Wheezing, allergy, and parasite infection in children in urban and rural Ethiopia.
Epidemiological studies in developing countries suggest that intestinal parasite infection may reduce the risk of asthma. Because this evidence is all derived from adults and older children, we have investigated the relation between parasite infection, wheezing, and allergen skin sensitization in nested case-control studies drawn from a survey of 7,155 children aged 1 to 4 years living in urban and rural areas of Jimma, Ethiopia. Infection with parasites was common, predominantly with Trichuris (54%), Ascaris (38%), and hookworm (10%). Wheezing in the past year was significantly more prevalent in urban (4.4%) than rural children (2.0%), and was less prevalent in those infected with Ascaris (age, sex, and urban/rural adjusted odds ratio, 0.5; 95% confidence interval, 0.3 to 0.9), particularly in relation to high-intensity infection. Similar, although nonsignificant, associations were found for hookworm (adjusted odds ratio, 0.6; 95% confidence interval, 0.2 to 1.8), but there was no suggestion of any relation to Trichuris infection. Dermatophagoides pteronyssinus and cockroach (Blattella germanica) skin sensitization was more prevalent in rural than urban children, and was unrelated to wheeze. We conclude that Ascaris and possibly hookworm infection protects against wheeze in young Ethiopian children, and that this effect is not mediated by inhibition of allergen sensitization.
Division of Respiratory Medicine, University of Nottingham City Hospital, United Kingdom.
Damtew
D
Dagoye
Zegaye
Z
Bekele
Kifle
K
Woldemichael
Hailu
H
Nida
Meselech
M
Yimam
Andy
A
Hall
Andrea J
AJ
Venn
John R
JR
Britton
Richard
R
Hubbard
Sarah A
SA
Lewis
D017677:Age Distribution; D001249:Asthma / Q000453:epidemiology* / Q000276:immunology; D016022:Case-Control Studies; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003876:Dermatitis, Atopic / Q000175:diagnosis / Q000453:epidemiology*; D003906:Developing Countries; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000453:epidemiology*; D007411:Intestinal Diseases, Parasitic / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D011336:Probability; D012135:Respiratory Sounds; D018570:Risk Assessment; D012424:Rural Population; D017678:Sex Distribution; D014505:Urban Population