- In a prospective cohort of 46,418 men, a score that characterizes the inflammatory potential of dietary intake was significantly associated with the risk of incident diverticulitis
- Diverticulitis was also associated with plasma levels of two biomarkers of chronic inflammation, C-reactive protein and interleukin-6
- Chronic, systemic inflammation potentially underlies the effects of diet on the development of diverticulitis, and an anti-inflammatory diet is a reasonable recommendation to patients who want to reduce their risk of the disease
No proven medical treatment exists for diverticulitis, largely because the etiology of the disease is poorly understood. According to conventional thinking, diverticulitis results from obstruction of a diverticulum, with subsequent ischemia and microperforation leading to inflammation. However, recent studies suggest chronic inflammation and changes in the gut microbiome may be key factors in the development of the disease.
Wenjie Ma, MBBS, ScD, research fellow at Massachusetts General Hospital, Andrew T. Chan, MD, MPH, director for cancer epidemiology in the Mass General Cancer Center, chief of the Clinical and Translational Epidemiology Unit (CTEU) in the Department of Medicine and vice chief for clinical research in the Division of Gastroenterology, and colleagues recently became the first to prospectively study the role of chronic inflammation in the pathogenesis of diverticulitis. In Clinical Gastroenterology and Hepatology, they confirm the inflammatory potential of diet and report that pre-diagnostic plasma levels of markers of inflammation are associated with incident diverticulitis.
The researchers analyzed 46,418 men in the Health Professionals Follow-Up Study, a prospective cohort of male health professionals who were 40 to 75 old at enrollment in 1986. They complete health questionnaires every two years, including a validated 131-item food frequency questionnaire every four years. These men were followed from 1986 through 2014 and did not report a diagnosis of diverticulitis, cancer or inflammatory bowel disease in 1986.
For each participant, the researchers calculated the Empiric Dietary Inflammatory Pattern (EDIP) score, the weighted sum of 18 food groups that indicates the inflammatory potential of diet. Specifically, high scores identify a dietary pattern most predictive of three plasma markers of chronic inflammation: C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor–receptor superfamily member 1B (TNFRSF1B).
Prospective Cohort Study
The researchers documented 1,110 cases of diverticulitis during the follow-up period. After adjustment for age and lifestyle factors, participants in the highest quintile of EDIP score had a 30% higher risk of diverticulitis than those in the lowest quintile (HR, 1.31; 95% CI, 1.07–1.60; P for trend = .01).
Further analysis suggested the association between EDIP score and diverticulitis might be attributable in part to the intake of red meat, which is considered a risk factor for diverticulitis, and dietary fiber, which is thought to be protective. Body mass index and vigorous exercise did not modify the association.
Nested Case-control Study
The researchers identified a subgroup of 310 participants who provided a blood sample between 1993 and 1995 and developed diverticulitis by the end of 2012. Each case was matched to one randomly selected diverticulitis-free control based on age at the time of blood draw, month and year of the blood draw and fasting status.
After adjustment for potential confounders:
- CRP: Participants in the highest quintile had an 85% higher risk of diverticulitis than participants in the lowest quintile (RR, 1.85; 95% CI, 1.04–3.30; P for trend = NS)
- IL-6: Participants in the highest quintile had twice the risk of diverticulitis compared with participants in the lowest quintile (RR, 2.04; 95% CI, 1.09–3.84; P for trend = NS)
- TNFRSF1B was not significantly associated with the risk of diverticulitis
These results support the view that low-grade chronic inflammation is a mechanistic pathway for diverticulitis. For patients who want to reduce their risk, a reasonable recommendation is to follow an anti-inflammatory diet. For example eating a high amount of green leafy vegetables, dark-yellow vegetables, coffee and tea and low consumption of red meat, processed meat, refined grain and sugary beverages.
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