Ageing with spinal cord injury: cross-sectional and longitudinal effects

Study design: Longitudinal and cross-sectional. Objective: To determine whether, for studies of ageing with a spinal cord i njury, the cross-sectional differences in outcomes across both age and year s post injury (YPI) differ from the longitudinal change. Setting: Two SCI centres in England: the National Spinal Injuries Centre in Aylesbury, and the Regional Spinal Injuries Centre in Southport. Methods: A total of 315 people who sustained spinal cord injuries prior to 1971 underwent comprehensive health and psychosocial status interviews at o ne or more of the study assessments (1990, 1993, 1996, and 1999). A range o f continuous and dichotomous outcomes was analyzed to detect both cross-sec tional differences by age and average individual changes over multiple meas urements. Results: Frequently, outcomes changed longitudinally without showing any cr oss-sectional differences. Cross-sectional age was more commonly associated with the worsening of a condition while cross-sectional YPI was commonly a ssociated with improvement. After controlling for cross-sectional effects, psychological measures generally showed minor deterioration, measures of co mmunity integration both improved and deteriorated, upper extremity pain in creased, lower enxtremity pain decreased, and participants tended to quit s moking. Conclusion: Using longitudinal findings that control for cross-sectional di fferences produces a more complete description of ageing with a spinal cord injury.