Height, weight and BMI measurements in each individual were converted to s.d. scores (SDS) adjusted for sex and age. Growth tempo, a measure of child's current height relative to height potential, was calculated as the child's height SDS minus their mean parental height SDS15. Associations between rs314276 and changes in growth tempo, weight and BMI SDS between ages 7 to 11 years were calculated using time series analyses (repeated measures ANOVA). Association between rs314276 and the onset of pubertal breast development in girls was calculated using a log-rank test. Cross-sectional associations between rs314276 and pubertal stage in girls and boys were done by ordinal logistic regression. All analyses assumed an additive genetic model, and were done using SPSS v.14 for Windows.
