Influence of thyroid status on pulmonary functions in bronchial asthma patients

BACKGROUND: Asthma is a serious global health problem affecting all age groups. It is being recognized for its health impact on the working status of adults, and uncontrolled asthma is associated with significant morbidity, mortality, and socioeconomic problems. The knowledge of comorbidities of asthma, including thyroid disorders, is important for its management. METHODOLOGY: A case–control study was conducted in 60 diagnosed patients of bronchial asthma in the age group of 20–40 years attending medicine outpatient departments and Chest Clinic of Lok Nayak Hospital, New Delhi. Thirty controls were taken from the normal population. Pulmonary function tests using "Schiller SP1 portable top spirometer" were done, and forced vital capacity (FVC), forced expiratory volume in 1st s (FEV1), FEV1/FVC ratio, and peak expiratory flow rate (PEFR) were analyzed. The thyroid function was assessed by estimating levels of serum thyroid-stimulating hormone (TSH), free T3, and free T4 using the Cobas e411 autoanalyzer. RESULTS: Based on TSH analysis of asthmatic patients, 25% were hypothyroid, 16.7% were hyperthyroid, and 58.3% were euthyroid. There were significant reductions in FEV1, FEV1/FVC ratio, and PEFR in asthmatics compared to controls, but no significant differences were found in these parameters among the asthmatics with different thyroid status. CONCLUSION: The thyroid functions varied in asthmatics. However, the variation in the thyroid function did not affect the pulmonary function in asthmatic patients.