Avaliação da associação entre tabagismo e índice de massa corporal segundo níveis de escolaridade

Abstract

The overweight and smoking, when both are present in an individual, are even more harmfulto health than when only one is present. However the relationship between smoking andoverweight is not fully known and the prevalence of obesity and smoking are higher in lowersocioeconomic level, including in Brazil. In this background, studies suggest that there is anassociation between smoking and BMI and educational level may influence this relationship.Thus, this study aimed to investigate the association between smoking and BMI and test thisassociation by educational levels in models stratified by sex in Brazilian population. It is across-sectional study developed from data from system participants VIGITEL from 26 statecapitals of Brazil and Federal District, 2009. Dependent variable was BMI, used ascontinuous. Independent variable of central interest was smoking, categorized as individualswho never smoked, ex-smokers, light smokers (smoke one to 19 cigarettes/day) and heavysmokers (smoke more than 20 cigarettes/day), and potential effect modifier variable wasschooling. Data processing and statistical analysis were done with the STATA 12.0, usingSTATAs survey suite of command. The interaction test was conducted with smoking andeducation variables. Multivariate models were additionally adjusted for age and the lifestylevariables (physical activity, consumption of alcoholic beverages, food consumption andmarital status). In this study there was an association between smoking and BMI and theeducation level presented statistically significant effect modifier for both sexes. However, thisdifference was more pronounced among men than among women. Heavy smokers men withlow education had lower mean BMI than who never smoked, while in high education, heavysmokers had higher mean BMI than who never smoked. In addition, ex-smokers men withhigh education had higher mean BMI than those who never smoked, which did not occur inlow education. Light smokers women in both educational level had lower mean BMI thanwho never smoked. The difference in the association between smoking and BMI byeducational level was not explained by lifestyle habits. Despite the incomplete knowledge ofthe mechanisms that cause the differences found in the study, smoking should not beconsidered an effective way to prevent obesity. Although BMI decreases in smokers, itsprevention also helps to prevent other diseases such as cardiovascular disease.