Table 3.
Risk of Uterine Leiomyomata in Relation to Soy Food Intake, Black Women's Health Study, United States, 2001–2007
| Category of Intake, No. of Servings |
P-Trend | ||||
| <1/Week | 1–3/Week | 4–6/Week | ≥7/Week | ||
| Total soy foods | |||||
| No. of cases | 1,614 | 144 | 54 | 59 | |
| No. of person-years | 46,051 | 4,349 | 1,313 | 1,779 | |
| IRR (95% CI)a | 1.00 (ref) | 0.95 (0.80, 1.13) | 1.17 (0.89, 1.54) | 0.98 (0.75, 1.27) | 0.86 |
| IRR (95% CI)b | 1.00 (ref) | 0.90 (0.76, 1.07) | 1.11 (0.84, 1.46) | 0.95 (0.73, 1.24) | 0.80 |
| Soy milk | |||||
| No. of cases | 1,709 | 97 | 25 | 40 | |
| No. of person-years | 48,842 | 2,818 | 673 | 1,160 | |
| IRR (95% CI)a | 1.00 (ref) | 1.00 (0.81, 1.22) | 1.06 (0.71, 1.58) | 1.00 (0.73, 1.37) | 0.91 |
| IRR (95% CI)b | 1.00 (ref) | 0.93 (0.75, 1.14) | 1.00 (0.67, 1.49) | 1.00 (0.73, 1.37) | 0.79 |
| <1/Week | 1–2/Week | ≥3/Week | |||
| Tofu | |||||
| No. of cases | 1,797 | 38 | 36 | ||
| No. of person-years | 51,488 | 1,068 | 936 | ||
| IRR (95% CI)a | 1.00 (ref) | 1.08 (0.78, 1.49) | 1.13 (0.81, 1.57) | 0.42 | |
| IRR (95% CI)b | 1.00 (ref) | 1.04 (0.75, 1.43) | 1.09 (0.78, 1.53) | 0.57 | |
| Soy/veggie burgers | |||||
| No. of cases | 1,776 | 72 | 23 | ||
| No. of person-years | 50,884 | 1,820 | 789 | ||
| IRR (95% CI)a | 1.00 (ref) | 1.16 (0.91, 1.46) | 0.85 (0.56, 1.29) | 0.99 | |
| IRR (95% CI)b | 1.00 (ref) | 1.13 (0.89, 1.43) | 0.81 (0.54, 1.23) | 0.75 |
Abbreviations: CI, confidence interval; IRR, incidence rate ratio; ref, referent.
a
Adjusted for age at start of questionnaire cycle, time period, and energy intake.
b
Adjusted for age, time period, energy intake, age at menarche, parity, age at first birth, years since last birth, ever use of oral contraceptives, age at first oral contraceptives use, vigorous exercise, smoking, alcohol intake, body mass index, diabetes, education, occupation, income, marital status, geographic region, and total dairy intake.