School lunch, policy, and environment are determinants for preventing childhood obesity: Evidence from a two-year nationwide prospective study.

To explore the effects of the school lunches related factors on student obesity rates. In this 2-year prospective census, we collected data on the obesity rate in 2007 and 2008 and school lunch data for 2007 from the Student Health Examination and School Health Profile Database. We used geographic information system software to collect spatial environmental data. Hierarchical regression was used to analysis data. A total of 2208 elementary and junior high schools, excluding offshore islands in Taiwan were collected. The highest obesity rate (13.5%) was observed at a school in which one school meal cost less than US$ 0.83 in 2008. The obesity rates in schools that employed dietitians were lower than in schools that did not (p<0.001 in 2007, 2008). School lunches and childhood obesity exert a greater effect on boys than on girls.