Lactose absorption and malabsorption in healthy German children: improved phenotypic resolution by simultaneous determination of breath hydrogen and carbon dioxide.

A total of 124 apparently healthy German children aged 8 to 10 years were examined for lactose absorption employing the breath hydrogen test with multiple breath collection. Analysis of the maximal change of breath hydrogen concentration (delta maxH2) 110 and 150 min after a lactose load of 30 g failed to yield a bimodal distribution separating lactose absorbers and malabsorbers as observed in adults. Comparison with an adult control group of 120 subjects showed that the mean CO2 concentration was significantly lower and the coefficient of variation was considerably higher in the breath samples of the children. The difference between the highest and the lowest CO2 concentration in the three samples obtained from each individual was also significantly higher in the group of children. Normalizing the children's H2 concentration values to the mean CO2 concentration in the total group (3.04%) yielded a bimodal distribution of the delta maxH2 values. Of 124 children, 18 were identified as lactose malabsorbers. The 14.5% frequency is similar to that observed in German adults.