The GPS was associated with only small differences in birthweight: the mean was 3.47 kilograms for those in the top decile vs. 3.41 kilograms for those in the bottom decile, a difference of 0.06 kilograms (p = 0.02) (Figure 6A–F). By age 8 years, the difference increased to 3.5 kilograms (p < 0.0001), with mean weight 27.9 versus 24.3 kilograms. By age 18 years, the difference reached 12.3 kilograms (p < 0.0001). Strikingly, this weight difference between top and bottom GPS deciles at age 18 years (12.3 kilograms) was comparable to that seen in participants in the UK Biobank at mean age 57 years (13.0 kilograms).
