Perceived smoking norms, socioenvironmental factors, personal attitudes and adolescent smoking in China: a mediation analysis with longitudinal data.

PURPOSE: To gather information on inter-relationships among risk factors affecting adolescent smoking for tobacco control in China, the world's largest tobacco producer and consumer.
METHOD: Longitudinal data were collected six months apart in 2003 from 813 students in grades 7, 8, 10, and 11 from two schools in Beijing, China. Linear regression was used to assess both the direct effect from predictor variables (smoking among influential others, pro-tobacco media, and attitudes toward smoking) on cigarette use and the indirect effect mediated through the perceived smoking norms (percentage of smokers among peers).
RESULTS: Among the 803 subjects (mean age of 15.5 years, SD = 1.7; 52.1% female), 18.3% of males and 1.7% of females smoked in the past 30 days. Smoking among influential others (best friends, father, mother, male teachers, female teachers, and adults in general) and perceived positive psychological and social rewards from smoking at baseline were associated with number of cigarettes smoked at follow-up, whereas exposure to pro-tobacco media was not significantly associated with smoking. The mediated effect was greater for adult smoking (70% to 90%) than for best friend smoking (11% to 16%).
CONCLUSION: Smoking among influential others and attitudes toward smoking influence adolescent smoking both directly and indirectly. The finding of the indirect effect mediated through perceived smoking norms expands our knowledge on smoking etiology. Effective adolescent smoking intervention programs in China need to include a component targeting adult smoking to reduce perceived smoking norms.