Risk of harm among gamblers in the general population as a function of level of participation in gambling activities

AIMS: To examine the relationship between gambling behaviours and risk of gambling-related harm in a nationally representative population sample. DESIGN: Risk curves of gambling frequency and expenditure (total amount and percentage of income) were plotted against harm from gambling. SETTING: Data derived from 19, 012 individuals participating in the Canadian Community Health Survey-Mental Health and Well-being cycle, a comprehensive interview-based survey conducted by Statistics Canada in 2002. MEASUREMENT: Gambling behaviours and related harms were assessed with the Canadian Problem Gambling Index. FINDINGS: Risk curves indicated the chances of experiencing gambling-related harm increased steadily the more often one gambles and the more money one invests in gambling. Receiver operating characteristic analysis identified the optimal limits for low-risk participation as gambling no more than two to three times per month, spending no more than 501-1,000 CAN dollars per year on gambling and investing no more than 1% of gross family income on gambling activities. Logistic regression modelling confirmed a significant increase in the risk of gambling-related harm (odds ratios ranging from 2.0 to 7.7) when these limits were exceeded. CONCLUSIONS: Risk curves are a promising methodology for examining the relationship between gambling participation and risk of harm. The development of low-risk gambling limits based on risk curve analysis appears to be feasible.