Data
The Longitudinal Surveys of Babies Born in the 21stCentury by the Japanese Ministry of Health, Labour and Welfare is a birth cohort that was described previously 7, 8. Babies born between January 10 and 17, 2001, in Japan were included in this study. The Ministry asked households to participate in the survey by explaining the purpose of obtaining basic data. The first survey was conducted at 6 months. Follow-up surveys were conducted at the ages of 1.5, 2.5, 3.5, 4.5, 5.5, 7, 8, 9, 10, and 11 years. We obtained permission from the Japanese Ministry of Health, Labour and Welfare to use the data for this study. The study protocol was approved by the Ethics Committee of Osaka International Cancer Institute (No. 1508119060 and 1508119060-2).