Epidemiological evidence from Western populations suggests that dairy food intake may reduce the risk of hypertension, probably through its calcium content. However, there are no epidemiological studies among Asian populations with generally lower dairy and calcium consumption.
The relation between dairy or calcium intake and risk of hypertension was evaluated in a Chinese population in Singapore.
The analysis included 37,124 Chinese men and women aged 45-74 y who participated in the Singapore Chinese Health Study in 1993-1998. The subjects included in the present study had no history of cancer, hypertension, or cardiovascular disease at baseline and completed ≥1 follow-up interview. Diet at baseline was assessed by using a validated 165-item semiquantitative food-frequency questionnaire. The occurrence of new, physician-diagnosed hypertension was ascertained through follow-up interviews during 1999-2004 and 2006-2010. The Cox proportional hazard regression method was used to compute HRs and 95% CIs with adjustment for potential confounders.
Dairy food intake was inversely associated with the risk of hypertension in a dose-dependent manner: HRs across quartiles were 1.00 (lowest quartile, reference), 0.97 (95% CI: 0.92, 1.02), 0.98 (95% CI: 0.92, 1.03), and 0.93 (95% CI: 0.88, 0.98) (P-trend = 0.01). Milk accounted for ∼80% of all dairy products consumed in this population. Daily milk drinkers had a lower risk of hypertension (HR: 0.94; 95% CI: 0.89, 0.99) than did nondrinkers. Nondairy calcium intake contributed 80% of total calcium intake. Although dairy calcium intake was associated with a lower risk of hypertension (HR comparing extreme quartiles: 0.88; 95% CI: 0.83, 0.94; P-trend < 0.001), there was no association for nondairy calcium intake (HR: 1.02; 95% CI: 0.94, 1.10; P-trend = 0.58).
Baseline dairy food intake, and specifically that of milk, may reduce the risk of developing hypertension in Chinese adults, and this may not be associated with the calcium component.