and 14.7% of women had malnutrition risk. Women who usually did not have enough money to make ends meet had more than four-fold increased odds of malnutrition risk (OR = 4.54; 95% CI: 2.26, 9.14) compared to their counterparts who had some money left over each month. This was only slightly attenuated after control for income and education, (OR = 4.08; 95% CI: 1.95, 8.52) remaining robust. These results show an association between financial strain and malnutrition risk, independent of income, in older women. Self-reported financial strain may be preferable to income as a screener for malnutrition risk in older adults in clinical and research settings.

Household and neighborhood conditions partially account for associations between education and physical capacity in the National Health and Aging Trends Study

Socioeconomic resources, such as education, prevent disability but are not readily modifiable. We tested the hypothesis that household and neighborhood conditions, which may be modifiable, partially account for associations between education and physical capacity in a population-based sample of older adults. The National Health and Aging Trends Study measured education (<high school, high school, some college, and ≥Bachelors), household and neighborhood conditions, using a 16-item environmental checklist and a 3-item social cohesion scale, and physical capacity with the Short Physical Performance Battery (SPPB), grip strength and peak expiratory flow. Structural equation models were used to decompose total educational effects into direct effects and indirect effects via household and neighborhood conditions, using sample weights and adjusting for age, sex, race/ethnicity, marital status, household size, BMI, self-reported health, and number of medical conditions in 6874 community-dwelling participants. Education was directly associated with SPPB scores (β = 0.055, p < 0.05) and peak flow (β = 0.095, p < 0.05), but not grip strength. Also, indirect effects were found for household disorder with SPPB scores (β = 0.013, p < 0.05), grip strength (β = 0.007, p < 0.05), and peak flow (β = 0.010, p < 0.05). Indirect effects were also found for street disorder with SPPB scores (β = 0.012, p < 0.05). Indirect effects of household and neighborhood conditions accounted for approximately 35%, 27% and 14% of the total association between education and SPPB scores, grip strength level, and peak expiratory flow level, respectively. Household disorder and street disorder partially accounted for educational disparities in physical capacity. However, educational disparities in SPPB scores and peak expiratory flow persisted after accounting for household and neighborhood conditions and chronic conditions, suggesting additional pathways. Interventions and policies aiming to support aging in place should consider addressing household-level and street-level disorder.

Socioeconomic Status, Race/Ethnicity, and Diurnal Cortisol Trajectories in Middle-Aged and Older Adults

Objectives Slow afternoon cortisol decline may be a marker of aging. We hypothesize that lower socioeconomic status (SES) and African American race are associated with lower waking cortisol and slower afternoon decline. Method Six salivary cortisol samples, collected within a 24-hr period from 566 cohort participants aged 56-78 years, were examined in random-effects models. SES measures included socioeconomic vulnerability (household income and assets <500% of poverty) and education (≥college, some college, and ≤high school). African Americans were compared with all others. Results Adjusting for age and sex, intermediate, but not low, education was associated with approximately 17% lower average waking cortisol and 1% slower decline, compared with high education. Socioeconomic vulnerability was not associated with waking cortisol or linear decline. Accounting for African American race/ethnicity, socioeconomic vulnerability was associated with a 3% faster decline, and education was not associated with cortisol. African Americans had 26% lower average waking cortisol and 1% slower decline than others. Discussion African American race/ethnicity, but not lower SES, was associated with lower waking cortisol and slower afternoon decline in middle-aged and older adults. This pattern is likely a marker of earlier biological aging in vulnerable groups. Race/ethnicity may compete with SES as a measure of cumulative vulnerability.

Community Characteristics are Associated with Blood Pressure Levels in a Racially Integrated Community

Community problems have been associated with higher, and community resources and social cohesion with lower, blood pressure. However, prior studies have not accounted for potential confounding by residential racial segregation. This study tested associations between community characteristics and blood pressure levels and prevalent hypertension in a racially integrated community. The Exploring Health Disparities in Integrated Communities Study measured blood pressure in residents of two contiguous racially integrated and low-income US Census Tracts. Community characteristics included a standardized community problem score and binary indicators for community social cohesion, having a community leader available, and having at least one community resource observed on the participant’s block. In adjusted models, greater community problems and proximity to resources were associated with lower systolic (β = −2.020, p = 0.028; β = −4.132, p = 0.010) and diastolic (β = −1.261, p = 0.038; β = −2.290, 0.031) blood pressure, respectively, among whites (n = 548). Social cohesion was associated with higher systolic (β = 4.905, p = 0.009) and diastolic blood pressure (β = 3.379, p = 0.008) among African Americans (n = 777). In one racially integrated low-income community, community characteristics were associated with blood pressure levels, and associations differed by race. Directions of associations for two findings differed from prior studies; greater community problem was associated with lower blood pressure in whites and community social cohesion was associated with higher blood pressure in African Americans. These findings may be due to exposure to adverse environmental conditions and hypertensive risk factors in this low-income community.