Dietary sodium intake and subsequent risk of cardiovascular disease in overweight adults

Context Dietary sodium is positively associated with blood pressure, and ecological and animal studies both have suggested that high dietary sodium intake increases stroke mortality. Objective To examine the risk of cardiovascular disease associated with dietary sodium intake in overweight and nonoverweight persons. Design Prospective cohort study. Setting The first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study, conducted in 1982-1984, 1986, 1987, and 1992. Participants Of those aged 25 to 74 years when the survey was conducted in 1971-1975 (14 407 participants), a total of 2688 overweight and 6797 nonoverweight persons were included in the analysis. Main outcome Measures Dietary sodium and energy intake were estimated at baseline using a single 24-hour dietary recall method. Incidence and mortality data for cardiovascular disease were obtained from medical records and death certificates. Results For overweight and nonoverweight persons, over an average of 19 years of follow-up, the total number of documented cases were as follows: 680 stroke events (210 fatal), 1727 coronary heart disease events (614 fatal), 895 cardiovascular disease deaths, and 2486 deaths from all causes. Among overweight persons with an average energy intake of 7452 kJ, a 100 mmol higher sodium intake was associated with a 32% increase (relative risk [RR], 1.32; 95% confidence interval [CI], 1.07-1.64; P = .01) in stroke incidence, 89% increase (RR, 1.89; 95% CI, 1.31-2.74; P<.001) in stroke mortality, 44% increase (RR, 1.44; 95% CI, 1.14-1.81; P = .002) in coronary heart disease mortality, 61% increase (RR, 1.61; 95% CI, 1.32-1.96; P<.001) in cardiovascular disease mortality, and 39% increase (RR, 1.39; 95% CI, 1.23-1.58; P<.001) in mortality from all causes. Dietary sodium intake was not significantly associated with cardiovascular disease risk in nonoverweight persons. Conclusions Our analysis indicates that high sodium intake is strongly and independently associated with an increased risk of cardiovascular disease and all-cause mortality in overweight persons.