Age-Dependent Associations Between 25-Hydroxy Vitamin D Levels and COPD Symptoms: Analysis of SPIROMICS.

Introduction: Age and vitamin D levels may affect symptom burden in chronic obstructive pulmonary disease (COPD). We used the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) to determine independent associations between vitamin D levels and COPD symptoms in different age strata.

Methods: Serum 25-hydroxy (OH)-vitamin D levels were modeled continuously and categorically (<20 ng/ml versus ≥20 ng/ml).