Body mass index, asthma, and respiratory symptoms: a population-based study

Souza, Elaine Cristina Caon de; Pizzichini, Marcia Margaret Menezes; Dias, Mirella; Cunha, Maíra Junkes; Matte, Darlan Lauricio; Karloh, Manuela; Maurici, Rosemeri; Pizzichini, Emilio

ABSTRACT Objective:

To estimate the prevalence of respiratory symptoms and asthma, according to body mass index (BMI), as well as to evaluate factors associated with physician-diagnosed asthma, in individuals ≥ 40 years of age.

Methods:

This was a population-based cross-sectional study conducted in Florianópolis, Brazil, with probability sampling. Data were collected during home visits. Demographic data were collected, as were reports of physician-diagnosed asthma, respiratory symptoms, medications in use, and comorbidities. Anthropometric measurements were taken. Individuals also underwent spirometry before and after bronchodilator administration. Individuals were categorized as being of normal weight (BMI < 25 kg/m2), overweight (25 kg/m2 ≥ BMI < 30 kg/m2), or obese (BMI ≥ 30 kg/m2).

Results:

A total of 1,026 individuals were evaluated, 274 (26.7%) were of normal weight, 436 (42.5%) were overweight, and 316 (30.8%) were obese. The prevalence of physician-diagnosed asthma was 11.0%. The prevalence of obesity was higher in women (p = 0.03), as it was in respondents with ≤ 4 years of schooling (p < 0.001) or a family income of 3-10 times the national minimum wage. Physician-diagnosed asthma was more common among obese individuals than among those who were overweight and those of normal weight (16.1%, 9.9%, and 8.0%, respectively; p = 0.04), as were dyspnea (35.5%, 22.5%, and 17.9%, respectively; p < 0.001) and wheezing in the last year (25.6%, 11.9%, and 14.6%, respectively; p < 0.001). These results were independent of patient smoking status. In addition, obese individuals were three times more likely to report physician-diagnosed asthma than were those of normal weight (p = 0.005).

Conclusions:

A report of physician-diagnosed asthma showed a significant association with being ≥ 40 years of age and with having a BMI ≥ 30 kg/m2. Being obese tripled the chance of physician-diagnosed asthma.

RESUMO Objetivo:

Estimar a prevalência de sintomas respiratórios e asma de acordo com o índice de massa corpórea (IMC) em indivíduos com idade ≥ 40 anos e avaliar os fatores associados ao relato de diagnóstico médico de asma.

Métodos:

Estudo transversal de base populacional realizado no município de Florianópolis (SC), com coleta domiciliar de dados e processo de amostragem probabilístico. Foram coletadas informações demográficas, assim como sobre relato de diagnóstico médico de asma, sintomas respiratórios, medicações em uso e comorbidades. Também foram realizadas medidas antropométricas e espirometria pré- e pós-broncodilatador. O IMC foi categorizado em normal (IMC < 25 kg/m2), sobrepeso (25 kg/m2 ≥ IMC < 30 kg/m2) e obesidade (IMC ≥ 30 kg/m2).

Resultados:

Foram avaliados 1.026 indivíduos, 274 (26,7%) com IMC normal, 436 (42,5%) com sobrepeso e 316 (30,8%) obesos. A prevalência de diagnóstico médico de asma foi de 11,0%. A prevalência de obesidade foi maior em mulheres (p = 0,03) e em entrevistados com escolaridade < 4 anos (p < 0,001) ou com renda familiar entre 3-10 salários mínimos. Obesos, quando comparados com aqueles com sobrepeso e peso normal, relataram mais frequentemente diagnóstico médico de asma (16,1%, 9,9% e 8,0%, respectivamente; p = 0,04), dispneia (35,5%, 22,5% e 17,9%, respectivamente; p < 0,001) e sibilos no último ano (25,6%, 11,9% e 14,6%, respectivamente; p < 0,001). Esses resultados foram independentes do status tabágico. Além disso, obesos tinham uma chance três vezes maior de relato de diagnóstico médico de asma do que não obesos (p = 0,005).

Conclusões:

Houve associação significativa entre o relato de diagnóstico médico de asma em indivíduos com idade ≥ 40 anos e IMC ≥ 30 kg/m2. Ser obeso triplicou a chance de diagnóstico médico de asma.