Table 5.

Risk ratios (RR) and 95% confidence intervals (CI)^* of ovulatory infertility associated with increasing fiber intake by 10 g/day in subgroups of the study population.

		Total fiber		Cereal fiber
Subgroup	Cases (n)	RR (95% CI)	P, interaction	RR (95% CI)	P, interaction
Age ≤ 32 years	214	1.03 (0.79 – 1.34)	0.02	0.94 (0.61 – 1.44)	0.02
Age > 32 years	224	0.82 (0.62 – 1.08)		0.56 (0.34 – 0.93)
Cycles ≥ 40 days	52	0.89 (0.69 – 1.16)	0.75	0.77 (0.52 – 1.14)	0.55
Cycles < 40 days	386	0.99 (0.62– 1.57)		0.60 (0.22 – 1.66)
BMI < 25	248	0.88 (0.65 – 1.19)	0.16	0.78 (0.49 – 1.22)	0.44
BMI ≥ 25	190	0.96 (0.71 – 1.30)		0.65 (0.36 – 1.20)
Nulliparous	208	0.75 (0.54 – 1.05)	0.03	0.79 (0.50 – 1.23)	0.39
Parous	230	1.06 (0.80 – 1.41)		0.66 (0.37 – 1.19)

^*Adjusted for age (continuous), calendar time (4 two-year intervals), 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), iron (quintiles) trans fatty acids (continuous), animal protein (continuous), vegetable protein (continuous), and glycemic load (continuous).