Smokers who pick up the habit while they are teenagers are at the greatest risk of developing genetic changes in lung tissue that have been linked to cancer--even after they quit smoking, new research suggests.
The findings, which appear in this month’s Journal of the National Cancer Institute, suggest that smoking during times of rapid lung growth and development may lead to long-lasting physiological changes.
“The research shows the effect of smoking is more long-lasting than people have thought in the past, even for ex-smokers,” said Sally Thurston, a researcher at Harvard University’s school of public health and a co-author of the study.
Researchers studied 143 lung-cancer patients; 136 were current or former smokers, and seven had never smoked. They found that the levels of DNA changes known as aromatic hydrophobic DNA adducts, which are linked to lung cancer, were significantly higher in the lung tissue of the patients who began smoking during their teenage years, compared with those who had started later in life.
Overall, the average age at which the patients started smoking was 17.
The ones who had started smoking between ages 7 and 14 had an average of 164 DNA alterations in their lung tissue. Among those who started smoking between ages 15 and 17, there were 115 DNA alterations, and among those who didn’t start until after they were 20, the alterations averaged 81.
The genetic alterations occur when the compounds in cigarette smoke break down and bind with DNA, causing mutations.
This is the first study to consider age at the onset of smoking as a predictor of smoke-related genetic damage, the researchers said.
Vulnerable Age: Students are most vulnerable to substance abuse while making the transition from elementary school to middle school, a new study concludes.
As early as age 9, students may begin experimenting with cigarettes, alcohol, and drugs, according to a survey by the National Parents’ Resource Institute for Drug Education, or PRIDE.
An 11- or 12-year-old in the 6th grade is four times more likely to be using alcohol, tobacco, or drugs such as marijuana and inhalants as a pupil in the 4th grade.
The PRIDE survey was described as the first national study of drug use and violence to include students as young as those in grades 4 to 6.
The survey also found that violence and the threat of violence was a concern for young students. One-third said they had been threatened by another student at school, and 27 percent reported that they had been physically injured by another student at least once.
More than 26,000 students in 22 states were surveyed.
The percentage of 6th graders who said they had smoked cigarettes in the past year was more than triple that of 4th graders--4.1 percent of 4th graders, compared with 14.8 percent of 6th graders.
The use of marijuana also more than triples between grades 5 and 6, the report says; 1.2 percent of 5th graders reported using marijuana in the past year, compared with 3.7 percent of 6th graders.
And the incidence of cigarette smoking and beer drinking roughly double between grades 5 and 6. The percentage of pupils who smoke cigarettes increases from 7 percent to 15 percent; the percentage of those who drink beer goes from 8 percent to 15 percent, the study says.
“It is clear from these numbers, the transition from the 5th to 6th grade is a critical moment as a child makes the decision whether to use drugs and engage in other bad behaviors,” said Thomas J. Gleaton, an author of the study and the president of the Atlanta-based PRIDE.
Mr. Gleaton said social factors such as a new group of friends could explain the large increases in risky behaviors between grades 5 and 6.
Other studies have shown a similar increase in drug use when children move from elementary to middle school, said Arthur Hughes, a researcher with the National Institute for Drug Abuse who has conducted comparison studies of drug-use surveys.
“This supports what we’ve seen from other studies,” Mr. Hughes said.
The PRIDE survey is available on the World Wide Web at www.prideusa.org.
Parents Set Example: Many parents need to change their own behavior, a report argues, in order to set a more healthful example for their children and to remain healthy enough to raise them.
The report, published this month by the Washington advocacy group Child Trends Inc., draws on a national survey of parents who live with children under age 18 and who are themselves age 54 or younger.
The survey asked about risky behaviors such as smoking and heavy use of alcohol, being overweight, and getting too little exercise, as well as good health habits.
The study found that the majority of parents in nearly all social groups were in good or excellent health, but that a parent’s health status was linked to education level, income, and age.
Risky behaviors were more common among single parents and parents with less education and lower incomes.
One in three mothers reported a high-risk behavior such as smoking, having a sedentary lifestyle, or drinking alcohol heavily; 43 percent of fathers said they engaged in one or more such risky behaviors.
Parents with higher education levels and higher family incomes generally reported fewer risky behaviors.
Copies of “Setting an Example: The Health, Medical Care, and Health-Related Behavior of American Parents” are available for $25 each from Publications/"Setting an Example,” Child Trends, 4301 Connecticut Ave. N.W., Suite 100, Washington, DC 20008.
--Adrienne D. Coles acoles@epe.org
