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

Abstract

The objective of this population-based cohort study was to investigate the association between a lifetime history of neck injury from a motor vehicle collision and the development of troublesome neck pain. The current evidence suggests that individuals with a history of neck injury in a traffic collision are more likely to experience future neck pain. However, these results may suffer from residual confounding. Therefore, there is a need to test this association in a large population-based cohort with adequate control of known confounders. We formed a cohort of 919 randomly sampled Saskatchewan adults with no or mild neck pain in September 1995. At baseline, participants were asked if they ever injured their neck in a motor vehicle collision. Six and twelve months later, we asked about the presence of troublesome neck pain (grade II-IV) on the chronic pain grade questionnaire. Multivariable Cox regression was used to estimate the association between a lifetime history of neck injury in a motor vehicle collision and the onset of troublesome neck pain while controlling for known confounders. The follow-up rate was 73.5% (676/919) at 6 months and 63.1% (580/919) at 1 year. We found a positive association between a history of neck injury in a motor vehicle collision and the onset of troublesome neck pain after controlling for bodily pain and body mass index (adjusted HRR = 2.14; 95% CI 1.12-4.10). Our analysis suggests that a history of neck injury in a motor vehicle collision is a risk factor for developing future troublesome neck pain. 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.

Full text

ORIGINAL ARTICLE
The association between a lifetime history of a neck injury
in a motor vehicle collision and future neck pain:
a population-based cohort study
Paul S. Nolet •Pierre Co
ˆte
´•J. David Cassidy •
Linda J. Carroll
Received: 26 September 2009 / Accepted: 11 February 2010 / Published online: 7 March 2010
ÓSpringer-Verlag 2010
Abstract The objective of this population-based cohort
study was to investigate the association between a lifetime
history of neck injury from a motor vehicle collision and
the development of troublesome neck pain. The current
evidence suggests that individuals with a history of neck
injury in a traffic collision are more likely to experience
future neck pain. However, these results may suffer from
residual confounding. Therefore, there is a need to test this
association in a large population-based cohort with ade-
quate control of known confounders. We formed a cohort
of 919 randomly sampled Saskatchewan adults with no or
mild neck pain in September 1995. At baseline, partici-
pants were asked if they ever injured their neck in a motor
vehicle collision. Six and twelve months later, we asked
about the presence of troublesome neck pain (grade II–IV)
on the chronic pain grade questionnaire. Multivariable Cox
regression was used to estimate the association between a
lifetime history of neck injury in a motor vehicle collision
and the onset of troublesome neck pain while controlling
for known confounders. The follow-up rate was 73.5%
(676/919) at 6 months and 63.1% (580/919) at 1 year. We
found a positive association between a history of neck
injury in a motor vehicle collision and the onset of trou-
blesome neck pain after controlling for bodily pain and
body mass index (adjusted HRR =2.14; 95% CI 1.12–
4.10). Our analysis suggests that a history of neck injury in
a motor vehicle collision is a risk factor for developing
future troublesome neck pain. 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.
Keywords Neck pain Whiplash Epidemiology 
Risk Cohort
Introduction
Whiplash is an acceleration–deceleration mechanism of
energy transfer to the neck that occurs in motor vehicle
collisions [10,24]. The trauma can lead to whiplash-
associated disorders (WAD), which includes neck pain and
other symptoms such as headache, dizziness, and upper
extremity numbness [24]. As many as 83% of individuals
involved in traffic collisions suffer from whiplash injuries
[10,24,26]. Consequently, WAD is a common source of
pain, disability, and health care utilization in the Western
world.
P. S. Nolet J. D. Cassidy
Centre of Research Expertise in Improved Disability Outcomes
(CREIDO), University Health Network Rehabilitation Solutions,
Toronto Western Hospital, Toronto, Canada
P. S. Nolet
Public Health Program, Lakehead University,
Thunder Bay, Canada
P. Co
ˆte
´J. D. Cassidy
Division of Epidemiology, Dalla Lana School of Public Health,
University of Toronto, Toronto, Canada
P. Co
ˆte
´J. D. Cassidy
Division of Health Care and Outcomes Research,
Toronto Western Research Institute, Toronto, Canada
L. J. Carroll
Department of Public Health Sciences, The Alberta Centre
for Injury Control and Research, School of Public Health,
University of Alberta, Alberta, Canada
P. S. Nolet (&)
86 Dawson Road, Unit 3, Guelph, ON N1H 1A8, Canada
e-mail: pnolet@rogers.com; pnolet@uhnresearch.ca
123
Eur Spine J (2010) 19:972–981
DOI 10.1007/s00586-010-1344-7

The recently published report of the Bone and Joint
Decade 2000–2010 Task Force on Neck Pain and its
Associated Disorders found that a significant proportion of
patients with WAD develop persistent or recurrent neck
pain. Specifically, more than 50% of patients report neck
pain 1 year after their injury [9]. Recovery from WAD is
negatively associated with initial symptom severity, post-
injury psychological distress, passive coping, and the
intense initial health care utilization [9].
It has been proposed that individuals with a history of
whiplash injuries are more likely to suffer from future
episodes of musculoskeletal pain, including neck pain, than
those without a history of whiplash injuries. This associa-
tion is supported by five studies conducted in various
source populations [4,7,11,15,16]. However, two
Lithuanian studies of individuals sampled from police
records did not support this association [18,23]. The
varying evidence reported in the literature is likely attri-
butable to the differences in study samples, exposure and
outcome definition and measurement, and to inadequate
control of confounding. Therefore, there is a need for a
rigorous, population-based cohort study where the associ-
ation between a lifetime history of neck injury in a motor
vehicle collision and future neck pain can be tested with
good control of confounding factors. The objective of this
study was to determine whether a lifetime history of neck
injury in a motor vehicle collision is associated with an
incident episode of troublesome neck pain.
Methods
Study design and source population
We used data from the Saskatchewan Health and Back Pain
Survey, a population-based mailed survey of the distribu-
tion, determinants, and risks of spinal disorders in the
province of Saskatchewan [11]. Saskatchewan is a Cana-
dian province of approximately one million inhabitants that
provides universal health care coverage. Eligible for the
study were Saskatchewan residents between the ages of 20
and 69 who held a valid Health Services card on August 31,
1995. Excluded were inmates of correctional facilities,
residents under the Office of the Public Trustee, foreign
students and workers holding employment or immigration
visas, and residents of special care homes [8].
An age-stratified random sample of residents was
selected from the Saskatchewan Health Insurance Regis-
tration File. The Health Insurance Registration File is a
representative and complete list of Saskatchewan residents
that includes more than 99% of the population. Saskatch-
ewan Health randomly selected the participants and mailed
all surveys to protect the confidentiality of the participants.
Participation was voluntary. The University of Saskatche-
wan Advisory Committee on Ethics in Human Experi-
mentation approved the Saskatchewan Health and Back
Pain Survey, and the analysis presented in this paper was
approved by the University Health Network Research
Ethics Board, Toronto, Canada.
Study sample and population at risk
Of the eligible 593,464 individuals, 2,184 were randomly
selected. One-hundred nineteen baseline questionnaires
were returned due to mailing errors, five because of ‘health
reasons’, four individuals had emigrated and one had died.
Of the 2,055 remaining participants, 1,133 (55.1%) returned
baseline questionnaires. Two questionnaires were com-
pleted by participants outside of the pre-determined age
range, and 30 participants did not complete the neck pain
questionnaire. Therefore, the eligible sample for this ana-
lysis includes 1,101 participants. A comparison of the eli-
gible population and the randomly selected sample revealed
no important differences in age, gender, and geographic
location of residence. However, a comparison of partici-
pants and non-participants suggested that older individuals,
women, those married, and those with intense non-disabling
neck pain were slightly more likely to participate [8].
The population at risk for this analysis includes indi-
viduals who reported grade 0 or I neck pain on the chronic
pain grade questionnaire (Table 1). This information was
collected in the baseline questionnaire. Given that most
individuals suffer from mild (trivial) neck pain annually,
we were interested in determining whether neck injury in a
motor vehicle collision was a risk factor for significant
neck problems.
Data collection
The baseline data were collected in September 1995, and
the follow-up data collected 6 and 12 months later. The
6-month follow-up questionnaire was sent to respondents
of the baseline questionnaire, and the 12-month follow-up
to respondents of the 6-month follow-up.
Table 1 Classification of neck pain grade (as reproduced from Co
ˆte
´
et al. [11])
Grade Scoring Interpretation
0 No pain, no disability No chronic pain
IPI\50; DP \3 Low pain intensity/low disability
II PI C50; DP \3 High pain intensity/low disability
III DP =3–4 High disability/moderately limiting
IV DP =5–6 High disability/severely limiting
PI pain intensity; DP disability points
Eur Spine J (2010) 19:972–981 973
123

Exposure
The exposure was measured by asking participants: ‘‘Have
you ever injured your neck in a motor vehicle accident?’’
Outcome
Neck pain was measured with the chronic pain question-
naire at baseline, and 6 and 12 months later. The ques-
tionnaire measures the 6-month period prevalence of neck
pain, and grades neck pain and its related disability into
five ordered categories, based on seven questions and has
been described elsewhere [11,28]. The instrument has
good psychometric properties [14]. Participants reporting
grade II, III or IV neck pain in the previous 6 months were
classified as having troublesome neck pain.
Potential confounders
The following potential confounders were identified a pri-
ori: demographic characteristics (age, gender, marital sta-
tus, and location of residence), socioeconomic variable
(education, income, and employment status), general health
(SF36), comorbidities, depression, cigarette smoking, BMI,
and exercise. We did not test the confounding effect of
baseline neck pain grade (grade 0 or I) because it lies on
the casual pathway between our exposure of a neck injury
in a motor vehicle collision and outcome of troublesome
neck pain. As such, it is an intermediate variable and does
not meet the definition of a confounder.
Socio-demographics
Gender, age, marital status, education level, income,
employment status, and location of residence (city, town,
village, rural municipality, and Indian Reserve) were
included in the analysis.
Health-related quality of life (SF36)
The Medical Outcomes Study SF-36 standard English-
Canadian version 1.0 was used to measure self-perceived
general health status [30]. The questionnaire assesses health-
related quality of life in eight domains: physical functioning,
bodily pain, role limitations due to physical health problems,
role limitations due to emotional health, mental health,
social functioning, vitality, and general health. The SF-36
has been shown to have high internal consistency [6] and
test–retest reliability [1]. The SF-36 has been shown to have
good validity in studies involving physical and mental health
criteria when compared to the longer questionnaire used in
the Medical Outcomes Study [29].
Comorbidities
The presence of comorbidities and their self-perceived
impact on health were measured with the comorbidity
questionnaire. The questionnaire includes questions about
allergies, arthritis, high blood pressure, heart/circulation,
digestive disorders, headache, and mental/emotional dis-
orders. The self-perceived impact of each comorbidity on
one’s health is rated on a 4-point ordinal scale as: (1) not at
all, (2) mild, (3) moderate, and (4) severe. The question-
naire has been shown to have good test–retest reliability
(ICC =0.93) and adequate face, concurrent, and conver-
gent validity [20,27].
Depressive symptomatology
The Center for Epidemiological Studies Depression scale
(CES-D) was used to measure depressive symptomatology
[19]. This questionnaire has a possible score of 60 with
16 as the cutoff score for depression in the general popu-
lation. The 16-point cutoff for depressive symptomatology
had a sensitivity of 100% for major depression and 88%
for the specificity [2]. The questionnaire has been shown
to be reliable and valid in various populations with good
internal consistency (alpha coefficients [0.85) [5,13,19,
20].
Exercise
Exercise frequency was measured with a question asking
the average number of days per week participating in a
minimum of 30 min of exercise. The question asked about
the frequency of exercise during the previous 6 months.
Cigarette smoking
Self-report of smoking status was obtained and categorized
as non-smoker, ex-smoker or current smoker.
Body mass index
Self-reported height and weight were used to calculate the
body mass index (BMI, kg/m
2
).
Analysis
We described the baseline characteristics of the sample
stratified by exposure status. We aimed to determine
whether loss to follow-up led to attrition bias by comparing
responders and non-responders to the 6 and 12-month
follow-ups by comparing the baseline characteristics of
exposed and non-exposed participants.
974 Eur Spine J (2010) 19:972–981
123

Our objective was to determine whether a history of
neck injury in a motor vehicle collision is independently
associated with the development of troublesome neck pain.
However, identifying confounders of the association
between a lifetime history of neck injury in a traffic col-
lision and troublesome neck pain is challenging. The dif-
ficulty lies in insuring that the variables considered as
potential confounders are indeed confounders and not
mediators of the association of interest. A mediator is an
intermediate effect of the exposure, and lies on the causal
pathway between the exposure and the outcome.
We built Cox proportional hazard models to measure the
association between a history of neck injury in a motor
vehicle collision and troublesome neck pain. Our modeling
included three steps. First, we built a univariate model to
estimate the crude association between our exposure and
outcome. Second, we built as series of bivariate models to
determine which variables were confounders of the asso-
ciation of interest. Variables that led to a 10% change in the
exposure regression coefficient were deemed to be con-
founders and included in the final model. Finally, our final
model included the exposure and all confounders identified
in the second step [22]. SPSS version 15 was used for the
analysis [25].
Results
Sample characteristics
Our population at risk included 919 participants. The fol-
low-up rate was 73.5% (676/919) at 6 months and 63.1%
(580/919) at 12 months.
Of the 919 eligible adults with grade 0 or I neck pain
at baseline, 122 (13.3%) reported a history of neck
injury in a motor vehicle collision. Fewer participants
with a history of neck injury in a motor vehicle collision
were married and a higher percentage lived in urban
Saskatchewan. A higher proportion of exposed than
unexposed individuals reported a household income of
less than $20,000 and fewer reported incomes over
$60,000. Further, more participant with a history of neck
injury worked part time or were unemployed, but fewer
were retired. With the exception of hypertension and low
back pain, all comorbidities were more common among
participants with a history of neck injury in a motor
vehicle collision. Further, the self-perceived impact of
comorbidities was more pronounced in individuals who
had a neck injury in a motor vehicle collision. Exposed
subjects (70.5%) were more likely to suffer from grade I
neck pain than unexposed (41.4%). The proportion of
current smokers was higher in the exposed group
(Table 2).
Attrition
In the group not exposed to a neck injury in a motor vehicle
collision, response to the follow-up survey was positively
associated with female gender. In the exposed group, non-
response to the follow-up survey was positively associated
with increased depression and headaches that moderately
to severely impact their health (Tables 3,4).
Association between history of neck injury in a motor
vehicle collision and troublesome neck pain
We found a positive crude association between a history of
neck injury in a motor vehicle collision and the develop-
ment 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 mildly reduced the strength of
the crude association (HRR =2.14; 95% CI 1.12–4.10).
Discussion
Our survey was the first North American cohort study to
investigate the association between a lifetime history of
neck injury resulting from a motor vehicle collision and the
development of troublesome neck pain. Our results suggest
that the incidence of troublesome neck pain is higher in
individuals who have a history of neck injury in a motor
vehicle collision.
Our study has limitations. Neck pain follows a recurrent
course and that risk factors for future episodes, such as
motor vehicle collisions, may have a mediating effect on
the incidence of pain and disability in those with a prior
history of neck pain. Future studies need to test this
hypothesis.
Our exposure, neck injury in a motor vehicle collision,
could suffer from differential misclassification. It is pos-
sible that participants with recurrent neck pain were more
likely to remember an injury in a traffic collision than those
who remained free of neck pain. However, we believe that
this bias had minimal impact on our results because it is
likely that all participants would remember an event such
as being injured in a motor vehicle collision. Data from two
studies support the view that individuals can recall injuries
sustained in a recent motor vehicle collision. Self-reported
motor vehicle collision injuries 12 months earlier in the
Canadian National Population Health Survey were not
significantly different from the police reported data from
Transport Canada [21]. Moreover, in a small sample of
young adults, self-reported injury over the previous 3 years
was comparable to hospital discharge file data and police
motor vehicle collision reports [3].
Eur Spine J (2010) 19:972–981 975
123

Table 2 Frequency distribution of the demographic socioeconomic
characteristics, comorbidities, and health-related characteristics by
exposure category at baseline
Characteristic History of neck injury
in motor vehicle collision
Yes (%) No (%)
Age (years) [mean (SD)] 42.0 (12.3) 44.9 (14.4)
Gender (no., %)
Male 45 (36.8) 406 (50.9)
Female 77 (63.2) 391 (49.1)
Marital status (no., %)
Married 86 (71.7) 605 (76.6)
Divorced 14 (11.6) 49 (6.2)
Widowed 3 (2.5) 20 (2.5)
Single 18 (14.9) 116 (14.7)
Location of residence (no., %)
Urban 65 (53.3) 278 (35.0)
Rural 57 (46.7) 517 (65.0)
Annual household income (no., %)
$0–20,000 27 (23.7) 140 (19.1)
$20,001–40,000 38 (33.3) 263 (35.8)
$40,001–60,000 28 (24.6) 171 (23.3)
Over $60,000 21 (18.4) 160 (21.8)
Education (no., %)
Less than grade 8 7 (5.8) 44 (5.6)
High school 29 (24.0) 171 (21.6)
High-school grade 36 (29.8) 207 (26.2)
Post-secondary 36 (29.8) 248 (31.4)
University grade 13 (10.7) 120 (15.2)
Full time worker (no., %)
Yes 60 (50.0) 408 (51.8)
No 60 (50.0) 380 (48.2)
Part time worker (no., %)
Yes 22 (18.3) 118 (15.0)
No 98 (81.7) 669 (85.0)
Unemployed (no., %)
Yes 11 (9.2) 38 (4.8)
No 109 (90.8) 750 (95.2)
Retired (no., %)
Yes 3 (2.5) 106 (13.5)
No 117 (97.5) 682 (86.5)
Homemaker (no., %)
Yes 23 (19.2) 134 (17.0)
No 97 (80.8) 654 (83.0)
Student (no., %)
Yes 7 (5.8) 30 (3.8)
No 113 (94.2) 758 (96.2)
Comorbidities
Allergy
Absent 57 (47.1) 472 (60.8)
No/Min impact on health 45 (37.2) 227 (29.3)
Table 2 continued
Characteristic History of neck injury
in motor vehicle collision
Yes (%) No (%)
Mod./Sev. impact on health 19 (15.7) 77 (9.9)
Arthritis
Absent 85 (71.4) 579 (75.1)
No/Min impact on health 17 (14.3) 129 (16.7)
Mod./Sev. impact on health 17 (14.3) 63 (8.2)
Breathing disorders
Absent 80 (66.7) 565 (72.4)
No/Min impact on health 29 (24.2) 169 (21.7)
Mod./Sev. impact on health 11 (9.2) 46 (5.9)
Cardiovascular disorders
Absent 98 (80.3) 687 (87.9)
No/Min impact on health 19 (15.6) 74 (9.5)
Mod./Sev. impact on health 5 (4.1) 21 (2.7)
Hypertension
Absent 103 (85.1) 666 (85.4)
No/Min impact on health 13 (10.7) 84 (10.8)
Mod./Sev. impact on health 5 (4.1) 30 (3.8)
Digestive disorders
Absent 88 (73.9) 596 (76.0)
No/Min impact on health 18 (15.1) 141 (18.0)
Mod./Sev. impact on health 13 (10.9) 47 (6.0)
Low back pain
Absent 31 (25.8) 254 (32.3)
Low intensity/low disability 68 (56.7) 394 (50.1)
High intensity/low disability 8 (6.7) 81 (10.3)
High disability 13 (10.8) 57 (7.3)
Depressive symptomatology
Absent 90 (75.6) 628 (83.0)
Present 29 (24.4) 129 (17.0)
Cigarette smoking
Never smoked 53 (44.9) 417 (54.0)
Past smoker 31 (26.3) 191 (24.7)
Current smoker 34 (28.8) 164 (21.2)
Body mass index (kg/m
2
)—quartiles
[28.71 31 (26.1) 196 (25.2)
25.77–28.71 28 (23.5) 203 (26.1)
23.42–25.76 32 (26.9) 186 (23.9)
B23.41 28 (23.5) 193 (24.8)
General health [Mean (SD)] 63.7 (14.5) 65.3 (12.6)
No. of days of exercise/week
[Mean (SD)]
2.93 (2.07) 2.83 (2.16)
Graded neck pain
Grade 0 36 (29.5) 467 (58.6)
Grade 1 86 (70.5) 330 (41.4)
Min minimal; Mod moderate; Sev severe
976 Eur Spine J (2010) 19:972–981
123

Table 3 Comparison of responders and non-responders at 6 months for frequency distribution of the demographic socioeconomic characteristics
and comorbidities by exposure category at baseline
Characteristic Exposed to neck injury in a MVC Not exposed to neck injury in MVC
Responder Non-responder Responder Non-responder
Age (years) [Mean (SD)] 43.5 (12.38) 39.3 (11.67) 46.1 (13.30) 40.8 (14.04)
Gender (no., %)
Male 28 (36.4) 17 (37.8) 304 (49.0) 102 (58.0)
Female 49 (63.6) 28 (62.2) 317 (51.0) 74 (42.0)
Marital status (no., %)
Married 54 (70.1) 32 (72.7) 480 (77.8) 125 (72.3)
Divorced 8 (10.4) 6 (13.6) 39 (6.3) 10 (5.8)
Widowed 2 (2.6) 1 (2.3) 20 (3.2) 0 (0.0)
Single 13 (16.9) 5 (11.4) 78 (12.6) 38 (22.0)
Location of residence (no., %)
Urban 41 (53.2) 24 (53.3) 224 (36.1) 54 (30.9)
Rural 36 (46.8) 21 (46.7) 396 (63.9) 121 (69.1)
Annual household income (no., %)
$0–20,000 13 (17.3) 14 (35.9) 102 (17.6) 38 (24.4)
$20,001–40,000 29 (38.7) 9 (23.1) 208 (36.0) 55 (35.3)
$40,001–60,000 19 (25.3) 9 (23.1) 134 (23.2) 37 (23.7)
Over $60,000 14 (18.7) 7 (17.9) 134 (23.2) 26 (16.7)
Education (no., %)
Less than grade 8 4 (5.2) 3 (6.8) 32 (5.2) 12 (6.9)
High school 16 (20.8) 13 (29.5) 128 (20.7) 43 (24.9)
High school grade 26 (33.8) 10 (22.7) 154 (25.0) 53 (30.6)
Post-secondary 21 (27.3) 15 (35.1) 199 (32.3) 49 (28.3)
University grade 10 (13.0) 3 (6.8) 104 (16.9) 16 (9.2)
Full time worker (no., %)
Yes 39 (51.3) 21 (47.7) 306 (49.8) 102 (58.6)
No 37 (48.7) 23 (52.3) 308 (50.2) 72 (41.4)
Part time worker (no., %)
Yes 16 (21.1) 6 (13.6) 94 (15.3) 24 (13.8)
No 60 (78.9) 38 (86.4) 519 (84.7) 150 (86.2)
Unemployed (no., %)
Yes 4 (5.3) 7 (15.9) 25 (4.1) 13 (7.5)
No 72 (94.7) 37 (84.1) 589 (95.9) 161 (92.5)
Retired (no., %)
Yes 2 (4.0) 1 (2.3) 98 (16.0) 8 (4.6)
No 74 (97.4) 43 (97.7) 516 (84.0) 166 (95.4)
Homemaker (no., %)
Yes 14 (18.4) 9 (20.5) 111 (18.1) 23 (13.2)
No 62 (81.6) 35 (79.5) 503 (81.9) 151 (86.8)
Student (no., %)
Yes 4 (5.3) 3 (6.8) 21 (3.4) 9 (5.2)
No 72 (94.7) 41 (93.2) 593 (96.6) 165 (94.8)
Comorbidities (no., %)
Allergy
Absent 36 (46.8) 21 (47.7) 361 (59.3) 111 (66.5)
No/Min impact on health 29 (37.7) 16 (36.4) 185 (30.4) 42 (25.1)
Mod./Sev. impact on health 12 (15.6) 7 (15.9) 63 (10.3) 14 (8.4)
Eur Spine J (2010) 19:972–981 977
123

Our analysis of attrition suggests that the hazard rate
ratio of this study could have been underestimated. A
higher percentage of females responded to the follow-up
surveys in the non-exposed group, and females are more
likely to report neck pain than males [17].
There were a lower percentage of responders in the
exposed group with depression at 6 months, and depression
is a risk factor for the development of neck pain [17].
Finally, in the exposed group, participants with headaches
that had a moderate to severe impact on health were less
likely to respond to the survey at both 6 and 12 months.
Attrition varied across employment status, education, and
income, but there was no clear trend in attrition to suggest
that the results were biased.
Our analysis may have underestimated the true effect of
neck injury in a motor vehicle collision on the development
of a future episode of troublesome neck pain. It is likely
that in excluding subjects with prevalent troublesome neck
pain from our cohort, we excluded some subjects that had
developed a new episode of troublesome neck pain (inci-
dent cases) after exposure to a motor vehicle collision but
prior to the baseline survey. Excluding these cases would
likely cause an underestimation of the true incidence of
troublesome neck pain after a motor vehicle collision.
Our study augments the evidence of a positive associa-
tion between neck injury in a motor vehicle collision and
future neck pain. The strength of our study is in our ability
to test for the confounding effect of more variables than
Table 3 continued
Characteristic Exposed to neck injury in a MVC Not exposed to neck injury in MVC
Responder Non-responder Responder Non-responder
Arthritis
Absent 53 (69.7) 32 (74.4) 445 (73.7) 134 (80.2)
No/Min impact on health 10 (13.2) 7 (16.3) 106 (17.5) 23 (13.8)
Mod./Sev. impact on health 13 (17.1) 4 (9.3) 53 (8.8) 10 (6.0)
Breathing disorders
Absent 56 (73.7) 24 (54.5) 444 (72.8) 121 (71.2)
No/Min impact on health 14 (18.4) 15 (34.1) 129 (21.1) 40 (23.5)
Mod./Sev. impact on health 6 (7.9) 5 (11.4) 37 (6.1) 9 (5.3)
Hypertension
Absent 68 (88.3) 35 (79.5) 517 (84.5) 149 (88.7)
No/Min impact on health 7 (9.1) 6 (13.6) 69 (11.3) 15 (8.9)
Mod./Sev. impact on health 2 (2.6) 3 (6.8) 26 (4.2) 4 (2.4)
Cardiovascular disorders
Absent 62 (80.5) 36 (80.0) 534 (87.3) 153 (90.0)
No/Min impact on health 12 (15.6) 7 (15.6) 61 (10.0) 13 (7.6)
Mod./Sev. impact on health 3 (3.9) 2 (4.4) 17 (2.8) 4 (2.4)
Digestive disorders
Absent 57 (75.0) 31 (72.1) 456 (74.3) 140 (82.4)
No/Min impact on health 12 (15.8) 6 (14.0) 121 (19.7) 20 (11.8)
Mod./Sev. impact on health 7 (9.2) 6 (14.0) 37 (6.0) 10 (5.9)
Low back pain
Absent 21 (27.6) 10 (22.7) 196 (31.9) 58 (33.7)
Low intensity/low disability 43 (56.6) 25 (56.8) 308 (50.2) 86 (50.0)
High intensity/low disability 3 (3.9) 5 (11.4) 66 (10.7) 15 (8.7)
High disability 9 (11.9) 4 (9.1) 44 (7.2) 13 (7.5)
Headache
Absent 32 (42.1) 14 (31.8) 303 (49.5) 88 (51.5)
No/min. impact on health 32 (42.1) 16 (36.4) 235 (38.4) 63 (36.8)
Mod./Sev. impact on health 12 (15.8) 14 (31.8) 74 (12.1) 20 (11.7)
Depressive symptomatology
Absent 59 (77.6) 31 (72.1) 493 (83.4) 135 (81.3)
Present 17 (22.4) 12 (27.9) 98 (16.6) 31 (18.7)
978 Eur Spine J (2010) 19:972–981
123

Table 4 Comparison of responders and non-responders at 12 months for frequency distribution of the demographic socioeconomic charac-
teristics and comorbidities by exposure category at baseline
Characteristic Exposed to neck injury in a MVC Not exposed to neck injury in MVC
Responder Non-responder Responder Non-responder
Age (years) [mean (SD)] 45.1 (12.62) 38.8 (11.14) 46.9 (12.96) 40.8 (13.40)
Gender (no., %)
Male 23 (37.7) 22 (36.1) 259 (48.5) 147 (55.9)
Female 38 (62.3) 39 (63.9) 275 (51.5) 116 (44.1)
Marital status (no., %)
Married 42 (68.9) 44 (73.3) 417 (78.7) 188 (72.3)
Divorced 7 (11.5) 7 (11.7) 32 (6.0) 17 (6.5)
Widowed 3 (4.9) 0 (0.0) 20 (3.8) 0 (0)
Single 9 (14.8) 9 (15.0) 61 (11.5) 55 (21.2)
Location of residence (no., %)
Urban 33 (54.1) 32 (52.5) 188 (35.2) 90 (34.5)
Rural 28 (45.9) 29 (47.5) 346 (64.8) 171 (65.5)
Annual household income (no., %)
$0–20,000 9 (15.3) 18 (32.7) 75 (15.2) 65 (27.2)
$20,001–40,000 22 (37.3) 16 (29.1) 185 (37.4) 78 (32.6)
$40,001–60,000 16 (27.1) 12 (21.8) 120 (24.2) 51 (21.3)
Over $60,000 12 (16.4) 9 (16.4) 115 (23.2) 45 (18.8)
Education (no., %)
Less than grade 8 3 (4.9) 4 (6.7) 27 (5.1) 17 (6.5)
High school 12 (19.7) 17 (23.3) 112 (21.1) 59 (22.7)
High school grade 22 (36.1) 14 (27.0) 129 (24.3) 78 (30.0)
Post-secondary 16 (26.2) 20 (33.3) 172 (32.5) 76 (29.2)
University grade 8 (13.1) 5 (8.3) 90 (17.0) 30 (11.5)
Full time worker (no., %)
Yes 36 (59.0) 24 (40.7) 261 (49.4) 147 (56.5)
No 25 (41.0) 35 (59.3) 267 (50.6) 113 (43.5)
Part time worker (no., %)
Yes 14 (23.0) 8 (13.6) 82 (15.6) 36 (13.8)
No 47 (77.0) 51 (86.4) 445 (84.4) 224 (86.2)
Unemployed (no., %)
Yes 1 (1.6) 10 (16.9) 16 (3.0) 22 (8.5)
No 60 (98.4) 49 (83.1) 512 (97.0) 238 (91.5)
Retired (no., %)
Yes 2 (3.3) 1 (1.7) 90 (17.0) 16 (6.2)
No 59 (96.7) 58 (98.3) 438 (83.0) 244 (93.8)
Homemaker (no., %)
Yes 10 (16.4) 13 (22.0) 95 (18.0) 39 (15.0)
No 51 (83.6) 46 (78.0) 433 (82.0) 221 (85.0)
Student (no., %)
Yes 1 (1.6) 6 (10.2) 14 (2.7) 16 (6.2)
No 60 (98.4) 53 (89.8) 514 (97.3) 244 (93.8)
Comorbidities (no., %)
Allergy
Absent 28 (45.9) 29 (48.3) 312 (59.5) 160 (63.5)
No/Min impact on health 24 (39.3) 21 (35.0) 158 (30.2) 69 (27.4)
Mod./Sev. impact on health 9 (14.8) 10 (16.7) 54 (10.3) 23 (9.1)
Eur Spine J (2010) 19:972–981 979
123

prior studies, which mostly controlled for age and gender
[4,7,15,16,18]. In our final model, we controlled for the
effects of baseline bodily pain and the BMI. It is possible
that bodily pain was in fact a mediating variable that lies on
the causal pathway between the exposure to neck injury in
a motor vehicle collision and the outcome of troublesome
neck pain.
Our results inform the debate surrounding the etiology
of neck pain in the population. Neck pain is a recurrent
disorder characterized by the periods of the fluctuating pain
and disability [12]. To date, few studies have identified risk
factors for the recurrent episodes of the neck pain. Our
study raises the hypothesis that a past history of a neck
injury in a MVC is one of the determinants of recurrent
neck pain. Our analysis provides the public, clinicians, and
insurers with evidence that a past neck injury in a motor
vehicle collision may have a significant role in the deve-
lopment of future episodes of pain and disability. While the
causal mechanisms linking a past history of neck injury
following a motor vehicle collision and future neck pain
remain unknown, it likely involves complex relationships
between biological, psychological, and social factors.
Future research needs to focus on elucidating these
mechanisms within the biopsychosocial model of health.
Table 4 continued
Characteristic Exposed to neck injury in a MVC Not exposed to neck injury in MVC
Responder Non-responder Responder Non-responder
Arthritis
Absent 41 (68.3) 44 (74.6) 383 (73.5) 196 (78.4)
No/Min impact on health 10 (16.7) 7 (11.9) 91 (17.5) 38 (15.2)
Mod./Sev. impact on health 9 (15.0) 8 (13.6) 47 (9.0) 16 (6.4)
Breathing disorders
Absent 44 (73.3) 36 (60.0) 386 (73.5) 179 (70.2)
No/Min impact on health 11 (18.3) 18 (30.0) 108 (20.6) 61 (23.9)
Mod./Sev. impact on health 5 (8.3) 6 (10.0) 31 (5.9) 15 (5.9)
Hypertension
Absent 54 (88.5) 49 (81.7) 444 (84.3) 222 (87.7)
No/Min impact on health 5 (8.2) 8 (13.3) 60 (11.4) 24 (9.5)
Mod./Sev. impact on health 2 (3.3) 3 (5.0) 23 (4.4) 7 (2.8)
Cardiovascular disorders
Absent 50 (82.0) 48 (78.7) 465 (88.4) 222 (86.7)
No/Min impact on health 8 (13.1) 11 (18.0) 49 (9.3) 25 (9.8)
Mod./Sev. impact on health 3 (4.9) 2 (3.3) 12 (2.3) 9 (3.5)
Digestive disorders
Absent 46 (76.7) 42 (71.2) 394 (74.6) 202 (78.9)
No/Min impact on health 10 (16.7) 8 (13.6) 101 (19.1) 40 (15.6)
Mod./Sev. impact on health 4 (6.7) 9 (15.3) 33 (6.3) 14 (5.5)
Low back pain
Absent 14 (23.0) 17 (28.8) 172 (32.6) 82 (31.8)
Low intensity/low disability 39 (63.9) 29 (49.2) 263 (49.8) 131 (50.8)
High intensity/low disability 2 (3.3) 6 (10.2) 52 (9.8) 29 (11.2)
High disability 6 (9.8) 7 (11.9) 41 (7.7) 16 (6.2)
Headache
Absent 25 (42.4) 21 (34.4) 262 (49.8) 129 (50.2)
No/min. impact on health 27 (45.8) 21 (34.4) 204 (38.8) 94 (36.6)
Mod./Sev. impact on health 7 (11.9) 19 (31.1) 60 (11.4) 34 (13.2)
Depressive symptomatology
Absent 47 (78.3) 43 (72.9) 433 (84.7) 195 (79.3)
Present 13 (21.7) 16 (27.1) 78 (15.3) 51 (20.7)
980 Eur Spine J (2010) 19:972–981
123

References
1. Beaton DC, Hogg-Johnson S, Bombardier C (1997) Evaluating
changes in health status: Reliability and responsiveness of five
generic health status measures in workers with musculoskeletal
disorders. J Clin Epidemiol 50(1):79–93
2. Beekman AT, Deeg DJ, Van Limbeek J, Braam AW, De Vries
MZ, Tilburg W (1997) Criterion validity of the Center for Epi-
demiologic Studies Depression Scale (CES-D): results from a
community-based sample of older participants in the Netherlands.
Psychol Med 27(1):231–235
3. Begg KJ, Langley JD, Williams SM (1999) Validity of self
reported crashes and injuries in a longitudinal study of young
adults. Injury Prev 5:142–144
4. Berglund A, Alfredsson L, Cassidy JD, Jensen I, Nygren A
˚
(2000) The association between exposure to a rear-end collision
and future neck or shoulder pain: a cohort study. J Clin Epidemiol
53:1089–1094
5. Boyd JH, Weissman MM, Thompson WD, Myers JK (1982)
Screening for depression in a community sample. Arch Gen
Psychiatry 39(10):1195–2000
6. Brazier JE, Harper R, Jones NM, O’Cathain A, Thomas KJ,
Usherwood T, Westlake L (1992) Validating the SF-36 health
survey questionnaire: new outcome measure for primary care. Br
Med J 305(6846):160–164
7. Bunketorp L, Stener-Victorin E, Carlsson J (2005) Neck pain
disability following motor vehicle accidents—a cohort study. Eur
Spine J 14:84–89
8. Carroll LJ, Cassidy JD, Co
ˆte
´P (2000) The Saskatchewan Health
and Back Pain Survey: the prevalence and factors associated with
depressive symptomatology in Saskatchewan adults. Can J Public
Health 91:459–464
9. Carroll LJ, Holm LW, Hogg-Johnson S, Co
ˆte
´P, Cassidy JD,
Haldeman S, Nordin M, Hurwitz EL, Carragee EJ, van der Velde
G, Peloso PM, Guzman J (2008) Course and prognostic factors
for neck pain in whiplash-associated disorders: results of the
Bone and Joint Decade 2000–2010 Task Force on Neck Pain and
its Associated Disorders. Spine 33(Suppl):S83–S92
10. Cassidy JD, Carroll LJ, Co
ˆte
´P, Lemstra M, Berglund A, Nygren
A
˚(2000) Effect of eliminating compensation for pain and suf-
fering on the outcome of insurance claims for whiplash injury. N
Engl J Med 342(16):1179–1186
11. Co
ˆte
´P, Cassidy JD, Carroll LJ (2000) Is a lifetime history of neck
injury in a traffic collision associated with prevalent neck pain,
headache and depressive symptomatology? Accid Anal Prev
32:151–159
12. Co
ˆte
´P, Cassidy JD, Carroll LJ, Kristman V (2004) The annual
incidence and course of neck pain in the general population: a
population-based cohort study. Pain 112(3):267–273
13. Devins GM, Orme CM, Costello CG, Minik YM, Frizzell B,
Stam HJ, Pullin WM (1988) Measuring depressive symptoms in
illness populations: psychiatric properties of the Center for Epi-
demiological Studies Depression (CES-D) Scale. Psychol Health
2:139–156
14. Elliott AM, Smith BH, Smith WC, Chambers WA (2000)
Changes in chronic pain severity over time: the chronic pain
grade as a valid measure. Pain 88:303–308
15. Freeman MD, Croft AC, Rossignol AM, Centeno CJ (2006)
Chronic neck pain and whiplash: a case-control study of the
relationship between acute whiplash injuries and chronic neck
pain. Pain Res Manage 11(2):79–83
16. Guez M, Hildingsson C, Nilsson M, Toolanen G (2002) The
prevalence of neck pain, a population-based study from northern
Sweden. Acta Orthop Scand 73(4):455–459
17. Hogg-Johnson S, van der Velde G, Carroll LJ, Holm LW,
Cassidy JD, Guzman J, Co
ˆte
´P, Haldeman S, Ammendolia C,
Carragee E, Hurwitz E, Nordin M, Peloso PM (2008) The burden
and determinants of neck pain in the general population: results
of the Bone and Joint Decade 2000–2010 Task Force on Neck
Pain. Spine 33(Suppl):S39–S51
18. Obelieniene D, Schrader H, Bovim G, Miseviciene I, Sand T
(1999) Pain after whiplash: a prospective controlled inception
cohort study. J Neurol Neurosurg Psychiatry 66:279–283
19. Radloff LS (1997) The CES-D scale: a self-report depression
scale for research in the general population. Appl Psychol Meas
1:385–401
20. Rezai M, Co
ˆte
´P, Cassidy JD, Carroll LJ (2009) The association
between prevalent neck pain and health-related quality of life: a
cross-sectional analysis. Eur Spine J 18(3):371–381
21. Roberts SE, Vingilis E, Wilk P, Seeley J (2008) A comparison of
self-reported motor vehicle collision injuries compared with
official collision data: an analysis of age and sex trends using the
Canadian National Population Health Survey and Transport
Canada data. Accid Anal Prev 40:559–566
22. Rothman KJ (2002) Epidemiology, an introduction. Oxford
University Press, New York
23. Schrader H, Obelieniene D, Bovim G, Surkiene D, Mickeviciene D,
Miseviciene I, Sand T (1996) Natural evolution of late whiplash
syndrome outside the medicolegal context. Lancet 347:1207–1211
24. Spitzer WO, Skovron ML, Salmi LR, Cassidy JD, Duranceau J,
Suissa S, Zeiss E (1995) Scientific monograph of the Quebec
Task Force on whiplash-associated disorders: redefining ‘‘whip-
lash’’ and its management. Spine 20(Suppl 8):1S–73S
25. SPSS for Windows, Rel. 11.0.1. (2006) SPSS Inc., Chicago
26. Versteegen GJ, Kingma J, Meijler WJ, ten Duis HJ (2000) Neck
sprain after motor vehicle accidents in drivers and passengers.
Eur Spine J 9:547–552
27. Vermeulen S (2006) Assessing the performance of a self-report
comorbidity scale. Msc thesis, Unpublished manuscript, Univer-
sity of Alberta
28. von Korff M, Ormel J, Keefe FJ, Dworkin SF (1992) Grading the
severity of chronic pain. Pain 50:133–149
29. Ware JE, Gandek B (1998) Overview of the SF-36 health survey
and the International Quality of Life Assessment (IQOLA) Pro-
ject. J Clin Epidemiol 51(11):903–912
30. Ware JE Jr, Snow KK, Kosinski M et al (1993) SF-36 health
survey: manual and interpretation guide. The Health Institute,
New England Medical Center, Boston
Eur Spine J (2010) 19:972–981 981
123