[Changes in asthma prevalence among school children during a 6 -year period: Influence of socioeconomic status].

BACKGROUND Asthma prevalence is increasing worldwide, especially in developing countries. AIM To determine the prevalence of asthma diagnosis and related symptoms in children, its changes during a 6-year period and the influence exerted by socioeconomic status. MATERIALS AND METHODS Cross-sectional study conducted among school children of Santiago. A sample of 4,561 children aged 6-7 and 13-14 years attending public schools (central district, medium-low and low socioeconomic status) and private schools (eastern districts, high socioecomic status) were surveyed. Dependent variables were asthma diagnosis (AD), wheezing during the last 12 months (WHE12) and frequency of episodes of wheezing (FEW). Prevalence odds ratios were calculated using regression models, adjusted for several confounding variables. RESULTS AD prevalence for the group as a whole was higher in boys than in girls (13.2% and 10.8%, respectively p =0.016). Prevalence rate of AD was also higher for children aged 13-14 than 6-7 years (13.8% and 10.1%, respectively p <0.01). An inverse association was found between SES and WHE12. Higher maternal education level was associated with lower prevalence of WHE12 in both age groups and with lower prevalence of FEW in 6-7 year-old children. Paternal education level was positively associated with AD among younger children. At the central district, increasing trends of WHE12 and FEW prevalence were observed during 1994-2000 among 6-7 years children. CONCLUSIONS A significant association was observed between socioeconomic status, asthma diagnosis and symptoms in school children living in Santiago. Data support an increasing trend of asthma prevalence and severity among 6-7 year-old children during the period 1994-2000.