Association between municipal socioeconomic or environmental factors and childhood obesity in Japan: An ecological study.

In Japan, there is a lack of large-scale, municipality-level reports on children with obesity. This study investigated the association of childhood obesity with municipal socioeconomic and environmental factors using school health check-up data. We used the School Health Records Database (SHR-DB) and the e-Stat (Portal Site of Official Statistics of Japan). We assessed the prevalence of obesity in third-grade elementary school children in each municipality in 2015. Obesity was defined using two criteria: the International Obesity Task Force (IOTF) and the Percentage of Overweight (POW) as defined by the Japanese Society for Pediatric Endocrinology. Multiple regression analysis was conducted, including environmental and social factors. This study included 62,898 participants from 134 municipalities. Significant factors associated with children with obesity included: percentage of mother-child(ren) households (regression coefficient: +1.21; 95% confidence interval [CI]: 0.25, 2.16), unemployment rate (+0.89; 95% CI: 0.49, 1.28), rate of population change (+0.13; 95% CI: 0.00, 0.25), financial power index (-2.88; 95% CI: -4.54, -1.22), percentage of population based on last school completed (university and graduate school) (-0.18; 95% CI: -0.27, -0.10), and rate of medical examination of persons insured by national health insurance (-0.07; 95% CI: -0.11, -0.03), under the IOTF criteria. These factors were found to be significant under both the IOTF and POW criteria. The findings of this study indicate that municipal socioeconomic and environmental factors influence childhood obesity in Japan and may contribute to the development of future public health policies and community-level interventions.