Atopy, asthma, and antibodies to Ascaris among rural and urban children in Kenya.
OBJECTIVE
The purpose of this study was to evaluate differences in the relationship between asthma and immune responses to allergens in children living in rural and urban areas of Kenya.


METHODS
Children (mean age, 11 years) from Kabati (n = 136), a rural village, and Thika (n = 129), a small town, were studied by skin testing and serum immunoglobulin E (IgE) and immunoglobulin G (IgG) antibody measurement. Asthma was evaluated by symptoms, as well as spirometry before and after vigorous exercise to test for exercised-induced bronchospasm (EIB). School children from a study performed in Atlanta, Georgia, were used for comparison of anthropometric and immunologic results.


RESULTS
Compared with the urban area of Kenya, children living in the rural area had a lower percentage of body fat, smaller and fewer skin test responses to allergens, a higher prevalence of IgE antibodies to Ascaris (67% vs 26%) and 10-fold higher total IgE. In the urban area of Kenya, there was a strong correlation between EIB and atopy determined both by IgE antibodies (P =.02) and skin tests (P =.002). By contrast, in the rural area, none of the 13 children with EIB were skin-test positive (vs 13/109 of children without EIB).


CONCLUSIONS
Among the rural children, there was no association between immune responses to allergens and airway-related symptoms or reactivity. The association between asthma and atopy seen in the town of Thika may represent an important step in the increase in asthma seen both in urban Africa and in the West.
Perzanowski
Matthew S
MS
University of Virginia Asthma and Allergic Diseases Center, Health Sciences Center, Charlottesville, 22908-1355, USA.
Ng'ang'a
Lucy W
LW
Carter
Melody C
MC
Odhiambo
Joseph
J
Ngari
Peter
P
Vaughan
John W
JW
Chapman
Martin D
MD
Kennedy
Malcolm W
MW
Platts-Mills
Thomas A E
TA
D000293:Adolescent; D000818:Animals; D000886:Anthropometry; D000909:Antibodies, Helminth / Q000097:blood*; D001200:Ascaris / Q000276:immunology*; D001249:Asthma / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology*; D016022:Case-Control Studies; D002648:Child; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology*; D007630:Kenya / Q000453:epidemiology; D016015:Logistic Models; D015995:Prevalence; D015656:Respiratory Mechanics; D012424:Rural Population; D018709:Statistics, Nonparametric; D014505:Urban Population
D000909:Antibodies, Helminth