TABLE 3.
Risk of ultrasound- or hysterectomy-confirmed uterine leiomyomata in relation to dietary glycemic load, stratified by age and education: the Black Women's Health Study, 1997–20071
| Quintile of glycemic load |
P for statistical interaction3 | ||||||
| 1 | 2 | 3 | 4 | 5 | P for linear trend2 | ||
| Age <35 y | |||||||
| Cases | 287 | 370 | 395 | 403 | 470 | ||
| Person-years | 10,721 | 11,489 | 12,581 | 13,120 | 14,105 | ||
| Model 1: IRR (95% CI)4 | 1.005 | 1.20 (1.03, 1.40) | 1.19 (1.02, 1.38) | 1.16 (1.00, 1.35) | 1.28 (1.11, 1.48) | 0.005 | |
| Model 2: IRR (95% CI)6 | 1.005 | 1.19 (1.02, 1.39) | 1.13 (0.97, 1.32) | 1.09 (0.93, 1.26) | 1.18 (1.02, 1.37) | 0.15 | 0.04 |
| Age ≥35 y | |||||||
| Cases | 805 | 805 | 807 | 753 | 705 | ||
| Person-years | 21,852 | 21,014 | 19,889 | 19,419 | 18,414 | 0.95 | |
| Model 1: IRR (95% CI)4 | 1.005 | 1.05 (0.95, 1.16) | 1.09 (0.99, 1.20) | 1.03 (0.93, 1.14) | 1.00 (0.91, 1.11) | ||
| Model 2: IRR (95% CI)6 | 1.005 | 1.03 (0.93, 1.14) | 1.06 (0.96, 1.17) | 0.99 (0.99, 1.10) | 0.94 (0.85, 1.05) | 0.19 | |
| Education <16 y | |||||||
| Cases | 559 | 578 | 526 | 548 | 619 | ||
| Person-years | 17,290 | 16,351 | 15,457 | 16,451 | 17,639 | ||
| Model 1: IRR (95% CI)4 | 1.005 | 1.10 (0.98, 1.24) | 1.07 (0.95, 1.20) | 1.04 (0.93, 1.17) | 1.10 (0.98, 1.24) | 0.22 | |
| Model 2: IRR (95% CI)6 | 1.005 | 1.08 (0.96, 1.21) | 1.02 (0.91, 1.16) | 0.98 (0.87, 1.11) | 1.03 (0.92, 1.16) | 0.99 | 0.90 |
| Education ≥16 y | |||||||
| Cases | 533 | 597 | 676 | 608 | 556 | ||
| Person-years | 15,284 | 16,152 | 17,013 | 16,088 | 14,880 | ||
| Model 1: IRR (95% CI)4 | 1.005 | 1.07 (0.96, 1.21) | 1.15 (1.02, 1.29) | 1.09 (0.97, 1.22) | 1.07 (0.95, 1.21) | 0.31 | |
| Model 2: IRR (95% CI)6 | 1.005 | 1.06 (0.94, 1.20) | 1.12 (1.00, 1.26) | 1.05 (0.94, 1.18) | 1.02 (0.90, 1.15) | 0.97 | |
IRR, incidence rate ratio.
P values for the 2-sided test for linear trend, modeling the quintile median as a continuous variable.
P values for the likelihood ratio test, comparing model 2 with a model that was further adjusted for the interaction between the binary exposure used for stratification and the glycemic load quintile median.
Adjusted for age, questionnaire cycle, and energy intake.
Reference group.
Adjusted for age, questionnaire cycle, total energy intake, servings of dairy foods, age at menarche, current use of hormonal contraception, BMI, diabetes, current alcohol consumption, cigarette smoking, vigorous physical activity, current US region of residence, marital status, household income, occupation, educational level, parity, age at first birth, and years since last birth.