Independent Association of Vitamin D With Physical Function in People With Chronic Spinal Cord Injury

Objective: To explore the relation between vitamin D and physical function outcomes in people with spinal cord injury (SCI).

Design: Cross-sectional study.

Setting: Rehabilitation institute.

Participants: Consecutive patients (N=100; 72 men and 28 women) with chronic SCI admitted to a rehabilitation program.

Interventions: Not applicable.

Main Outcome Measures: Functional independence in activities of daily living (ADL) and leisure time physical activity (LTPA) were assessed as measures of physical function.

Results: Vitamin D deficiency (<20ng/mL) was found in 78 patients: they exhibited a significantly higher body mass index, lower functional independence in ADL, and were engaged in a significantly poorer weekly LTPA. At the linear multiple regression analysis, lower 25-hydroxyvitamin D levels showed significant independent associations with poorer functional independence in ADL (β=.59; 95% confidence interval, .36-.82; P<.0001) and with poorer LTPA (β=2.35; 95% confidence interval, 0.77-3.94; P=.004), after adjustment for other predictors of physical function outcomes selected by univariate analyses.

Conclusions: In people with chronic SCI, a low vitamin D level represents an independent predictor of poor physical function.