Adjusteda means of serum IGF-I, IGFBP-3, and molar ratio (IGF-I:IGFBP-3), by reproductive historyb and hormonal variables, Singapore Chinese Health Study
Predictor | Number of subjects | IGF-I (ng/ml) | IGFBP-3 (ng/ml) | Molar ratio (IGF-I:IGFBP-3)*1000 |
---|---|---|---|---|
Age at menarche | ||||
<17 years | 274 | 128 | 4233 | 107 |
≥17 years | 52 | 112 | 3956 | 100 |
P | 0.06 | 0.04 | 0.21 | |
Age when periods became regular | ||||
<17 years | 256 | 128 | 4254 | 106 |
≥17 years | 60 | 113 | 3912 | 103 |
Never became regular | 10 | 116 | 3831 | 102 |
P for <17 yrs vs. ≥17 yrs | 0.06 | 0.003 | 0.47 | |
Age at first birth | ||||
Nulliparous | 20 | 125 | 4174 | 107 |
≤30 yrs | 276 | 124 | 4189 | 104 |
>30 yrs | 30 | 138 | 4240 | 116 |
P for (nullip. or ≤30 yrs vs. >30 yrs) | 0.26 | 0.85 | 0.13 | |
Use of oral contraceptivesc | ||||
Never | 241 | 128 | 4213 | 108 |
Ex, >25 years at start | 64 | 137 | 4236 | 114 |
Ex, ≤25 years at start | 20 | 113 | 4109 | 98 |
P | 0.09 | 0.69 | 0.09 |
a Adjusted for age, BMI, and physical activity.
b Women who reportedly stopped bleeding, but had undergone a hysterectomy without double oophorectomy and an age at specimen collection <55 years were assigned an undetermined menopausal status.
c Only a single woman reported current use of oral contraceptives. She was excluded from the analysis.