A large European multisite study conducted by Krasimira Aleksandrova and colleagues, entitled “Combined impact of healthy lifestyle factors on colorectal cancer: a large European cohort study” was published this week in BMC Medicine journal. The study aimed to evaluate the combined impact of different healthy lifestyle factors in terms of population attributable risks overall and according to colon and rectal cancer anatomical sub-site and by sex.
Colorectal cancer (CRC) is the third most common cancer in men (746,000 cases per year, 10.0% of the total cancer incidence) and the second in women (614,000 cases per year, 9.2% of the total cancer incidence) worldwide. Excess body weight, physical activity, smoking, alcohol consumption and certain dietary factors are individually related to CRC risk. However, their joint effect remains unclear.
A total of 347,237 participants (age 25 to 70 years) took part in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Participants provided dietary and lifestyle information at study baseline and after 12 years follow up, 3,759 incident CRC cases were identified. Healthy lifestyle index (HLI) were composed of five potentially modifiable lifestyle factors – healthy weight, physical activity, non-smoking, limited alcohol consumption and a healthy diet.
Results indicated that a decrease in the number of HLI was associated with an increase in new CRC cases. Overall, 16% of the new CRC cases were attributable to non adherence to a combination of all five healthy lifestyle behaviours included in the index. The associations were stronger among men compared to women, particularly for rectal cancer. If these associations were causal, 16% of the new CRC cases (22% in men and 11% in women) would have been prevented had all participants been following all five healthy lifestyles.
The team concluded that combined lifestyle factors were associated with a lower incidence of CRC in European populations characterized by western lifestyles. From a preventative perspective, strategies considering the targeting of multiple lifestyle factors may provide practical means for improved CRC prevention.