Diverticulitis is a condition of the digestive system that occurs when small pouches, known as diverticula, become inflamed or infected. These pouches develop when weak areas in the intestinal wall bulge outward over time. This formation of pouches is called diverticulosis and is particularly common in older adults.
By the age of 60, approximately half of all adults are estimated to have diverticulosis. While the exact cause of diverticulosis is still unclear, a mix of factors including age, genetics, underlying medical conditions, and lifestyle choices may all contribute.
In most cases, diverticulosis causes no symptoms, which is why many people are unaware they even have it. However, if one of these pouches tears or becomes infected, the result is diverticulitis. This can trigger sudden and persistent abdominal pain, typically worsening over a few days.
Although fewer than 5% of people with diverticulosis go on to develop diverticulitis, once you’ve had it, there’s a significant chance it could recur. Understanding the possible causes and contributing risk factors may help you lower your risk of developing diverticulitis in the future.
Theories Behind the Cause
There is no definitive explanation as to why diverticulitis develops, but several prominent theories have emerged to help researchers understand what might trigger the inflammation or infection of the pouches.
trapped stool or bacteria
One possibility is that stool or bacteria gets lodged inside the diverticula. Once trapped, the bacteria can multiply, leading to infection and resulting in symptoms such as pain, cramping, and fever.
microbiome changes
The gut microbiome contains a vast array of organisms, including beneficial bacteria. These microbes work together to support digestion and immune function. Disruptions—such as those caused by antibiotics or drastic dietary changes—can throw off this balance, potentially increasing the risk of inflammation and diverticulitis.
chronic inflammation
While short-term inflammation is the body’s way of healing injuries or fighting infection, chronic inflammation can become harmful over time. Some researchers believe that persistent inflammation in the colon, perhaps influenced by diet or autoimmune disorders, may raise the likelihood of developing diverticulitis.
Is Diverticulitis Hereditary?
Recent studies suggest that diverticulosis and diverticulitis may have a genetic component. Having a parent or sibling with the condition may increase your own risk.
specific genes linked to diverticulitis
Genes such as ARHGAP15, COLQ, and FAM155A have been associated with diverticular disease. These genes are believed to influence immune response and inflammation. Variants of the FAM155A gene, in particular, have been tied to a higher risk of developing diverticulitis.
Researchers estimate that genetics account for about 40% to 50% of the risk. However, a genetic predisposition does not guarantee that you will develop diverticulitis. Environmental and lifestyle factors also play a major role.
Who Is at Risk?
While only a small percentage of people with diverticulosis will progress to diverticulitis, certain demographics are more prone to the condition.
age and sex
Diverticulitis is most common in people over 60. Among younger individuals under age 50, it tends to be more frequent in those assigned male at birth. In contrast, among older adults, it is slightly more common in those assigned female at birth.
ethnicity
Statistically, White Americans are more likely to develop diverticulitis than Black or Latinx Americans.
Risk Factors That Increase Your Chances
There are several environmental and lifestyle factors that can elevate your risk of developing diverticulitis. Many of these are modifiable, meaning you can take steps to reduce your risk.
low-fiber diet
Eating too little fiber and consuming too much red meat while neglecting fruits and vegetables can make your stool harder to pass. This puts added pressure on your intestines, potentially leading to the formation of diverticula. People with higher fiber intake are significantly less likely to develop diverticulitis.
smoking
Smoking contributes to chronic inflammation and negatively affects intestinal muscle tone and function. Nicotine in cigarettes can impair gut motility, which is thought to increase the likelihood of diverticulitis.
obesity
Having a body mass index (BMI) of 30 or higher has been linked to an increased risk. Excess body fat can create systemic inflammation and may also alter the gut microbiome, both of which are risk factors for diverticulitis.
certain medications
Drugs such as NSAIDs, corticosteroids, and opioids are associated with a higher risk. These medications may weaken the bowel walls or increase the risk of tears, potentially leading to bleeding or infection in the diverticula.
lack of physical activity
A sedentary lifestyle can raise the risk of diverticulitis. Regular physical exercise may help reduce this risk by about 25%, possibly due to better bowel motility and reduced inflammation.
underlying health conditions
Health problems such as high blood pressure and immune system deficiencies (e.g., kidney disease) have been correlated with a greater risk of diverticulitis.
geographical differences
Western nations tend to have higher rates of diverticulitis, which is often attributed to low-fiber, high-sugar diets. Populations in regions where fiber-rich diets are more common tend to experience fewer cases.
A Quick Review
Diverticulitis occurs when small intestinal pouches become inflamed or infected. While the exact cause remains unclear, it is believed to result from a combination of genetic vulnerability, lifestyle factors, and environmental influences.
The condition is more common in aging populations and in countries where low-fiber diets are widespread. Smoking, lack of exercise, certain medications, and obesity are all associated with increased risk.
Taking preventive steps—such as eating more fiber, staying physically active, and avoiding smoking—may reduce your chances of experiencing diverticulitis, especially if you already have diverticulosis.
