Table IV.
Relative risks (RRs) of ovulatory infertility associated with the specified isocaloric substitution of protein
| Age and energy-adjusted | Multivariate adjusted * | |||
|---|---|---|---|---|
| RR (95% CI) | p | RR (95% CI) | p | |
| Substitution for the average mixture of other energy sources † | ||||
| Animal Protein (5% of energy) | 1.18 (1.01, 1.37) | 0.03 | 1.19 (1.03, 1.38) | 0.02 |
| Vegetable Protein (5% of energy) | 0.73 (0.47, 1.13) | 0.15 | 0.64 (0.40, 1.03) | 0.07 |
| Total Protein (5% of energy) § | 1.17 (0.99, 1.38) | 0.06 | 1.18 (1.01, 1.38) | 0.04 |
| Substitution for carbohydrates ‡ | ||||
| Animal Protein (5% of energy) | 1.20 (1.02, 1.40) | 0.03 | 1.19 (1.02, 1.39) | 0.03 |
| Vegetable Protein (5% of energy) | 0.52 (0.30, 0.91) | 0.02 | 0.57 (0.32, 1.00) | 0.05 |
| Total Protein (5% of energy) § | 1.22 (1.04, 1.44) | 0.02 | 1.22 (1.04, 1.43) | 0.01 |
Adjusted for age (continuous), calendar time (4 two-year intervals) and total energy intake (continuous), body mass index (<20, 20–24.9, 25–29.9, ≥30 and missing), parity (0, 1, ≥2 and missing), smoking history (never, past 1–4 cig/day, past 5–14 cig/day, past 15–24 cig/day, past ≥ 25 cig/day or unknown amount, current 1–4 cig/day, current 5–14 cig/day, current 15–24 cig/day and current ≥ 25 cig/day or unknown amount), physical activity (<3 MET-h/wk, 3–8.9 MET-h/wk, 9–17.9 MET-h/wk, 18–26.9 MET-h/wk, 27–41.9 MET-h/wk, ≥ 42 MET-h/wk and missing), oral contraceptive use (current user, never user, past user 0–23 months ago, past user 24–47 months ago, past user 48–71 months ago, past user 72–95 months ago, past user 96–119 months ago, past user ≥ 120 months ago and missing), frequency of multivitamin use (non-users, ≤2 tablets/week, 3 to 5 tablets/week, ≥6 tablets/week and missing), intake of alcohol (no intake, < 2 g/day, 2–4.9 g/day, ≥ 5 g/day), coffee (<1 serving/month, 1 serving/month, 2–6 servings/week, 1 serving/day, 2–3 servings/day, ≥ 4 servings/day) and quintiles of intake of retinol and iron.
From separate models including linear terms for each type of protein and total energy intake as predictors.
From a single model including as predictors linear terms for intakes of animal and vegetable protein, major types of fatty acids (saturated, mono-unsaturated, poly-unsaturated and trans-unsaturated) and total energy.
Total protein was entered into a different model not including the specific types of protein.