Research Review By Dr. Paul Nolet©

Date Posted:

May 2010

Study Title:

The association between a lifetime history of a neck injury in a motor vehicle collision and future neck pain: a population-based cohort study

Authors:

Nolet PS, Côté P, Cassidy JD, Carroll LJ

Author's Affiliations:

Centre of Research Expertise in Improved Disability Outcomes (CREIDO), University Health Network Rehabilitation Solutions, Toronto Western Hospital, Toronto, Canada.

Publication Information:

European Spine Journal 2010; early online release March 7, 2010.

Background Information:

Neck injury in a motor vehicle collision and future neck pain is a controversial topic in the medical literature. Two often cited studies from Lithuania show no association between a rear-end collision and neck pain one year later. Many in this study did not report neck pain after the rear end collision and may not have actually been injured (1, 2). A cohort study from Sweden by Berglund et al. (2000) found that those with a neck injury in a rear-end collision were 2.7 times more likely to experience neck pain often or always 7 years later than those in the control group. In the group that had a rear-end collision but did not report a neck injury, seven years later they were no more likely to have neck pain than the control group (3).

These studies did not control for confounding factors or distinguish between trivial and troublesome neck pain. Therefore, there was a need for a rigorous, population-based cohort study where the association between a lifetime history of neck injury in a motor vehicle collision and future troublesome neck pain could be tested while controlling for confounders.

Pertinent Results:

In this study there was a positive crude association between a history of neck injury in a motor vehicle collision and the development of troublesome neck pain at 6 and/or 12 months (HRR = 2.43; 95% CI 1.28–4.60). Age and gender did not alter this association. However, scores on the bodily pain scale of the SF-36 and BMI slightly reduced the strength of the crude association (HRR = 2.14; 95% CI 1.12–4.10).

Clinical Application & Conclusions:

This analysis provides clinicians with evidence that a past neck injury in a motor vehicle collision may have a significant role in the development of future episodes of pain and disability. The consequences of a neck injury in a motor vehicle collision can have long lasting effects and predispose individuals to experience recurrent episodes of neck pain.
  • This study tested the association between a lifetime history of neck injury in a motor vehicle collision and the development of troublesome neck pain in a cohort from the general population.
  • Those who report a history of a neck injury in a motor vehicle collision are twice as likely to experience a future episode of troublesome neck pain.
  • The results add support to the hypothesis that a lifetime history of neck trauma may predispose individuals to suffer from future episodes of neck pain and disability.

Study Methods:

This study used data from the Saskatchewan Health and Back Pain Survey. The population at risk was 919 subjects with no or mild neck pain at the start of the survey. There were 122 subjects from the population at risk who reported a history of neck injury in a motor vehicle collision. The outcome was troublesome neck pain on the von Korff Chronic Pain Grade Questionnaire (grade II to grade IV). There was a 73.5% (676/919) response rate at 6 months and 63.1% response rate at 12 months.

The study also tested for the confounding effects of demographic characteristics (age, gender, marital status and location of residence), Socioeconomic variables (education, income and employment status), general health (SF36), comorbidities, depression, cigarette smoking, BMI and exercise. Cox Regression was used to test the strength of association between a lifetime history of neck injury in a motor vehicle collision and the onset of troublesome neck pain over the one year follow up of the survey.

Study Strengths / Weaknesses:

This study was a phase III risk study, according to the criteria described in the Bone & Joint Decade 2000-2010, Task Force on Neck Pain and Its Associated Disorders. The study tested the strength of association between a history of neck injury in a motor vehicle collision and the outcome (an episode of troublesome neck pain) while controlling for a variety of confounding factors. The strength of this study was the ability to differentiate between trivial neck pain and more clinically significant troublesome neck pain. This study was also able to look at the issue of temporality.

In an earlier cross-sectional study from the Saskatchewan Health and Back Pain Survey by Côté et al., they were unable to address the issue of temporality. The study was published in Accident Analysis & Prevention (2000) and examined the association between a lifetime history of neck injury in a traffic collision and prevalent neck pain reported in the baseline survey. In this study they did not know when the injury occurred relative to the development of neck pain (4). The current study was able to better address this issue. The outcome of a new episode of troublesome neck pain at six and twelve months follow-up occurred sometime after the reported neck injury in a motor vehicle collision.

This study also had weaknesses. We do not know if those with recurring neck pain prior to the neck injury are more likely to report being injured in a motor vehicle collision. The study also excluded all those in the survey with troublesome neck pain at baseline. This study only looked at subjects that had no or mild neck pain at the start of the survey. In doing so the study may have excluded some subjects that had a recurrence of neck pain during the baseline survey but after a neck injury in a motor vehicle collision. This would mean the results may have underestimated the true effect of neck injury on a future episode of troublesome neck pain.

The study in controlling for baseline bodily pain on the SF-36, may have controlled for a mediator instead of a confounding variable. A mediator is on the causal pathway between the neck injury in a motor vehicle collision and the outcome of troublesome neck pain and does not meet the definition of a confounder. In other words the neck injury can lead to bodily pain which leads to a new episode of troublesome neck pain. This would have caused the results of the study to be underestimated.

Additional References:

  1. Schrader H, Obelieniene D, Bovim G et al. Natural evolution of late whiplash syndrome outside the medicolegal context. Lancet 1996; 347:1207–1211.
  2. Obelieniene D, Schrader H, Bovim G et al. Pain after whiplash: a prospective controlled inception cohort study. J Neurol Neurosurg Psychiatry 1999; 66:279-283.
  3. Berglund A, Alfredsson L, Cassidy JD et al. The association between exposure to a rear-end collision and future neck or shoulder pain: a cohort study. J Clin Epidemiol 2000; 53:1089–1094.
  4. Côté P, Cassidy JD, Carroll LJ. Is a lifetime history of neck injury in a traffic collision associated with prevalent neck pain, headache and depressive symptomatology? Accident Analysis & Prevention 2000; 32:151-159.