[Social impact of literacy in the household: analysis of the association with smoking in illiterate co-residents in Brazil].

Objective To investigate the social impact of literacy on the smoking behavior of illiterate individuals who share the household with literate individuals. Method This cross-sectional study employed data from the 2008 Brazilian National Household Survey (Pesquisa Nacional por Amostra de Domicílios, PNAD). Smokers were defined as individuals reporting use of any tobacco product daily or less than daily. The literacy profiles of residents were identified. Poisson regressions adjusted for skin color, age, and maximum level of literacy in the household were performed. Four groups were analyzed: men living in rural areas, men living in urban areas, women living in rural areas, and women living in urban areas. Results For urban men, the presence of literate women only in the household was a protection factor against smoking (prevalence ratio, PR: 0.77; 95%CI: 0.71-0.82) vs. households in which all the males were illiterate. The same protective effect was found for rural men (PR: 0.79; 95%CI: 0.73-0.85). In turn, the presence of literate men only living in the same household with illiterate men did not provide protection against smoking in any case (PR: 0.93; 95%CI: 0.83-1.03 for the urban subsample; and PR: 0.99; 95%CI: 0.88-1.11 for the rural subsample). Illiterate women benefited from the presence of both literate men (PR: 0.77; 95%CI: 0.71-0.84 for the urban sample; and PR: 0.78; 95%CI: 0.69-0.89 for the rural subsample) and literate women (PR: 0.81; 95%CI: 0.72-0.92 for the urban subsample; and PR: 0.75; IC95%: 0.60-0.93 for the rural subsample). Conclusions Literate women seem to have positively affected illiterate co-residents of both sexes. This result is in agreement with reports showing broad advantages of female schooling.