Disaccharidase activities in Belgian children: reference intervals and comparison with non-Belgian Caucasian children

Aim: To establish reference values for disaccharidase activities in Belgian children and to compare enzyme activities with those of non‐Belgian Caucasian children. Methods: Data from Belgian children who had undergone endoscopic jejunal biopsies (1994–2000) for suspected malabsorption were reviewed. The patients were divided into three groups based on histology: (A) normal (n= 201), (B) moderate changes (n= 58) and (C) (sub)total atrophy (n= 14). The 95% reference limits for disaccharidase activities (U/g protein) were calculated for group A after exclusion of patients with a positive hydrogen breath test, a history of lactose intolerance or coeliac disease (final population: n=151, 0.1–12 y). Values were compared with those of 34 non‐Belgian Caucasian children with normal histology (28 of Mediterranean origin). Results: The reference limits (90% confidence interval) were 86 (65–111)–423 (366–494) for maltase, 9 (6–12)–91 (78–122) for lactase and 24 (18–30)–155 (120–184) for sucrase. No gender‐related differences in enzyme activities were found. Lactase levels showed a slight decrease with increasing age. Disaccharidase activities of children with histologically confirmed mucosal injury were significantly lower than those of children with normal histology: median values for groups A, B and C were 208, 181 and 96, respectively, for maltase, 40, 28 and 7, respectively, for lactase and 69, 54 and 25, respectively, for sucrase. Median disaccharidase activities in biopsies with normal histology were lower in non‐Belgian children, the difference being only statistically significant for lactase, 33 versus 40. Conclusion: The reference values for Belgian children are well in line with other reported values from Caucasian children. Although enzyme activities are lower in children with histologically confirmed mucosal damage, they do not allow differentiation between histology groups. Lower lactase values were found in non‐Belgian children.