Bad air causes rise in allergies, study shows

Allergies and asthma are on the rise - and researchers
blame pollution, second-hand smoke and other factors.

Pollution among the factors causing more allergies among children - and figures are set to rise

Three-quarters of parents with at least one child under the age of three report that the child has allergies, a study shows - and researchers warn the figure will grow.

Some 58 per cent of the youngsters had eczema or a skin allergy, 32 per cent had rhinitis or hay fever and 25 per cent airway allergies such as asthma.

Some of the children suffered more than one type of allergy.

The findings of the survey by the Allergy Association, commissioned by the University of Hong Kong, were based on interviews with 511 parents.

Only 30 per cent of the children were believed to have inherited the condition from their parents - meaning the rest might be down to factors such as pollution, exposure to second-hand smoke, Cesarean delivery or not being breastfed exclusively in their first six months.

"We have seen many more allergy cases in this generation than the last," said Dr Marco Ho Hok-kung, chairman of the association.

"I believe the number is only going to rise in the future, in keeping with the global trend. It is vital to understand the risk of allergies and take preventive measures."

Allergies could affect the long-term growth of infants, said Ho. Some research suggests that infants who develop an allergy before the age of two have a 24 per cent increased risk of developing emotional problems later in life.

Families with children suffering from allergies often have to devote a lot of effort to preventing exposure to allergens such as peanuts, milk or seafood in meals and dust mites at home.

According to the World Health Organisation, 40 to 50 per cent of children across the globe are bothered by one or more types of allergy.

Ho said if either parent had an allergy, there was a 30 per cent chance of their child inheriting it. This increased to 50 per cent if both parents were sufferers. And in general, every child has 5 to 15 per cent chance of developing an allergy even if neither parent has the condition.

Paediatrician Dr Alfred Tam Yat-cheung said risks could be attributed to environmental factors such as pollution and exposure to second-hand smoke. They could be reduced by giving birth naturally and feeding the babies only breast milk in their first six months, he said.

Source: South China Morning Post

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Smoking bans linked with 'successive reductions' in preterm birth

• No decreasing trend was evident in the years or months before the bans 
• The study supports the notion that smoking bans have public health benefits from early life

It is well established that smoking during pregnancy impairs the growth of an unborn child and shortens gestation. Exposure to second-hand smoke has also been found to affect birth outcomes, yet little is known about the impact of recent smoke-free legislation on birth weight and preterm birth.

So a team of researchers, lead by Dr Tim Nawrot from Hasselt University, investigated whether recent smoking bans in Belgium were followed by changes in preterm delivery. In Belgium, smoke-free legislation was implemented in three phases (in public places and most workplaces in January 2006, in restaurants in January 2007, and in bars serving food in January 2010).

The researchers analysed 606,877 live, single-born babies delivered at 24-44 weeks of gestation in Flanders from 2002 to 2011. Preterm birth was defined as birth before 37 weeks.

They found reductions in the risk of preterm birth after the introduction of each phase of the smoking ban. No decreasing trend was evident in the years or months before the bans.

The results show a reduction in the risk of preterm births of 3.13% on 1 January 2007 (ban on smoking in restaurants), and a further reduction in the risk of 2.65% after 1 January 2010 (ban on smoking in bars serving food). These changes could not be explained by several other factors - both at the individual level, such as mother's age and socioeconomic status - and at the population level, such as changes in air pollution and influenza epidemics.

Given that even a mild reduction in gestational age has been linked in other studies to adverse health outcomes in early and later life, our study has important public health implications, say the authors.

"Our study shows a consistent pattern of reduction in the risk of preterm delivery with successive population interventions to restrict smoking. It supports the notion that smoking bans have public health benefits even from early life. More and more countries in Europe are adopting stricter legislation on smoking in public places. These results underscore the public health benefit of smoking ban policies."

Second-Hand Smoke Linked to Behavior Problems in Children

It is a known fact that active maternal smoking during pregnancy has negative effects on child health, such as attention deficit and hyperactivity disorder (ADHD). However, new research suggests that exposure to second hand smoke, or environmental tobacco smoke (ETS), may be just as harmful.

In one of the first studies of its kind, researchers from the University of Pennsylvania School of Nursing examined data from 646 mother-child pairs in China, where more than 70 percent of men smoke, and concluded that 25% children of whose mothers were exposed to smoke exhibited behavior problems compared to 16% of children of unexposed mothers.

“Such findings could inform public health efforts to reduce public smoking and underscores the need for including ETS avoidance as a potential component of prenatal care among pregnant women,” said lead-author Jianghong-Liu, PhD, RN, FAAN, associate professor at Penn Nursing.

Using the Child Behavior Checklist (CBCL), a widely used, 99-item scale for assessing behavioral and emotional problems in children, researchers determined children of mothers with ETS exposure had 10% more prevalence of externalizing behavior problems than children of unexposed mothers. The results took factors like parental education, occupation, psychological problems and marriage status into account. The full results were published online this week in the journal NeuroToxicology.

Externalizing behavior problems included attention problems and aggression. Children of passive smoking mothers demonstrated worse performance on tests of speech and language skills, intelligence, and behavioral outcomes (conduct disorders).

“Given the high prevalence of ETS exposure among pregnant women in China and the far-reaching effects of child behavioral disturbance on public health outcomes, it is critical to reduce ETS exposure in order to improve the health of not only mothers and their children but that of society at large,” said Dr. Liu. “The key message for pregnant women is to protect their growing fetus from exposure to secondhand smoke.”

While additional, more longitudinal, research is needed to validate the findings, the researchers agree that this study gives some clarity to the relationship between ETS and behavioral disturbance in children.