Table 4.
Odds ratios and 95% confidence intervals for breast cancer risk according to pre-specified categories of circulating 25(OH)D concentration by seasona
| Pre-specified categories, nmol/L | Continuousb | P value | |||||
|---|---|---|---|---|---|---|---|
| < 50 | 50-74 | 75+ | P trend | ||||
| Winter (Jan., Feb., March, April) | |||||||
| Both cohortsc | Cases/controls | 391/704 | 244/472 | 65/116 | |||
| OR (95% CI) | 1.0 (ref) | 0.94 (0.77, 1.15) | 1.06 (0.76, 1.48) | 0.95 | 0.97 (0.82, 1.15) | 0.74 | |
| NYUWHS | Cases/controls | 193/331 | 105/217 | 35/65 | |||
| OR (95% CI) | 1.0 (ref) | 0.82 (0.61, 1.10) | 0.91 (0.58, 1.44) | 0.35 | 0.90 (0.73, 1.13) | 0.37 | |
| NSMSC | Cases/controls | 198/373 | 139/255 | 30/51 | |||
| OR (95% CI) | 1.0 (ref) | 1.10 (0.83, 1.46) | 1.25 (0.76, 2.06) | 0.34 | 1.11 (0.85, 1.47) | 0.44 | |
| Summer (July, Aug., Sept.) | |||||||
| Both cohortsc | Cases/controls | 113/186 | 217/348 | 99/212 | |||
| OR (95% CI) | 1.0 (ref) | 1.02 (0.75, 1.38) | 0.76 (0.53, 1.09) | 0.14 | 0.82 (0.64, 1.05) | 0.12 | |
| NYUWHS | Cases/controls | 77/121 | 125/190 | 67/148 | |||
| OR (95% CI) | 1.0 (ref) | 1.07 (0.73, 1.56) | 0.69 (0.45, 1.07) | 0.10 | 0.80 (0.60, 1.07) | 0.14 | |
| NSMSC | Cases/controls | 36/65 | 92/158 | 32/64 | |||
| R (95% CI) | 1.0 (ref) | 0.99 (0.59, 1.67) | 0.89 (0.46, 1.70) | 0.72 | 0.88 (0.52, 1.47) | 0.61 | |
aAdjusted for age at menarche (continuous), family history of breast cancer (no or yes), age at first birth/parity (≤ 20, 21-25, 26-30, > 30 years, nulliparous), body mass index (continuous), hormone replacement therapy use (never or ever), and alcohol consumption (continuous). bOdds ratio (OR) for a doubling in 25(OH)D level. cAdjusted for cohort in addition to all factors 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.