The role of economic and educational factors in asthma: Evidence from the Portuguese Health Survey

SummaryObjectiveTo evaluate the importance of economic and educational factors in determining the risk of asthma in adults.Study design and methodsThis was a cross-sectional study in a representative sample of Portuguese adults (20,977 females and 18,663 males) from the main regions of mainland Portugal. Participants were categorized according to years of education (⩽4, 5–9, 10–12 and >12 years) and income (⩽314, 315–547, 548–815 and >815 Euros/month). Information on asthma was based on answers to the following question: ‘Have you had asthma in the previous year?’ Logistic regression models were fitted to estimate the magnitude of the association between asthma and education/income, adjusting for confounders (body mass index, age, smoking habits, physical activity, area of residence, number of household members and income/education).ResultsIn females and males, the odds of having asthma decreased with increasing income (P-value for trend <0.001), with odds ratios of 0.52 [95% confidence intervals (CI) 0.41–0.66] and 0.55 (95%CI 0.44–0.68) for those with a monthly income >815 Euros compared with those with a monthly income ⩽314 Euros, respectively. For both genders, the odds of having asthma were not significantly associated with years of education.ConclusionA significant positive association between per capita national income and asthma reinforces that public policy should stress the importance of economic growth as a means for preventing asthma occurrence and improving quality of life.