Dietary salt intake increases with age in Japanese adults

Excess salt intake is linked to cardiovascular disease as well as hypertension, but whether individual salt intake increases with age has not been studied. The present study was designed to test the hypothesis that individual salt intake increases with age in Japanese adults. In this retrospective observational follow-up study, men and women age ≥30 years who participated in a baseline health checkup (2008-2009) at our center and had a health checkup 10 years later (n = 2598) were enrolled and salt intake was estimated by spot urine analysis. Yearly changes in salt intake were also assessed in participants with complete annual data over the course of 10 years from baseline (n = 1543). The follow-up study demonstrated increased salt intake (8.8 ± 2.0 to 9.3 ± 2.1 g/d, P < .001) with increasing age (54.0 ± 9.7 to 64.0 ± 9.8 years). Salt intake increased year over year in participants who had a health checkup annually for the 10-year follow-up period (n = 1543; analysis of variance, P < .001). Cross-sectional analyses using propensity-matched model revealed similar regional levels of salt intake in the baseline period (8.9 ± 2.0 g/d, 55.8 ± 11.4 years, n = 5018) and at 10 years (8.8 ± 2.0 g/d, P = .21; 55.9 ± 13.0 years, P = .65, n = 5105). These results suggest that dietary salt intake increases with age in Japanese adults, which should be considered in devising population-based strategies to lower dietary salt intake.