ObjectiveThese cross-sectional analyses of the Coronary Artery Risk Development in Young Adults (CARDIA) data were stimulated by previous CARDIA analyses that showed an adverse association between hostility and several health behaviors: physical activity, cigarette smoking, alcohol consumption, and caloric intake, in both black and white men and women, such that the higher the hostility, the worse the health behavior profile. The current study investigated whether high social support was associated with better health behavior than low social support in individuals with high hostility scores.MethodsThe subjects were 5115 healthy black and white men and women ranging in age from 18 to 30 years. The hypothesis was that the association between hostility and certain adverse health behaviors would be diminished in the presence of high social support. Race-gender specific median cutpoints of the Cook-Medley Hostility scale and an index of social support defined levels of high and low hostility and social support.ResultsAfter controlling for age and body mass index (BMI), support was positively associated with more exercise in all groups except black women, but when coupled with high hostility, this positive association between support and exercise remained only in men. White women with high support were less often smokers but this association did not hold when examined only in the high-hostile group. Black men and white women with high support in the presence of high hostility consumed more alcohol, but the amount was moderate.ConclusionsWe conclude that social support in the presence of high hostility only sometimes reduces the association of hostility to adverse health behaviors and that these effects are complex. Additional research investigating types of social support on health behavior in different race-gender groups is advocated.