Race/Ethnicity and Hypertension: The Role of Social Support

Compared to whites, blacks experience a higher prevalence of hypertension and are diagnosed at younger ages,1–3 but the sources of disparities are not well understood. Controlling for age, gender, socioeconomic status (SES), health status, and health behaviors has only partially explained disparities.4,5 A number of psychosocial measures have been associated with hypertension,5–9 including social support.5,10 Social support is the product of interpersonal relationships that may directly affect health or act as a buffer against stressors that are deleterious to health.11,12 Studies restricted to all white or all black samples have found greater levels of social support to be associated with lower blood pressure (BP) or lower incidence of hypertension.6,10,13–18 Studies of race differences in the amount and type of social support received have been conducted with conflicting results. When race differences were found, blacks were less likely to receive social support,19 more likely to have smaller social networks, and more likely to have social support come from family members as compared to whites.19,20 Other studies have found that whites and blacks give and receive similar amounts of social support,21–23 specifically among older populations, where the need for social support may be more evident, and thus may be received more frequently. Race/ethnic differences in social support may play an important role in the association between race/ethnicity and hypertension. However, studies of the inter-relationship between race, social support, and hypertension are scarce.10,24 There is also a dearth of research on ethnicity, social support, and hypertension, particularly comparing Hispanics to non-Hispanic whites.25 Among Hispanics, Mexican Americans are the largest minority group in the United States.26 The prevalence of hypertension is lower among Mexican Americans compared to whites.27 However, studies of the effect of social support on hypertension in Mexican Americans or on ethnic differences in hypertension are few.28 In general, Mexican Americans receive more support from family than friends,29 and a higher level of social support among Mexican Americans has been proposed as a reason for a lower prevalence of hypertension compared to whites.30 Because social support may buffer against stressors that lead to hypertension, the strength of the association between race and hypertension may be weaker among those with social support as compared to those without social support. Conversely, because the prevalence of hypertension among Mexican Americans is lower compared to whites,27 ethnic differences will be greatest among those with social support; that is, the odds of hypertension should be lowest among Mexican Americans with the most social support, thus the Mexican-American/white odds ratio (OR) of hypertension should be lowest among those with the most social support and should approach one as social support decreases. Hence, the objective of this study is to determine whether the association between race (black vs. white) and hypertension, and ethnicity (Mexican American vs. white) and hypertension varies by level of social support. Specifically, it is hypothesized that the race differences in hypertension will be attenuated among those with social support as compared to those without social support, and ethnic differences will be greater among those with social support compared to those without social support.