Table 4.
Associations between soy isoflavone intake (mg per day) and never having been pregnant in the Adventist Health Study-2
| Isoflavone intake (mg/day) | Number of women/never pregnant women | Estimated relative risk (95% CI) for never been pregnant |
|---|---|---|
| <10 | 3,808/558 | 1.0 |
| 10–19 | 1,226/208 | 1.14 (1.03, 1.26) |
| 20–29 | 850/129 | 0.98 (0.86, 1.12) |
| 30–39 | 492/85 | 1.10 (0.95, 1.27) |
| 40–49 | 308/52 | 1.11 (0.92, 1.33) |
| 50+ | 528/103 | 1.15 (1.02, 1.29) |
| All | 7,212/1,135 | |
| P-value for linear trend | 0.03 |
Notes: Adjusted for age when completing the lifestyle questionnaire, educational level, and marital status. Women aged 41–50 when completing the lifestyle questionnaire.
Abbreviation: CI, confidence interval.