Alexithymia and 7.5-year incidence of compensated low back pain in 1207 urban public transit operators.

OBJECTIVE

Alexithymia, a lack of emotional awareness, was positively associated with self-reported low back pain (LBP) in cross-sectional studies. We assessed the association of alexithymia with 7.5-year incidence of LBP prospectively in a cohort study of 1207 San Francisco transit operators.

METHODS

Alexithymia was measured by the 20-item Toronto Alexithymia Scale (TAS-20). LBP was assessed by physician-confirmed diagnoses from administrative workers' compensation data. Cox proportional hazards analyses controlled for demographic, behavioral, and physical and psychosocial job factors measured by questionnaire and interview.

RESULTS

Of all drivers, 27.7% (n=334) filed compensated claims for LBP injuries with workers' compensation insurance during the 7.5-year observation time. The hazard ratios from the fully adjusted model were 0.73 (0.56-0.96) for the TAS-20 scale and 0.82 (0.69-0.98) for the subscale "difficulty describing feelings." Alexithymia scores did not predict the duration of compensated work disability.

CONCLUSION

In contrast to previous cross-sectional positive associations between alexithymia and LBP, alexithymia is negatively associated with compensated LBP claims. We hypothesize that shame and reporting behavior may explain these inconsistent results.