Objective: To illustrate quantitatively the effect of the aging of the population on the prevalence of chronic disorders by comparing the projected frequency of musculoskeletal (MSK) disorders in 3 comparatively "young" countries, Australia, Canada, and the United States, and 3 comparatively "old" countries, France, the United Kingdom, and Sweden.
Methods: Age specific rates for MSK disability in Canada were applied to World Bank population estimates and projects to estimate prevalence rates and numbers of persons with MSK disability in the years 1985, 2000, 2010, and 2020.
Results: The age structure of the populations affected baseline rates for MSK disability. Increases in both prevalence and numbers affected are expected for all countries between 1985 and 2020, up to a 34% increase in prevalence in Canada, and an 88% increase in numbers in Australia.
Conclusion: The aging of the population is likely to result in a disproportionate increase in the number of people with chronic disabling disorders, which will be taking place against a background of a decreasing or static number of young adults, with implications for meeting needs for health care and community support.