Sodium excretion and health-related quality of life: the results from the Korea National Health and Nutrition Examination Survey 2010–2011

Little is known about the effect of sodium intake on health-related quality of life (HR-QOL). In this study, we investigated the association between estimated 24-h urine sodium and HR-QOL in Korean adults.In this cross-sectional study, we analyzed 10,672 participants from Korea National Health and Nutrition Examination Survey (KNHANES) 2010~2011. To assess sodium intake, 24-h urine sodium excretion was estimated from random urine sodium and creatinine using the Kawasaki formula. HR-QOL was assessed using EQ-5D (EuroQol five-dimension) index calculated from Korean version of the EQ-5D questionnaire. Low HR-QOL was defined as the lowest quartile of the EQ-5D index. Participants were divided into three groups according to their estimated 24-h urine sodium level (low,2.0 g/day; moderate, 2.0~3.9 g/day; high,4.0 g/day).Adjusted means of EQ-5D index were 0.975, 0.995, and 0.991 in the low, moderate, and high estimated 24-h urine sodium group, respectively (P = 0.003 for low vs. moderate, P = 0.078 for high vs. moderate). In a multiple logistic analysis, the odds ratio (OR) for low EQ-5D index in the low estimated 24-h urine sodium group compared to the moderate group was 1.87 (95% confidence interval (CI), 1.33-2.64; P 0.001). The OR in the high estimated 24-h urine sodium group compared to the moderate group was 1.09 (95% CI, 0.95-1.24; P = 0.218).Low estimated 24-h urine sodium rather than high estimated 24-h urine sodium was associated with low HR-QOL in representative Korean adults. Further studies are warranted to verify the effect of sodium intake on HR-QOL and the adequate-level sodium restriction in terms of HR-QOL.