AbstractBackgroundNot all risk factors have the same weight in dementia development, and the combinations of common risk factors differs across individuals and populations. The goal of this study is to estimate the potential population impact of modifiable risk factors for dementia in Canada, and to identify the combinations of the modifiable risk factors that could prevent many dementia cases in Canadian adults.MethodThis is a secondary analysis of data from the Canadian Longitudinal Study on Aging Comprehensive Cohort (n = 30,009). The prevalence and population attributable fraction (PAF) of 12 modifiable lifestyle risk factors established in the Lancet Commission Report 2020 were calculated using baseline data. The prevalence of every possible dyad, triad, and tetrad combination of the risk factors was estimated. All analyses were stratified by 2 sex strata (male, female) and 4 age strata (45‐54, 55‐64, 65‐74, 75+).ResultThe combined PAF of the 12 lifestyle risk factors was 49% in the Canadian population. The single risk factors that contributed the most were physical inactivity (11.3%), hearing loss (6.9%), and obesity (6.9%) in Canada, whereas social isolation (0.4%), alcohol (1.1%), and smoking (1.4%) had substantially smaller effects (Table 1). The most prevalent risk factor dyad was physical inactivity and sleep disturbance (34%). Obesity, physical inactivity, and sleep disturbance was the most prevalent risk factor triad (14%). The tetrad of hearing loss, obesity, physical inactivity, and sleep disturbance had the highest prevalence (4.9%). The prevalent risk factor combinations were similar in the two younger age groups and both sexes, but not in the two older age groups (Table 2).ConclusionNearly 50% of dementia cases in Canada can be prevented by modifying 12 lifestyle risk factors. The most prevalent combinations of risk factors differ before and after the age of 65, but not by sex. The most prevalent risk factor combinations consist of physical inactivity, sleep disturbance and obesity in the two younger age groups, and hearing loss, sleep disturbance and obesity in the two older age groups. These findings may help strategically target tailoring multidomain dementia intervention programs to have the greatest impact in the Canadian population.