Table IV.
Hazard ratios (95% CIs) for early menopause by level of moderate and strenuous activity in adolescence and young adulthood; Nurses’ Health Study II (1989–2011)
| Physical activity (h/week) | n Cases | Moderate activity | n Cases | Strenuous activity |
|---|---|---|---|---|
| HR (95% CI)a | HR (95% CI)a | |||
| Age 12–13 (grades 7–8) | ||||
| None | 118 | 1 | 243 | 1 |
| >0–<1 | 177 | 1.12 (0.89, 1.41) | 179 | 1.08 (0.89, 1.31) |
| 1–2 | 645 | 1.01 (0.83, 1.23) | 500 | 0.96 (0.82, 1.12) |
| 3–4 | 585 | 1.08 (0.89, 1.32) | 479 | 1.03 (0.88, 1.20) |
| 5–6 | 284 | 0.98 (0.79, 1.22) | 349 | 1.03 (0.87, 1.21) |
| 7–10 | 140 | 0.91 (0.71, 1.17) | 206 | 0.97 (0.80, 1.17) |
| ≥11 | 110 | 0.99 (0.76, 1.28) | 138 | 0.98 (0.79, 1.20) |
| P-trend | 0.29 | 0.80 | ||
| Age 14–17 (grades 9–12) | ||||
| None | 106 | 1 | 222 | 1 |
| >0–<1 | 174 | 1.14 (0.89, 1.45) | 183 | 1.12 (0.92, 1.36) |
| 1–2 | 639 | 1.04 (0.84, 1.27) | 463 | 0.91 (0.77, 1.06) |
| 3–4 | 588 | 1.11 (0.90, 1.36) | 448 | 0.93 (0.79, 1.09) |
| 5–6 | 290 | 1.01 (0.80, 1.26) | 360 | 0.97 (0.82, 1.14) |
| 7–10 | 152 | 1.00 (0.78, 1.28) | 238 | 0.94 (0.78, 1.13) |
| ≥11 | 109 | 1.10 (0.84, 1.43) | 187 | 0.97 (0.79, 1.17) |
| P-trend | 0.85 | 0.76 | ||
| Age 18–22 | ||||
| None | 127 | 1 | 299 | 1 |
| >0–<1 | 207 | 0.99 (0.79, 1.24) | 290 | 1.03 (0.88, 1.21) |
| 1–2 | 665 | 1.04 (0.86, 1.25) | 575 | 1.01 (0.87, 1.16) |
| 3–4 | 577 | 1.10 (0.91, 1.33) | 449 | 1.05 (0.90, 1.21) |
| 5–6 | 283 | 1.03 (0.83, 1.27) | 249 | 0.97 (0.82, 1.15) |
| 7–10 | 118 | 0.94 (0.73, 1.21) | 137 | 1.06 (0.86, 1.30) |
| ≥11 | 77 | 1.06 (0.79, 1.40) | 88 | 1.17 (0.92, 1.49) |
| P-trend | 0.97 | 0.31 | ||
aAdjusted for age (continuous, months), BMI (<18.5, 18.5-<25, 25-<30 or ≥30 kg/m2), pack-years of smoking (0–10, 11–20 or ≥21), age at menarche (continuous), parity (nulliparous, 1–2, or ≥3), breastfeeding duration (in months; continuous), oral contraceptive use (never/past/current), % of calories from vegetable protein (quintiles), alcohol intake (<10, ≥10 g/day) and intake of vitamin D from dairy source (quintiles).