Regional disparities in obesity/emaciation and income in schoolchildren in Osaka City.

BACKGROUND: We assessed the association between socioeconomic status at residential area-level in the 24 wards of Osaka City, differentiated by indices of mean income-related deprivation, and inequalities in childhood obesity and emaciation. METHODS: Data from representative samples of 26 474 schoolchildren (first and fifth grades of elementary school, and third grade of junior high school [i.e. ninth grade of elementary school]) in Osaka City taken from a somatometric check in spring 2016 were analyzed. The cross-sectional association between socioeconomic factors, that is, the census-based annual income of each ward, and the prevalence of childhood overweight/obesity and emaciation, was examined. RESULTS: The prevalence of overweight/obesity in boys and girls in the first and fifth grades of elementary school and the third grade of junior high school was 3.98% and 4.53%, 10.18% and 8.69%, and 7.02% and 5.55%, respectively. The prevalence of emaciation in boys and girls in the first and fifth grades of elementary school, and the third grade of junior high school was 0.14% and 0.10%, 0.46% and 1.06% and 3.95% and 3.05%, respectively. Mean physical value, expressed as % degree of overweight, had a negative correlation with mean annual income of each ward in girls in the first and fifth grades of elementary school, girls in the third grade of junior high school and boys in the first grade of elementary school. CONCLUSIONS: Overweight/obesity at school age is greatly affected by poverty. Efforts should be made to prevent emaciation not only in girls, but also in boys, in junior high school.