Associations between vitamin D and pulmonary function in chronic spinal cord injury.

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), forced vital capacity (FVC), and FEV/FVC.

RESULTS

Adjusted and unadjusted for a number of confounders, there was no significant association between plasma vitamin D levels and FEV, FVC, or FEV/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 Conclusion: There was no significant cross-sectional association between plasma vitamin D and FEV, FVC, or FEV/FVC in this cohort of individuals with chronic SCI.