Relative proportions of participants ingesting vitamin D supplements during the study and at follow-up.

1Seasonal groupings for winter and spring included data from two time points (i.e. September 2009 and September 2010 for winter and December 2009 and December 2010 for spring).2The relative proportion of participants taking Vitamin D supplements of different doses at the end of different seasons was compared to the relative proportion at the end of Winter (September), estimated using repeated-measures negative binomial regression and expressed as an incidence rate ratio (IRR; 95% confidence intervals; P-values).3Follow-up: at the end of Winter (September) 2011, nine months after the final study time point and after participant were released from restricting vitamin D supplementation (study exclusion criterion was>800 IU/day).

1. 冬、春季节分组纳入了两个时间节点的数据：冬季组对应2009年9月与2010年9月，春季组对应2009年12月与2010年12月。
2. 本研究比较了不同季节结束时服用不同剂量维生素D（Vitamin D）补充剂的受试者相对比例与冬季（9月）结束时的相对比例；分析采用重复测量负二项回归进行估算，结果以发生率比（incidence rate ratio, IRR）、95%置信区间及P值表示。
3. 随访节点设置为2011年9月（冬季末），此时距末次研究时间点已过去9个月，且受试者已解除维生素D补充限制（研究排除标准为每日摄入量＞800国际单位（IU））。