Water, other fluids, and fatal coronary heart disease: the Adventist Health Study.

Whole blood viscosity, plasma viscosity, hematocrit, and fibrinogen are considered independent risk factors for coronary heart disease and can be elevated by dehydration. The associations between fatal coronary heart disease and intake of water and fluids other than water were examined among the 8,280 male and 12,017 female participants aged 38-100 years who were without heart disease, stroke, or diabetes at baseline in 1976 in the Adventist Health Study, a prospective cohort study. A total of 246 fatal coronary heart disease events occurred during the 6-year follow-up. High daily intakes of water (five or more glasses) compared with low (two or fewer glasses) were associated with a relative risk in men of 0.46 (95% confidence interval (CI): 0.28, 0.75; p trend = 0.001) and, in women, of 0.59 (95% CI: 0.36, 0.97). A high versus low intake of fluids other than water was associated with a relative risk of 2.47 (95% CI: 1.04, 5.88) in women and of 1.46 (95% CI: 0.7, 3.03) in men. All associations remained virtually unchanged in multivariate analysis adjusting for age, smoking, hypertension, body mass index, education, and (in women only) hormone replacement therapy. Fluid intake as a putative coronary heart disease risk factor may deserve further consideration in other populations or using other study designs.