Left ventricular mass independently associates with 24-hour sodium excretion in young masked hypertensive adults: The African-PREDICT study.

BACKGROUND: Due to the known contribution of excess sodium intake on elevations in blood pressure, salt reduction regulations are being introduced in countries all over the world. To study the contribution of sodium intake on cardiovascular disease development, we determined whether left ventricular mass associates with sodium excretion in young adults free from overt cardiovascular disease and those with masked hypertension. METHODS: We included 681 participants (41% men and 50% black) in a cross-sectional analysis from the African-PREDICT study with complete 24-hour urine collections and successful ambulatory blood pressure monitoring (>70% valid readings). The participants were categorized as normotensive (n = 534) or masked hypertensive (n = 147). In addition, we determined left ventricular mass index (LVMI) along with traditional risk factors. RESULTS: Masked hypertensive individuals had higher sodium excretion (149 vs. 128 mmol/L/day) and LVMI (78.1 vs. 69.6 g/m2) than normotensives. In single, partial and multiple regression analyses, LVMI independently associated with higher sodium excretion in the total group of young adults (ß = 0.089; p = 0.011). This result was also evident among masked hypertensives (ß = 0.215; p = 0.008), but not in normotensives (ß = 0.054; p = 0.134). CONCLUSION: Our results indicated that higher sodium excretion (reflecting a higher salt intake) may contribute to increased left ventricular mass, potentially driven by the early development of masked or undetected hypertension.

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

BACKGROUND/OBJECTIVES: 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. SUBJECTS/METHODS: 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). RESULTS: 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). CONCLUSIONS: 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.