Table 2.
Association between plasma insulin levels (at birth, in childhood and longitudinal trajectories) with age at menarche
| Insulin concentration or tertile (µIU/mL) | n | TR (95% CI) | Mean shift (in mo) of age at menarche (95% CI) | P value |
|---|---|---|---|---|
| At birth (cord blood) | ||||
| T1: <9.8 | 130 | 1.00 | Reference | |
| T2: 9.9–18.4 | 131 | 0.97 (0.94, 1.00) | −5.42 (−0.15, −10.51) | 0.044 |
| T3: >18.4 | 130 | 0.96 (0.93, 0.99) | −6.58 (−1.37, −11.65) | 0.014 |
| A doubling of insulin level | 391 | 0.99 (0.98, 1.00) | −1.95 (−0.33, −3.53) | 0.018 |
| Childhood* | ||||
| T1: <9.4 | 111 | 1.00 | Reference | |
| T2: 9.5–18.2 | 112 | 0.97 (0.94, 1.00) | −5.00 (−0.19, −9.65) | 0.041 |
| T3: >18.3 | 112 | 0.97 (0.94, 1.00) | −4.95 (−0.25, −9.52) | 0.039 |
| A doubling of insulin level | 335 | 0.99 (0.98, 1.00) | −2.07 (−0.48, −3.65) | 0.011 |
| Trajectory* | ||||
| Consistently low | 82 | 1.00 | Reference | |
| Decreasing | 63 | 1.00 (0.96, 1.04) | 0.30 (−6.29, 7.17) | 0.931 |
| Increasing | 55 | 0.99 (0.95, 1.03) | −1.62 (−7.82, 4.85) | 0.620 |
| Consistently high | 68 | 0.96 (0.93, 1.00) | −6.25 (−0.38, −11.88) | 0.037 |
Adjusted for maternal age, educational attainment, race and ethnicity, smoking status during pregnancy, prepregnancy BMI, diabetes status during pregnancy, hypertensive disorders in pregnancy, maternal age at menarche categories, child’s fetal growth status, and preterm birth; mo, months; T, tertile.
*
Further adjusted for age at which plasma insulin was measured and the hour of day at the study visit in addition to the abovementioned covariates.