J Can Chiropr Assoc 2003 (Dec); 47 (4): 284–290 ~ FULL TEXT
Pierre Côté, DC, PhD, J. David Cassidy, DC, PhD, Linda Carroll, PhD
Institute for Work & Health,
Toronto, Canada and the Department of Public Health Sciences,
University of Toronto,
Background: There are few population-based studies on the epidemiology of neck pain in the general population.
Purpose: To synthesize the findings of two large population-based studies of the epidemiology of neck pain and whiplash-associated disorders from the province of Saskatchewan, Canada.
Study Design and Methods: We conducted two population-based cohort studies of neck pain and its related disability in Saskatchewan, Canada. First, the Saskatchewan Health and Back Pain Survey was designed to determine the prevalence and factors associated with neck pain in randomly selected adults. Second, we conducted a cohort study of the incidence and prognosis of whiplash and studied whether a change in the insurance system from tort to no-fault was related to a reduction in the number of whiplash claims and faster recovery.
Results: In 1995, the six-month prevalence of neck pain was 54.2% and 4.6% of adults experienced disabling neck pain in the previous six-months. Neck pain was associated with education, comorbidities, smoking, self-reported general health and a history of neck injury in a motor vehicle collision. The incidence of treated and/or compensated whiplash injury was reestimated at 834/100,000 adults in 1994, and dropped by 28% to 598/100,000 adults in 1995, after tort reform. Compared to tort, the median time-to-recovery was more than 230 days faster under no-fault. The strongest predictors of recovery were age, gender, education, injury severity, lawyer involvement and type of initial care provider.
Conclusion: Neck pain is a public health problem. The incidence and prognosis of whiplash injuries are greatly influenced by compensation for pain and suffering, legal factors, injury severity and sociodemographic characteristics. Overall, neck pain is a multifaceted disabling problem that deserves more attention. When treating patients with neck pain, clinicians need to recognize that it is more than a physical problem and that its prognosis is influenced by broader determinants of health.
From the Full-Text Article:
Since the mid 1980’s, we have witnessed a slow, but constant
increase in the amount of attention paid to the problem
of neck pain in the general population. The growing
interest in neck pain is mainly linked to the escalating
disability burden and compensation costs associated with
neck pain related to automobile collisions and occupational
injuries. As a result, epidemiologists started to investigate
the magnitude, causes and prognosis of neck pain
in the population. 
Until 1998, there were no reports of the epidemiology of
neck pain in North America and very little was known
about the incidence and prognosis of whiplash. Studies
from Finland, Sweden and Norway had reported that the
lifetime prevalence of neck pain was 71% and that between
12% and 34% of adults experienced neck pain
annually. [2–6] The literature suggests that the prevalence of
neck pain increases with age and that it is more common in
women. Moreover, neck pain is more prevalent among
lower socioeconomic status groups, those performing repetitive, static work or physically demanding work, those
with previous neck trauma, and among those suffering
from comorbid conditions such as depression, low back
pain and headache. [1, 7]
In 1995, the Quebec Task Force (QTF) on Whiplash–
Associated Disorders conducted an extensive review of
the literature on whiplash and found that very little was
known about its epidemiology.  The QTF found that the
incidence of whiplash claims in Canada varied with the
type of insurance system in place in the various provinces.
For example, the 1987 incidence of whiplash claims in
Quebec (which operated under a no–fault system) was 70/
100,000 persons compared to 720/100,000 persons in Saskatchewan
(which operated under a tort system).  Furthermore,
the QTF suggested that the prognosis of whiplash
was favorable for most individuals. According to the Quebec
cohort 50%, 87% and 97% of claimants settled within
one, six and twelve months respectively. 
The general objective of this paper is to summarize the
epidemiological knowledge gained from two population–based
studies of neck pain in the Saskatchewan adult
population. Our specific objectives are:
1) to present the
prevalence and factors associated with neck pain and its
related disability and
2) to present the incidence and prognosis
for whiplash under two different insurance systems.
The Saskatchewan Health and Back Pain Survey
The Saskatchewan Health and Back Pain Survey was a
prospective population–based mailed survey of the distribution
and determinants of spinal disorders in the province
of Saskatchewan. The survey methodology and internal
validity of the survey are described in detail elsewhere. [9–11]
In summary, 2,055 randomly selected Saskatchewan
adults between the ages of 20–69 years were invited to
participate. A total of 1,133 subjects participated (55%).
The results reviewed in this paper relate to the crosssectional
data (index survey) collected in September 1995.
How common is neck pain?
We measured the point, six–month and lifetime prevalence
of neck pain. Neck pain was defined as pain located between
the occiput and the third thoracic vertebra. The six–month
prevalence of neck pain was classified by grades of
severity according to the Chronic Pain Questionnaire. [12–14]
The questionnaire provides five ordered grades derived
from the severity of pain and disability reported by a subject
(Table 1). Grade I corresponds to mild, non–disabling
pain. Grade II refers to high intensity pain that does not
limit activities. Grades III–IV refers to disabling neck pain.
Overall, 66.7% (95% CI; 63.8–69.5) of the subjects
reported that they had experienced neck pain during their
lifetime and 22.2% (95% CI; 19.7–24.7) suffered from
neck pain on the day of the survey.  Moreover, 54.2%
(95% CI 51.4–56.5) of the sample experienced neck pain
in the six months before the survey. The majority of
subjects (39.7% (95% CI 36.7–42.7)) had suffered from
mild (Grade I) neck pain, and 10.1% (95% CI 8.2–11.9) of
the sample had suffered from intense (Grade II) neck pain
during the previous six months. More importantly, disabling
(Grades III–IV) neck pain affected 4.6% (95%
CI 3.5–5.8) of the study sample in the previous six months.
Finally, the six–month prevalence of mild neck pain gradually
decreased from the 20–29 year–old age group to the
60–69 group.  The prevalence of intense and disabling
neck pain did not significantly vary with age. All grades of
neck pain were more common in women (58.8% (95% CI
54.8–62.7)) than men (47.2% (95% CI 42.4–51.5)). These
figures suggest that while neck pain is very common in the
population, most is mild in nature and does not interfere
with activities of daily living.
Neck pain and general health
To investigate the multifaceted nature of neck pain, we
collected variables that belong to four specific domains:
demographic (age–group, gender, marital status, location of residence)
socioeconomic (annual household income, education, employment status),
comorbidities (allergy, respiratory disorders, hypertension, cardiovascular disorders, digestive disorders, headache, depressive symptomatology, low back pain), and
general health variables (previous injury to the neck, cigarette smoking, body mass index, exercise general health). 
Our age and gender–adjusted multivariable analysis showed strong associations between all grades of neck pain severity and disabling low back pain (Grade III–IV), headaches that moderately or severely impact on health, a history of neck injury in a motor vehicle collision. [7, 15] However, those who did not graduate from high school were less likely to report mild neck pain. Moreover, smokers and subjects who reported cardiovascular problems or digestive problems that moderately/severely impacted on their health were more likely to have experienced disabling neck pain in the previous six months. These results are clinically relevant because they suggest that disabling neck pain is more common in those who have poorer health.
The psychological side of neck pain
Although it is well established that pain and depression are
related with each other, there is limited knowledge about
the relationship between levels of pain severity and depression
in the general population. Furthermore, very little
is known about the coping strategies used by individuals
with neck pain to cope with their condition. To explore
these issues we collected data on depressive symptomatology
using the Center for Epidemiological Studies–
Depression Scale (CES-D) and coping strategies using the
short-form Pain Management Inventory (PMI). [11, 16] Coping
strategies were categorized into active (strategies that
involve taking responsibility for pain management and include
attempts to control the pain or to function in spite of
pain) and passive (strategies that involve giving responsibility
for pain management to an outside source or allowing
other areas of life to be adversely affected by pain). For
the analyses involving depressive symptomatology and
coping, we combined neck and low back pain into one
category and used the higher of the two pain grades to
reflect the overall spinal pain grade. 
Our analysis showed that Grades II, III and IV neck/low
back pain were independently and strongly associated with
depressive symptomatology  suggesting that those who
suffer from disabling pain are more likely to also suffer
from clinical or sub-clinical depression. Furthermore, we
found that increasing severity of pain and disability was
positively associated with greater use of passive coping
strategies. [16, 17] In other words, subjects who reported Grade
III-IV neck/low back pain were more likely to cope passively
with their pain. We did not find independent associations
between neck/low back pain and active coping. [16, 17]
Therefore, encouraging patients to limit the use of passive
coping strategies may be helpful when managing disabling
neck and low back pain.
A population-based inception cohort study
of whiplash injuries in Saskatchewan
We designed a population-based study to determine the
incidence and prognosis of whiplash. The study population
included all Saskatchewan residents who filed an insurance
claim for whiplash injuries between July 1994 and
December 1995. Until December 31, 1994, the automobile
insurance system in Saskatchewan operated under tort legislation.
However, on January 1, 1995 the system changed
to no-fault and compensation for pain and suffering was
eliminated and so were most legal actions. The study
methodology is described in detail elsewhere. [18, 19] In summary,
83% (7,462) of all eligible traffic injury claims
(9,006) involved whiplash injuries. Baseline information
was obtained from all subjects and those who consented to
be followed-up were contacted at six weeks and at four,
eight and 12 months.
Incidence of whiplash claims
Following the introduction of no-fault insurance, the incidence
of whiplash claims in Saskatchewan decreased by
28% from 417/100,000 persons during the last six-moths
of tort to 302/100,000 and 296/100,000 during the first and
second six-month periods of no-fault respectively.  Overall,
the incidence of whiplash was higher in women. The
incidence peaked in the 18–23 years age-group, gradually
decreasing thereafter. Following the introduction of the no-fault
insurance the incidence of whiplash mainly decreased
in men and in those between the ages of 18–39 years. 
Prognosis of whiplash injuries
We used time-to-claim-closure as a measure of time-to-recovery.
Time-to-claim-closure is the number of days
from the date of injury to the date that the claim is closed.
It usually coincides with the end of treatment, the attainment
of maximal medical improvement, or with the end of
income replacement benefits. We studied the validity of
time-to-claim-closure as a marker of health recovery and
found that faster claim closure is strongly and independently
associated with lower neck pain intensity, better
physical functioning and the absence of depressive symptoms.  In other words, on any given day those who closed their claim had significantly less neck pain, better physical
functioning and less depressive symptomatology compared
to those whose claims remained open. These findings
were consistent during the tort and no-fault insurance
The median time-to-claim closure for whiplash injuries
dropped by 54% from 433 days under the tort system to
approximately 200 days under the no-fault system.  At
one year, 57% and 28% of claimants were still being
compensated under the tort and no-fault systems respectively.
Our results contrast with the Quebec Cohort findings
and suggest that in Saskatchewan, chronic whiplash is
very common and that recovery occurs at a much slower
rate than it does in Quebec. 
The concept of recovery
Recovery from soft-tissue injuries such as whiplash is an
ill-defined construct that often based on patient self-report
and/or an assessment by a physician. This can be problematic,
since symptoms, signs and other clinical findings can
vary significantly because of subjective interpretations. In
contrast to a fracture, the recovery from whiplash is difficult
to objectively document because the underlying pathology
is not clear. Recently Beaton et al.,  have shown
that being better is a multidimensional, dynamic and individualized
process. In their study of workers who suffered
from work-related musculoskeletal disorders of the upper
limb, being better was not only reflected in changes in the
state of the disorder (resolution), but also on adjustment of
activities to work around the disorder (readjustment) and/
or on adaptation to living with the disorder (redefinition).
Although resolution of symptoms is a common criteria
used in determining improvement, a complete disappearance
of pain and other symptoms is not necessary to
achieve recovery. Individuals may have recovered when
the severity of their symptoms has changed by an acceptable
level, or when they have reached a certain threshold
of pain or function with which they can cope. Others may
define recovery as the ability to adjust to their daily activities
by modifying their environment while avoiding
exacerbating their condition. Finally, other people may
redefine their health after an injury by integrating pain as
part of their lives. 
The model of recovery used in our studies builds on the
model developed by Beaton et al.  Accordingly, recovery
is conceptualized as a process that includes resolution of
symptoms, adjustment to life and redefinition of health.
However, these constructs are applied at the population
rather than at the patient level. Therefore, the concept of
recovery should be appraised with a population-based
perspective rather than a clinical one and inferences should
not be made about the status of specific subjects. It is
entirely possible that subgroups of subjects followed different
recovery trajectories that would not fit with the population-
based average estimates. It is under these assumptions,
that we have modeled the hazard of a whiplash claim being
closed given various levels neck pain intensity, physical
functioning and depressive symptomatology.
Finally, the administrative process guiding the management
of insurance claims provides further support to the
concept that claim closure is related to the health status of
claimants. In Saskatchewan, the claim of individuals with
whiplash injury remains, in principle, open until Saskatchewan
Government Insurance, no longer pays indemnity, or
medical benefits. In theory, this suggests that claimants
whose claims are closed have reached a level of health that
allows them to resume their normal activities of daily
living, or that they no longer require health care for their
Which factors predict the recovery from whiplash?
We studied early predictors for recovery separately under
the tort and no–fault systems of insurance.  Under both
systems, older age, higher neck pain intensity, greater percentage
of the body in pain, lawyer involvement and initial
health–care provision by chiropractors or combinations of
chiropractors, physical therapists and physicians were detrimental
for recovery. In addition, not being at fault for the
collision (i.e., being a victim) slowed recovery under the
tort system only, since fault is not an issue in a no–fault
plan. Also, the presence of reduced or painful jaw movement
and concentration problems slowed recovery for tort
claimants. Overall, pain intensity and spread was more
important in delaying recovery under tort, and this might
be explained by the benefits paid for pain and suffering
under tort laws. No–fault claimants with minor fractures,
memory problems and numbness or pain in the upper extremities
also had a poor prognosis. These findings indicate
that recovery is determined by a range of factors,
some of which are related to the insurance system.
The results of our research demonstrate that neck pain is a
public health problem and a common source of disability
in the general population. Although most neck pain experienced
by adults is mild in nature, almost 5% of the population
suffers from neck pain disability during any six–month
period. This finding emphasises the importance of developing
effective secondary prevention strategies that will
decrease the burden of disability related to neck pain.
We have shown that neck pain is associated with a
mixture of other chronic health conditions such as headache,
cardiovascular problems and low back pain. This has
significant implications for clinicians who must consider
the presence of these comorbidities when establishing the
plan of management and prognosis of their patients. Therefore,
disabling neck pain should not be viewed in isolation,
but rather as one of several comorbid conditions that tend
to cluster in patients with other chronic health problems.
Like others before us, we have found that individuals
with a previous history of whiplash injuries may be more
likely to suffer from disabling neck problems. This observation
was strengthened by the findings from our population–
based study of whiplash injuries that demonstrated
that between 28% and 57% of claimants with whiplash
injuries had not recovered by one year. But by far the most
important finding in our recent research is that the insurance
and compensation system under which whiplash
claims are filed has the strongest influence on the recovery
of patients. On average, tort claimants took twice as long
to recover from their injuries than similar claimants under
the no–fault system. Furthermore, regardless of the insurance
system, the involvement of a lawyer early in the
claim process considerably delayed the recovery of claimants.
In addition, there was a strong prognostic effect
associated with initial health care consultation that deserves
further investigation. These results suggest that
societal, legal, economic, and clinical practices have a
direct impact on the recovery process of patients with
So, what have we learned about the epidemiology of
neck pain from our population based studies in Saskatchewan?
Obviously, what is often viewed as a simple clinical
problem can rapidly develop into a complex disorder where
physical, psychological, compensation, legal and other
societal forces all interact to cause disability. Although
complex, the prevention of chronic neck pain and its related
disability could be accomplished by designing clinical,
legal and insurance policies that address the various
factors that impact on its development. For these policies
to be successful, clinicians, researchers and policy makers
need to consider the broader causes of disability, rather
than focus only on the clinical and individual issues.
The Saskatchewan Health and Back Pain Survey was supported
by the Chiropractors’ Association of Saskatchewan
and Saskatchewan Health. The Population–based Inception
Cohort study of Traffic Injuries in Saskatchewan was
supported by Saskatchewan Government Insurance and by
Health Canada through the National Health Research and
Development Program (grant # 6606–6599–004). The participation
of Pierre Côté was made possible by a Doctoral
Fellowship Training Award from Health Canada through
the National Health Research and Development Program
and through the Institute for Work & Health by the
Workplace Safety and Insurance Board of Ontario. Drs.
Cassidy and Carroll are supported by Health Scholar
Awards from the Alberta Heritage Foundation for Medical
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