Table 4.
Generalized linear models evaluating the association between the average protein intakes before ovulation (menstruation, midfollicular phase)a and risk of anovulation
| Unadjusted | Adjustedb | Carbohydrate Substitution Modelc | Fat Substitution Modeld | Protein Substitution Modele | |||
|---|---|---|---|---|---|---|---|
| Anovulatory n (%) | RR (95% CI) | RR (95% CI) | RR (95% CI) | RR (95% CI) | |||
| Total protein (% energy) | Tertile 1 | 16 (38) | 0.93 (0.52, 1.68) | 0.83 (0.45, 1.51) | 0.73 (0.38, 1.42) | 0.77 (0.38, 1.56) | – |
| Tertile 2 | 18 (43) | Reference | Reference | Reference | Reference | – | |
| Tertile 3 | 8 (19) | 0.45 (0.23, 0.88) | 0.65 (0.34, 1.24) | 0.56 (0.28, 1.14) | 0.52 (0.25, 1.08) | – | |
| Animal protein f (% energy) | Tertile 1 | 16 (38) | 1.00 (0.56, 1.79) | 0.98 (0.46, 2.06) | 0.98 (0.46, 2.08) | 1.01 (0.47, 2.19) | 1.11 (0.49, 2.48) |
| Tertile 2 | 16 (38) | Reference | Reference | Reference | Reference | Reference | |
| Tertile 3 | 10 (24) | 0.59 (0.30, 1.13) | 0.81 (0.39, 1.68) | 0.81 (0.39, 1.68) | 0.78 (0.36, 1.67) | 0.67 (0.24, 1.89) | |
| Vegetable protein g (% energy) | Tertile 1 | 17 (40) | 2.05 (1.08, 3.90) | 2.53 (1.21, 5.26) | 2.51 (1.21, 5.20) | 2.52 (1.21, 5.26) | 2.65 (1.24, 5.63) |
| Tertile 2 | 9 (21) | Reference | Reference | Reference | Reference | Reference | |
| Tertile 3 | 16 (38) | 1.52 (0.82, 2.82) | 0.95 (0.44, 2.05) | 0.95 (0.43, 2.10) | 0.95 (0.43, 2.08) | 0.90 (0.40, 2.00) |
Abbreviations: BMI, body mass index; CI, confidence interval; RR, risk ratio.
a Mean energy from total protein intake before ovulation, tertile 1: 4.3%–13.3% of energy; tertile 2: 13.3%–16.4% of energy; tertile 3: 16.4%–36.3% of energy. Mean energy from animal protein intake, tertile 1: 0.1%–7.9% of energy; tertile 2, 7.9%–11.2% of energy; tertile 3, 11.2%–34.4% of energy. Mean energy from vegetable protein intake, tertile 1, 1.6%–4.5% of energy; tertile 2, 4.5%–5.9% of energy; tertile 3, 5.9%–19.2% of energy.
b Adjusted for age, race, BMI, physical activity, alcohol, blood cadmium, mercury, and lead concentrations, and fiber and total energy intakes.
c Adjusted for age, race, BMI, physical activity, alcohol, blood cadmium, mercury, and lead concentrations, and fiber, total energy, and fat intakes.
d Adjusted for age, race, BMI, physical activity, alcohol, blood cadmium, mercury, and lead concentrations, and fiber, total energy, and carbohydrate intakes.
e Adjusted for age, race, BMI, physical activity, alcohol, blood cadmium, mercury, and lead concentrations, and fiber, total energy, fat, carbohydrate, and other types of protein intakes (ie, animal protein models were adjusted for vegetable protein and vegetable protein models were adjusted for animal protein).
f Derived from consumption of red meats (beef, veal, lamb, pork, game, and organ meats), poultry, processed meats (cured pork, cold cuts, and sausage), fish (fish and shellfish), and eggs.
g Derived from consumption of meat alternatives (veggie burgers, tofu, tempeh, textured vegetable protein, and soy nut), legumes (dried beans, mature lima beans, refried beans, and beans in sauce and recipe), nuts and seeds, and nut and seed butters.