Abstract
CONTEXT/OBJECTIVE: Individuals with chronic spinal cord injury (SCI) have an increased risk of morbidity and mortality attributable to respiratory diseases. Previous studies in non-SCI populations suggest that vitamin D may be a determinant of respiratory health. Therefore, we sought to assess if lower vitamin D levels were associated with decreased pulmonary function in persons with chronic SCI. DESIGN: Cross-sectional study. SETTING: Veterans Affairs Medical Center. PARTICIPANTS: 312 participants (260 men and 52 women) with chronic SCI recruited from VA Boston and the community participating in an epidemiologic study to assess factors influencing respiratory health. METHODS: Participants provided a blood sample, completed a respiratory health questionnaire, and underwent spirometry. Linear regression methods were used to assess cross-sectional associations between plasma 25-hydroxyviatmin D and spirometric measures of pulmonary function. OUTCOME MEASURES: Forced expiratory volume in one second (FEV(1)), forced vital capacity (FVC), and FEV(1)/FVC. RESULTS: Adjusted and unadjusted for a number of confounders, there was no significant association between plasma vitamin D levels and FEV(1), FVC, or FEV(1)/FVC. For example, in fully adjusted models, each 10 ng/ml increase in vitamin D was associated with a 4.4 ml (95%CI -64.4, 73.2, P = 0.90) ml change in FEV(1.) Conclusion: There was no significant cross-sectional association between plasma vitamin D and FEV(1), FVC, or FEV(1)/FVC in this cohort of individuals with chronic SCI.