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Week 19 / 2008: Smoking is partly genetic

According to a recent doctoral dissertation, our genes explain to a great extent our smoking behaviour and key factors sustaining nicotine dependence. Other factors such as socio-economic status, including educational background and marital status, are associated with a person’s ability to stop smoking.

Ulla Broms, who defended her doctoral dissertation at the University of Helsinki on Saturday, conducted a study that involved 9,000 Finnish twins and their family members. They responded to questionnaires and were interviewed, and from some gene samples were taken.

Three out of four smokers were nicotine-dependent. Most heavy smokers develop nicotine dependence, but also those who smoke less may develop nicotine dependence.

According to Broms’ study, more that one-third of the differences in nicotine dependencies is explained by genes. She points out, however, that in spite of hereditary disposition, one can become dependent on cigarettes only if one starts smoking.

Genes explain approximately one-half of the variation in starting and stopping smoking and how much people smoke. “Genetic factors seem to have a greater impact on men in terms of starting and stopping smoking. With women, genes seem to have a greater effect on the amount smoked,” says Broms.

The level of education and professional status predict the cessation pattern. With men, cessation can be predicted by entering cohabitance or marriage, and overall, living in a steady relationship seemed to promote cessation.

Broms also developed a nicotine dependency indicator which helps determine the various characteristics in dependency, such as compulsiveness and continuation.
“The indicators will allow us to show on an individual level which element of dependency will prove hardest for a person. This provides tremendous help when tailoring the right method to support the cessation of smoking,” Broms says.

.Text: Päivi Lehtinen
Photo: University of Helsinki
Translation: AAC Noodi

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