Systemic inflammation and reduced pulmonary function in chronic spinal cord injury.

OBJECTIVE

To evaluate the relationship between systemic inflammation and pulmonary function in persons with chronic spinal cord injury (SCI).

DESIGN

Cross-sectional study.

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

Fifty-nine men with chronic SCI participating in a prior epidemiologic study.

METHODS

Standardized assessment of pulmonary function and measurement of plasma C-reactive protein (CRP) and interleukin-6 (IL-6).

MAIN OUTCOME MEASUREMENTS: Forced expiratory volume in 1 second (FEV(1)) and forced vital capacity (FVC).

RESULTS

Persons with the highest values of IL-6 had the lowest %-predicted FEV(1) and FVC. There was a significant inverse linear trend between quartile of IL-6 and %-predicted FEV(1) (P < .001) and FVC (P < .006), unadjusted and adjusted for SCI level and completeness of injury, obstructive lung disease history, smoking, and body mass index (P = .010-.039). Although not as strong as for IL-6, there also were similar trends for %-predicted FEV(1) and FVC with CRP.

CONCLUSIONS

In chronic SCI, higher levels of IL-6 and CRP were associated with a lower FEV(1) and FVC, independent of level and completeness of injury. These results suggest that the reduction of pulmonary function after SCI is related not only to neuromuscular impairment but also to factors that promote systemic inflammation.