Relationship of household salt intake level with long-term all-cause and cardiovascular disease mortality in Japan: NIPPON DATA80

In Asian countries, a major source of salt intake is from seasoning or table salt added at home. However, little is known about the adverse effects of salt intake evaluated according to household unit. We investigated the relationship between household salt intake level and mortality from all-cause and cardiovascular diseases (CVDs). Participants included 8702 individuals (56% women) who were living with someone else and who were aged 30–79 years and enrolled in the National Nutritional Survey of Japan in 1980 with a 24-year follow-up. Household nutrient intake was evaluated using a 3-day weighing record method in which all foods and beverages consumed by any of the household members were recorded. The household salt intake level was defined as the amount of salt consumed (g) per 1000 kcal of total energy intake in each household, and its average was 6.25 (2.02) g/1000 kcal. During the follow-up, there were 2360 deaths (787 CVD, 168 coronary heart disease [CHD], and 361 stroke). Cox proportional hazard ratios (HRs) for an increment of 2 g/1000 kcal in household salt intake were calculated and adjusting for sex, age, body mass index, smoking status, alcohol consumption status, self-reported work exertion level, household potassium intake, household saturated fatty acid intake, and household long-chain n-3 polyunsaturated fatty acid intake. The HRs (95% confidence intervals) were 1.07 (1.02, 1.12) for all-cause mortality, 1.11 (1.03, 1.19) for CVD, 1.25 (1.08, 1.44) for CHD, and 1.12 (1.00, 1.25) for stroke. The household salt intake level was significantly associated with long-term risk of all-cause, CVD, CHD, and stroke mortality in a representative Japanese population.