Table 2.
Hazard ratio (95% CI) of coronary heart disease according to quintiles of isoflavone intake
| Quintile of isoflavone intake | P trend | |||||
|---|---|---|---|---|---|---|
| 1 (low) | 2 | 3 | 4 | 5 (high) | ||
| NHS | ||||||
| Median intake, mg/d | 0.16 | 0.26 | 0.37 | 0.52 | 1.43 | |
| No. of case/person years | 773/373857 | 713/373776 | 650/372196 | 744/374260 | 628/375486 | |
| Rate per 100,000 person-years | 207 | 191 | 175 | 199 | 167 | |
| Age-adjusted model* | 1 | 0.92 (0.83, 1.02) | 0.85 (0.77, 0.95) | 1.00 (0.90, 1.11) | 0.85 (0.76, 0.94) | 0.02 |
| Multivariable-adjusted model† | 1 | 0.91 (0.82, 1.01) | 0.81 (0.73, 0.90) | 0.87 (0.79, 0.97) | 0.84 (0.75, 0.93) | 0.02 |
| Fully-adjusted model‡ | 1 | 0.91 (0.83, 1.01) | 0.82 (0.73, 0.91) | 0.88 (0.79, 0.97) | 0.88 (0.79, 0.98) | 0.22 |
| NHS II | ||||||
| Median intake, mg/d | 0.11 | 0.20 | 0.33 | 0.52 | 2.31 | |
| No. of case/person years | 158/405480 | 136/408747 | 155/404086 | 127/404120 | 89/407379 | |
| Rate per 100,000 person-years | 39 | 33 | 38 | 31 | 22 | |
| Age-adjusted model* | 1 | 0.87 (0.69, 1.09) | 0.93 (0.75, 1.17) | 0.75 (0.59, 0.95) | 0.53 (0.41, 0.69) | <0.001 |
| Multivariable-adjusted model† | 1 | 0.92 (0.73, 1.16) | 0.93 (0.74, 1.17) | 0.68 (0.53, 0.86) | 0.62 (0.47, 0.81) | <0.001 |
| Fully-adjusted model‡ | 1 | 0.94 (0.74, 1.18) | 0.97 (0.77, 1.22) | 0.72 (0.56, 0.91) | 0.70 (0.53, 0.92) | 0.01 |
| HPFS | ||||||
| Median intake, mg/d | 0.18 | 0.29 | 0.43 | 0.66 | 2.22 | |
| No. of case/person years | 956/184211 | 883/186621 | 870/184926 | 829/184812 | 648/186166 | |
| Rate per 100,000 person-years | 519 | 473 | 470 | 449 | 348 | |
| Age-adjusted model* | 1 | 0.91 (0.83, 1.00) | 0.93 (0.85, 1.03) | 0.96 (0.87, 1.05) | 0.78 (0.71, 0.86) | <0.001 |
| Multivariable-adjusted model† | 1 | 0.91 (0.83, 1.00) | 0.93 (0.84, 1.02) | 0.93 (0.85, 1.03) | 0.82 (0.74, 0.91) | 0.001 |
| Fully-adjusted model‡ | 1 | 0.92 (0.84, 1.02) | 0.94 (0.85, 1.03) | 0.95 (0.86, 1.04) | 0.89 (0.80, 0.99) | 0.12 |
| Pooled§ | ||||||
| Age-adjusted model* | 1 | 0.91 (0.85, 0.97) | 0.90 (0.84, 0.96) | 0.96 (0.90, 1.02) | 0.79 (0.73, 0.85) | <0.001 |
| Multivariable-adjusted model† | 1 | 0.91 (0.85, 0.98) | 0.88 (0.82, 0.94) | 0.88 (0.83, 0.95) | 0.81 (0.76, 0.87) | <0.001 |
| Fully-adjusted model‡ | 1 | 0.92 (0.86, 0.98) | 0.89 (0.83, 0.95) | 0.90 (0.84, 0.96) | 0.87 (0.81, 0.94) | 0.008 |
CI, confidence interval; HPFS, Health Professionals Follow-up Study; NHS, Nurses’ Health Study.
Cumulative average energy-adjusted intake from the 1984 questionnaire for NHS, the 1991 questionnaire for NHS II, and 1986 questionnaire for HPFS.
Estimates are calculated in Cox proportional hazards models. Age-adjusted model, adjusted for age (years);
Multivariable-adjusted model, further adjusted for ethnicity (Caucasian, African American, Asian, or other ethnicity), self-rated socioeconomic status (top 30%, median 40%, or bottom 30%, for women), partner’s education (<high school, high school, or above college, for women), smoking status (never, former, current [1–14, 15–24, or ≥25 cigarettes/day], or missing), alcohol intake (0, 0.1–4.9, 5.0–14.9, and ≥15.0 g/day for women, 0, 0.1–4.9, 5.0–29.9, and ≥30.0 g/day for men, or missing), physical activity (metabolic equivalents of tasks-hr/week), multivitamin use (yes/no), aspirin use (yes/no), history of hypertension (yes/no) and hypercholesterolemia (yes/no), family history of myocardial infarction (yes/no), menopausal status and post-menopausal hormone use (pre-menopause, post-menopause [never, former, or current hormone use], or missing, for women), oral contraceptive use (yes, no, or missing, NHSII only), body mass index (kg/m2), and total energy intake (kcal/day) based on age-adjusted model.
Fully-adjusted model, further adjusted for modified alternative health eating index score, based on multivariable-adjusted model.
Results from each cohort were pooled using fixed-effects model.