Results of the National Cooperative Inner-City Asthma Study (NCICAS) environmental intervention to reduce cockroach allergen exposure in inner-city homes
Pj. Gergen et al., Results of the National Cooperative Inner-City Asthma Study (NCICAS) environmental intervention to reduce cockroach allergen exposure in inner-city homes, J ALLERG CL, 103(3), 1999, pp. 501-506
Background: Cockroach allergen is important in asthma. Practical methods to
reduce exposure are needed.
Objective: We sought to evaluate the effectiveness of house cleaning and pr
ofessional extermination on lowering cockroach antigen Levels in inner-city
dwellings.
Methods: As part of the National Cooperative Inner-City Asthma Study interv
ention, 265 of 331 families with asthmatic children who had positive skin t
est responses to cockroach allergen consented to a professional home exterm
ination with 2 applications of a cockroach insecticide (Abamectin, Avert) c
ombined with directed education on cockroach allergen removal. On a random
subset of 48 homes undergoing cockroach extermination in the intervention g
roup, Bla g 1 was measured in settled dust from the kitchen, bedroom, and T
V/living room. The first sample was collected 1 week before extermination,
with additional samples after the exterminations at approximately 2, 6, and
12 months after the first sample. Self-reported problems with cockroaches
were collected at baseline and after 12 months of follow-up in both the int
ervention and control group.
Results: The geometric mean kitchen lever of Bla g 1 decreased at 2 months
(33.6 U/g) relative to preextermination levels (68.7 U/g, P < .05). The per
cent of kitchens with over 8 U/g of Bla 1 followed a similar pattern, but o
nly the decrease from preextermination to 6-month levels was significant (8
6.8% vs 64.3%, P < .05). By the 12-month visit, the allergen burden had ret
urned to or exceeded baseline levels. Except for an increase in the bedroom
at 2 months (8.9 U/g vs 11.1 U/g, P < .05), no other significant change wa
s seen. Only about 50% of the families followed the cleaning instructions;
no greater effect was found in these homes. Self-reported problems with coc
kroaches showed no difference between the intervention and control group af
ter I year of follow-up.
Conclusions: Despite a significant, but short-lived, decrease the cockroach
allergen burden remained well above levels previously found to be clinical
ly significant.