> Busy roads linked to early births
> Smoking during pregnancy linked to heart disease

"Busy roads linked to early births"

ABC Science Online, Annabel McGilvray
April 5, 2011

The study found pregnancy times were reduced by up to 4.4 per cent, from 40 weeks to 38.2 weeks (Reuters: Michaela Rehle)

Expectant mothers living close to high traffic areas may be at increased risk of early birth, new Australian research says.

A cohort study by a group from the Queensland University of Technology's Institute of Health and Biomedical Innovation (IHBI) has found that babies are born earlier when their mothers are living within 400 metres of clusters of freeways and main roads.

In an article published this week in the online journal Environmental Health, the Queensland team suggest air pollution is likely to be the major factor affecting these mothers.

Lead researcher Associate Professor Adrian Barnett says their results support the findings of four similar studies in Canada, United States, Taiwan and the Netherlands with the evidence increasingly suggesting traffic pollution may be compared to the long-term effect of tobacco smoke.

"We have a very similar route of exposure, there's a complex mix of chemicals involved and there's a broad range of health effects," he said.

The latest findings have important public health implications given that pre-term babies stay in hospital longer after birth and are at increased risk of death and disability.

Previous Australian research has linked proximity to traffic pollution to small foetus size and to the development of asthma in children.

Professor Barnett says that it is time policy-makers think more generally about ensuring the most vulnerable population groups are situated away from busy traffic.

"High up the list would be hospitals, schools and old age people's homes. They should be kept as far away from major roads as possible," he said.

"But the best thing we can do really is to reduce the amount of traffic pollution, either by reducing the amount that we drive or making our vehicles cleaner."


Plotting risk factors

The study questioned 970 mothers in Logan City, south of Brisbane, about their birth outcomes and socioeconomic status.

The researchers then plotted each mother's address using Geographic Information System (GIS) software and drew concentric circles around each home out to 500 metres.

The road sections within each circle were counted and classified as freeways, highways or main roads. The results showed that there was no statistically significant effect on birth times for those mothers living in the proximity of one freeway, highway or main road.

But there was an effect when the neighbourhood included a cluster of roads.

When socio-economic status and whether a mother smoked were taken into account, the study found that most of the health effects occurred for those living within 200 metres of high concentrations of freeways and main roads.

The effects kept occurring up to about 400 metres.

Pregnancy times were reduced by 4.4 per cent, from 40 weeks to 38.2 weeks, for those living closer within 400 metres of freeway clusters, and by 1.1 per cent to 39.6 weeks for those within the same range of a cluster of main roads.

The reasons for the reductions have not yet been determined.

"My feeling is that it's more likely to be the toxins in the air pollution, but we can't definitively rule out noise yet," Professor Barnett said.

Associate Professor Peter Franklin, of the School of Population Health at the University of Western Australia, has looked at the link between asthma and traffic pollution.

He says this study is the latest in a growing swathe of evidence that pollution damages the health of children.

"Although the effect of air pollution on gestational age in this study is small, the results are generally consistent with other research," he said.

"The increasing evidence, including the current study, needs to be considered by city and town planners as they design road networks and housing developments to cater for our growing population."

Source: http://www.abc.net.au/news/stories/2011/04/05/3183016.htm

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"Smoking during pregnancy linked to heart disease"

ABC Science Online, Mary Gearin
June 22, 2011

Australian researchers believe they have found the first evidence that women who smoke while pregnant affect their child's cardiovascular health for years to come.

The University of Sydney study found pre-natal exposure to a mother's smoking decreased the amount of good cholesterol in children, which may increase their risk of eventual heart attacks and strokes by up to 20 per cent.

It was already common knowledge that smoking while pregnant was harmful, but even so, this study yielded more significant results than the scientists were expecting.

David Celermajer, a professor of cardiology at the University of Sydney, says he was "gobsmacked". He and his colleagues studied 328 healthy eight-year-olds and found some bore the lingering imprint of their mother's pregnant smoking.

"Most studies suggest that if you stop smoking, eight years later a lot of your risk has reduced," he said.

"The reason we were gobsmacked is here are kids who were exposed to another person's smoke when they were growing in their mum's belly and eight years later, eight years after being removed from that ... they've still got a footprint on it," he said.

"That's the staggering part. To the best of my knowledge no-one has ever shown before that smoking [while] pregnant has a prolonged effect on body changes in offspring."

The results of the study, published today in the European Heart Journal, relied on questionnaires about the mother's smoking habits filled in shortly after the children's birth, and blood samples from the children.

The researchers found the children whose mothers reported smoking while pregnant had less high-density lipoprotein (HDL) or so-called "good cholesterol" than children whose mothers had not smoked.

HDL protects against heart disease and stroke.

The study found the smoking mother's children have 1.3 millimoles per litre of HDL compared to a more normal level of 1.5.

Professor Celermajer says the difference is "very significant".

"Heart disease remains the number one killer in Australia, so even a small increase in risk above the general population represents a massive number of people that are potentially affected," he said.

"Roughly, for every 1 per cent reduction in the good cholesterol, there's a 1 per cent increase in heart attack risk.

"And what we've found in this study is up to a 20 per cent reduction in the good cholesterol levels of these children of mums who have smoked during pregnancy ... so we postulate that they're up to 20 per cent risk higher of heart attack and stroke during their lifetimes."

Professor Celermajer said the researchers were looking to find out whether smoking in pregnancy was related to high blood pressure in children.

"And it wasn't. We also looked as to whether smoking in pregnancy actually caused the blood vessels to thicken up. And it didn't," he said.

"But we suspect that may be because these kids [are] only eight years old and that these are things that may turn out to be the case in future, but we obviously have to follow up these children longer."

Professor Celermajer says the study results are not just a wake-up call for mums-to-be, but should lead everyone to contemplate their own mothers' habits.

"For kids whose mums did smoke - and they can't wind back the clock now - they have to be particularly careful of the way they live their lives to maximise their heart health, by not smoking themselves and by having healthy diet and exercise habits," he said.

"So there's a real take-home message for the kids too, not just for the mums."

Source: http://www.abc.net.au/news/stories/2011/06/22/3250010.htm

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