MedWire News: Young people who are regularly exposed to secondhand tobacco smoke at home and in vehicles face an increased risk of nicotine dependence, researchers warn.

Nicotine is the chemical component in tobacco that is primarily responsible for addiction to smoking, which is associated with an increased risk of many diseases and conditions, including chronic obstructive pulmonary disease, lung cancer and heart disease.

Dr Jennifer O'Loughlin, from Centre de recherche du Centre Hospitalier de l'Université de Montréal in Quebec, Canada, and team studied data on 1488 children, aged between 10 and 12 years, who were participating in a study of tobacco use and other behaviour associated with negative health effects.

All the children, who came from a wide variety of social backgrounds and who had never smoked themselves, completed questionnaires on the smoking habits of their patents and exposure to secondhand tobacco smoke in the home.

They were also assessed for signs of nicotine dependence and withdrawal, such as depressed mood, trouble sleeping, irritability, anxiety, restlessness, trouble concentrating and increased appetite.

In total, 69 of the participants showed signs of nicotine dependence.

Analysis revealed that exposure to secondhand smoke in the home was associated with a 10% increased risk of nicotine dependence symptoms, while exposure to secondhand smoke in a vehicle was associated with a 20% increased risk of such symptoms.

The findings remained true after accounting for peer and sibling smoking habits, notes the team.

"Increased exposure to second-hand smoke, both in cars and homes, was associated with an increased likelihood of children reporting nicotine dependence symptoms, even though these children had never smoked," summarised Dr O'Loughlin.

She concluded: "These findings support the need for public health interventions that promote non-smoking in the presence of children, and uphold policies to restrict smoking in vehicles when children are present."

The research is published in the journal Addictive Behaviors.

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