Several previous reports have quantified the effects of risk factors on cancer incidence and mortality; however, most were restricted to one risk factor, one site of cancer, or one population. Majid Ezzati, (Harvard School of Public Health, Boston, MA, USA) and colleagues estimated the worldwide and regional mortality from site-specific cancers attributable to nine risk factors using comparable methods. For every risk factor the investigators undertook a comprehensive review of published studies and sources such as government reports. They also reanalysed original data sources and performed meta-analyses of epidemiological studies.
The researchers found that overweight and obesity, low fruit and vegetable intake, physical inactivity, smoking, alcohol, unsafe sex, urban air pollution, indoor smoke from household use of coal, and contaminated injections in health-care settings accounted for over a third of cancer deaths worldwide. Smoking, alcohol use, and low fruit and vegetable intake were the leading risk factors for death from cancer worldwide in low and middle-income countries. In high-income countries, smoking, alcohol use, overweight, and obesity were the most important causes of cancer.
Dr Ezzati states: "Primary prevention through life-style and environmental interventions remains the main route for reducing the global cancer burden. If implemented, reduction of exposure to well-known behavioural and environmental risk factors would prevent a substantial proportion of deaths from cancer." (Quote by e-mail; does not appear in published paper)
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