The effects of obesity on pulmonary function in adults with asthma

OBJECTIVE: While the effects of obesity on asthma are unclear, an increased body mass index (BMI) is known to enhance the symptoms and severity of asthma and to impair asthma control. The present study evaluates the effects of nutritional habits and obesity on pulmonary function and asthma control in individuals with asthma. METHODS: This cross-sectional study included 60 obese respondents and 60 respondents with normal body weight, who were referred to pulmonology clinics over a period of 2 months. The anthropometric measurements and macro–micro nutrient consumption records of the patients in both groups were obtained, and the two groups were compared in terms of pulmonary function and asthma control test (ACT) scores. RESULTS: The mean age of the normal weight and obese respondents was 39.55 ± 11.0 and 45.1 ± 10.3 years, respectively. The ACT scores of the respondents decreased significantly with increasing BMI, waist circumference (WC), and waist–hip ratio (WHR) measurements (P < 0.05). The obese respondents had a lower mean forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), midexpiratory flow (MEF) between 25% and 75% of the maximal expiration (MEF(25–75)), MEF(75), MEF(50), MEF(25), and FEV(1)/FVC values when compared to the respondents with normal weight (P < 0.05). The total energy and carbohydrate intake was higher in the obese respondents, while their total protein intake was lower when compared to the normal weight respondents (P < 0.05), and a significant positive correlation was found between the omega 3 intake and ACT scores of the respondents (P < 0.05). CONCLUSIONS: Pulmonary functions and ACT scores decrease with increasing BMI, WC, and WHR. Obese respondents with asthma should be referred to diet clinics to improve their asthma symptoms.