Are non-allergenic environmental factors important in asthma?
OBJECTIVE
To review the roles of viral respiratory tract infections, environmental tobacco smoke and air pollution in asthma.


METHODS
MEDLINE (1992-1995) searches were conducted for publications on asthma, environmental tobacco smoke, ozone, nitrogen dioxide and particulates.


METHODS
Representative original experimental and epidemiological studies and reviews of viral infections in asthma.


RESULTS
Respiratory virus infections are the most common and important trigger of asthma attacks in children and probably also in adults. Their role in promoting development of asthma is not so clear. Exposure to environmental tobacco smoke is almost certainly responsible for some cases of childhood asthma, and can also trigger symptoms of bronchoconstriction in adults with asthma. Exposure to ozone or nitrogen dioxide is associated with symptoms, impaired lung function, bronchial hyperresponsiveness and hospital presentations for asthma. These pollutants may also act as cofactors in the development of allergen-specific bronchial hyperresponsiveness.


CONCLUSIONS
Research on preventing upper respiratory viral infections may reduce asthma morbidity. The move to non-smoking workplaces is welcome, but new interventions are needed to prevent young women taking up smoking and subsequently exposing their children. The ambient air quality guideline for ozone should be revised and a health-based guideline for respirable particulates introduced.
Department of Social and Preventive Medicine, Monash University, Melbourne, VIC.
M J
MJ
Abramson
G B
GB
Marks
P K
PK
Pattemore
D000397:Air Pollution / Q000009:adverse effects; D001249:Asthma / Q000209:etiology*; D006801:Humans; D012141:Respiratory Tract Infections / Q000150:complications; D014028:Tobacco Smoke Pollution / Q000009:adverse effects; D014777:Virus Diseases / Q000150:complications
D014028:Tobacco Smoke Pollution