Our results indicate that $2.1 billion, or about 2.5% of the total direct health care costs in Canada in 1999, are attributable to physical inactivity. A similar figure was recently reported for the United States ($24 billion or 2.4% of the US health care expenditures).45
We found that 33% of deaths from CAD, colon cancer and type 2 diabetes could hypothetically be prevented by eliminating physical inactivity. Similarly, it has been estimated that about one-third of the deaths from CAD, colon cancer and diabetes in the US are attributable to inactivity.46
The cost of obesity in Canada was estimated to be $1.8 billion in 1997.43
When this value is inflated to 1999 dollars using the increase of 10.3% that occurred in total health care expenditures between 1997 and 1999 (from $78.0 billion to $86.0 billion), the cost of obesity would be $2.0 billion. Thus, our cost estimates for physical inactivity are similar to those for obesity. Given the significant association between physical inactivity and obesity, a portion of the health care costs attributable to obesity is also attributable to physical inactivity.47
However, it is unlikely that the costs attributable to inactivity and obesity are simply additive; the relative contributions of physical inactivity and excessive caloric intake to obesity have not been determined. More research is needed to determine the total costs attributable to physical inactivity, taking into account the overlapping costs of inactivity-related obesity.
Estimates from our study suggest a saving of $150 million per year with a reduction of 10% in the prevalence of physical inactivity.5
Thus, even a modest reduction would have a significant effect on the health of Canadians. However, one would not expect sweeping health care savings immediately following a reduction in the level of inactivity because the benefits of a physically active lifestyle accrue over a lifetime.
Our methods have several limitations. The EBIC
data were for 1993, and we assumed that the relative proportions of expenditures for each illness did not change dramatically between 1993 and 1999. Furthermore, the EBIC
reported expenditures for major categories of disease, such that expenditures for colon cancer, breast cancer, type 2 diabetes and hypertension had to be estimated from prevalence and incidence data or from expenditure data from the United States. However, these limitations likely had only a marginal effect on our estimates, and the use of these methods allows a comparison of results to those for obesity derived using similar methods.43
Our estimates of the economic costs of physical inactivity are likely conservative. We calculated only the direct health care costs of inactivity and made no attempt to estimate indirect costs, which include lost productivity due to premature death and disability due to illness. In addition to the diseases included in our analysis, physical inactivity has been associated with dyslipidemia, anxiety, depression, poorer quality of life and premature admission to an institution or geriatric care.2
However, the effect sizes for these conditions and situations are generally small, and there is little consensus on these issues. Like most behaviours, physical activity is difficult to measure accurately. Thus, in using estimates of physical activity rather than objective measures of physical fitness, the studies included in the meta-analysis likely underestimated the health effects associated with an active lifestyle.
Conversely, we have also not accounted for the potential costs of physical activity promotion. The implementation of nation-wide intervention programs and campaigns to promote physical activity is an expensive prospect; the costs are undoubtedly lower than the health care expenses associated with treating inactivity-related illnesses, however.
Our estimates are based on RRs from prospective longitudinal studies, which may not always translate into actual benefits when tested in randomized controlled trials. A fundamental assumption is that changes in physical activity (though promotion) will result in changes in disease risk. Although there are randomized controlled trials on the effects of physical activity on risk factors for disease (such as blood lipid levels), there is little information on whether physical activity interventions can change one's risk for disease per se. However, 2 longitudinal prospective studies48,49
have shown that increases in physical fitness or physical activity levels can reduce the risk of death from all causes.
Given the limitations in the data and the lack of randomized controlled trials to evaluate the long-term effectiveness of exercise interventions, more research on the effects of changes in physical activity levels on health care costs is needed. In a public health context, the finding that physical inactivity accounts for about 2.5% of the current direct health care costs is very important. The costs attributable to cigarette smoking in Canada were estimated to be 3.8% of total health care costs in 1992.50
Given the considerable efforts that have been aimed at curbing the prevalence of smoking in Canada, public health campaigns directed at increasing physical activity in the population should be no less aggressive and persistent.