"We found that parents quitting smoking early, before their children reach third grade, is associated with nearly double the chances that their children would quit smoking in young adulthood," said Jonathan Bricker, Ph.D., a clinical psychologist and staff scientist in Fred Hutchinson's Public Health Sciences Division. These findings appear in the March issue of Addiction, which is published by the London-based Society for the Study of Addiction.
Since the early 1990s, the prevalence of daily smoking among young adults has risen by nearly 40 percent, giving those between 18 and 24 the unfortunate distinction of being more likely to smoke cigarettes than any other age group, according to the Centers for Disease Control and Prevention. What's more, low quitting rates among young-adult smokers underscore the need to find ways to help young adults quit, Bricker said.
"Overall, these findings suggest that helping parents quit smoking should be considered in future public-health interventions that target youth smoking," Bricker said.
These findings build on an earlier study by Bricker and colleagues, published in the May 2003 issue of Addiction, which that found parents who quit smoking before their children reached third grade significantly reduced their child's odds of becoming a smoker by their senior year of high school.
"Taken together, these two studies suggest that parents who quit smoking by the time their children are 8 or 9 years old may help prevent their children from becoming adolescent smokers and, if they do start, may help them quit smoking in young adulthood," said Bricker, also a clinical instructor in the University of Washington Department of Psychiatry and Behavioral Sciences.
The most surprising finding of the study, Bricker said, was that parents who quit smoking late, when their child was between third and 12th grade, had no impact on their child's quitting behavior in early adulthood.
"We had thought that parents quitting late might serve as a recent model of behavior that their children could remember and emulate, but our data did not show a significant result for late quitting," Bricker said. One possible explanation, he said, was lack of statistical power in their data; there simply were not enough young-adult quitters whose parents were late quitters enrolled in their study.
"Scientists should look into the late-quitting question," Bricker said. "It is conceivable that parents' late quitting may also help young adults quit, but we simply did not find any significant result for the question."
The findings are based on data collected from 1,553 Washington families that included at least one parent with a history of regular smoking and a child who smoked at least weekly by 12th grade. The students in the study were part of the landmark Hutchinson Smoking Prevention Project, the largest and longest school-based intervention trial ever conducted in smoking-prevention research, involving nearly 8,400 students and 600 teachers throughout 40 school districts in Washington. The National Cancer Institute funded the research.
Information on parents' smoking behavior was collected when the children were in the third grade (8 or 9 years old) and again at 11th grade (16 or 17 years old). Information on the children's smoking behavior was collected when the children were in 12th grade (17 or 18 years old) and again two years after high school.
"This study is unique because it is the first prospective study to follow a large group of parents and children over time to examine whether parents' quitting behavior might be related to their young-adult children quitting smoking," Bricker said.
However, Bricker cautions that only a randomized controlled trial would be able to conclusively determine whether the association between parental and young-adult smoking cessation is a true cause-and-effect relationship.
In the meantime, the results of the current analysis suggest that it may be beneficial to include parents in primary smoking-prevention programs for children. "Prevention programs need to reach the parents as well as the children," Bricker said. "We need parents to realize that if they quit smoking, they may be helping their young-adult children to quit smoking in the future."
Parents who would like to quit are encouraged to contact their primary physician for smoking-cessation guidance, Bricker said. Resources for free smoking-cessation assistance include:
"The first step to quit smoking is becoming personally motivated to quit," Bricker said. "This study could help tip the motivational balance for parents - or prospective parents - who want to take the next step and do something about their smoking behavior, both for their own health and for that of their child."
Fred Hutchinson Cancer Research Center, home of three Nobel laureates, is an independent, nonprofit research institution dedicated to the development and advancement of biomedical research to eliminate cancer and other potentially fatal diseases. Fred Hutchinson receives more funding from the National Institutes of Health than any other independent U.S. research center. Recognized internationally for its pioneering work in bone-marrow transplantation, the center's four scientific divisions collaborate to form a unique environment for conducting basic and applied science. Fred Hutchinson, in collaboration with its clinical and research partners, the University of Washington and Children's Hospital and Regional Medical Center, is the only National Cancer Institute-designated comprehensive cancer center in the Pacific Northwest and is one of 40 nationwide. For more information, visit the center's Web site at www.fhcrc.org.
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