Role of mid expiratory flow rate as an early marker in diagnosing small airway disease in overweight automobile mechanics

Air pollution from diesel exhaust is a major respiratory hazard for workers exposed to it in enclosed space. Diesel exhaust, in addition to generating pollutants like hydrocarbons, oxides of nitrogen and carbon is a major contributor to particulate matter in most places of the world. Due to the greater surface area they carry a much larger fraction of toxic compounds and remain airborne for long periods of time and deposit in greater numbers in small airways and deeper into the lungs than larger sized particle, causing chronic inflammation and obstruction of the airways. Mid expiratory flow rate is one of the spirometric variables which indicates the function of small airways. In this modern world factors associated with lifestyle have also been identified as causing a deterioration of lung function. Overweight and obesity are related with a higher risk of different co-morbidities but their relationship with small airway disease is still under discussion. The present study was conducted in a private motor vehicle showroom and garage, located in Mangalore. Study group consisted of total of 120 employees (30-40 years) who worked in the automobile industry for a minimum of 6 years and control group consisted of 120 (30-40 years) subjects who were working in air conditioned environment and were not exposed to any dust and fumes. Their body mass index was calculated and Forced expiratory flow 25-75 recorded with a spirometer. In high BMI group, the cases showed significantly low values when compared to that of controls.. Our study says that the overweight people exposed to pollution are more prone to develop small airway disease than the normal or underweight people and a decrease in the measure of FEF 25-75% has been interpreted as an early predictor for small airway obstruction.