Starting to diet seems to double the odds a teenage girl will begin smoking, a University of Florida study has found.

UF researchers, who analyzed the dieting and smoking practices of 8,000 adolescents, did not find the same link in boys, who were also less likely than girls to diet, according to findings released Friday in the American Journal of Health Promotion.

“Dieting was a significant predictor of initiation of regular smoking among females,” said Mildred Maldonado-Molina, Ph.D., a UF assistant professor of epidemiology and health policy research and lead author of the study. “We were expecting that this relationship was going to be stronger among females. That has been well-documented, especially because (nicotine) can suppress your appetite.

“In boys we found something we don’t understand yet,” she said. “We found that those who were inactive dieters, those who first started dieting and then stopped, were more likely to engage in smoking behaviors.”

The researchers derived their findings from the answers of 7,795 adolescents who were surveyed during the first two waves of the National Longitudinal Study of Adolescent Health, completed in 1994 and 1996. The teens were in seventh, eighth and ninth grade when surveyed.

UF researchers included the answers of adolescents who said they were trying to lose weight and divided the group into four units: non-dieters, new dieters, former dieters and consistent dieters, who said they were dieting both times they were surveyed. They excluded teens who were already smokers and those who admitted to taking diet pills, vomiting and using other unhealthy weight-loss tactics.

“That group (of teens who were beginning to diet) was the one we were most interested in, seeing how the start of one behavior related to initiation of smoking,” Maldonado-Molina said.

Researchers also found that girls who consistently dieted were more likely to smoke.

Still, the number of children smoking in the United States has dropped in the 10 years since the first two waves of the survey were completed. In 1995, about 35 percent of high school students smoked regularly, according to the Centers for Disease Control and Prevention. Now about 23 percent of high-school age children reportedly smoke and 8 percent of middle school students do. The percentage of girls who smoke is slightly higher in both age groups, according to a 2006 CDC report on tobacco use among youth.

“In the last decade there has been a decrease in smoking among adolescents, in part because of all the campaigns and policies against smoking,” Maldonado-Molina said. “On the other hand, the practices of dieting are going up in both females and males. We don’t know if we did this study right now if that relationship between smoking and dieting is going to be stronger (among females) or different among males.”

Smoking to suppress the appetite may be one reason why some dieting teens pick up the habit, Maldonado-Molina said. But nicotine’s ability to suppress the appetite may not be the only reason teenagers are more likely to smoke after they start dieting, said S. Bryn Austin, Sc.D., an assistant professor of pediatrics in the division of adolescent medicine at Children’s Hospital Boston and Harvard Medical School.

“It’s also possible that dieting itself is making people more vulnerable to smoking,” Austin said, noting that animal studies have shown a link between food deprivation using substances such as tobacco. “If (animals) are extremely food-deprived, they will use more drugs.”

Despite the link, Maldonado-Molina said parents shouldn’t go on red alert if their child starts a diet. Some dieting practices, such as eating balanced meals, can be a part of a healthy lifestyle, she said.

“This doesn’t mean if your child starts dieting they are going to start smoking,” she said. “I think (parents should) be vigilant and talk about it. It’s looking for those changes in behavior.”