Priscilla Marsicovetere is Assistant Professor of Medical Education and Surgery, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, and Program Director for the Franklin Pierce University, PA Program, Lebanon, New Hampshire. She practices with Emergency Services of New England, Springfield Hospital, Springfield, Vermont.
The author has no financial relationships to disclose.
In a 2013 retrospective cohort study of 9,116 patients with uncomplicated diverticulosis and 922 patients who developed diverticulitis that required hospitalization, Maguire et al examined the association of prediagnostic serum levels of vitamin D and diverticulitis.24 Among patients with diverticulosis, higher prediagnostic levels of 25-hydroxyvitamin D were significantly associated with a lower risk for diverticulitis—indicating that vitamin D deficiency could be involved in the pathogenesis of diverticulitis.
The association between diverticulitis and vitamin D levels was supported by an additional study in 2015, in which the authors investigated the association between ultraviolet (UV) light and diverticulitis.25 They identified nonelective diverticulitis admissions in the Nationwide Inpatient Sample database and linked hospital locations to geographic UV data. They examined UV exposure in relation to risk for admission for diverticulitis and found that, compared with high-UV (UV4) areas, low-UV (UV1) areas had a higher rate of diverticulitis (751.8/100,000 admissions, compared with 668.1/100,000 admissions, respectively [P < .001]), diverticular abscess (12.0% compared with 9.7% [P < .001]), and colectomy (13.5% compared with 11.5% [P < .001]). They also observed significant seasonal variation, with a lower rate of diverticulitis in winter (645/100,000 admissions) compared with summer (748/100,000 admissions [P < .001]). Because UV exposure largely determines vitamin D status, these findings are thought to support a role for vitamin D in the pathogenesis of diverticulitis.
Genetics
Two studies found an association between genetics and diverticular disease. A 2012 study using The Swedish Twin Registry found that if one twin is affected with the disease, the odds that the other will be affected was 7.15 in monozygotic (identical) twins and 3.20 in dizygotic (fraternal) twins.26 A 2013 Danish twin study found a relative risk of 2.92 in twin siblings compared to the general population.27 Both studies estimated the genetic contribution to diverticular disease to be 40% to 50%.26,27
Obesity
Several large prospective studies have shown a positive association between high BMI, waist circumference, and waist-to-hip ratio and risk for diverticulitis.4 A BMI > 30 was found to increase the relative risk of acute diverticulitis by 1.78, compared with a normal BMI.17 In a large, prospective, population-based cohort study in 2016, Jamal Talabani et al found that obese persons had twice the risk for admission for acute colonic diverticulitis than normal-weight persons did.28 Waist circumference and waist-to-hip ratio were also independently associated with risk for diverticulitis. The pathophysiology of the associations is not clearly understood but may involve pro-inflammatory changes of adipose tissue, which secrete cytokines that promote an inflammatory response, and changes in gut microbiota.4,12
Physical activity
Data on the association of physical activity and diverticulitis is inconsistent. Some studies have found as much as a 25% decrease in the risk for diverticulitis with increased physical activity; more recent studies (2013 and 2016), on the other hand, found no association between diverticulosis and physical activity.11,17,19,28
