A study from University of Calgary and Health Services of Alberta and published in the Canadian Medical Association Journal, sought to assign definitive percentages to 24 potential causes of cancer based on data analysis of those with cancer in Alberta in 2012.
40.8% of cancer cases in Alberta (42.4% in women and 38.7% in men) were found to be attributable to ‘modifiable lifestyle’ and ‘environmental risk’ factors. This is a very similar finding to Parkin and colleagues in the UK in 2010, where the figure was 42.7% of all cancers.
Three factors led to the most cancers - tobacco smoking, physical inactivity and excess body weight. Tobacco smoking was linked to 15.7% of cancer cases, physical inactivity to 7.2% and excess body weight to 4.3%. No other factor was above 4%.
Chris Woollams, former Oxford University Biochemist and founder of CANCERactive said, "What is interesting is that the three ’lifestyle causes’ Health Authorities and CRUK go on about, smoking, lack of exercise, and being overweight, actually only account for 27.2% of total cancer cases. When you look at estimates for environmental toxins and their input at around 35%, it puts the efforts to prevent cancer into perspective. These cancer bodies are looking in the wrong direction - it’s their friends at chemical companies they should be chastising."
In this study the risk factors analysed were smoking (both active and passive), being overweight and obesity, inadequate physical activity, diet (inadequate fruit and vegetable consumption, inadequate fibre intake, excess red and processed meat consumption, salt consumption, inadequate calcium and vitamin D intake), alcohol, hormones (oral contraceptives and hormone therapy), infections (Epstein-Barr virus, hepatitis B and C viruses, human papillomavirus, Helicobacter pylori), air pollution, natural and artificial ultraviolet radiation, radon and water disinfection by-products.