INTRODUCTION The relationship between 25-hydroxy-vitamin D (25-OH-vitamin D) and COPD outcomes remains unclear. Using the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS), we determined associations between baseline 25-OH-vitamin D and cross-sectional and longitudinal lung function and COPD exacerbations. METHODS Serum 25-OH-vitamin D level was measured in stored samples from 1609 SPIROMICS participants with COPD. 25-OH-vitamin D levels were modeled continuously and dichotomized as deficient (<20 ng/ml) vs. not deficient (≥20 ng/ml). Outcomes of interest included %-predicted FEV1 (current and one-year longitudinal decline) and COPD exacerbations (separately any and severe, occurring in prior year and first year of follow-up). RESULTS Vitamin D deficiency was present in 21% of the cohort and was more prevalent in the younger-aged, active smokers, and African-Americans. Vitamin D deficiency was independently associated with 4.11 lower FEV1 %-predicted at enrollment (95% CI -6.90 to -1.34 %-predicted, P=0.004), 1.27 %-predicted greater rate-of-FEV1-decline after one year (95% CI -2.32 to -0.22 %-predicted/yr; P=0.02), and higher odds of any COPD exacerbation in the prior year (OR 1.32; 95% CI 1.00-1.74; P=0.049). Each 10 ng/ml decrease in 25-OH-vitamin D was associated with lower baseline lung function [-1.27 %-predicted (95% CI -2.32 to -0.22 %-predicted); P=0.02] and increased odds of any exacerbation in the year prior to enrollment [OR 1.11 (95% CI 1.01-1.22); P=0.04]. INTERPRETATION Vitamin D deficiency is associated with worse cross-sectional and longitudinal lung function and increased odds of prior COPD exacerbations. These findings identify 25-OH-vitamin D levels as a potentially useful marker of adverse COPD-related outcomes.

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25-羟基维生素 D 水平、肺功能和 COPD 恶化结果之间的关联：SPIROMICS 队列分析

简介 25-羟基维生素 D (25-OH-维生素 D) 与 COPD 结局之间的关系仍不清楚。利用 COPD 研究 (SPIROMICS) 中的亚群和中间结果测量，我们确定了基线 25-OH-维生素 D 与横断面和纵向肺功能以及 COPD 恶化之间的关联。方法 测量 1609 名患有 COPD 的 SPIROMICS 参与者的储存样本中的血清 25-OH-维生素 D 水平。25-OH-维生素 D 水平连续建模并分为缺乏 (<20 ng/ml) 和不缺乏 (≥20 ng/ml)。感兴趣的结果包括预测的 FEV1 百分比（当前和一年的纵向下降）和 COPD 恶化（分别为任何和严重，发生在前一年和随访第一年）。结果 21% 的人群存在维生素 D 缺乏症，并且在年轻人、活跃吸烟者和非裔美国人中更为普遍。维生素 D 缺乏与入组时 4.11 较低的 FEV1 % 预测独立相关（95% CI -6.90 至 -1.34 % 预测，P=0.004），1.27 % 预测一年后 FEV1 下降率较高（95 % CI -2.32 至 -0.22 % 预测/年；P=0.02），并且前一年任何 COPD 恶化的几率较高（OR 1.32；95% CI 1.00-1.74；P=0.049）。25-OH-维生素 D 每减少 10 ng/ml 与基线肺功能降低相关[-1.27%-预测（95% CI -2.32 至 -0.22%-预测）；P=0.02]并且入组前一年内任何恶化的几率增加[OR 1.11 (95% CI 1.01-1.22)；P=0.04]。解释 维生素 D 缺乏与横断面和纵向肺功能较差以及先前 COPD 恶化的几率增加有关。这些发现将 25-OH-维生素 D 水平确定为 COPD 相关不良后果的潜在有用标志。