Children of those mothers with earlier menarche had taller heights at age 9 y (by 0.41 cm/y; p < 0.001), increased body weight (0.80 kg/y; p < 0.001) and BMI (0.29 kg/m2/y; p < 0.001; Table 1). Most of the gain in BMI was attributable to greater fat mass index (0.22 kg/m2/y; p < 0.001) rather than lean mass index (0.05 kg/m2/y; p < 0.001). Daughters of mothers with earlier menarche were themselves more likely to report early menarche (before age 11 y; p < 0.001; Table 1). Compared with children of mothers in the oldest menarche quintile (≥15 y), children of mothers in the earliest menarche quintile (≤11 y) had a nearly 3-fold increased risk of obesity (OR 2.91, 95% CI 2.02–4.19; p < 0.001, adjusted for sex, age, and mother's education). The risk of obesity was similar in boys and girls (p-value for interaction = 0.9; Figure 1), and it was only partially attenuated by further adjustment for mother's BMI (OR 2.15, 95% CI 1.46–3.17; p < 0.001; Figure 1).
