Dietary sodium:potassium ratio and CVD risk factors among Japanese adults: a retrospective cross-sectional study of pooled data from the National Health and Nutrition Survey, 2003-2017

Few studies have reported associations between the Na:K ratio and risk factors related to CVD among the general population in Asian countries. This study aimed to investigate the dietary Na:K ratio association with CVD risk factors among Japanese adults. This retrospective cross-sectional study included 48 800 Japanese participants (19 386 men and 29 414 women) aged >= 20 years, registered in the 2003-2017 National Health and Nutrition Survey. Multivariate OR and 95 % CI for risk of hypertension, high glycated HbA1c levels, hypercholesterolaemia, low serum levels of HDL-cholesterol and high non-HDL-cholesterol levels according to the Na:K ratio were estimated using logistic regression models. Dietary Na:K ratio decreased for both men and women from 2003 to 2017. Higher Na:K ratio and higher hypertension prevalence were observed (multivariate OR (fifth v. first quintiles) 1 center dot 27, 95 % CI 1 center dot 15, 1 center dot 40; P-for trend < 0 center dot 001 for men and 1 center dot 12, 95 % CI 1 center dot 01, 1 center dot 23; P-for trend = 0 center dot 007 for women). Higher Na:K ratio was associated with higher prevalence of high HbA1c levels in men (multivariate OR 1 center dot 56, 95 % CI 1 center dot 24, 1 center dot 96). Prevalence of low HDL-cholesterol levels was increased with higher Na:K ratio (P-for trend =0 center dot 002 for men and <0 center dot 001 for women). No significant associations were found between Na:K ratio and hypercholesterolaemia in men or high non-HDL-cholesterol levels in both men and women. Our findings suggest that dietary Na:K ratio is associated with several CVD risk factors among Japanese adults.