The study found that other factors early in life also increased the risk of later smoking, including stress, a parent with high school or less education, being from a one-parent household, drinking alcohol, poor academic performance, and poor conduct. Each factor affected the risk to differing degrees in black and white girls.
The study, which appears in the June issue of Preventive Medicine, was based on data from the NHLBI-sponsored Growth and Health Study (NGHS). Lead investigator Dr. Carolyn Voorhees of The Johns Hopkins University Medical School and an NHLBI Research Fellow at the time of the study, led the analysis with collaborators at the University of California at Berkeley, CA, Children's Hospital Medical Center in Cincinnati, OH, Westat, Inc, in Rockville, MD, and the Maryland Medical Research Institute in Baltimore, MD.
"Getting youths not to start smoking has been very hard," said NHLBI Director Dr. Claude Lenfant. "Many environmental, social, and psychological factors are involved in determining which youths are at most risk. By helping to identify key factors involved in girls' decisions to smoke, the study may lead to the development of more effective smoking prevention programs."
"Many of the factors identified in this study as increasing girls' risk of becoming smokers were not even on our radar screens 10 years ago," said Voorhees, "and the drive for thinness among black girls has not been previously reported."
National surveys show that teenage smoking, especially among whites, is on the rise, with the biggest increase being among high school seniors. More than 3,000 young persons start smoking each day, according to Federal estimates. Current predictions are that, in the United States, more than 5 million of today's young smokers will go on to die of a tobacco-related illness.
NGHS involved 2,379 black and white girls at three locations-Richmond, CA, Cincinnati, OH, and metropolitan Washington, DC. The girls were followed for 9 years and were ages 9 and 10 at the start of the study.
Researchers looked at five categories of smoking. The categories were based on the number of days a girl had smoked over 30 days: No smoking, experimental (5 or fewer days), occasional (6-19 days), regular (20-29 days), and daily (30 days).
Researchers also assessed the girls' blood lipids, blood pressure, food intake, and physical activity. Additionally, girls underwent in-depth interviews on various subject areas. Most assessments were repeated annually. Information on parental and guardian education and other topics also was gathered.
In this study, researchers compared the effects of risk factors for becoming a daily smoker in black and white girls, as well as examining the impact of each risk factor independently for each group.
Among the study's other key findings were:
White girls were more likely than black girls to become daily smokers, while black girls were likely than white girls to become experimental or occasional smokers.
For black girls, weight concerns and a drive for thinness at ages 11-12 were the most important factors leading to daily smoking at ages 18-19.
For white girls, in addition to weight concerns at ages 11-12, poor conduct and stress at those ages and having a one-parent household were the most important factors leading to daily smoking at ages 18-19.
"The findings show that we need to offer young teenage girls healthy ways of controlling their weight and dealing with stress," said Dr. Eva Obarzanek, NGHS project officer at NHLBI. "But we also must provide smoking prevention and cessation programs through schools, community, and other outlets."
To interview a scientist about this study, contact the NHLBI Communications Office at (301) 496-4236.
NHLBI press releases, fact sheets, and other materials are available online at: www.nhlbi.nih.gov