Cigarette Smoking Among High School Students — 11 States, 1991-1997

Morbidity and Mortality Weekly Report, August 13, 1999

Tobacco use is the single leading preventable cause of death in the United States [1]. Preventing initiation of tobacco use is a public health priority. Approximately 80% of persons who use tobacco begin before age 18 years [1], and the prevalence of cigarette smoking among high school students nationwide increased during the 1990s [2]. This report presents findings of a study that examined trends in cigarette smoking among high school students in 11 states that collected Youth Risk Behavior Survey (YRBS) data during the 1990s. In six of the 11 states, the prevalence of current smoking and frequent smoking increased among high school students.

The Youth Risk Behavior Surveillance System measures the prevalence of health-risk behaviors among adolescents through biennial representative school-based surveys conducted separately at the national, state, and local levels. In 1997, 39 states conducted YRBS. This report presents YRBS results from 11 state surveys conducted by state education and health agencies where representative data were obtained (i.e., a scientifically selected sample, an overall response rate of [greater than or equal to]60%, and appropriate survey documentation) in 1997 and in at least two additional years since 1991. The 1991, 1993, 1995, and 1997 state surveys used a two-stage cluster sample design to produce representative samples of 9th- to 12th-grade students in each participating state. Data were available from 1991 to 1997 in Alabama, South Carolina, South Dakota, and Utah and from 1993 to 1997 in Hawaii, Massachusetts, Mississippi, Montana, Nevada, Vermont, and West Virginia. Across all sites and years, sample sizes ranged from 1192 to 8636, school response rates ranged from 70% to 100%, student response rates ranged from 61% to 91%, and overall response rates ranged from 60% to 87%.

For each of the cross-sectional surveys, students completed an anonymous self-administered questionnaire that included questions about cigarette smoking. The wording of these questions was identical in each survey. Lifetime cigarette smoking was defined as having ever smoked cigarettes, even one or two puffs. Current cigarette smoking was defined as smoking on [greater than or equal to]1 of the 30 days preceding the survey, and frequent cigarette smoking was defined as smoking on [greater than or equal to]20 of the 30 days preceding the survey. Students were asked at what age they first smoked a whole cigarette. Beginning in 1993, students were asked whether they smoked cigarettes on school property on [greater than or equal to]1 of the 30 days preceding the survey.

Data were weighted to provide estimates generalizable to all public school students in grades 9-12 in each state. The relative percentage change in behavior from the earliest survey conducted (baseline) to 1997 was calculated as the 1997 prevalence minus the baseline prevalence divided by the baseline prevalence. SUDAAN was used for all data analysis. Secular trends were analyzed using logistic regression analyses that controlled for sex, grade, and race/ethnicity (except in Vermont, where students were not asked about race/ethnicity) and that simultaneously assessed linear and higher order (i.e., quadratic) time effects [3]. Quadratic trends suggest a significant but nonlinear trend in the data over time. When the trend includes significant linear and quadratic components, the data demonstrate some nonlinear variation (e.g., leveling off or change in direction) in addition to a linear effect. In 1993, Alabama did not ask students about lifetime, current, or frequent smoking or the age at which students smok ed their first cigarette; therefore, only linear trend analyses were performed for Alabama for those variables.

In South Carolina, South Dakota, and Vermont, lifetime smoking among high school students significantly increased linearly from baseline to 1997 (Table 1). The percentage increase in these states was 2%, 8%, and 5%, respectively. Massachusetts and Nevada showed significant quadratic trends, with the highest prevalence occurring in 1995.

The prevalence of current smoking significantly increased linearly in Alabama, Massachusetts, Mississippi, Montana, South Carolina, and South Dakota (Table 2) with percentage increases of 29%, 14%, 13%, 24%, 51%, and 42%, respectively. Massachusetts also showed a significant quadratic trend, with leveling between 1995 and 1997. South Carolina showed a significant quadratic trend, with leveling between 1991 and 1993 followed by increases in 1995 and 1997.

In Alabama, Massachusetts, Montana, South Carolina, South Dakota, and Vermont frequent smoking significantly increased linearly from baseline to 1997 (Table 2) with percentage increases of 26%, 19%, 52%, 39%, 49%, and 21%, respectively. Vermont also showed a significant quadratic trend, with leveling between 1995 and 1997.

The proportion of students who reported smoking a whole cigarette before age 13 years significantly decreased linearly from baseline to 1997 in Nevada and Utah (Table 3). The percentage decrease was 17% in Nevada and 32% in Utah. Utah also showed a significant quadratic trend, with leveling between 1993 and 1995 before a decline in 1997.