Plasma Adiponectin and the Risk of Hypertension in White and Black Postmenopausal Women

BACKGROUND: Adiponectin may have a protective role in the development of obesity-related metabolic and vascular disorders, including hypertension. We conducted a prospective, nested case control study to investigate the relation between baseline plasma adiponectin, measures of adiposity, and subsequent risk of hypertension. METHODS: We selected 400 white and 400 black postmenopausal women, age <70 years, who developed incident hypertension during 5.9-year follow-up and an equal number of age- and race-matched controls in the Women's Health Initiative Observational Study. We measured plasma concentrations of total adiponectin in their baseline blood samples. RESULTS: In crude matched models, plasma adiponectin was inversely associated with risk of hypertension among both white and black women. The association appeared to be nonlinear in white women but dose related in black women. Adjustment for lifestyle factors, measures of obesity, and obesity-related clinical factors attenuated these associations. The multivariable relative risk (95% CI) of hypertension across increasing quartiles of plasma adiponectin were 1.00, 0.98 (0.66-1.46), 0.63 (0.41-0.97), and 0.92 (0.60-1.42) in white women (P(trend): 0.38) and 1.00, 0.96 (0.64-1.46), 0.83 (0.53-1.29), and 0.58 (0.36-0.94) in black women (P(trend): 0.02). Further adjustment for inflammatory markers and endothelial markers eliminated the association in white, but not black, women. CONCLUSIONS: In this prospective, nested case control study, we found an inverse association between plasma adiponectin and risk of hypertension in white and black postmenopausal women. The reduced risk of hypertension was limited to only intermediate concentrations of adiponectin in white women whereas it was graded across quartiles of adiponectin in black women.