A Study of Association of Body Mass Index With Severity of Bronchial Asthma in 132 Patients

Abstract

As the prevalence of both obesity and severity of asthma are in increasing trend, we study association between body mass index (BMI) and asthma severity in cross sectional study. OBJECTIVE: To study association between Body mass index and Asthma severity METHODOLOGYWe included adults (age >13yrs), who are diagnosed as patients of asthma by Pulmonologist and who are non -smoker, without any other lung pathology, are not on long term systemic steroids. Total of 132 patients, divided into fallowing BMI categories: Underweight (BMI<18.5), Normal weight (BMI 18.5-25), Over weight and obese (BMI>25). Asthma severity measured using GINA severity classification. Data is collected and tabulated. RESULTS: 1) Comparing %FEV1of expected value of underweight (mean% FEV1of expected-70.57+/-13.78), and overweight and obese (mean% FEV1of expected-60.125+/-17.28) with normal weight (mean % FEV1 of expected-74.19+/-15.08); we find over weight and obese have significantly low %FEV1of expected (Z=3.97; P<0.001). 2) Scatter graph of % FEV1 of expected values against BMI indicate significant negative correlation(r= -0.249; p<0.01).3) By applying chi-square test, there is significant association between overweight and obese with moderate to severe asthma(x2=14.01; p<0.001); also attributable risk (AR) found to be 49.01%. CONCLUSION: In asthmatic patient there is negative correlation between %FEV1of expected and BMI; Severity of asthma is more in over weight and obese patient; and obesity will be modifiable risk factor for severity of asthma. KEYWORDS: Body Mass Index, FEV1 (Forced Vital Capacity in first second)INTRODUCTION: Asthma is one of the most common non communicable diseases in human societies. This disease is reported to have an incidence of 5-10% in different societies. There are various genetic and environmental risk factors, the most important of which is a family history of Atopy. Other risk factors include high and low birth weights, premature birth, smoking mothers, salty food and obesity. (1) Both asthma and obesity are chronic diseases with different features, exposing the individual to various social, economic, cultural and medical problems. Many risk factors have been identified for asthma attacks, and the relationship between changes in weight, especially obesity, and asthma has been proposed in view of the fact that there is an established relationship between BMI and decreased FEV1. Considering the ever-growing obesity even among youths and children, resulting from limited physical activity associated with industrial life and consumption of high-calorie food. However, it is not known which causes which, since changes in the respiratory physiology associated with obesity and reduced FVC are known to increase asthma, and, on the other hand, problems associated with asthma and increased asthma attacks during physical activity lead to limited activity in these patients, and hence their obesity.