Quit smoking before your kids reach third grade

Nine-year Public Health Sciences study reveals window of opportunity for smoking parents to increase the chances of raising smoke-free children

A PHS study shows if both parents quit smoking by the time their child is 8 or 9, the child's odds of becoming a smoker drop by nearly 40 percent.

New findings from the Public Health Sciences Division may provide a compelling reason for smoking parents of young children to kick the habit. Researchers have found that parents who quit smoking before their child reaches third grade will significantly reduce their child's odds of becoming a smoker by the time their senior year of high school rolls around.

Specifically, if one parent quits by the time the child is 8 or 9, the child's odds of being a daily or monthly smoker at age 17 or 18 decrease by 25 percent. If both parents quit, the child's chances of smoking drops by nearly 40 percent, according to Jonathan B. Bricker and colleagues at Fred Hutchinson and the University of Washington.

"Statistics show that if a child reaches age 18 without becoming a smoker, his or her odds of remaining smoke-free are around 90 percent. Therefore, our results indicate that if all smoking parents were to quit by the time their children were around age 8, it could prevent 136,000 young people in the United States from becoming daily, long-term smokers," said Bricker, a research associate in the center's Cancer Prevention and Trials Program.

The most surprising finding of the study, Bricker said, was that parental influence on smoking was not affected by the child's age when the last parent quit, as long as it was by the time the child was 8 or 9. "It didn't matter whether one or both parents quit when the child was a baby, a toddler or in third grade," Bricker said. "The most important thing was that they quit." More research is needed, however, to determine the benefits, if any, of parental-smoking cessation after children are 8 or 9.

There also was no evidence that parent or child gender had any impact on the link between parental-smoking cessation and children's smoking behavior; mothers were no more influential than fathers and girls were no more susceptible than boys.

Not surprisingly, those least likely to smoke were the children of parents who had never taken up the habit. Smoking prevalence in 12th grade was 14 percent when neither parents had ever smoked as compared to 37 percent when both parents were current smokers and 26 percent when both parents had quit by the time the child was in third grade.

The study appears in this month's issue of the journal Addiction. Co-authors include PHS colleagues Dr. Arthur Peterson, Dr. Robyn Andersen, Kathleen Kealy and Patrick Marek; and UW colleagues Dr. Irwin Sarason and Dr. Brian LeRoux.

The findings are based on data collected from more than 3,000 children and parents in 20 school districts in Washington. Information on parents' smoking behavior was collected when the children were in the third grade (8 or 9 years old), and data on children's smoking behavior was collected nine years later, when the children were in 12th grade (17 or 18 years old). Student self-reports of smoking activity were found to be largely accurate as verified through saliva tests that checked for the presence of cotinine, a by-product of nicotine.

"This study is unique because it is the first prospective study to follow a large group of parents and children over time to examine the relationship between parental-smoking cessation when children are young and how it relates to smoking behavior in late adolescence," said Bricker, who's also a doctoral candidate in clinical psychology in the UW Department of Psychology.

Impact may be even greater

How and why are children impacted by parental-smoking cessation?
Jonathan Bricker and colleagues suspect it's largely because parents who've quit may engage in anti-smoking behaviors that reduce their children's overall exposure to cigarettes, from requesting nonsmoking sections in restaurants to banning smoking at home.

While more research into the mechanisms of parental influence is needed, researchers do know is that the window of vulnerability for smoking tends to open around age 8 and close around age 20. This "smoking-acquisition period" may be influenced by a combination of genetics, and parental and peer models of smoking. It also may stem from a child's desire to emulate adult behavior, Bricker said, although in reality, only about 25 percent of adults smoke.

"Because adolescence is a period in which children are developing an identity as an adult, they are, in a sense, trying on behaviors like trying on clothes amd such. Behaviors they think will make them feel like adults."

Kick the smoking habit today!