Pregnant women who live near urban highways are at greater risk of delivering premature babies or babies with low birth weight, new research suggests.
Researchers from the University of Montreal and the University of South Australia have found that affluent women who live within 200 metres of a highway have a 58 per cent greater risk of delivering a premature baby.
They also have an 81 per cent greater risk of having a baby with low birth weight.
The researchers analyzed data from 100,000 births in the Montreal area over a five-year span. The findings are published in the August edition of the Journal of Epidemiology and Community Health.
"Advantaged mothers may be more susceptible to highway pollution, possibly because they have been protected from other hazards present in low income neighbourhoods," Dr. Melissa G�n�reux, of the University of Montreal and Maisonneuve-Rosemont Hospital, said in a statement.
Women in low-income neighbourhoods are more likely to smoke and have a poor diet, which are considered risk factors for delivering premature or low birth weight babies.
The findings are significant because premature babies and babies with low birth weight are at greater risk for a number of health problems, such as breathing and feeding difficulties, hypothermia, jaundice, impaired brain development and even death.
Abstract:
Neighbourhood socioeconomic status, maternal education and adverse birth outcomes among mothers living near highways
M G�n�reux, N Auger, M Goneau, M Daniel
Background: Residential proximity to highways is a potential proxy for exposure to traffic-related pollution that has been linked to adverse birth outcomes. We evaluated whether proximity to highway interacts with individual and neighbourhood socioeconomic status (SES) to influence birth outcomes.
Methods: The study population consisted of all live singleton births in Montr�al, Canada, from 1997 to 2001 (n = 99 819). Proximity was defined as residing within 200 m of a highway. Neighbourhood SES was measured for census tracts as the proportion of families below the low-income threshold. Individual SES was represented by maternal education. Using multilevel logistic regression, the odds of preterm birth (PTB), low birthweight (LBW) and small-for-gestational-age (SGA) birth were calculated for mothers residing in proximity to highways, accounting for individual and neighbourhood SES. Effect modification between SES and proximity to highway was tested for each outcome.
Results: In wealthy neighbourhoods, proximity to highway was associated with an elevated odds of PTB (OR 1.58, 95% CI 1.23 to 2.04), LBW (OR 1.81, 95% CI 1.36 to 2.41) and SGA birth (OR 1.32, 95% CI 1.05 to 1.66). For highly educated mothers, proximity to highway was associated with PTB (OR 1.25, 95% CI 1.07 to 1.46) and LBW (OR 1.24, 95% CI 1.03 to 1.49), but the association was borderline for SGA birth (OR 1.15, 95% CI 1.00 to 1.32). Proximity to highway was not associated with birth outcomes in other maternal and neighbourhood SES categories.
Conclusion: Counterintuitively, high SES mothers may be more likely than low SES mothers to experience adverse births associated with residential proximity to highway.
