With increasing numbers of randomized controlled trials (RCTs) investigating potential health events of vitamin D supplementation, a better understanding is required of the risk factors for adverse events and for study withdrawals. This analysis aimed to identify baseline risk factors of reporting an adverse event in a multi-year randomized double-blinded placebo-controlled trial of vitamin D supplementation. The secondary aim was to investigate if adverse events were associated with study withdrawals. We analyzed data from the Vitamin D Assessment (ViDA) study: 5110 adults, aged 50-84 years, living in Auckland, New Zealand. Monthly doses of 100,000 IU vitamin D3 or placebo were mailed to participants homes, with a questionnaire to collect data on adverse events and adherence to the study capsule (initially monthly, then 4-monthly). Median follow-up was 3.3 years. Data were analysed using multivariable log-binomial regression and Cox-regression. During the follow-up period, 818 people reported adverse events and 412 withdrew or stopped returning questionnaires. Vitamin D was not associated with reporting of adverse events. Of sociodemographic factors, ethnicity was associated with reporting adverse events: compared to European participants, Maori and Pacific Islander people were more likely to report an adverse event. Non-smokers were more likely to report an adverse event, compared to smokers (adjusted hazard ratio (HR) = 1.80; 95%CI = 1.24, 2.62); as were those who had reported a history of depression (adjusted HR = 1.27; 95%CI = 1.01, 1.60) or a recent cough or cold (adjusted HR = 1.22; 95%CI = 1.03, 1.44) at baseline. Reporting of adverse events was not associated with withdrawals (adjusted HR = 1.12; 95%CI = 0.86, 1.46). These data did not identify any clear pattern in the factors associated with self-reported adverse events, which themselves did not increase risk of withdrawals.

中文翻译：

---

在一项基于人群的维生素D补充试验中，报告不良事件和退出研究的危险因素。

随着越来越多的随机对照试验（RCT）调查补充维生素D的潜在健康事件，需要对不良事件和退出研究的危险因素有更好的了解。这项分析的目的是在一项为期多年的补充维生素D的随机双盲安慰剂对照试验中，确定报告不良事件的基线风险因素。次要目的是调查不良事件是否与研究退出有关。我们分析了维生素D评估（ViDA）研究的数据：5110名年龄在50-84岁的成年人，居住在新西兰的奥克兰。将每月剂量为100,000 IU的维生素D3或安慰剂邮寄到参与者家中，并附有调查表以收集有关不良事件和对研究胶囊的依从性的数据（最初是每月一次，然后是4个月一次）。中位随访时间为3。3年。使用多变量对数二项式回归和Cox回归分析数据。在随访期间，有818人报告了不良事件，有412人撤回或停止返回问卷。维生素D与不良事件的报告无关。在社会人口统计学因素中，种族与不良事件的报告有关：与欧洲参与者相比，毛利人和太平洋岛民的人更有可能报告不良事件。与吸烟者相比，非吸烟者更有可能报告不良事件（调整后的危险比（HR）= 1.80； 95％CI = 1.24，2.62）；基线时曾有抑郁史（调整后的HR = 1.27； 95％CI = 1.01，1.60）或最近咳嗽或感冒（调整后的HR = 1.22； 95％CI = 1.03，1.44）的患者也是如此。不良事件的报告与停药无关（校正后的HR = 1.12； 95％CI = 0.86，1.46）。这些数据并未在与自我报告的不良事件相关的因素中识别出任何明确的模式，这些因素本身并没有增加退出的风险。