Relations between dietary sodium and potassium intakes and mortality from cardiovascular disease: the Japan Collaborative Cohort Study for Evaluation of Cancer Risks

Background: Limited evidence is available about the relations between sodium and potassium intakes and cardiovascular disease in the general population. Objective: The objective was to investigate relations between sodium and potassium intakes and cardiovascular disease in Asian populations whose mean sodium intake is generally high. Design: Between 1988 and 1990, a total of 58 730 Japanese subjects (n = 23 119 men and 35 611 women) aged 40-79 y with no history of stroke, coronary heart disease, or cancer completed a lifestyle questionnaire including food intake frequency under the Japan Collaborative Cohort Study for Evaluation of Cancer Risk sponsored by the Ministry of Education, Sports and Science. Results: After 745 161 person-years of follow-up, we documented 986 deaths from stroke (153 subarachnoid hemorrhages, 227 intraparenchymal hemorrhages, and 510 ischemic strokes) and 424 deaths from coronary heart disease. Sodium intake was positively associated with mortality from total stroke, ischemic stroke, and total cardiovascular disease. The multivariable hazard ratio for the highest versus the lowest quintiles of sodium intake after adjustment for age, sex, and cardiovascular disease risk factors was 1.55 (95% CI: 1.21, 2.00; P for trend < 0.001) for total stroke, 2.04 (95 % CI: 1.41, 2.94; P for trend < 0.001) for ischemic stroke, and 1.42 (95% CI: 1.20, 1.69; P for trend < 0.001) for total cardiovascular disease. Potassium intake was inversely associated with mortality from coronary heart disease and total cardiovascular disease. The multivariable hazard ratio for the highest versus the lowest quintiles of potassium intake was 0.65 (95% CI: 0.39,1.06; P for trend = 0.083) for coronary heart disease and 0.73 (95% CI: 0.59, 0.92; P for trend = 0.0 18) for total cardiovascular disease, and these associations were more evident for women than for men. Conclusions: A high sodium intake and a low potassium intake may increase the risk of mortality from cardiovascular disease.