Living healthily could substantially lower the risk of developing diverticulitis, even for people with a higher genetic predisposition, according to new research published in Gut.
The findings highlight the powerful role of lifestyle choices in reducing the likelihood of this common digestive condition, which affects the large intestine.
Diverticulitis occurs when small bulges or pouches in the lining of the colon become inflamed or infected.
The condition is a frequent cause of hospital admissions and can lead to serious complications requiring emergency surgery.
To explore how lifestyle and genetics interact in relation to diverticulitis risk, researchers examined data from over 179,000 participants enrolled in three major long-term studies: the Nurses’ Health Study, NHSII, and the Health Professionals Follow-Up Study.
Each participant was assigned a healthy lifestyle score ranging from zero to five, based on five factors: body weight, smoking status, physical activity, dietary fibre intake, and consumption of red and processed meats.
Over two decades of follow-up, more than 10,000 new cases of diverticulitis were recorded. The analysis showed that each positive step in the lifestyle score was linked to a 12% reduction in risk.
Participants with the healthiest lifestyles — scoring five — were 50% less likely to develop diverticulitis than those scoring zero.
Individual lifestyle choices also made a clear difference. For example, being overweight raised the risk by 32%, while obesity increased it by 44%.
Smokers and former smokers faced a 13 to 17% higher risk compared to those who had never smoked.
Greater physical activity reduced the likelihood of diverticulitis by 16%, while higher fibre intake lowered risk by 14%. In contrast, consuming more red and processed meat raised the risk by 9%.
The influence of genetics was assessed through a polygenic risk score (PRS) calculated from genetic data of over 36,000 individuals.
Higher PRS was strongly linked to increased diverticulitis risk — those with a higher genetic risk were up to 58% more likely to develop the condition, especially under the age of 60.
However, a healthy lifestyle appeared to counteract genetic susceptibility. People with the highest genetic risk but who followed healthier habits were 50% less likely to develop diverticulitis than those with poor lifestyle choices. Further analysis suggested that between 23% and 42% of cases could potentially be prevented through healthy living, regardless of genetic risk.
These results were consistent across multiple racial groups, and confirmed in two additional large datasets, including the Southern Community Cohort Study and the Mass General Brigham Biobank.
While the study is observational and cannot establish direct cause-and-effect, it underscores the significant impact of modifiable behaviours. According to the authors, even individuals at high genetic risk can benefit greatly from adopting simple healthy habits.
