Lactose malabsorption in children and adolescents: diagnosis through breath hydrogen test using cow milk

Abstract

Objective: to determine the prevalence of lactose malabsorption and its association with skin color and age in children and teenagers attending public schools in Porto Alegre, Brazil. Methods: a cross-sectional study was performed with 225 subjects between 8 and 18 years attending two public schools in Porto Alegre, Brazil. Patients were randomly selected. Subjects were classified according to skin color (white and nonwhite) and age group (8 to 12 and 13 to 18 years). Lactose malabsorption was diagnosed using the breath hydrogen test after ingestion of 250 ml of whole cow milk. The test lasted for 3 hours, with collections after fasting and 60, 120, and 180 minutes after milk ingestion. Malabsorption was determined in the presence of increase of >20 ppm in hydrogen concentration regarding the basal levels. Results: two-hundred and twenty-five students were studied, with a mean age ± standard deviation of 12.2 ± 2.0 years. The subjects consisted of 134 females (59.6%); 154 white (68.4%); and 71 nonwhite. Lactose malabsorption was observed in 19/225 cases (8.4%). It was diagnosed in 8/154 white patients (5.2%) and in 11/71 nonwhite patients (15.5%) (P= 0.02). Regarding the age group, we found 15/143 cases of malabsorption in students between 8 and 12 years (10.5%), and 4/82 cases in students between 13 and 18 years (4.9%) (P = 0.227). Conclusions: the prevalence of lactose malabsorption in students attending public schools in Porto Alegre is significant, especially if we consider that the physiological doses (250 ml of milk) were used for diagnosis. The malabsorption rate was higher among nonwhite children, which confirms the influence of race on primary adult type hypolactasia. No association was observed between lactose malabsorption and age group.

Correlation between lactose absorption and the C/T-13910 and G/A-22018 mutations of the lactase-phlorizin hydrolase (LCT) gene in adult-type hypolactasia

“…The prevalence of adult-type primary hypolactasia, assessed by the lactose tolerance test, ranges from 38% in Caucasians to 95% in Blacks (17,18), with high regional differences due to the ethnic heterogeneity of the Brazilian population. An 8.4% prevalence of lactose malabsorption assessed by the HBT has been shown in the Brazilian pediatric population (19). Recently, a 53% prevalence of hypolactasia was identified in white individuals and a 91% prevalence was identified in nonwhite individuals by measuring lactase activity by immunohistochemistry in the duodenal mucosa (13).…”

Perspectives for Early Genetic Screening of Lactose Intolerance: - 13910C/T Polymorphism Tracking in the MCM6 Gene

“…In these, considering the -13910C/T polymorphism as a diagnostic test for lactose intolerance, the CC genotype presence was estimated to have a sensitivity of 100%, specificity of 83%, positive predictive value of 76% and negative predictive value of 100% [20][21][22]. Another study was carried out in Brazil, specifically in children under lactose intolerance suspicion, was performed by means of expired H2 test without the genetic test, being the prevalence of 84% of lactose malabsorption in this Brazilian pediatric population [34].…”