ACE gene haplotypes and social networks: Using a biocultural framework to investigate blood pressure variation in African Americans

Abstract

Deaths due to hypertension in the US are highest among African Americans, who have a higher prevalence of hypertension and more severe hypertensive symptoms. Research indicates that there are both genetic and sociocultural risk factors for hypertension. Racial disparities in hypertension also likely involve genetic and sociocultural factors, but the factors may interact and manifest differently across racial groups. Here we use a biocultural approach to integrate genetic and social network data to better understand variation in blood pressure. We assay genetic variation at the angiotensin I converting enzyme gene (ACE) and analyze social network composition and structure in African Americans living in Tallahassee, FL (n = 138). We demonstrate that models including both genetic and social network data explain significantly more variation in blood pressure and have better model diagnostics than do models including only one datatype. Specifically, optimal models for systolic and diastolic blood pressure explain a notable 35% and 21%, respectively, of blood pressure variation. Analysis of the social networks reveals that individuals whose networks are dominated by family connections and are more fragmented have higher blood pressure. Historically, family support has been associated with better mental and physical health, but our results suggest that those family connections can also take a toll on health. These findings raise compelling questions regarding the roles of genetics, family, and social environment in hypertension in the African American community and suggest that interactions among these factors may help explain racial disparities in hypertension more accurately than any of the factors alone.

Financial strain and stressful social environment drive depressive symptoms, whileFKBP5variant intensifies the effect, in African Americans living in Tallahassee

“…Researchers typically invoke social networks as a source of social support, but personal networks can also be a source of strain. In a previous study with the same population of African Americans, we found that systolic and diastolic blood pressure were significantly elevated in individuals with networks dominated by family members [28]. In the current study, we show that depression is associated with the percentage of the network comprised of people who cause participants stress or worry.…”

“…Social networks are being used more frequently to quantify aspects of an individual's social environment. Variation in network composition and structure have been linked to a range of outcomes including happiness, obesity, and blood pressure [26][27][28]. Researchers typically invoke social networks as a source of social support, but personal networks can also be a source of strain.…”

“…Data for this study come from the HEAT Heart Health study, a community-based participatory research (CBPR) project of the Health Equity Alliance of Tallahassee (HEAT). Study participants were selected from a multistage probability sample of African Americans living in Tallahassee, Florida, as described in Fuller et al [28]. Cluster analysis of neighborhood level markers of socioeconomic status and racial composition were used to group census blocks.…”

“…The characteristics of the network (e.g., average age of alters, number of women, number of family members, etc) can then be used to investigate outcomes of interest. Social networks have been shown to influence a range of mental and physical health outcomes, including happiness, obesity and blood pressure [26][27][28]. Rosenquist et al [29] found that high and low scores on the Center for Epidemiological Studies Depression (CES-D) Scale were highly correlated with network members' scores and that female friends were particularly influential.…”

Behavioral and social scientists’ reflections on genomics: a systematic evaluation within the Society of Behavioral Medicine

“…For example, Fuller et al tested whether social network structure influenced the well-established association of angiotensin 1 converting enzyme gene (ACE) with hypertension among African Americans. Inclusion of both genetic haplotype and family social structure measures yielded a better fitting predictive model for both systolic and diastolic blood pressure compared to either component alone [14]. In the clinical setting, others have demonstrated how incorporating genetic risk information into primary care discussions can lessen patient perceptions of personal blame that can inhibit their receptivity to providers' weight management recommendations [15].…”