This study compiled the 5 biennial YRBSS data from 1999 to 2007 to investigate the EWLP trends based on the demographic characteristics by sex, race, and grade level. The EWLPs include fasting, taking diet pills/powder without doctor's advice, and vomiting or taking laxatives to lose weight during the past 30 days.
Our analysis, which included 72,122 responses, showed nearly 18% students engaged in at least one EWLP. The prevalence rates increased from 1999 (17.2%) to 2001 (19.4%) and decreased to 16.2% in 2007. Female students represent more than two-thirds (67.5%) of students who were engaged in the EWLPs (OR=2.29, 95% CI=2.20-2.38). Twenty-two percent of American Indian/Alaskan Native students engaged in the EWLPs, representing the highest prevalence amongst ethnical groups, while only 14% for Asian students, representing the lowest. The EWLPs evenly distributed throughout grades, even after stratified by sex. The longitudinal trends by sex, grade, and ethnicity fluctuated similar to the same pattern of overall trend. The grade-cohort effects were also examined and found inconsistent trends over years. Results suggest the prevention efforts should focus more on females without special tendency by grades.