171 A RTÍCULO DE I NVESTIGACIÓN Rev Méd Chile 2004; 132: 171-182 Consumo de tabaco en población menor de 18 años: estudio de prevalencia en escolares de Chile Gonzalo Valdivia 1 , Franco Simonetti a , Patricio Cumsille a , Valeria Ramírez a , Carmen Gloria Hidalgo a , Beatriz Palma a , Juan Carrasco b . Smoking habit in school age children, in Chile Background: In Chile, there is no information about the preva- lence of smoking among basic and high school students. Aim: To study the prevalence of smok- ing among school age population. Material and Methods: A cross sectional survey was con- ducted during 2001, assessing tobacco use and smoking habit in a representative sample of 15.119 randomly selected students. Results: Sixty four percent of students had smoked at least once in their lifetime. Eighteen percent of students smoked daily and 15%, occasionally. The fig- ures for women were higher (19 and 18% respectively). The mean age for the first contact with smoking was 12.3 years and, for starting the smoking habit, 13.2 years. Smokers increased the amount of cigarettes during weekends. Higher prevalence rates of smoking were observed in stu- dents from the Southern region of the country and of lower socioeconomic levels. From the 3rd grade on, there is an increased risk of having contact with tobacco and smoking for the first time and from 6th grade on, this risk becomes permanent. The adjusted Odds Ratio to be a smoker is significantly higher when the mother is a current or irregular smoker (OR 1.9 95 CI; 1.7-2.0). Conclusions: High smoking prevalence rates were detected in this survey, mainly in women. The risk for smoking starts early during school life. Therefore, health promotion pro- grams must include elementary and high school students (Rev Méd Chile 2004; 132: 171-82). ( Key Words: Adolescent behavior; Data collection; Smoking) Recibido el 16 de julio, 2003. Aceptado en versión corregida el 26 de noviembre, 2003. 1 Departamento de Salud Pública, Facultad de Medicina, Escuela de Psicología, Pontificia Universidad Católica de Chile. Santiago, Chile. a Psicólogo b Estudiante de Medicina, Pontificia Universidad Católica de Chile. Correspondencia a: Dr. Gonzalo Valdivia Cabrera. Departa- mento de Salud Pública, Facultad de Medicina, Pontificia Universidad Católica de Chile. Marcoleta 352, Santiago Chi- le. Fax: 6331840. E mail: valdivia@med.puc.cl factores de riesgo de enfermedad crónica 1-3 . Las intervenciones para modificar el perfil de algunos de estos factores, como ser el consumo de alcohol y tabaco, requieren disponer de información actualizada sobre la prevalencia de ellos en la población. Chile cuenta con adecuada informa- ción epidemiológica en población adulta, espe- cialmente en cuanto a consumo de tabaco 2-8 . Sin C hile se encuentra en una situación de transición epidemiológica avanzada y en su población se ha constatado una alta frecuencia de