Socioeconomic variations in the prevalence and incidence of Parkinson's disease: a population-based analysis.
BACKGROUND
For many chronic conditions, lower socioeconomic status is associated with higher rates of disease. Previous research has not investigated whether this inverse relationship exists for Parkinson's disease (PD). The purpose was to investigate the association between socioeconomic status and prevalence and incidence of PD.


METHODS
The study was conducted using population-based administrative data from Manitoba, Canada. PD cases were identified from diagnoses in hospital and physician records. Area-level census data on average household income and residential postal codes in health insurance registration files were used to assign PD cases to urban and rural income quintiles. Annual adjusted prevalence and incidence estimates were calculated for fiscal years 1987/88-2006/07. Hypotheses about differences between quintiles in average estimates and average rates of change were tested using generalised linear models with generalised estimating equations.


RESULTS
The estimated prevalence of PD increased over the 20-year-period but incidence remained unchanged. In urban regions, average prevalence and incidence estimates were significantly higher for the lowest income quintile than the highest quintile. In rural regions, average prevalence estimates were significantly higher for the lowest quintile than for the highest quintile but incidence estimates were not significantly different. The annual rate of increase in the PD prevalence was significantly different for the lowest urban and rural income quintiles.


CONCLUSIONS
There is a greater burden of PD in low-income areas. An understanding of socioeconomic inequalities is useful when formulating hypotheses about factors associated with disease onset and developing equity-oriented policies about access to healthcare resources.
Lix
Lisa M
LM
School of Public Health, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada. lisa.lix@usask.ca
Hobson
Douglas E
DE
Azimaee
Mahmoud
M
Leslie
William D
WD
Burchill
Charles
C
Hobson
Shaun
S
D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008350:Manitoba / Q000453:epidemiology; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology*; D011203:Poverty / Q000706:statistics & numerical data; D015995:Prevalence; D012923:Social Class; D012959:Socioeconomic Factors; D055815:Young Adult