More Young People Are Getting Diverticulitis — Here’s Why

You’ve probably seen headlines about the rising rates of colorectal cancer among people under 50. But did you know that other digestive diseases are also increasing among young people? One of them is diverticulitis, the inflammation of small pouches that form in the colon.

Diverticulitis is not fun, but there are ways to treat it and to prevent getting it in the first place. Here’s everything you need to know about the condition and why young people are getting it more.

What causes diverticulitis?  

Diverticulitis is the inflammation of small pouches, called diverticula, that form in weak spots in the wall of your colon.

“It’s like when a car tire is weak in one area and it bulges out,” says David Flum, MD, MPH, a researcher and general surgeon at UW Medicine and a professor of surgery, public health and pharmacy at UW School of Medicine.

Diverticula are very common and not inherently harmful — in fact, 80% of people will have them by the time they’re 80 years old. Diverticulitis often comes on suddenly. It can be mild — and easily treated with rest and diet changes — or severe. Severe diverticulitis causes acute abdominal pain on your lower left side, along with fever, nausea and changes in your stool. The most extreme cases require emergency surgery.

For some people, these episodes become chronic and, like many inflammatory digestive conditions, it’s not clear what triggers them.

“It's vexing because it has a recurrent nature to it — for a lot of people, it doesn't just happen once and go away; it occurs multiple times over the course of multiple years,” says Flum. “It can lead to a lot of distress and quality of life limitations.”

Why are more young people getting it?

Until recently, diverticulitis was thought of as a disease in people over 60 — the older you get, the more time for diverticula to form. But that’s beginning to change.  

“We’re seeing more and more occurrence in people who are younger, in their 20s, 30s and 40s, and the average age of first diagnosis has come down over the last two decades,” says Flum.

Younger people's cases tend to be more severe, as well. A recent study found that from 2005 to 2020, the proportion of adults in the U.S. under 50 admitted to the hospital for diverticulitis increased from 18.5% to 28.2%. 

Researchers still don’t know exactly what is causing this increase in diverticulitis among younger people, but it seems likely to be tied to inflammation of the gut in general.  

“If you think about it that way, anything that increases inflammation in the gut is likely going to increase episodes of diverticulitis,” says Flum. “And we think that more people have more inflammation at younger ages now than ever before due to diet, external factors and maybe environmental factors.”

This theory also helps explain the increase in other inflammatory bowel diseases in Western society, like Crohn’s and ulcerative colitis. Gut inflammation could also be connected to the increase in colorectal cancer in people under 50.

How can you prevent it from happening in the first place?

Because diverticulitis often becomes chronic, it’s ideal to prevent it in the first place. While, again, it’s not entirely clear what causes it — and it likely has a genetic component that’s not in anyone’s control — there is one lifestyle factor that is highly correlated with the disease: your diet.  

“We think diets that are high in red meat, high in heavy alcohol use and low in fiber can increase the risk of diverticulitis,” says Mariam Hantouli, MD, a research assistant professor in UW School of Medicine’s Department of Surgery. “And diets that are higher in fruits and vegetables and nuts and lean meat seem to be associated with decreased risk of diverticulitis.”

In other words, the best thing you can do to prevent diverticulitis is to load your plate up with fruit, vegetables and whole grains. Flum recommends the Mediterranean Diet, in particular, which emphasizes veggies, whole grains and lean proteins.

He also stresses the importance of regular exercise, maintaining a healthy weight and not overusing nonsteroidal anti-inflammatory drugs like ibuprofen.  

What do we know about preventing recurrence?

If you do get diverticulitis, there is good news and bad news. The good news is that the disease is very treatable.  

“The vast majority of people don't need surgery and really don't even need to be hospitalized,” says Flum.  

The bad news is that after you get it the first time, there is a 20% chance it’s going to recur, and if it recurs once, it’s more likely to come back a third and fourth time. And unfortunately, doctors don’t actually know what will help prevent recurrence.  

“Right now, we all recommend a high fiber diet for patients despite the lack of evidence on how much that actually decreases the risk of diverticulitis in the future,” says Hantouli.  

She is part of a team led by Flum investigating this with funding from the National Institutes of Health and the Patient-Centered Outcomes Research Institute. They're conducting a randomized control trial, the most reliable kind of medical study, that compares the effects of the Mediterranean Diet on recurrence and inflammatory markers in the gut versus the standard recommendation of a high fiber diet. They hope to have results later this year.  

What about severe cases?

For the small minority of people who get a more severe form of diverticulitis, it can be an ordeal.  

“For some people, the diverticula get so inflamed and infected that it really is an actual hole in the diverticula, bacteria escape and it causes a pus pocket to form in the belly,” says Flum.

This is extremely painful and requires going to the hospital to get the pus drained with a needle or sometimes a more major abdominal surgery that requires stool to be diverted into a colostomy bag. These treatments are very effective, but they are disruptive and invasive, and because there is no way to know when an episode will occur, it can be hard for people to travel or even leave the house.  

Some people even opt for an elective surgery to remove the part of colon with the diverticula prophylactically to avoid emergency surgery and prevent recurrence.  

But UW researchers are also looking into whether this is the best choice — they’ve found that 80% to 90% of emergency surgeries happen in the first episode, meaning that if you get it again, it’s unlikely to be so severe you’ll need surgery. And if you didn’t need surgery the first time, you’re also unlikely to need it for future recurrences.  

Flum and his team are conducting another study that is further investigating whether elective surgery or medical management and lifestyle changes lead to bigger improvements in the quality of life of 254 people with diverticulitis — it’s the largest randomized control trial of its kind in the world.  

So while living with recurrent diverticulitis can be challenging, researchers like Flum and Hantouli are trying to get answers for how to better treat and manage the condition.  

And in the meantime, the best thing you can do for your gut is to eat more vegetables, fruits and nuts and stay active as much as you’re able.