Psychosocial mediators of racial differences in nighttime blood pressure dipping among normotensive adults.

Shallow declines in nocturnal compared with diurnal blood pressure (BP dipping) have been associated with cardiovascular disease. In U.S. samples, Blacks demonstrate less BP dipping compared with Whites. In a sample of 60 Black and 60 White normotensive adults we examined stress, social integration (including parental status), social support, and hostility as potential mediators of the association between race and BP dipping. The effect of race on diastolic BP dipping was partially mediated by parental status. The effect of race on heart rate dipping was partially mediated by stressful life events. No psychosocial factors mediated the relation between race and systolic BP dipping. Although psychosocial factors appear to account for some of the observed racial differences in nocturnal blood pressure decline, our data suggest that these differences cannot be attributed entirely to covarying psychosocial effects.