An evidence-based review of aging of the body systems following spinal cord injury

Study design: Systematic review. Objective: To systematically review evidence on aging of the body systems after spinal cord injury (SCI). Setting: Toronto, Ontario and Vancouver, British Columbia, Canada. Methods: Electronic databases (MEDLINE/PubMed, CINAHL, EMBASE and PsycINFO), were searched for studies published between 1980 and 2009. The search was augmented by reviewing the reference lists of relevant papers. Non-intervention studies that were longitudinal or cross-sectional with able-bodied controls that were at minimum matched on chronological age were included for review. Levels of evidence were assigned to the study design using a modified Sackett scale. Results: Of the 74 studies selected for inclusion, 16 were longitudinal in design. The hypothesis that SCI represents a model for premature aging is supported by a large proportion of level 5 evidence for the cardiovascular and endocrine systems, level 2, 4 and 5 evidence for the musculoskeletal system, and limited level 5 evidence for the immune system. Only a few level 4 and 5 studies for the respiratory system were found. The evidence on the genitourinary system, gastrointestinal system, and for skin and subcutaneous tissues provide level 4 and 5 evidence that premature aging may not be occurring. The evidence on the nervous system does not provide evidence of premature aging as a result of SCI. Conclusions: Premature aging appears to occur in some systems after SCI. Additional longitudinal studies are required to confirm these findings. Sponsorship: Rick Hansen Institute; Ontario Neurotrauma Foundation. Spinal Cord (2011) 49, 684-701; doi:10.1038/sc.2010.178; published online 14 December 2010