Low body mass index (BMI) among men entering adult life is associated with an increased incidence of Crohn disease (CD) and ulcerative colitis (UC) up to 40 years later, according to a study published online April 23 in Scientific Reports. Michael A. Mendall, M.D., from Croydon University Hospital in the United Kingdom, and colleagues explored the impact of BMI in men entering adult life on their long-term risk for developing inflammatory bowel disease using data from 377,957 men born from 1939 to 1959.

Adult life is associate

BMI is measure at draft boards (mean age, 19 years) with men follow from 1977 (or time of examination) through 2015. The researchers find that during 13 million person-years of follow-up, 1,523 men develop CD and 3,323 developed UC. Compare with men of normal weight, the risk for CD was as follows: hazard ratio, 1.35 (95% confidence interval, 1.12 to 1.62) for BMI <18.5 kg/m²; hazard ratio, 0.83 (95% confidence interval, 0.68 to 1.02) for BMI 25 to 29.9 kg/m²; and hazard ratio, 1.20 (95%  confidence interval, 0.75 to 1.90) for BMI >30 kg/m².

Until age 60 years, the increase risk for CD in underweight is maintain and was not explain by know effects of smoking. Minor inverse associations are seen for UC. A U-shape association between BMI and CD is sees with restrict cubic splines; but not for UC. “Smoking to fully explain our findings would have had to be associated with an implausibly large effect on BMI;l” the authors write.

Minor inverse associations

n medicine, inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn’s disease and ulcerative colitis. Ulcerative colitis and Crohn’s disease are long-term conditions that involve inflammation of the gut. Ulcerative colitis only affects the colon (large intestine). Crohn’s disease can affect any part of the digestive system; from the mouth to the anus.

People of any age can get IBD, but it’s usually diagnose between the ages of 15 and 40. There are also some less common types of IBD, which you can find out about on the Crohn’s and Colitis UK website. Not everyone has all of these symptoms, and some people may have additional symptoms, including fever, vomiting and anaemia.

 Symptoms of Crohn’s disease

Joint pain (arthritis), painful red eyes (iritis); painful red skin nodules (erythema nodosum) and jaundice (primary sclerosing cholangitis) are less commonly associate with IBD. The symptoms of IBD can come and go. There may be times when the symptoms are severe (flare-ups); follow by long periods when there are few or no symptoms at all (remission). Read more about the symptoms of ulcerative colitis and the symptoms of Crohn’s disease.