The effect of road vehicle traffic pollution on asthma is still not clearly understood. However, any effect is likely to be most marked among those who live within 150 m of a main road, because this is the distance within which concentrations of primary vehicle traffic pollutants are raised above ambient background levels. We have investigated the relation between proximity of the family home to the nearest main road, estimated objectively using geographical information system software, and the risk of wheeze in the past year in a case-control sample of 6,147 primary schoolchildren (age 4 to 11 yr) and a random cross-sectional sample of 3,709 secondary schoolchildren (age 11 to 16 yr) in Nottingham, United Kingdom. Among children living within 150 m of a main road, the risk of wheeze increased with increasing proximity by an odds ratio (OR) of 1.08 (95% confidence interval [CI] 1.00 to 1.16) per 30-m increment in primary schoolchildren, and 1.16 (1.02 to 1.32) in secondary schoolchildren. Most of the increased risk was localized to within 90 m of the roadside. Among primary schoolchildren, effects were stronger in girls than boys (p(interaction) = 0.02). Living within approximately 90 m of a main road is associated with a proximity-related increase in the risk of wheezing illness in children.

No abstract

No abstract

Objectives-To investigate the relation between local road traYc activity and the occurrence, severity, and persistence of wheeze in children. Methods-Data on wheeze and asthma were collected in a cross sectional questionnaire survey of 22 968 primary school children (age 4-11) and 27 826 secondary school children (age 11-16) in the Nottingham area. Direct measures of road traYc flow were made in the locality of each school and combined with Local Authority traYc data for major roads to estimate local traYc activity in vehicle metres/day/ km 2 . Assessment of the eVects of potential confounders was performed in nested case-control groups of 6576 primary and 5936 secondary children. Data on frequency of wheeze were collected for the cases to study disease severity. Longitudinal data on a historical cohort of 883 children who reported wheeze when aged 4-11 in 1988 were used to study the persistence of wheeze into adolescence. Results-Unadjusted prevalence of wheeze in the past year within schools varied widely but was not associated with traYc activity in the school locality (weighted regression coeYcient =−0.01, p=0.93 for primary schools, =−0.18, p=0.26 for secondary schools). The risk of wheeze in individual primary school children was not associated with traYc activity analysed as a continuous variable, although there was some suggestion of a weak, non-linear plateau eVect. Similar eVects were found for diagnosed asthma and recent cough. There was no evidence of any relation between traYc activity and risk of wheeze in secondary school children. There were positive but non-significant dose related eVects of traYc activity on wheeze severity in primary and secondary children and on persistence of wheeze in the longitudinal cohort. Conclusions-TraYc activity in the school locality is not a major determinant of wheeze in children. (Occup Environ Med 2000;57:152-158)