Association between childhood obesity and familial salt intake: analysis of data from Korean National Health and Nutrition Examination Survey, 2014-2017

High salt intake is known as a risk factor of childhood obesity. As family members share not only genes but also their diet habit, parents' salt intake may affect to their children's obesity. In this study, we investigated correlations between childhood obesity and parents' or children's sodium intakes based on a nationwide survey data. From the Korean National Health and Nutrition Examination Survey data from 2014 to 2017, 802 boys and 657 girls aged 10-18 years, and their parents were included. BMI z-score and 24-hour urinary sodium excretion, which is estimated through Tanaka's equation, were used to examine associations between obesity and sodium intakes. The BMI status and the prevalence of obesity between children and their parents showed strong positive correlations in both sexes (all p < 0.001). The urinary sodium excretion between children and their parents showed positive correlations in both sexes (all p < 0.05). Children with higher urinary sodium excretion showed higher BMI (in both sexes, p < 0.001) and higher parental obesity compared to those with lower urinary sodium excretion, however, statistical significances of the latter relationship were varied by sex. In conclusion, our study suggests close relationship between childhood obesity and their sodium intakes, which also correlate well with parental BMIs and diet behavior. Therefore, parental education and active participation could be crucial in regulating childhood obesity.