Abstract
Few studies have assessed the association of resting heart rate (RHR) through young adulthood with incident hypertension by middle age. We investigated the association between RHR measured over 30 years with incident hypertension in a cohort of young Black and White men and women. A joint longitudinal time-to-event model consisting of a mixed random effects submodel, quadratic in follow-up time, and a survival submodel adjusted for confounders, was used to determine hazard ratios for a 10 bpm higher RHR. Race-sex specific effects were examined in a single joint model that included interactions of race-sex groups with longitudinal RHR. Out of 5115 participants enrolled in year 0 (1985-1986), after excluding prevalent cases of hypertension at baseline, 1615 men and 2273 women were included in the analytic cohort. Hypertension event rates per 1000 person-years were 42.5 and 25.7 in Black and White men, respectively, and 36.2 and 15.3 in Black and White women, respectively. The hazard ratios for a 10 bpm higher RHR were 1.47 (95% CI, 1.23-1.75), 1.51 (95% CI, 1.28-1.78), 1.48 (95% CI, 1.26-1.73), and 1.02, (95% CI, 0.89-1.17) for Black men, White men, White women, and Black women, respectively. Higher RHR during young adulthood is associated with a greater risk of incident hypertension by middle age. The association is similarly strong in Black men, White men, and White women, but absent in Black women, which may suggest racial differences in the effect of sympathetic nervous activity on hypertension among women.