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Babies exposed to air pollution in womb more likely to develop asthma: UBC study

Researchers have found that babies born to mothers who live near a major road or highway have a 25 per cent increased risk of developing asthma before age 6.

Babies born to mothers who are exposed to air pollution from traffic during pregnancy have an increased risk of developing asthma in early childhood, suggests a new study from the University of British Columbia.

The study, which followed more than 65,000 children in Metro Vancouver from birth until the age of 10, found that those whose mothers lived near major roads or highways during pregnancy have a 25 per cent increased risk of developing asthma before the age of 6.

That risk was highest for babies born to mothers over the age of 35, the researchers found.

“That was a striking result because in B.C., we happen to have the highest rates of pregnant moms that are the oldest in Canada,” said Hind Sbihi, lead author and research associate in UBC’s School of Population and Public Health. “What this means is, if you’re over 35 and pregnant, you probably want to pay more attention (to air pollution) than a mother who is 28 or 30.”

For the study, the largest of its kind, researchers analyzed provincial health data for 65,254 children born between 1999 and 2002. They also assessed pregnant mothers’ exposure to traffic-related air pollutants, like black carbon, fine particulate matter, nitrogen dioxide, and nitric oxide, based on proximity to major roads and highways.

Following the children for 10 years, researchers found that 6,948 children were diagnosed with asthma before age 5, while 1,711 were diagnosed between the ages of 6 and 10.

After controlling for factors like low birth weight, gestational period, breastfeeding and socio-economic factors, researchers found the risk of developing asthma was associated with increases in the levels of traffic-related air pollution.

The researchers also found that children born at low birth weight were more susceptible to respiratory problems as a result of air pollution.

Lead author Sbihi said the findings highlight the importance for expectant mothers of paying attention to air pollution levels.

She urged pregnant women to check the Air Quality Health Index, an initiative between Environment Canada and Health Canada, before doing outdoor exercise.

“As a pregnant mom, I would say use that before you decide that you want to go for your morning stroll,” she said. “It takes 10 seconds to check and then you can make a decision.”

The study was published in February’s issue of European Respiratory Journal. 

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