Association of asthma symptoms and severity with indoor bioaerosols.
BACKGROUND
In this study, repeated measurements were made of levels of mold spores, bacteria, and dust-mite allergens over a 7-month period in the homes of asthmatics, and relationships with measures of asthma severity were evaluated.


METHODS
A sample of 57 asthmatic individuals, living in 44 homes in East Moline, Illinois, and nearby communities, participated in a panel study. The homes were visited up to nine times during the study to collect air and dust samples. Asthma severity indicators were derived from questionnaire data and from the daily health records from the panel study. Associations between indoor levels of mold spores, bacteria, and dust-mite allergens were tested with several asthma severity indicators.


RESULTS
There was evidence of associations between all asthma severity measures and levels of total and gram-negative bacteria, but mold-spore abundance was associated only with emergency room (ER) visits for asthma. No significant associations were found with house-dust-mite allergen and any of the asthma severity indicators, but the levels of dust-mite allergen were low, with median concentrations of 0.18 microg/g dust Der f 1 and 0.19 microg/g dust Der p 1.


CONCLUSIONS
Some evidence was found for associations of increased concentrations of gram-negative bacteria and mold spores with asthma severity, particularly with ER visits. No association was found between house-dust-mite allergen and asthma severity indicators; however, the mite-allergen levels in the study homes were generally well below the proposed threshold level of 2 microg/g dust.
Ross
M A
MA
Office of Air Quality Planning and Standards, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
Curtis
L
L
Scheff
P A
PA
Hryhorczuk
D O
DO
Ramakrishnan
V
V
Wadden
R A
RA
Persky
V W
VW
D000336:Aerosols / Q000032:analysis*; D000389:Air Conditioning; D000391:Air Microbiology; D016902:Air Pollution, Indoor / Q000009:adverse effects* / Q000032:analysis; D000818:Animals; D039741:Antigens, Dermatophagoides; D001249:Asthma / Q000382:microbiology*; D015169:Colony Count, Microbial; D004391:Dust / Q000032:analysis; D005260:Female; D006023:Glycoproteins / Q000302:isolation & purification; D006801:Humans; D006813:Humidity; D012720:Severity of Illness Index
D000336:Aerosols; D039741:Antigens, Dermatophagoides; D004391:Dust; D006023:Glycoproteins