Abatement of cockroach allergen (Bla g 1) in low-income, urban housing: A randomized controlled trial.
BACKGROUND
Clinically relevant reductions in exposure to cockroach allergen, an important risk factor for asthma in inner-city households, have proven difficult to achieve in intervention trials.


OBJECTIVE
This study investigated a method for the abatement of cockroach allergen in low-income, urban homes. The goal was to reduce mean Bla g 1 concentrations below the previously proposed thresholds for allergic sensitization and asthma morbidity.


METHODS
A prerandomized, nonmasked trial with 16 intervention and 15 control homes was conducted. Study inclusion was based on 50 to 500 cockroaches trapped in a 3-day period. The interventions consisted of occupant education, placement of insecticide bait, and professional cleaning. Vacuumed dust and multiple swab samples were collected at 0, 1, 2, 4, and 6 months in intervention homes and at 0 and 6 months in control homes. Room maps containing cockroach and allergen data were used to guide and monitor the interventions.


RESULTS
From 0 to 6 months among intervention homes, geometric mean Bla g 1 concentrations (U/g dust) decreased from 633 to 24 on kitchen floors (96% reduction), from 25 to 4.3 on living room floors/sofas (83% reduction), from 46 to 7.3 on bedroom floors (84% reduction), and from 6.1 to 1.0 in bedroom beds (84% reduction). These reductions, with the exception of that on the bedroom floor (P =.06), were statistically significant relative to changes in control homes.


CONCLUSIONS
Substantial reductions in cockroach allergen levels can be achieved in inner-city homes. In this study, allergen levels were reduced below the sensitization threshold (2 U/g) in beds, arguably the most relevant site for exposure, and below the asthma morbidity threshold (8 U/g) on bedroom floors and living room floors/sofas. The level on kitchen floors, although reduced 96%, remained above the asthma morbidity threshold. Future studies will test the intervention's effectiveness in asthma prevention trials.
Arbes
Samuel J
SJ
Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Sever
Michelle
M
Archer
Janet
J
Long
Elizabeth H
EH
Gore
J Chad
JC
Schal
Coby
C
Walter
Michelle
M
Nuebler
Betsy
B
Vaughn
Ben
B
Mitchell
Herman
H
Liu
Eric
E
Collette
Nicholas
N
Adler
Peter
P
Sandel
Megan
M
Zeldin
Darryl C
DC
D000485:Allergens / Q000032:analysis* / Q000276:immunology; D052179:Antigens, Plant; D004056:Differential Threshold; D006796:Household Work; D006798:Housing; D006801:Humans; D007114:Immunization; D007300:Insect Control; D007306:Insecticides / Q000494:pharmacology; D009994:Osmolar Concentration; D010353:Patient Education as Topic; D011204:Poverty Areas; D014505:Urban Population
D000485:Allergens; D052179:Antigens, Plant; D007306:Insecticides; C105482:allergen Bla g 1