Lactose malabsorption in children and adolescents with inflammatory bowel disease.

Lactose breath hydrogen tests were given to 70 children and adolescents with chronic ulcerative colitis and Crohn's disease in order to determine the prevalence of lactose malabsorption in childhood inflammatory bowel disease. Twenty-nine percent of these patients demonstrated lactose malabsorption; the majority of these children (70%) experienced gastro-intestinal symptoms during the test. The prevalence was not significantly different whether the diagnosis was ulcerative colitis or Crohn's disease. With the exception of those with diffuse small bowel disease, the location of intestinal involvement with Crohn's disease and the severity of clinical symptoms did not affect lactose malabsorption. Lactose malabsorption was not more frequent in patients with inflammatory bowel disease than in a group of children with recurrent abdominal pain and normal gastrointestinal x-rays, although significant differences in the prevalence of lactose malabsorption were observed in relation to ethnic background. Milk incubated with commercially available yeast lactase (lactAid, Surgarlo Co., Atlantic City, N.J.) for greater than 24 h prevented an increase in breath hydrogen when administered to 6 patients previously shown to have lactose malabsorption.