Monday, 11 December, 2017

Traffic pollution linked to low birth weight of unborn babies, study reveals

Hyde Park is the better place to exercise Credit Michael Kemp  Alamy Stock Hyde Park is the better place to exercise Credit Michael Kemp Alamy Stock
Melissa Porter | 06 December, 2017, 18:54

According to the study carried out by Imperial College London researchers, exposure to road traffic air pollution in London during pregnancy is linked to an increased risk of low-birth weight babies born at full term.

Researchers estimated average monthly concentrations of traffic-related pollutants by looking at the mother's home address at the time of birth.

The study is expected to promote awareness that prenatal exposure to small particle air pollution is harmful to unborn infants. They also found that the average annual concentration of PM2.5 in 2013 was 15.3 g m3, and also estimated that reducing the PM2.5 concentration by 10% would approximately prevent 3% (90) of babies being born at full-term with low birth weight in London each year.

After analyzing the data using statistical models, the researchers found that increases in traffic-related air pollutants-particularly PM2.5-were linked with 2%-6% increased odds of low birth weight and 1%-3% increased odds of being small for gestational age, even after road traffic noise was accounted for. Volunteers walked for two hours midday at one of two London locations: in a relatively quiet part of Hyde Park or along a busy section of Oxford Street, where pollution-including black carbon, nitrogen dioxide, and fine particulate matter from diesel exhaust fumes-regularly exceeds air quality limits set by the World Health Organization.

"These are issues that mean we really need to reduce pollution by controlling traffic".

The study was funded by the British Heart Foundation, whose chief executive Simon Gillespie said: 'Exercise is crucial in reducing the risk of a heart attack or stroke, but it seems unsafe levels of air pollution could be erasing these benefits in older adults.

The study tested 119 people aged over sixty, 40 of whom were healthy, 40 with a medically-stable lung condition, COPD, and 39 with stable ischaemic heart disease.

Going for a brisk walk is one of the best ways for older people to exercise and stay healthy - unless your route takes you along Oxford Street that is. Arteries became less stiff in those walking in Hyde Park with a maximum change from baseline of more than 24% in healthy and COPD volunteers, and more than 19% in heart disease patients.

Commenting on the results, Fan Chung, Professor of Respiratory Medicine and Head of Experimental Studies Medicine at the National Heart & Lung Institute at Imperial College London and senior author of the study, said: "These findings are important as for many people, such as the elderly or those with chronic disease, very often the only exercise they can do is to walk". By comparison, a walk along Oxford Street led to a smaller increase during the first hours and no increase later.

Blood flow also increased after exercise, with decreases in blood pressure and an increase in heart rate.

"This adds to the growing body of evidence showing the negative cardiovascular and respiratory impacts of even a short, two-hour exposure to motor traffic pollution", says Junfeng "Jim" Zhang, professor of global and environmental health at Duke University. "We suggest that, where possible, older adults walk in parks or other green spaces away from busy roads".

The study was funded by the British Heart Foundation.