Epidemiology of altered intestinal permeability to lactulose and mannitol in Guatemalan infants

Background: Subclinical alterations of small intestinal function have been reported frequently in tropical countries. Studies of small intestinal perm eability to lactulose and mannitol were therefore completed in Guatemalan i nfants from a low-income, periurban community to assess the prevalence of a ltered intestinal function and the factors associated with this condition. Methods: Two hundred studies were successfully completed in 158 infants who had been free of diarrhea for at least 1 week before the day of study. Uri nary concentrations of lactulose and mannitol during the 5-hour period afte r ingestion of 400 mg/kg body weight of lactulose and 100 mg/kg body weight of mannitol were measured by gas-liquid chromatography and compared by age group, feeding practices, anthropometric indexes, and serum iron and zinc concentrations. Results: The overall prevalence of altered intestinal permeability (defined as a ratio of urinary recovery of lactulose to mannitol [L/M] greater than or equal to 0.07) was 30%. The urinary L/M recovery ratio was positively a ssociated with age: low weight for age; and, in infants less than 6 months of age, non-breast-feeding. Children with serum iron concentrations less th an 7.16 mu M/l (40 mu g/dl) had higher median L/M ratios (L/M = 0.968; 95% confidence interval [CI], 0.054, 0.085) than those with iron levels higher than this cutoff (L/M = 0.052; CI = 0.046, 0.058; p = 0.038). The median ur inary UM recovery ratio in 10 currently asymptomatic infants who had diarrh ea during the week before testing (0.087; CI = 0.49, 0.154) was higher than that in children who had been free from diarrhea for at least 1 week (0.05 2; CI = 0.048, 0.056, p = 0.01). Conclusion: Age, feeding practices, low weight-for-age, low serum iron conc entration, and recent diarrhea were all associated with altered intestinal function in this group of Guatemalan infants.