Sunday, September 27, 2009

Another study shows benefits of healthy lifestyle

Results from part of a major European study of the effects of diet and lifestyle on chronic illness confirm the benefits of a range of healthy behaviours, showing significant reductions in risks of cancer and cardiovascular disease.

European Prospective Investigation into Cancer and Nutrition (EPIC) is a large (n>500,000, recruited between 1994 and 1998) ongoing study involving ten European countries; it is designed to investigate the relationships between diet, nutritional status, lifestyle and environmental factors and the incidence of cancer and other chronic diseases. This report is from EPIC-Potsdam, which covers the German participants in the study. The authors examined the effects of four potential factors: never smoking, having a body mass index (BMI) lower than 30, performing 3.5 h/wk or more of physical activity, and adhering to healthy dietary principles (high intake of fruits, vegetables, and whole-grain bread and low meat consumption). The 4 factors (healthy, 1 point; unhealthy, 0 points) were summed to form an index that ranged from 0 to 4. Outcomes included confirmed incident type 2 diabetes mellitus, myocardial infarction, stroke, and cancer; mean follow-up was 7.8 years.

There were 27,548 participants originally recruited, of whom 23,153 (8965 men and 14 188 women) were included in the analyses: main reason for exclusion was self-report of diabetes, cardiovascular disease or cancer at baseline (n=3,130). Mean age at baseline was 49.3 years; few had no healthy factors (score 0, 4%) and 9% had all four. Over the follow-up period reported, 2,006 developed an outcome event: despite the small number of individuals with a zero score, enough adverse events occurred in this group to allow reliable evaluation.

After adjustment for confounding factors, the hazard ratio for developing a chronic disease decreased progressively as the number of healthy factors increased. Participants with all 4 factors at baseline had a 78% (95% CI, 72% to 83%) lower risk of developing a chronic disease: compared to those with zero scores, reductions in risk for the specific diseases were diabetes, 93% (95% CI, 88% to 95%), myocardial infarction 81% (95% CI, 47% to 93%), stroke 50% (95% CI, –18% to 79%), and cancer 36% (95% CI, 5% to 57%). Those with intermediate scores had lower risks, with some combinations being more protective than others (e.g. never smoking plus BMI <30: HR 0.28; 95% CI, 0.23 to 0.34).

Overall, the authors conclude that their results confirm the benefits of a healthy lifestyle, and note that adoption of a few healthy behaviours can result in significant reductions in morbidity. They therefore reinforce current recommendations for lifestyles: adherence to all four could produce enormous reductions in the onset of chronic diseases such as diabetes, cardiovascular disease, and cancer.

An accompanying Comment discusses the study.

Arch Intern Med 2009; 169: 1355-62 (link to abstract); Arch Intern Med 2009; 169: 1362-3 (Comment, link to abstract)
Further information on EPIC is available from the study website

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