Aircraft type and other risk factors for spinal disorders: data from 19,673 military cockpit aircrew

Many assume that exposure to flight in high-performance aircraft (HPA) or rotary wing aircraft (RWA) increases the risk of spinal disorders compared to other fixed wing aircraft (FWA). However, this association has yet to be confirmed. This study explores the relationship between flight in different aircraft and the development of lumbar and cervical spine disorders.

The flight records of 19,673 U.S. Air Force (USAF) cockpit aircrew officers were examined for entries with a spinal disorder diagnosis in an existing aircrew health information database. Univariate and multivariate analyses were employed to examine the association between aircraft type, other variables, and spinal disorders.

In stratified analysis of HPA and FWA, but not RWA categories, statistically significant unadjusted associations were observed between flight hours and cervical [HPA: odds ratio (OR) = 2.80, FWA: OR = 4.73] and lumbar disorders (HPA: OR = 2.46, FWA: OR = 3.01). After adjustment for birth year in a stratified multivariate analysis, these associations were no longer statistically significant. In all three aircraft types, statistically significant adjusted associations were observed between older birth year category and both cervical (HPA: OR = 3.82, FWA: OR = 5.88) and lumbar disorders (HPA: OR = 4.16, RWA: OR = 2.96, FWA: OR = 2.39).

The risk produced by exposure to HPA, RWA, or FWA as measured by flight hours may be overshadowed by that produced by birth year, which was the strongest predictor for spinal disorders in this study. Future endeavors should more closely examine the association between age and accrual of flight hours in various aircraft types in order to accurately direct preventive measures.