A hierarchical model for studying risk factors for childhood diarrhoea: a case-control study in a middle-income country.
OBJECTIVE
To identify factors associated with diarrhoea occurrence in children in a city in a middle-income country, with high access to water and sanitation.


METHODS
A case-control study in the city of Salvador, north-eastern Brazil was conducted from November 2002 to August 2004. The study population consisted of children presenting at a health facility. A total of 1688 cases of diarrhoea and 1676 controls were selected. Data collection was by a questionnaire and structured observation during home visits. The explanatory variables were grouped according to a conceptual model defined previously. Analysis was done using a hierarchical approach, to provide a more dynamic view of the transmission characteristics of childhood diarrhoea. Non-conditional logistic regression was used, and odds ratio and population-attributable fractions were estimated.


RESULTS
Socioeconomic factors contributed most to determining diarrhoea occurrence, followed by interpersonal contact, while factors related to food preparation, the environment and water and sanitation made a smaller contribution.


CONCLUSIONS
The findings indicate that the transmission of diarrhoea is influenced by factors from all hierarchical levels, with interpersonal transmission playing a relatively higher role than previously thought. This is compatible with a predominance of viruses and other agents spread by interpersonal routes including Shigella, Giardia and Cryptosporidium. Diarrhoea control strategies in similar settings (middle-income countries in which a large proportion of the population has access to water and sanitation) must give greater emphasis to policies geared towards reducing person-to-person transmission for the prevention of diarrhoea.
Instituto de Saúde Coletiva, Federal University of Bahia, Salvador, Brazil.
Suzana R
SR
Ferrer
Agostino
A
Strina
Sandra R
SR
Jesus
Hugo C
HC
Ribeiro
Sandy
S
Cairncross
Laura C
LC
Rodrigues
Mauricio L
ML
Barreto
D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003968:Diarrhea, Infantile / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005506:Food Contamination; D006801:Humans; D006920:Hygiene; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D015233:Models, Statistical; D016017:Odds Ratio; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012499:Sanitation; D012931:Social Environment; D012959:Socioeconomic Factors; D014881:Water Supply