Sodium density and obesity; the Korea National Health and Nutrition Examination Survey 2007-2010

BACKGROUND/OBJECTIVES: It is unclear whether the amount of sodium consumed and the degree of saltiness of food is associated with obesity. We examined the association between sodium intake and obesity using the concept of sodium density. SUBJECTS/METHODS: This study included 5025 children (7-18 years) and 20 586 adults (>= 19 years) who participated in the Korean National Health and Nutrition Examination Survey(KNHANES), 2007-2010. We defined sodium density(mg/g) as the ratio of daily dietary sodium intake (mg/day) and daily food weight consumed (g/day). We examined the association between sodium density and obesity, and abdominal obesity in children and adults. RESULTS: The overall prevalences of obesity and abdominal obesity were 31.4 and 24.5%, respectively, in adults and 4.5 and 6.5%, respectively, in children. The multivariate-adjusted odds ratio (OR) for obesity in adults with the highest quintile of sodium density compared with the lowest quintile was 1.18 (95% confidence interval (Cl), 1.04-1.35), and a significant dose-response association (P for trend = 0.002) was observed. The OR for abdominal obesity in adults with the highest quintile of sodium density was not statistically significant after adjusting for confounding factors, but showed a significant dose-response association (P for trend = 0.043). In children, OR values for obesity and abdominal obesity in the highest quintile of sodium density were 1.78 (95% Cl, 1.13-2.80) and 2.13 (95% Cl, 1.16-3.91), respectively, and both showed significant dose-response associations (P for trend <0.001). CONCLUSIONS: Our results indicate that high sodium intake may be a potential risk factor for weight gain independent of calorie intake. European Journal of Clinical Nutrition (2013) 67, 141-146; doi:10.1038/ejcn.2012.204; published online 19 December 2012