jueves, 8 de julio de 2010

Cigarette Use Among High School Students --- United States, 1991--2009



Cigarette Use Among High School Students --- United States, 1991--2009
Weekly
July 9, 2010 / 59(26);797-801



Understanding the trends in the prevalence of cigarette smoking among youths enables policy makers to target prevention resources more effectively. Every 2 years, CDC analyzes data from the national Youth Risk Behavior Survey (YRBS) to evaluate trends in cigarette use among high school students in the United States. This report updates a previous report (1) and describes results of CDC's 2010 analysis of YRBS data from 1991--2009 for three measures: ever smoked cigarettes, current cigarette use, and current frequent cigarette use. For ever smoked cigarettes, the prevalence did not change from 1991 (70.1%) to 1999 (70.4%), declined to 58.4% in 2003, and then declined more gradually, to 46.3% in 2009. For current cigarette use, the prevalence increased from 27.5% in 1991 to 36.4% in 1997, declined to 21.9% in 2003, and then declined more gradually, to 19.5% in 2009. For current frequent cigarette use, the prevalence increased from 12.7% in 1991 to 16.8% in 1999, declined to 9.7% in 2003, and then declined more gradually, to 7.3% in 2009. For all three measures, rates began to decline in the late 1990s, but the rate of decline slowed during 2003--2009. To increase the rate of decline in cigarette use among high school students, reductions in advertising, promotions, and commercial availability of tobacco products should be combined with full implementation of communitywide, comprehensive tobacco control programs (2--5).

The biennial national YRBS, a component of CDC's Youth Risk Behavior Surveillance System, used independent, three-stage cluster samples for the 1991--2009 surveys to obtain cross-sectional data representative of public and private school students in grades 9--12 in all 50 states and the District of Columbia.* For each survey, students completed anonymous, self-administered questionnaires that included identically worded questions about cigarette use. During 1991--2009, the number of participating schools ranged from 110 to 159, and the number of participating students ranged from 10,904 to 16,410. School response rates ranged from 70% to 81%, student response rates ranged from 83% to 90%, and the overall response rates ranged from 60% to 71%.

For this analysis, ever smoked cigarettes was defined as ever trying cigarette smoking, even one or two puffs; current cigarette use was defined as smoking cigarettes on at least 1 day during the 30 days before the survey; and current frequent cigarette use was defined as smoking cigarettes on 20 or more days during the 30 days before the survey. Race/ethnicity data were analyzed only for non-Hispanic black, non-Hispanic white, and Hispanic students (who might be of any race); the numbers of students from other racial/ethnic groups were too small for meaningful analysis. Data were weighted to provide national estimates, and the statistical software used for all data analyses accounted for the complex sample design. Temporal changes were analyzed using logistic regression analyses, which controlled for sex, race/ethnicity, and grade and simultaneously assessed linear, quadratic, and cubic time effects (p<0.05).†

Significant linear, quadratic, and cubic effects were detected for all three measures (Table 1 and Figure 1). The percentage of students who ever smoked cigarettes did not change from 1991 (70.1%) to 1999 (70.4%), declined to 58.4% in 2003, and then declined more gradually to 46.3% in 2009. The percentage of students who reported current cigarette use increased from 27.5% in 1991 to 36.4% in 1997, declined to 21.9% in 2003, and declined more gradually to 19.5% in 2009. The percentage of students who reported current frequent cigarette use increased from 12.7% in 1991 to 16.8% in 1999, declined to 9.7% in 2003, and then declined more gradually to 7.3% in 2009.

For current cigarette use, trend analyses were conducted by sex, race/ethnicity, and grade in school (Figures 2 and 3). Significant linear, quadratic, and cubic effects similar to the overall analysis were observed for current cigarette use among female students overall, white female students, black students overall, black male students, 9th-grade students, and 10th-grade students (Table 2). Among male students overall, white students overall, white male students, Hispanic male students, and 11th-grade students, current cigarette use increased from 1991 to 1997, declined from 1997 to 2003, and then remained stable. Among Hispanic students overall and Hispanic female students, current cigarette use increased from 1991 to 1995, declined from 1995 to 2003, and then remained stable. Among 12th-grade students, current cigarette use increased from 1991 to 1999, declined from 1999 to 2003, and then remained stable. Among black female students, only linear and quadratic effects were observed, indicating that the prevalence of current cigarette use increased from 1991 to 1999 and then declined, with no slowing or leveling off.

Reported by
Office on Smoking and Health, Div of Adolescent and School Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.


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Cigarette Use Among High School Students --- United States, 1991--2009

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