Table 3.
Combined effect of birth weight and adult adiposity on risk of GDM in the Nurses’ Health Study II (n=21,647)
| N of women (n of GDM cases) | Relative Riska (95% CI) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Birth weight Category (lbs) | Birth weight Category (lbs) | |||||||||
| Adult BMI centileb | Mean BMI | <5.5 | 5.5–6.9 | 7.0–8.4 | 8.5+ | <5.5 | 5.5–6.9 | 7.0–8.4 | 8.5+ | RR per category birth weightc |
| <7th | 18 | 122 (9) | 509 (27) | 648 (24) | 152 (5) | 0.88 (0.45–1.74) | 0.80 (0.53–1.17) | 0.57 (0.37–0.86) | 0.51 (0.21–1.23) | 0.86 (0.69–1.09) |
| 7th–37th | 20 | 422 (19) | 2086 (115) | 3178 (129) | 852 (35) | 0.60 (0.37–0.98) | 0.83 (0.67–1.03) | 0.65 (0.53–0.79) | 0.65 (0.45–0.92) | 0.94 (0.85–1.04) |
| 37th–86th | 23 | 663 (44) | 3053 (214) | 5164 (319) | 1614 (79) | 0.87 (0.62–1.23) | 1.07 (0.89–1.27) | 1.00 (ref) | 0.76 (0.60–0.98) | 0.94 (0.88–1.00) |
| >86th | 31 | 218 (29) | 871 (112) | 1562 (172) | 533 (54) | 1.75 (1.16–2.64) | 1.99 (1.60–2.48) | 1.77 (1.47–2.14) | 1.52 (1.13–2.04) | 0.94 (0.86–1.02) |
| RR per unit BMI | 1.07 (1.03–1.11) | 1.08 (1.06–1.10) | 1.09 (1.07–1.10) | 1.07 (1.04–1.10) | ||||||
a
RR adjusted for age, race, prematurity, smoking, maternal and paternal history of type 2 diabetes, age of first birth, parity, physical activity
b
BMI centiles calculated using self-reported BMI at baseline in 1989 and corresponding to the percentiles of birth weight by each category (to the nearest whole percent)
c
Test for interaction between BMI and birthweight by cross-product was non-significant (p= 0.37).