Breath hydrogen studies of lactose malabsorption in children resident in New Zealand, Cook Islands and Western Samoa

Abstract

Lactose malabsorption (LM) in children was diagnosed by an elevated breath hydrogen (BH) level following a 10g lactose load. A portable gas chromatograph and a semiconductor detector, designed and constructed for use in the Pacific Islands is described. Following verification on known malabsorber and. normal subjects, the technique was used to determine the prevalence of LM in Europeans at Auckland and Rarotonga, and in Samoans at two locations in Auckland and two locations in Western Samoa. The prevalence of LM in Europeans was significantly (p<0.01) higher at Rarotonga than at Auckland. For Samoans, the prevalence of LM was significantly (p<0.01) higher in Western Samoa than at Auckland. The prevalence of LM was very highly significantly (p<0.001) related to race. Each child tested for LM filled in a questionaire to determine attitude, consumption of and perceived intolerance to milk, milk biscuits and ice cream. Lactose malabsorption was significantly (p<0.05) correlated to milk consumption and to attitude to dairy products, but not to sex, age, and perceived intolerance. The consumption of dairy products was very highly significantly (p<0.0001) correlated to attitude, and highly significantly (p<0.001) correlated to location and perceived intolerance. There was no significant correlation between consumption and race, sex or age. Perceived intolerance to individual dairy products was significantly correlated to attitude to milk (p<0.0001), milk biscuits (p<0.02) and ice cream (p<0.001). Perceived intolerance was not related to age, sex, race, location or the actual symptoms following the consumption of 10g lactose. The unexpected finding of increased LM in the Pacific Islands, was investigated further by studying the LM status of the Medical Team during a visit to western Samoa, and by performing a microbiological survey of water quality. It was found that half of the Medical Team 3/6, became malabsorbers during the week spent in Western Samoa. On returning to New Zealand it was shown that lactase levels took 3 months to normalise. The water supply in Western Samoa was shown to contain very high levels of coliform bacteria. The currently held hypothesis that genetic factors are solely involved in the onset of LM, was not supported. The evidence from the survey supported environmental factors are also involved in adult onset LM. The hypothesis suggesting that dietary lactose was a requirement for retaining elevated lactase levels, was tested using Galactosemic and Phenyl Ketonuria patients. None of the patients had developed LM although they had been on a low lactose diet for years, hence the theory was not supported. The BH method proved highly successful in diagnosing LM with many of the children actually enjoying it.