Environmental and behavioural risk factors for prolonged diarrhoea in Nigerian children.

Prolonged diarrhoea is a particular health concern because it contributes significantly to diarrhoea-related deaths. Studies of risk factors for prolonged or persistent diarrhoea are virtually nonexistent in Africa. In the present study conducted in a semi-urban area of Lagos, we used a case-control design to evaluate the roles of household environment, mothers' food hygiene behaviour, and child-care practices as possible risk factors for prolonged diarrhoea in children 6-36 months old. A total of 628 children were studied. During the 3 1/2 months surveillance period, 166 children became ill with diarrhoea and 20 of the 166 (12.0%) had prolonged episodes (> 7 days). Persistent diarrhoea (> 14 days) accounted for only 2.4% (6 of 251) of all episodes. This analysis of risk factors is focussed on the 20 cases of prolonged diarrhoea and 206 randomly selected controls who experienced no diarrhoea during the surveillance period. A significantly high risk of prolonged diarrhoea was found among children who were given ogi, a maize pap, as the main diet (odds ratio = 4.13). Children who were fed mainly with foods bought from street vendors also had a significantly higher risk (odds ratio = 2.91) of prolonged diarrhoea. No association was found between domestic, environmental, and personal hygiene practices and prolonged diarrhoea. Foods from street vendors may serve as one source of diarrhoeal illnesses in Lagos and such episodes could be prolonged following repeated exposure, especially in children who are fed mainly with a low-energy and low-nutrient-density diet such as ogi.