Passive smoking in cars linked to hayfever and wheezing in children

MedWire News: Children who are regularly exposed to second-hand tobacco smoke when travelling by car have significantly higher rates of hayfever and wheezing than those without such exposure, results of an Irish study show.

Previous research has shown that regular exposure to second-hand smoke is associated with an increased risk of respiratory diseases in adults.

Writing in the European Respiratory Journal, Professor Luke Clancy, from the Tobacco Free Research Institute in Dublin, and team explain: “Children may be more vulnerable to second-hand smoke-induced respiratory diseases due to smaller airways and greater oxygen demand, as well as a less-mature immune system.”

But they add that “there is no evidence quantifying second-hand smoke -induced respiratory health effects in children exposed to second-hand smoke in cars”.

To address this, the team studied 2809 children, aged 13–14 years, selected randomly from schools throughout Ireland.

All the children completed questionnaires detailing their exposure to second-hand smoke at home and in the car, and whether they themselves smoked.

They were also asked whether they had ever suffered from asthma, hayfever, wheezing and other respiratory health problems.

The team found that, overall, nearly 15% of the children surveyed were regularly exposed to tobacco smoke when travelling by car.

After accounting for tobacco smoke exposure at home and other factors, the researchers found that children exposed to second-hand tobacco smoke in cars were 35% more likely to suffer from wheezing and 30% more likely to have hayfever symptoms than those who were not exposed to second-hand smoke in cars.

However, the team found no significant association between exposure to second-hand smoke in cars and an increased prevalence of asthma among children.

Professor Clancy and team comment: “Despite this study showing a tendency towards an increased likelihood of respiratory and allergic symptoms in children when exposed to second-hand smoke in cars, comprehensive longitudinal studies across different population settings are imperative.”

However, the researchers add: “Assuming a causal relation, such adverse respiratory symptoms could have a knock-on effect on school absenteeism, and also on being at greater risk for future second-hand smoke related morbidity [illness] and mortality.”

They conclude: “These results add further support to efforts to push ahead with legislation supporting smoke-free cars in Ireland but needs to be adequately substantiated with further evidence from elsewhere.”