What is Diverticulosis?
Diverticulosis is the presence of multiple outpouchings (diverticula) of the intestinal wall that originate from the colonic lumen, caused by herniation of the mucosa and muscularis mucosa through the muscular layer at sites where blood vessels penetrate the colon wall. 1, 2
Anatomical Definition
- Diverticula are acquired structural abnormalities where the inner lining of the colon protrudes through weak points in the muscular wall, specifically at locations where arteries penetrate to supply the colonic mucosa 3, 4
- This condition is asymptomatic in the vast majority of affected individuals and represents an anatomical finding rather than a disease state 2, 4
Epidemiology in Adults Over 40
Age-Related Prevalence
- The prevalence increases dramatically with age: 32.6% in patients aged 50-59 years, rising to 71.4% in those aged 80 years or older 5
- In patients under 40 years, prevalence is less than 10%, but this increases to an estimated 50-66% in those over 80 years 6
- Overall prevalence in general populations undergoing endoscopy is approximately 42%, with 17.5% in unselected general populations 4
Geographic Variations
- In Western populations, diverticula predominantly affect the left colon (sigmoid region) in approximately 90% of cases 7
- In Asian populations, 70-74% of diverticular disease affects the right colon (cecum), representing a dramatic geographic difference 7
- Diverticulosis remains uncommon in Africa (historically 1.85% prevalence), though recent data show increasing rates (up to 10.6%) related to adoption of Western dietary patterns low in fiber 5, 7
Pathophysiology
- The development involves abnormal colonic motility, inadequate dietary fiber intake, and chronic low-grade inflammation 3, 2
- Genetic factors play a role, including variants in the TNFSF15 gene, and familial associations have been documented 1, 4
- The condition is associated with connective tissue disorders (polycystic kidney disease, Marfan syndrome, Ehlers-Danlos syndrome) 1
Clinical Significance
Asymptomatic Nature
- Most individuals with diverticulosis (approximately 75%) remain entirely asymptomatic throughout their lives 2
- The condition is typically discovered incidentally during colonoscopy or imaging performed for other reasons 5
Risk of Complications
- Only 1-4% of patients with diverticulosis will develop acute diverticulitis (inflammation/infection of diverticula) during their lifetime 1, 8
- Among those who do develop diverticulitis, approximately 12% will experience complications such as abscess, perforation, fistula, or stricture 8
- The lifetime risk of developing acute left-sided colonic diverticulitis is approximately 4% among patients with diverticulosis 5
Symptomatic Diverticular Disease
- Approximately 25% of individuals with diverticulosis develop symptomatic diverticular disease, which can range from symptomatic uncomplicated disease to complications like diverticulitis or diverticular hemorrhage 2
Important Clinical Distinctions
Diverticulosis must be distinguished from diverticulitis: diverticulosis is simply the anatomical presence of diverticula without inflammation, while diverticulitis involves inflammation and/or infection of these diverticula with clinical symptoms 1, 2