High consumption of red meat, particularly unprocessed red meat, is associated with an increased risk for diverticulitis, according to a study published online January 9 in Gut.

"Our fidings were generally in line with our prior early analysis that red meat, but not poultry or fish, is associated with an increased risk of diverticular disease," write Yin Cao, ScD, from the Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, and colleagues.

However, the current cohort included longer follow-up and twice as many cases, which allowed the researchers to restrict their analysis to diverticulitis alone and exclude related conditions.

Dr Cao and colleagues analyzed prospectively collected data from 46,461 men to test the association between meat consumption (total red meat, red unprocessed meat, red processed meat, poultry, and fish) and the risk for incident diverticulitis.

The men were participants in the Health Professionals Follow-Up Study and were 40 to 75 years of age at the time of enrollment in 1986. During the 26-year follow-up (through 2012), the men responded to questionnaires every 2 years to collect data on demographics, lifestyle, medical history, and disease outcomes, and every 4 years to collect data on dietary intake.

There were 764 cases of incident diverticulitis during the 651,970 person-years of follow-up.

Men in the highest quintile of total red meat consumption had the highest risk for incident diverticulitis (relative risk [RR], 1.58; 95% confidence interval [CI], 1.19 - 2.11; P for trend = .01) compared with men in the lowest quintile for this category. The RR was determined after adjusting for variables such as fiber intake, age, activity, nonsteroidal anti-inflammatory use, smoking history, and body mass index.

The researchers found that this association was stronger for unprocessed red meat (RR for the highest vs lowest quintiles: 1.51; 95% CI, 1.12 - 2.03; P for trend = .03) compared with processed red meat (RR, 1.03; 95% CI, 0.78 - 1.35; P for trend = .26).

The authors also note that the relative risk for diverticulitis increased by 18% for each serving of red meat per week, but that the risk plateaued after 6 servings per week.

Further, they found that substituting poultry or fish for one serving of unprocessed red meat per day reduced the relative risk by 20% (RR, 0.80; 95% CI, 0.63 - 0.99), after adjusting for other factors.

The authors found no increased diverticulitis risk associated with fish or poultry consumption

Men with a previous diagnosis of diverticulosis, inflammatory bowel disease, or gastrointestinal cancer at baseline, as well as those lacking data on meat, poultry, and fish intake, were excluded from the analysis. The authors defined diverticulitis as "abdominal pain attributed to diverticular disease and one of the following criteria: (1) complicated by perforation, abscess, fistula or obstruction; (2) requiring hospitalization, antibiotics or surgery or (3) pain categorized as severe or acute or abdominal pain presenting with fever, requiring medication or evaluated using abdominal CT."

The authors note that the data may not be generalizable to other populations and acknowledge study limitations such as the possible misclassification of self-reported outcomes, inaccurate recall of meat consumption, or the potential for residual confounding.

Although the mechanism underlying these associations is unclear, Dr Cao and colleagues conclude, "[t]he findings may provide practical dietary guidance for patients at risk of diverticulitis."

Funding for this study was provided through grants from the National Institutes of Health. The authors have disclosed no relevant financial relationships.

Gut. Published online January 9, 2017. Abstract

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