Table 4.
Multivariable adjusted mean mammographic density by total vitamin D and calcium intake at baseline, stratified by category of percent density at baseline, Women's Health Initiative Mammogram Density Study (n = 808).
| Percent Density (95% Confidence Interval) by Category of Percent Density |
|||
|---|---|---|---|
| Nutrient | < 1 % (n = 212) | 1 - < 10% (n = 388) | ≥ 10% (n = 208) |
| Total Vitamin D intake (IU/day) | |||
| < 100 | 0.5 (0.4, 0.6) | 3.7 (2.8, 4.6) | 18.1 (14.4, 21.8) |
| 100 – 199 | 0.6 (0.4, 0.7) | 4.5 (3.5, 5.6) | 23.3 (20.2, 26.4) |
| 200 – 399 | 0.4 (0.2, 0.5) | 3.7 (2.9, 4.4) | 19.8 (16.0, 23.6) |
| ≥ 400 | 0.5 (0.4, 0.6) | 3.6 (2.7, 4.6) | 16.9 (12.3, 21.5) |
| P = 0.16 | P = 0.79 | P = 0.67 | |
| Vitamin D from food sources (IU/day) | |||
| < 100 | 0.5 (0.4, 0.6) | 3.6 (2.9, 4.2) | 17.0 (13.7, 20.3) |
| 100 – 150 | 0.5 (0.4, 0.6) | 4.4 (3.5, 5.2) | 20.0 (17.4, 22.7) |
| 150 – 199 | 0.5 (0.4, 0.6) | 3.9 (3.0, 4.8) | 22.6 (19.3, 25.9) |
| ≥ 200 | 0.4 (0.3, 0.5) | 3.7 (3.1, 4.3) | 20.6 (17.1, 24.1) |
| P = 0.26 | P = 0.50 | P = 0.15 | |
| Vitamin D from supplements only | |||
| No | 0.5 (0.4, 0.6) | 3.8 (3.0, 4.5) | 22.4 (19.1, 25.7) |
| Yes | 0.5 (0.3, 0.6) | 3.9 (3.1, 4.8) | 17.1 (12.7, 21.4) |
| P = 0.72 | P = 0.91 | P = 0.09 | |
| Total calcium intake (mg/day) | |||
| < 500 | 0.5 (0.4, 0.6) | 3.4 (2.6, 4.3) | 20.5 (16.5, 24.4) |
| 500 – 749 | 0.6 (0.5, 0.7) | 4.2 (3.5, 5.0) | 19.8 (16.0, 23.5) |
| 750 – 999 | 0.5 (0.4, 0.6) | 4.0 (3.2, 4.9) | 21.8 (18.2, 25.4) |
| ≥ 1000 | 0.4 (0.4, 0.5) | 3.6 (3.0, 4.2) | 19.5 (16.8, 22.2) |
| P = 0.07 | P = 0.66 | P = 0.85 | |
| Calcium from food sources (mg/day) | |||
| < 500 | 0.5 (0.4, 0.6) | 4.0 (3.2, 4.9) | 20.3 (16.7, 23.8) |
| 500 – 649 | 0.5 (0.4, 0.6) | 4.2 (3.5, 4.9) | 19.1 (15.0, 23.1) |
| 650 – 799 | 0.5 (0.3, 0.6) | 3.1 (2.2, 4.0) | 18.8 (15.2, 22.5) |
| ≥ 800 | 0.5 (0.4, 0.6) | 3.7 (3.2, 4.3) | 21.6 (18.8, 24.4) |
| P = 0.93 | P = 0.48 | P = 0.27 | |
| Calcium from supplements | |||
| None | 0.6 (0.5, 0.7) | 3.9 (3.3, 4.5) | 21.1 (18.6, 23.6) |
| < 500 | 0.4 (0.3, 0.5) | 3.8 (3.0, 4.6) | 20.2 (16.4, 24.1) |
| ≥ 500 | 0.5 (0.3, 0.6) | 3.7 (2.9, 4.6) | 19.0 (16.0, 22.0) |
| P = 0.97 | P = 0.48 | P = 0.17 | |
Adjusted for covariates in Model 1: age, race/ethnicity, body mass index, age at menarche, parity, oral contraceptive use and duration, previous HT use/duration, HT trial randomization assignment, family history of breast cancer, education, alcohol intake, smoking, total calorie intake, physical activity, Gail risk, and use of multivitamins.