A study by researchers at the Johns Hopkins Bloomberg School of Public Health has found that state laws mandating taxes on beer, limitations on cigarette vending machines, and the increased availability of family planning clinics appear to help youth avoid risky behaviors such as drinking, smoking, and unsafe sex. Although previous studies have shown that vending machine restrictions and taxes on beer reduced teen smoking and drinking, this study is one of only a few which show that the increased availability of family planning clinics and condoms reduces unsafe sexual behavior in adolescents. The study’s results were presented April 30, 2001 at the Pediatric Academic Societies Conference held in Baltimore, Maryland. Lead author David M. Bishai, MD, PhD, MPH, assistant professor of population and family health sciences at the Johns Hopkins Bloomberg School of Public Health, said, "There is a popular misperception that family planning clinics cause teenagers to have more sex. We found evidence of an opposite association. Where there were more family planning clinics, there was more abstinence, and among teens who were having sex there were fewer sexual partners." For the study, the researchers developed a new statistical model that can make simultaneous estimates about the effects of several different government policies on three seemingly unrelated teenage risk behaviors. The success of this model, they said, provides evidence that one or more common unobservable factors run through all three risky behaviors in youth. Some of these unobservable factors, the authors suggest, may be connected to teens’ impatience or their eagerness for immediate gratification, which prevent some youths from sensing the threat of future trouble from unseemly behaviors. Some adolescents are unable to make the connection between risky behavior today and an eventual bad outcome, or they simply think that the future bad outcome will not be that bad. The researchers obtained data from the Youth Risk Behavior Surveys (YRBS), which were developed in 1995 and given nationally to a cross-section of youth by the Centers for Disease Control and Prevention (CDC). That same year, the YRBS was also conducted locally by 20 separate U.S. states and cities. The researchers combined the YRBS data with information on alcohol prices, as well as with state statistics on cigarettes and beer taxes, teen drinking and smoking, vending machine access, and the accessibility of reproductive health services. The authors developed a statistical model of teen-age risk-taking based on the assumption that the three risky behaviors under study were related by a set of unobservable factors common to all, and that this interrelationship allowed simultaneous estimation of the frequency of smoking and drinking, and the numbers of sex partners. The model’s estimates confirmed earlier findings that the prevalence of these risky behaviors generally increases with age and is less common in boys. African-American youth were less likely to smoke or use alcohol than children of other racial backgrounds but, as has been found in other studies, at any given age they were more likely to engage in sexual intercourse. State beer taxes were associated with a statistically significant reduction in the frequency of alcohol use. Similarly, increasing the availability of Title X family planning clinics was associated in the model with a statistically significant reduction in the number of sex partners. Laws limiting vending machine access had a statistically significant deterrent effect among youth who smoked, but cigarette taxes did not. Co-author Daniel C. Mercer, MS, graduate student at the Johns Hopkins Bloomberg School of Public Health, said, "There are patterns of teenage behavior that are lost when each risky activity is studied separately. Studying more than one teen behavior at a time can tell us more than doing it the old way. With the new technique we can actually learn more about the effects of state policies on these behaviors." Support for this study was provided by the Faculty Innovation Fund of the Johns Hopkins Bloomberg School of Public Health. Public Affairs Media Contact:
Tim Parsons @ 410.955.6878 or paffairs@jhsph.edu
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