Healthy lifestyle could protect against Crohn’s disease and colitis…


Boston – Avoiding risk factors and living a healthy lifestyle could prevent up to 60% of all inflammatory bowel disease. This is the result of an analysis of 3 US prospective observational studies Gut (2022: DOI: 10.1136/ gutjnl-2022-328174) confirmed in 3 European studies.

Ulcerative colitis and Crohn’s disease are closely linked to lifestyle in industrialized countries. In the second half of the 20th century, the number of cases increased sharply, especially in North America and Europe. In the meantime, they seem to have reached a plateau here or are even declining slightly, while there is a significant increase in some economic growth countries in Asia and South America, but also in Africa.

Epidemiologists link the increase to some modifiable risk factors, with differences between ulcerative colitis and Crohn’s disease. People who have never smoked and are not obese are less likely to develop Crohn’s disease. On the other hand, smokers and obese people are less likely to develop ulcerative colitis.

Other “low risk” criteria that protect against Crohn’s disease also include avoiding non-steroidal anti-inflammatory drugs (NSAIDs), physical activity and a high intake of fruit, vegetables and fiber. In ulcerative colitis, avoidance of NSAIDs and high consumption of fruit and vegetables are among the “low risk” criteria. In addition, avoiding red meat and consuming polyunsaturated fatty acids appear to protect against this disease.

A team led by Hamed Khalili from Massachusetts General Hospital in Boston used the risk factors mentioned to form a simple risk score (MRS), in which failure to achieve the 6 individual goals was given a point of 1.

For Crohn’s disease, the goals were: BMI under 30, never smoker, less than 2 NSAIDs per week, top quintile for exercise, fruit/vegetable consumption, and fiber. In ulcerative colitis, the protective factors were: a BMI of 30 or greater, active smoking, less than 2 NSAIDs per week, and the top quintile for fruit/vegetables and monounsaturated fat and the bottom quintile for red meat consumption. Whoever achieves all goals has 0 points, whoever misses all goals has 6 points.

The researchers initially applied the MRS to the two “Nurses Health Studies” and to the “Health Professionals Follow-up Study”. There, over 5.1 million person-years, there were 346 cases of Crohn’s disease and 456 cases of colitis come colitis.

Result: People who missed all 6 targets were 4.15 times more likely to develop Crohn’s disease than people who missed at most 1 target. The adjusted hazard ratio of 4.15 was significant with a 95% confidence interval of 1.95 to 8.84. For ulcerative colitis, the adjusted hazard ratio was 2.78 (1.47-5.25).

Extrapolated to the population, 42.9% (12.2-66.1%) of Crohn’s disease and 44.4% (9.0-69.8%) of ulcerative colitis cases could be avoided if the population would avoid the risks mentioned (except for a maximum of 1). The prerequisite, however, is that the risk factors identified in epidemiological studies are based on causality, which is never entirely certain.

In a second calculation, the researchers examined the influence of a healthy lifestyle. The basis was the recommendations of US professional societies.

These included: BMI between 18.5 and 25; never smoke; at least 7.5 weekly MET hours (MET is the calorie consumption in excess of the basal metabolic rate); at least 8 daily servings of fruits and vegetables; less than half a daily serving of red meat; at least 25 g fiber/day; at least 2 weekly servings of fish; at least half a daily serving of nuts/seeds; and a maximum of 1 alcoholic drink/day for women or 2 for men.

Here, too, a clear influence on the risk of disease was recognizable. According to Khalili’s calculations, a healthy lifestyle could reduce 61.1% (16.8-84.9%) of Crohn’s disease and 42.2% (1.7-70.9%) of ulcerative colitis cases prevent – ​​but here too on the condition that the correlation is based on causality.

The researchers verified the results in 3 European cohort studies. These were the Swedish Mammography Cohort with 37,275 participants, the Cohort of Swedish Men with 40,810 participants and the European Prospective Investigation into Cancer and Nutrition (EPIC) with 404,144 participants. The results were confirmed for both MRS and healthy lifestyle.

The results do not mean that people can safely avoid both diseases by avoiding the risk factors and living a healthy lifestyle. One of the limitations of the study is that some established risk factors from early life were not considered.

These are, for example, antibiotic treatments in childhood and environmental factors, while breastfeeding is said to protect against disease. The influence of other factors is currently being investigated. This includes the intake of emulsifiers, which are mainly found in complex, industrially produced foods. They could damage the intestinal lining and facilitate the entry of bacteria, which then trigger the chronic inflammation. © rme/

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