Obesity and irritable bowel syndrome: a comprehensive review.

Obesity and irritable bowel syndrome (IBS) are prevalent in the United States and cause significant morbidity in those affected. However, it is unclear whether obesity is more prevalent in those affected by IBS or if IBS is more prevalent in obese persons. To evaluate the association between obesity and IBS, a comprehensive review was performed by searching MEDLINE and Embase from 1980 through July 2012. Studies were included if 1 of the outcomes examined the relationship between excess body weight or obesity and IBS. A total of 11 studies (2 pediatric and 9 adult) investigated the relationship between obesity and IBS. The prevalence of obesity in children with IBS ranged from 24.8% to 42%. In adults, the prevalence of IBS in obese subjects varied from 11.6% to 24%, depending on the study population. Two studies did not show increased odds of IBS in obese patients; however, 2 studies showed that symptoms were more severe in obese patients affected by IBS, while 1 of these studies demonstrated that IBS symptom severity improved after bariatric surgery. The findings of this comprehensive review of the literature suggest that the frequency of IBS in obese children and adults is variable and depends on the study population. Due to the heterogeneity in study populations, outcome assessment, and methodology in the existing literature, further studies are needed to determine whether obesity is associated with IBS.