Pre-injury health-related factors in relation to self-reported whiplash: longitudinal data from the HUNT study, Norway

Abstract

To examine if pre-injury health-related factors are associated with the subsequent report of whiplash, and more specifically, both whiplash and neck pain. Longitudinal population study of 40,751 persons participating in two consecutive health surveys with 11 years interval. We used logistic regression to estimate odds ratio (OR) for reporting whiplash or whiplash with neck pain lasting at least 3 months last year, related to pre-injury health as indicated by subjective health, mental and physical impairment, use of health services, and use of medication. All associations were adjusted for socio-demographic factors. The OR for reporting whiplash was increased in people reporting poor health at baseline. The ORs varied from 1.47 (95% CI 1.13-1.91) in people visiting a general practitioner (GP) last year to 3.07 (95% CI 2.00-4.73) in people who reported poor subjective health. The OR associated with physical impairment and mental impairment was 2.69 (95% CI 1.75-4.14) and 2.49 (95% CI 1.31-4.74), respectively. Analysis of reporting both whiplash and neck pain gave somewhat stronger association, with ORs varying from 1.50 (95% CI 1.07-2.09) in people visiting a GP last year to 5.70 (95% CI 3.18-10.23) in people reporting poor subjective health. Physical impairment was associated with an OR of 3.48 (95% CI 2.12-5.69) and mental impairment with an OR of 3.02 (95% CI 1.46-6.22). Impaired self-reported pre-injury health was strongly associated with the reporting of a whiplash trauma, especially in conjunction with neck pain. This may indicate that individuals have, already before the trauma, adopted an illness role or behaviour which is extended into and influence the report of a whiplash injury. The finding is in support of a functional somatic disorder model for whiplash.