Air pollution linked to birth weight
A study has found that increases in traffic related air pollutants were associated with 2% to 6% increased odds of low birth weight, even after taking account of road traffic noise.
The study, led by researchers from the MRC-PHE Centre for Environment and Health at Imperial College London and published in the BMJ, used national birth registers to identify over 540,000 live, single, full-term births occurring in the Greater London area between 2006 and 2010. The mother's home address at time of birth was recorded and average monthly concentrations of traffic related pollutants - nitrogen dioxide (NO2), nitrogen oxides (NOx), and fine particulate matter (PM2.5) from traffic exhaust and non-exhaust sources, such as brakes or tyre wear - as well as larger particulate matter (PM10) were estimated. Average day and night-time road traffic noise levels were also estimated.
Using statistical models to analyse the data, the researchers found that increases in traffic related air pollutants - especially PM2.5 - were associated with 2% to 6% increased odds of low birth weight and 1% to 3% increased odds of being small for gestational age, even after taking account of road traffic noise.
"With the annual number of births projected to continue increasing in London, the absolute health burden will increase at the population level, unless air quality in London improves," the study authors conclude.
The findings held true after other potentially influential factors were taken into account, such as mother’s age, ethnicity and deprivation. However, an observational study cannot show a causal link between air pollution and birth weight and the authors also point to limitations, such as whether they have fully adjusted for deprivation.
The study was funded by the cross-research council Environmental Exposures & Health Initiative, led by the Natural Environment Research Council, in conjunction with the MRC, the Economic and Social Research Council, the Department of Environment, Food and Rural Affairs, and Department of Health.
- Read the full article on the MRC website - including details of another study which suggests that exposure to city air pollution is enough to counter the positive health effects of exercise in over 60s
Please sign up to our weekly newsletter to keep up to date: