Effect of Dietary Calcium and Milk Consumption on Risk of Thromboembolic Stroke in Older Middle-aged Men

Abstract

Evidence suggests that dietary calcium is protective against hypertension. This report examines whether the effect has an influence on thromboembolic stroke. Since 1965, the Honolulu Heart Program has followed a cohort of men in a study of cardiovascular disease. This report examines the effect of baseline dietary calcium and milk intake on stroke risk in 22 years of follow-up in 3150 older middle-aged men (55 to 68 years). Men who were nondrinkers of milk experienced stroke at twice the rate (P < .05) of men who consumed 16 oz/d or more (7.9 versus 3.7 per 100, respectively). While the rate of stroke decreased with increasing milk intake (P < .05), the decline in stroke risk with increased consumption was modest for those who consumed under 16 oz/d. Intake of dietary calcium was also associated with a reduced risk of stroke (P < .01), although its association was confounded with milk consumption. Calcium intake from nondairy sources was not related to stroke, suggesting that other constituents or covariates related to milk consumption may be important. We conclude that an association between milk consumption and a reduced risk of stroke in older middle-aged men cannot be explained by intake of dietary calcium. Since milk is often part of a diverse pattern of dietary intake, it is difficult to determine whether milk consumption has a direct role in reducing the risk of stroke. Data suggest that consumption of milk in older middle age is not harmful, and when combined with a balanced diet, weight control, and physical activity, reductions in the risk of stroke may occur.