Estimation of Causal Effect of Age at Menarche on Pubertal Height Growth Using Mendelian Randomization

We use Mendelian randomization to estimate the causal effect of age at menarche on late pubertal height growth and total pubertal height growth. The instrument SNPs selected from the exposure genome-wide association study (GWAS) are validated in additional population-matched exposure GWASs. Based on the inverse variance weighting method, there is a positive causal relationship of age at menarche on late pubertal growth ([Formula: see text] , 95% CI: (0.34, 0.78), [Formula: see text]) and on total pubertal growth ([Formula: see text] , 95% CI: (0.14, 0.58), [Formula: see text]). If the instrument SNPs are not validated in additional exposure GWASs, the estimated effect on late pubertal height growth increases by 3.6% to [Formula: see text] (95% CI: (0.42, 0.73), [Formula: see text]) while the estimates on total pubertal height growth increases by 41.7% to [Formula: see text] (95% CI: (0.35, 0.67), [Formula: see text]).