Table 3.
Odds ratios and 95% confidence intervals for breast cancer risk according to season-adjusted circulating levels of 25(OH)D (by quintiles and as a continuous variable)
| Quintiles | Continuous | |||||||
|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | P trend | OR (95% CI)a | P value | |
| Both cohorts | ||||||||
| Cases/controls | 311/589 | 362/588 | 309/588 | 315/588 | 288/587 | |||
| Unadjusted model | 1.0 (ref) | 1.18 (0.97, 1.43) | 0.99 (0.81, 1.21) | 1.02 (0.84, 1.24) | 0.93 (0.76, 1.14) | 0.18 | 0.94 (0.84, 1.06) | 0.31 |
| Adjusted modelb | 1.0 (ref) | 1.16 (0.95, 1.42) | 1.00 (0.81, 1.22) | 1.04 (0.85, 1.27) | 0.94 (0.76, 1.16) | 0.30 | 0.95 (0.84, 1.08) | 0.44 |
| Adjusted modelc | 1.0 (ref) | 1.16 (0.95, 1.42) | 0.99 (0.81, 1.21) | 1.03 (0.84, 1.27) | 0.94 (0.76, 1.16) | 0.27 | 0.95 (0.84, 1.07) | 0.40 |
| NYUWHS | ||||||||
| Cases/controls | 191/329 | 190/328 | 176/329 | 170/328 | 166/328 | |||
| Unadjusted model | 1.0 (ref) | 0.99 (0.76, 1.29) | 0.92 (0.71, 1.20) | 0.89 (0.69, 1.16) | 0.86 (0.66, 1.12) | 0.18 | 0.91 (0.79, 1.05) | 0.21 |
| Adjusted modelb | 1.0 (ref) | 0.98 (0.75, 1.28) | 0.94 (0.72, 1.23) | 0.92 (0.70, 1.21) | 0.88 (0.67, 1.16) | 0.31 | 0.93 (0.80, 1.08) | 0.34 |
| Adjusted modelc | 1.0 (ref) | 1.00 (0.76, 1.31) | 0.95 (0.73, 1.24) | 0.93 (0.71, 1.22) | 0.90 (0.68, 1.19) | 0.37 | 0.94 (0.81, 1.09) | 0.42 |
| NSMSC | ||||||||
| Cases/controls | 120/260 | 172/260 | 133/259 | 145/260 | 122/259 | |||
| Unadjusted model | 1.0 (ref) | 1.47 (1.09, 1.97) | 1.10 (0.81, 1.49) | 1.22 (0.90, 1.64) | 1.03 (0.75, 1.40) | 0.62 | 1.00 (0.82, 1.23) | 0.99 |
| Adjusted modelb | 1.0 (ref) | 1.48 (1.08, 2.01) | 1.09 (0.79, 1.49) | 1.26 (0.92, 1.72) | 1.05 (0.76, 1.46) | 0.74 | 1.02 (0.82, 1.26) | 0.89 |
| Adjusted modelc | 1.0 (ref) | 1.46 (1.07, 1.99) | 1.08 (0.79, 1.48) | 1.24 (0.91, 1.70) | 1.04 (0.75, 1.45) | 0.71 | 1.01 (0.81, 1.26) | 0.94 |
aOdds ratio (OR) for a doubling in 25(OH)D level. bAdjusted for age at menarche (continuous), age at first birth/parity (≤ 20, 21-25, 26-30, > 30 years, nulliparous), family history of breast cancer (no or yes), body mass index (continuous), hormone replacement therapy use (never or ever), and alcohol consumption (continuous). cAdjusted for physical activity and multivitamin use in addition to variables in footnote a. 25(OH)D, 25-hydroxyvitamin D; CI, confidence interval; NSMSC, Northern Sweden Mammary Screening Cohort; NYUWHS, New York University Women's Health Study; ref, reference.