Table 2.
Associations between early-life exposures and timing of thelarche in the Sister Study cohort (N = 49,162)
| Early thelarche (≤ 10 years)a,b | Late thelarche (≥ 14 years)a,b | ||||
|---|---|---|---|---|---|
| N | OR | 95% CI | OR | 95% CI | |
| Maternal pregnancy characteristics | |||||
| Diabetes | |||||
| Any | 458 | 1.20 | 0.93, 1.54 | 0.91 | 0.70, 1.17 |
| Gestational diabetes | 215 | 0.79 | 0.52, 1.21 | 0.87 | 0.60, 1.25 |
| Pre-pregnancy diabetes | 223 | 1.72 | 1.24, 2.38 | 0.88 | 0.60, 1.29 |
| None | 43,594 | 1 | Ref | 1 | Ref |
| Gestational hypertensive disorder | |||||
| Any | 1709 | 1.25 | 1.09, 1.43 | 0.96 | 0.84, 1.10 |
| Pre-eclampsia | 887 | 1.32 | 1.10, 1.58 | 0.99 | 0.83, 1.19 |
| Gestational hypertension | 626 | 1.12 | 0.90, 1.40 | 0.80 | 0.64, 1.01 |
| None | 35,299 | 1 | Ref | 1 | Ref |
| DES use | |||||
| Yes | 1142 | 1.23 | 1.04, 1.45 | 1.02 | 0.86, 1.19 |
| No | 40,641 | 1 | Ref | 1 | Ref |
| Smoking during pregnancy | |||||
| Yes | 14,878 | 1.20 | 1.13, 1.27 | 1.02 | 0.97, 1.08 |
| No | 31,875 | 1 | Ref | 1 | Ref |
| Farm exposure | |||||
| Work and residence | 5730 | 1.00 | 0.92, 1.09 | 0.94 | 0.87, 1.02 |
| Work only | 627 | 1.06 | 0.84, 1.33 | 1.21 | 0.99, 1.48 |
| Residence only | 2040 | 0.98 | 0.86, 1.12 | 0.86 | 0.76, 0.98 |
| None | 39,169 | 1 | Ref | 1 | Ref |
| Age at delivery | |||||
| < 20 years | 2334 | 1.30 | 1.16, 1.47 | 0.93 | 0.82, 1.05 |
| 20–24 years | 11,512 | 1.09 | 1.01, 1.17 | 0.97 | 0.91, 1.03 |
| 25–29 years | 14,679 | 1 | Ref | 1 | Ref |
| 30–34 years | 11,208 | 0.95 | 0.88, 1.02 | 0.95 | 0.89, 1.01 |
| 35–39 years | 6414 | 0.99 | 0.90, 1.08 | 0.94 | 0.87, 1.02 |
| ≥ 40 years | 2430 | 0.95 | 0.83, 1.08 | 1.00 | 0.89, 1.12 |
| Birth and infancy characteristics | |||||
| Firstborn | |||||
| Yes | 11,294 | 1.25 | 1.17, 1.33 | 0.84 | 0.79, 0.89 |
| No | 37,606 | 1 | Ref | 1 | Ref |
| Birthweight | |||||
| < 2500 g | 3729 | 1.06 | 0.96, 1.17 | 1.15 | 1.05, 1.25 |
| 2500–3999 g | 29,505 | 1 | Ref | 1 | Ref |
| ≥ 4000 g | 3,338 | 1.00 | 0.90, 1.11 | 0.99 | 0.90, 1.09 |
| Multiple birth | |||||
| Yes | 1541 | 0.87 | 0.74, 1.02 | 1.11 | 0.98, 1.27 |
| No | 47,614 | 1 | Ref | 1 | Ref |
| Gestational age at birth | |||||
| Born ≥ 1 month before due date | 990 | 0.91 | 0.75, 1.11 | 1.16 | 0.99, 1.37 |
| Born 2–4 weeks before due date | 1904 | 1.06 | 0.92, 1.21 | 0.93 | 0.81, 1.06 |
| Not born ≥ 2 weeks before due date | 19,940 | 1 | Ref | 1 | Ref |
| Ever breastfed | |||||
| Yes | 22,369 | 0.98 | 0.93, 1.04 | 0.95 | 0.90, 1.00 |
| No | 23,116 | 1 | Ref | 1 | Ref |
| Ever fed soy formula | |||||
| Yes | 1195 | 1.10 | 0.93, 1.30 | 1.07 | 0.92, 1.25 |
| No | 39,559 | 1 | Ref | 1 | Ref |
aAdjusted for birth cohort, race/ethnicity and childhood family income
bReferent group is thelarche at 11–13 years