FHW Wong, CY Yeung, AYC Tam, KW Fung

Abstract

280 Chinese school children were investigated for lactose malabsorption by the breath hydrogen (H₂) test. A modified anaesthetic bag system was developed to obtain the end-expiratory fraction of the expired air for the test. This has proven to be a highly efficient equipment to obtain the end-expiratory portion of a single breath from children. An oral lactose load of 1 gm/kg body weight was used, and the response in the rise of breath H₂ was studied. The results showed two children populations, with an apparent cut-off point of 20 ppm which is the conventional criteria for distinguishing the lactose-absorbers from the malabsorbers, with the latter demonstrating higher breath H₂ responses. Blood glucose profile studies have also validated the breath H₂ test to be useful in identifying lactose malabsorption in children. The frequency of lactose malabsorption in Chinese children as inferred by the breath H₂ test was found to rise from 21% at 3-5 years to over 57% beyond 6 years of age. Milk produced less breath H₂ than equivalent amount of aqueous lactose in the same children studied.