Association between serum 25(OH)D, DBP, and the 25(OH)D:DBP molar ratio, and the risk of colorectal cancer, ATBC Study.

Conditional logistic regression was used for all models. OR = odds ratio; CI = confidence interval.1Cut-points for season specific quartiles (nmol/L): winter = Q1: ≤18.3, Q2: >18.3–≤26.9, Q3: >26.9–≤42.0, Q4: >42.0; summer = Q1: ≤27.0, Q2: >27.0 and ≤38.7, Q3: >38.7–≤53.4, Q4: >53.4.2Conditioned on the matching factors age at randomization and date of blood collection.3Conditioned on the matching factors age at randomization and date of blood collection and adjusted for years of smoking, serum α-tocopherol, serum β-carotene, serum retinol, BMI, height, and physical activity.4Adjusted for factors in model 2 with additional adjustment for quartiles of 25(OH)D or DBP.

所有模型均采用条件logistic回归分析。OR即优势比（odds ratio），CI即置信区间（confidence interval）。
1. 按季节划分的四分位数切点值（单位：纳摩尔每升，nmol/L）：冬季四分位数分组为Q1：≤18.3，Q2：>18.3～≤26.9，Q3：>26.9～≤42.0，Q4：>42.0；夏季四分位数分组为Q1：≤27.0，Q2：>27.0～≤38.7，Q3：>38.7～≤53.4，Q4：>53.4。
2. 以随机入组年龄与采血日期作为匹配因素进行条件校正。
3. 以随机入组年龄与采血日期作为匹配因素进行条件校正，并对吸烟年限、血清α-生育酚、血清β-胡萝卜素、血清视黄醇、体质量指数（BMI）、身高以及体力活动水平进行调整。
4. 在模型2的校正因素基础上，额外对25(OH)D或DBP的四分位数进行校正。