The impact of sampling and measurement on the prevalence of self-reported pain in Canada.
BACKGROUND
Pain is an important public health problem in Canada. International estimates of general population pain prevalence range from 2% to 46%.


OBJECTIVE
The purpose of this paper is to critically examine the potentially misleading use of overall prevalence estimates in the pain literature and to use two Canadian population-based surveys to assess the impact of sampling and measurement on prevalence.


METHODS
Two of the secondary data sets used were the 1996/97 National Population and Health Survey (NPHS) and the Canadian Multicentre Osteoporosis Study (CaMos). This paper is based on the assessment of chronic pain in the NPHS, and the assessment of short term pain using the Medical Outcomes Trust's 36-item health survey and the Health Utilities Index, both collected by CaMos. Data are presented as frequencies and percentages overall and stratified by age and sex. CaMos prevalence estimates were age- and sex-standardized to the NPHS population.


RESULTS
The overall prevalence of pain was 39% for one-week pain, 66% for four-week pain and 15% for chronic pain. Women were more likely to report pain than men and the prevalence of pain increased with age.


CONCLUSIONS
This study yields useful information about the self-reported responses to a variety of questions assessing pain in the general population. Responses to the different questions likely represent different categories of pain, such as short term versus chronic pain, which in turn may have different epidemiological risk factors and profiles. Longitudinal studies of the epidemiology, predictors and natural history of chronic pain are urgently needed in the Canadian population.
Van Den Kerkhof
Elizabeth G
EG
Queen's University, Kingston General Hospital, Kingston, Canada. ev5@post.queensu.ca
Hopman
Wilma M
WM
Towheed
Tanveer E
TE
Anastassiades
Tassos P
TP
Goldstein
David H
DH
D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology*; D010147:Pain Measurement / Q000379:methods* / Q000706:statistics & numerical data*; D010358:Patient Participation / Q000523:psychology / Q000706:statistics & numerical data*; D011446:Prospective Studies; D015983:Selection Bias