Table 2.
Mean differences (95% CIs) of log AMH levels in 1996–99, by reproductive factors (n=1618), Nurses’ Health Study 2.
| Reproductive Factor | No. of Participants | MV1 | MV2 | MV3 | |||
|---|---|---|---|---|---|---|---|
|
| |||||||
| β | 95% CI | β | 95% CI | β | 95% CI | ||
|
| |||||||
| Parity | |||||||
| 0 | 310 | REF | -- | REF | -- | REF | -- |
| 1 | 261 | 0.24 | (0.002, 0.48) | 0.16 | (−0.06, 0.39) | 0.11 | (−0.12, 0.34) |
| 2 | 595 | 0.33 | (0.13, 0.53) | 0.22 | (0.03, 0.42) | 0.13 | (−0.08, 0.34) |
| ≥ 3 | 451 | 0.42 | (0.21, 0.64) | 0.27 | (0.07, 0.47) | 0.11 | (−0.12, 0.36) |
| Per pregnancy | 0.10 | 0.06 | 0.01 | ||||
| p-trend =0.0005 | p-trend = 0.02 | p-trend = 0.82 | |||||
| Cumulative total breastfeeding duration (mo.) | |||||||
| 0 – <1 | 436 | REF | -- | REF | -- | REF | -- |
| 1 – 6 | 176 | 0.08 | (−0.17, 0.33) | −0.004 | (−0.24, 0.23) | −0.02 | (−0.27, 0.24) |
| 7 – 12 | 240 | 0.19 | (−0.03, 0.42) | 0.09 | (−0.13, 0.30) | 0.07 | (−0.16, 0.31) |
| 13 – 18 | 225 | 0.36 | (0.13, 0.60) | 0.18 | (−0.04, 0.40) | 0.17 | (−0.08, 0.41) |
| 19 – 24 | 158 | 0.34 | (0.08, 0.61) | 0.11 | (−0.14,0.36) | 0.09 | (−0.20, 0.38) |
| ≥25 | 369 | 0.55 | (0.35, 0.75) | 0.35 | (0.16, 0.55) | 0.33 | (0.08, 0.58) |
| Per month | 0.01 | 0.01 | 0.01 | ||||
| p-trend <0.0001 | p-trend = 0.0006 | p-trend = 0.009 | |||||
| Cumulative exclusive breastfeeding duration (mo.) | |||||||
| 0 – <1 | 707 | REF | -- | REF | -- | REF | -- |
| 1 – 6 | 289 | 0.23 | (0.03, 0.43) | 0.12 | (−0.07, 0.30) | 0.09 | (−0.10, 0.29) |
| 7 – 12 | 345 | 0.32 | (0.13, 0.51) | 0.18 | (0.01, 0.36) | 0.16 | (−0.03, 0.34) |
| 13 – 18 | 171 | 0.53 | (0.29, 0.78) | 0.38 | (0.15, 0.61) | 0.34 | (0.10, 0.58) |
| ≥19 | 70 | 0.36 | (0.006, 0.72) | 0.26 | (−0.07, 0.59) | 0.20 | (−0.17, 0.56) |
| Per month | 0.02 | 0.02 | 0.02 | ||||
| p-trend <0.0001 | p-trend = 0.0005 | p-trend = 0.008 | |||||
MV1: adjusted for age at blood collection (age, age2) and assay characteristics (fasting status [dichotomous], time of blood collection [4 categories], season of blood collection [winter, spring, fall, summer], luteal day [4 categories])
MV2: MV1 + further adjusted for pack-years of smoking (continuous), smoking status (never, current, former), BMI (continuous), exogenous hormone use (dichotomous), duration of oral contraceptive use (never, 1–23, 24–71, 72–119, ≥120 months), years until cycle became regular (never, <1, 1 – 2, 3 – 4, ≥5 years), infertility history (dichotomous), age at menarche (≤11, 12, ≥13 years), and alcohol intake (never, ≤6 drinks per week, 1 drink per day, ≥2 drinks per day)
MV3: MV2 + further adjusted for other reproductive factor: cumulative total breastfeeding duration (continuous) or parity (continuous)