Overview

Abstract (English)

Cancer Incidence Attributable to Modifiable Risk Factors in Alberta, Canada in 2012 describes the results of a project that the cancer burden attributable to 24 modifiable lifestyle and environmental risk factors in the province of Alberta. The cancer risk factors included in this project were identified through the International Agency for Research on Cancer (IARC) Monograph Series, the World Cancer Research Fund (WCRF) Report and the peer-reviewed epidemiologic literature. The selected exposures can be classified into the categories of tobacco consumption and exposure, environmental factors (air, water and soil contaminants), infectious agents, hormone therapies, dietary intake characteristics and energy imbalance. The population attributable risk (PAR) was used to provide an estimate of the proportion of the cancer burden in Alberta that can be attributed to these 24 risk factors and therefore represent the proportion of cancer that could theoretically be prevented by removal of the exposure in the province. This is the first time that a comprehensive estimation of cancer burden associated with these modifiable lifestyle and environmental risk factors, has been estimated in Alberta. Three main types of data were required to estimate the individual PARs associated with each risk factor at each relevant cancer site: the magnitude of the risk association between individual risk factors and cancer sites; the prevalence (%) of the risk factor among adults in Alberta; and age-sex-site-specific cancer incidence in Alberta in 2012. Risk estimates used to quantify the magnitude of the association between risk factors and individual cancer sites were obtained from reports from international collaborative groups (IARC, WCRF) and a review of the peer-reviewed epidemiologic literature. Prevalence data for the risk factors of interest were obtained from Statistics Canada surveys, publically available government databases, the published peer-reviewed literature and consultation with relevant experts. Cancer incidence data for Alberta were obtained from the Alberta Cancer Registry for the year 2012, the most recent year for which data were available. Risk estimate and prevalence data were combined toprovide estimates of the population attributable cancer risk for each risk factor and these PAR estimates were combined with cancer incidence data to estimate the number of cases of each cancer type that could be attributed to individual risk factors in 2012. PAR estimates for individual risk factors were combined to estimate the overall proportion of cancer in Alberta in 2012 that could be attributed to the full set of 24 modifiable risk factors. Of the 24 modifiable risk factors included in this project, active tobacco consumption (15.7%), physical inactivity (7.2%) and excess body weight (4.3%) were the leading causes of cancer in Alberta in 2012. Overall the 24 modifiable lifestyle and environmental risk factors examined here were together responsible for 42.3% or 6,699 excess cases of incident cancer in 2012. Considering men and women separately, 40.2% of cancers in men (3,278 cases) and 43.9% of cancers in women (3,372 cases) could be attributed to the included risk factors. The cancer sites where the largest proportions of cancer incidence could be explained by these 24 modifiable risk factors were cervix (100%), lung (85.1%), larynx (81.4%), endometrium (80.1%) and esophagus (79.9%). Active tobacco smoking was the most important risk factor for each of lung, laryngeal and esophageal cancers, whereas the burden of endometrial cancer was most attributable to physical inactivity and excess body weight. The burden of cervical cancer was entirely attributed to Human Papillomavirus (HPV) infection, as HPV infection is seen in all cervical cancer cases and is required for the development of cervical cancer. Physical inactivity and excess body weight were also leading causes of breast and colorectal cancers, which were two of the most common types of cancer diagnosed in Alberta in 2012 .

Abstract (French)

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