RESUMEN
BACKGROUND: Studies have suggested that asthma in obese individuals differs from the classic asthma phenotype, presenting as a disease that is more difficult to control. OBJECTIVE: The objective of the present study was to determine whether obesity, age or a combination of the two are associated with worse spirometry parameters in patients with asthma. METHODS: This was an observational cross-sectional study involving patients over 18 years of age who had been diagnosed with asthma (allergic or nonallergic). We evaluated the results of their spirometric tests. The patients were classified in accordance with two criteria: body mass index (BMI) and age. Based on their BMIs, the patients were divided into three groups: normal weight, overweight and obese. Patients were also separated into two categories by age: 18-59 years of age; and ≥ 60 years of age. RESULTS: We evaluated 451 patients with asthma and their spirometry tests. In the present study, the pulmonary function parameters were negatively correlated with BMI and age (P < 0.05). We found that there was a statistically significant correlation between spirometric values and BMI among patients 18-59 years of age (P < 0.001), however, among patients over 60, we did not observe this negative association. CONCLUSIONS AND CLINICAL RELEVANCE: The spirometric values decreased significantly in proportion to the increase of BMI and age in patients with asthma, especially among young adults. There was no negative correlation between BMI and FEV(1) in the group ≥ 60 years of age, suggesting that perhaps the time of disease is a major factor in the loss of lung function than weight gain in the elderly.