A positive association between dietary sodium intake and obesity and central obesity: results from the National Health and Nutrition Examination Survey 1999-2006.

The link between sodium and obesity has been accumulated over years. However, there has been few data reported on such sodium-obesity association from the general US population. This study is designed to assess the hypothesis that dietary sodium intake is independently and positively associated with obesity, central obesity, and measures of body composition among generally healthy US adults. We analyzed data on 9162 healthy participants aged 24 to 48 years (4813 men and 4349 women) with at least one valid diet recall from the 8-year National Health and Nutrition Examination Survey (1999-2006). Measures of body composition, including fat mass, lean mass, and total fat percent, were determined by dual-energy x-ray absorptiometry. We assessed the association between dietary sodium and obesity and measures of body composition by using multivariable logistic regression models. After adjustment for total energy intake and other prespecified confounders, high sodium intake (>2300 mg/d) was significantly associated with elevated risk of obesity and central obesity as compared with moderate sodium intake (1500-2300 mg/d). On average, each 1-g/d increment in dietary sodium intake resulted in a 15% (odds ratio, 1.15; 95% confidence interval, 1.00-1.33) increase in the risk of obesity and 24% (odds ratio, 1.24; 95% confidence interval, 1.11-1.39) increase in the risk of central obesity. After stratification by sex and ethnicity, significant associations between sodium and obesity/abdominal obesity were apparent only among women and non-Hispanic whites. In addition, all measures of body composition were positively associated with sodium consumption levels. We found that high sodium intake is independently associated with elevated risk of obesity and central obesity in the general US adult population.