Case-control study of hospital admission with asthma in children aged 5-14 years: relation with road traffic in north west London.
BACKGROUND
Evidence for an association between road traffic pollution and asthma is inconclusive. We report a case-control study of hospital admissions for asthma and respiratory illness among children aged 5-14 in relation to proxy markers of traffic related pollution.


METHODS
The study was based on routine hospital admissions data in 1992/3 and 1993/4 for North Thames (West) health region within the M25 motorway. Cases were defined as emergency admissions for asthma (n = 1380) or all respiratory illness including asthma (n = 2131), and controls (n = 5703) were other emergency admissions excluding accidents. Cases and controls were compared with respect to distance of residence from nearest main road or roads with peak hour traffic >1000 vehicles and traffic volume within 150 m of residence, obtained by Geographical Information System techniques. Statistical analysis included adjustment for age, sex, admitting hospital, and a deprivation score for the census enumeration district of residence.


RESULTS
Adjusted odds ratios of hospital admission for asthma and respiratory illness for children living within 150 m of a main road compared with those living further away were, respectively, 0.93 (95% CI 0.82 to 1.06) and 1.02 (95% CI 0.92 to 1.14).


CONCLUSIONS
This study showed no association between risk of hospital admission for asthma or respiratory illness among children aged 5-14 and proxy markers of road traffic pollution.
Wilkinson
P
P
Environmental Epidemiology Unit, Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
Elliott
P
P
Grundy
C
C
Shaddick
G
G
Thakrar
B
B
Walls
P
P
Falconer
S
S
D000293:Adolescent; D001249:Asthma / Q000453:epidemiology / Q000209:etiology* / Q000628:therapy; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006769:Hospitals, General; D006801:Humans; D008131:London / Q000453:epidemiology; D008297:Male; D016017:Odds Ratio; D012120:Respiration Disorders / Q000453:epidemiology / Q000209:etiology* / Q000628:therapy; D012307:Risk Factors; D001335:Vehicle Emissions / Q000009:adverse effects*
D001335:Vehicle Emissions