Smoking cigarettes won't help teenage girls lose weight, but it may stunt teen boys' growth, a Canadian study suggests.
The study, published online March 17 in the journal Annals of Epidemiology, found that teenage boys who smoke are on average 2.54 centimetres shorter than non-smokers.
"Girls who smoked did not end up skinnier than girls who did not smoke. They ended up having a similar height and BMI," lead author Dr. Jennifer O'Loughlin, with the Department of Social and Preventive Medicine at the University of Montreal, told CBC News in an e-mail.
"However the evidence presented supports the old adage 'Don’t smoke. It will stunt your growth', at least in boys."
The study said the effect on boys' heights may be because they are still growing when they start to smoke.
The researchers surveyed 1,293 Montreal teens from age 12 through 17 every three months about their smoking and lifestyle habits.
O'Loughlin said the researchers were most surprised to find that there was no link between weight and smoking habits.
O'Loughlin said the findings can be integrated into prevention messages to help persuade teens not to start smoking.
"Girls might not start smoking if they realize that they will not end up skinnier than girls who don’t smoke," she said. "Boys may not start smoking if they think they might end up shorter and smaller overall if they smoke."
She said the findings "might also help uncover the reasons why smoking affects birth weight and possibly growth in adolescents."
The study is part of the Natural History of Nicotine Dependence in Teens Study, funded by the Canadian Cancer Society.