Inverse association between dairy intake and hypertension : the Rotterdam Study 1 , 2

Background: Little is known about the effect of different types of dairy food products on the development of hypertension. Objective: The objective was to determine whether the incidence of hypertension in older Dutch subjects is associated with intake of dairy products. Design: We examined the relation between dairy intake and incident hypertension in 2245 participants of the Rotterdam Study aged 55 y with complete dietary and blood pressure data, who were free of hypertension at baseline (1990–1993). Blood pressure was reexamined in 1993–1995 and in 1997–1999. Hazard ratios (HRs) with 95% CIs for 2and 6-y incidence of hypertension were obtained in quartiles of energy-adjusted dairy intake, with adjustment for age, sex, BMI, smoking, educational level, dietary factors, and intake of alcohol and total energy. Results: Risk of hypertension after 2 y of follow-up (664 incident cases) was inversely associated with dairy product intake. After adjustment for confounders, HRs (95% CIs) were 1.00, 0.82 (0.67, 1.02), 0.67 (0.54, 0.84), and 0.76 (0.61, 0.95) in consecutive quartiles of total dairy product intake (P for trend 1⁄4 0.008). Corresponding HRs for low-fat dairy products were 1.00, 0.75 (0.60, 0.92), 0.77 (0.63, 0.96), and 0.69 (0.56, 0.86) (P for trend 1⁄4 0.003). Analysis of specific types of dairy products showed an inverse association with milk and milk products (P for trend 1⁄4 0.07) and no association with high-fat dairy or cheese (P . 0.6). After 6 y of follow-up (984 incident cases), the associations with hypertension were attenuated to risk reductions of ’20% for both total and lowfat dairy products between the extreme quartiles of intake (P for trend 1⁄4 0.07 and 0.09, respectively). Conclusion: Intake of low-fat dairy products may contribute to the prevention of hypertension at an older age. Am J Clin Nutr 2009;89:1–7.