What characterizes individuals developing chronic whiplash?: The Nord-Trøndelag Health Study (HUNT)

Abstract

Objective

Most individuals experiencing whiplash accidents recover rapidly. A considerable proportion, however, develop chronic symptoms. Psychological factors may slow recovery, possibly by increasing the likelihood of other symptoms being misattributed to, and amplified by the whiplash injury. We aimed to investigate how pre-injury mental and somatic symptoms, self-rated health, use of health-services and medications, health-behavior and socio-demographics predict the development of chronic whiplash.

Methods

Data from two waves of a large, population based study (HUNT2 (baseline) and HUNT3) were used. Individuals reporting no whiplash at baseline were identified in HUNT3. Characteristics reported at baseline were compared between those who had developed chronic whiplash in HUNT3 (n = 199) and those who had not (n = 20,600), using Pearson's chi-squared tests, independent sample t-tests and logistic regression analyses.

Results

Individuals developing chronic whiplash reported worse baseline health than those reporting no chronic whiplash. Poor self-rated health was a strong risk factor for subsequent chronic whiplash (OR = 2.26, 95%CI: 1.68–3.04). Musculoskeletal pain also increased the risk (OR = 1.21, 95%CI: 1.15–1.26), as did diffuse somatic symptoms (OR = 2.09, 95%CI: 1.47–2.96), use of different health services (OR = 1.31, 95%CI: 1.19–1.45), high use of medications (OR = 1.28, 95%CI: 1.14–1.43) and symptoms of anxiety (OR = 1.93, 95%CI: 1.39–2.68). Physical activity was protective (OR = 0.67, 95%CI: 0.49–0.91). Most socio-demographic variables were not significantly associated with chronic whiplash.

Conclusion

Poor somatic and mental pre-injury health increased the risk of subsequent chronic whiplash. This suggests that chronic whiplash is not merely an organic disorder, and highlights the importance of individual expectations, symptom reattribution and amplification in development of chronic whiplash.

Introduction

Whiplash is a common term used to describe injuries of the neck usually associated with motor vehicle rear end collisions [1], [2]. Whiplash injuries are generally considered uncomplicated soft tissue injuries — fractures and dislocations are excluded [3]. Most patients who experience whiplash injuries recover within a few weeks [1], [4], [5]. However, a considerable proportion of patients develop chronic whiplash with continued disabling symptoms after six months [1], [3], [4], [6], [7].

It has been proposed that psychological factors may slow recovery [8] — possibly by increasing the likelihood of other symptoms being misattributed to the whiplash injury [9]. Patients with chronic whiplash report higher levels of anxiety and depression than the general population [10], [11]. They also report more head and neck pain [12], [13], [14], [15], [16] and more somatic symptoms from body areas not affected by a neck trauma; like gastrointestinal symptoms, palpitations, shortness of breath and sleep disturbances [12], [15], [17], [18], [19], [20].

An experimental study using placebo rear-end collisions found that 20% of participants reported a whiplash injury 1–3 days after the “accident” [21]. Further, symptom reporting was more common among participants with greater levels of self-reported emotional distress and health concerns before the “accident” [21]. Reviews of psychological risk factors in back and neck pain have also confirmed the association between psychological distress, anxiety and depression and the chronicity of neck and back injuries [22], [23].

The fact that recovery from whiplash and prognosis seems to vary strongly by country also highlights the role of psychological expectations in recovery. Low rates of continuing disability following whiplash injury have been found in Greece, Germany and Lithuania. In Norway and North America where, it has been argued, the populations are more aware of whiplash following car accidents and have expectations of continuing symptoms following the injury, high rates have been found [24]. A recent Swedish study found a strong relationship between expectations of recovery measured soon after the whiplash injury and disability at six months [25]. Individuals who did not expect to fully recover were more likely to be disabled at follow-up.

The disentangling of the role of psychological factors in whiplash injury disability is difficult in cross-sectional research and even in longitudinal studies where data is not collected prior to the accident. Recently, work using large epidemiological datasets has allowed the examination of how prognostic variables collected before the whiplash injury influence recovery trajectories.

In this study, we used data from two waves of a large, population based Norwegian study (HUNT2 and HUNT3) to investigate how prior perceived health, use of health-services, health behavior, musculoskeletal complaints, diffuse somatic symptoms, previous medical diagnoses as well as depression and anxiety predicted development of chronic whiplash. Based on previous cross-sectional studies we hypothesized that previous symptom complaints and anxiety and depression in particular would be associated with the development of a chronic whiplash condition.