Lactose malabsorption and giardiasis in Basotho school children.

The prevalence of primary, adult-type, lactose malabsorption was assessed by means of the hydrogen breath test after intake of 360 ml of full cream milk (approximately 18 g lactose) in 96 randomly selected Basotho school children, aged 5-15 years. Of 86 children who did not have diarrhoea in the previous week 82 (85%) were lactose malabsorbers, while 4 (5%) could not be classified because of undetectable hydrogen excretion. Milk intolerance presenting as diarrhoea was significantly (p less than 0.01) more common in children who associated previous abdominal complaints with milk intake and/or did not like milk. A negative hydrogen breath test was significantly (p less than 0.05) more often observed in children who had diarrhoea in the previous week. Giardia was present in 18 (19%) of 93 children. The incidence of giardiasis did not correlate with the presence of lactose malabsorption in children without diarrhoea in the previous week. However, milk intolerance presenting as diarrhoea was significantly (p less than 0.05) more common in children with giardiasis. The findings support the use of physiological quantities of milk in Basotho school children.