Lactose maldigestion: increased age-related prevalence in institutionalized children.

A study was performed to determine whether the age-related prevalence of lactose maldigestion is increased in healthy institutionalized children. Previous malnutrition did not exclude children from study. The control children had no prior history of malnutrition or hospital admissions for diarrhea. The anthropometric comparison showed the institutionalized children to be shorter and lighter than the controls, but they were of normal weight by stature, suggesting a normal recent nutritional state. Fasting breath hydrogen tests were performed following an oral dose of lactose 1 g/kg, given as a 10% solution. A rise of breath hydrogen of greater than or equal to 20 ppm was considered to indicate lactose maldigestion. Twenty-two of 44 controls and 39 of 49 study children were lactose maldigesters (p less than 0.01). The control children showed an age-related increase in the prevalence of lactose maldigestion, from 31.6% at age less than 5 years to 75% at age greater than 9 years. The institutionalized children, by comparison had an increased prevalence of 78.8% in the group under 5 years of age (p = 0.002). Equally high prevalence rates were found at all ages tested. At follow-up, lactose maldigestion was persistent in the majority of the study children. This had no nutritional impact despite a regular milk intake. The distinction between acquired and primary lactose maldigestion is of no practical significance in these children.