A parent's dependence on nicotine, in addition to the act of smoking cigarettes, may be an important determinant of their teen's smoking behavior, according to a new study.

"The main message and what's really new is the emphasis on dependence or addiction," said lead author Denise B. Kandel of the Mailman School of Public Health at Columbia University in New York.

"When parents are addicted to tobacco the risk of children becoming dependent on nicotine is greater," Kandel told Reuters Health by phone.

Parent smoking had been tied to teen smoking before, but often with smaller studies of 300 to 1,000 cases, she said.

For this study, Kandel and her coauthors used survey data collected between 2004 and 2012 from 35,000 pairs of a parent and a 12- to 17-year-old. The surveys asked about smoking behavior and nicotine dependence.

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"Nicotine is the most addictive psychoactive substance that exists," said Maria Melchior of the French National Institute of Health and Medical Research, who was not part of the new study.

"However, some individuals can smoke occasionally without becoming dependent," Melchior told Reuters Health by email. This may be determined by genes involved in the brain's reward system or with the way nicotine is metabolized, she said.

A parent's current nicotine dependence - their cravings for cigarettes, feelings of withdrawal when not smoking, preferring to smoke over other activities, and other characteristics - was strongly associated with whether or not the teen had ever tried smoking, whereas a parent's nondependent smoking or former smoking were not tied to teen smoking as strongly. Mothers had a greater effect than fathers, the authors found.

Women smoke less than men, so women who smoke may be more dependent on nicotine, Melchior said.

It is also plausible that mothers influence child behaviors more than fathers because they tend to spend more time with their children and serve as a role model for health behaviors, she said.

Parental nicotine dependence, but not current or former smoking, was tied to teen dependence.

Other factors, like parental education, marital status, and parenting and adolescents' mental health, beliefs about smoking, perception of schoolmates' smoking, and other substance use affected teen smoking and dependence risk, the authors reported in the American Journal of Public Health.

Teen depression, but not parental depression, was tied to teen smoking, Kandel said.

"I think every behavior has a genetic and environmental component to it," Kandel said.

Parents genetically disposed to nicotine addiction may have children who have the same genetic disposition, but there is no doubt that parental behavior has a strong influence on children as well, she said.

"While teen smokers of currently smoking parents, particularly if the parents report dependence, are the most likely to smoke, children of former smokers are still more likely to have smoked than children of parents who never smoked, confirming past studies," Mike Vuolo of the sociology department at The Ohio State University in Columbus told Reuters Health by email.

Vuolo was not part of the new study.

"The thing to do is to try to reduce smoking among adults," Kandel said. Adult and teen smoking have both declined in recent years, but parents may still not realize just how much influence they have on their children, she said.

Intervening with smoking parents while their children are small and helping them quit could result in reduced smoking among teens, she said.