Substance-attributable morbidity and mortality changes to Canada's epidemiological profile: measurable differences over a ten-year period.

BACKGROUND Substance use is responsible for a large burden of disease in Canada, however updated data are needed for health care planning and policy development. This study replicates and makes improvements on 1992 estimates of substance-attributable morbidity and mortality for the year 2002. There are two objectives, the main one being to compare the substance-attributable morbidity and mortality in 1992 with 2002 using the same methods of calculation, and the second, to compare the two different methods of estimating the substance-attributable mortality and morbidity in 2002. METHOD Estimates of substance-attributable burden were made by combining relative risk data with exposure prevalence data and disease-related mortality and morbidity information from national databases. First, identical relative risk estimates for 1992 were used with the 2002 data in order to draw direct comparisons. In a second analysis, updated relative risk and attributable disease information (post-1992) was used to better estimate the mortality and morbidity for Canada in 2002. RESULTS Overall, from 1992 to 2002, there were relative increases in substance-attributable mortality estimates for alcohol and illegal drugs, where the latter relatively increased more; and a relative decrease in tobacco-attributable mortality. In terms of absolute numbers in combined risk factors, deaths and hospital days for those under 70 years of age decreased mainly due to tobacco. Comparisons of the two methods showed that the updated method resulted in more conservative numbers than previous calculations. INTERPRETATION There is an unacceptably high burden of substance-attributable disease in Canada in the early 2000s. Exposure changes and epidemiological shifts in population and diseases over the last 10 years have affected where the burden lies, but it is still vital to incorporate policy-based initiatives that have proven to be effective in reducing substance-attributable burden in practice.