Seventy-five adult asthmatic patients with clinical remission underwent spirometry. Only 8.3% of the subjects demonstrated normal spirometry. The others had reduced vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximum mid-expiratory flow rate (MMF) and peak flow rate (PEFR). This study demonstrates that asthma can cause irreversible airflow obstruction and there is a poor relationship between symptoms in asthmatics and their respiratory function test results.
Study site: Chest clinic, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
Respiratory function testing was done using a portable electronic spirometer in 223 normal Malay subjects between the ages of 15 to 75 years. Tests of FEV1, FVC, PEFR, and MMF were recorded using standard forced expiratory maneuvers. Malay adults have lower respiratory function values compared to Caucasians and other Asians.
Spirometric recordings of 1098 Malaysian children who were free of respiratory symptoms were examined by least square regression analysis of log-transformed lung function data. Ethnic differences were observed in FVC, FEV1, and FEF25-75 independent of father's education, exposure to passive smoking, wood stove, kerosene stove and mosquito repellents, family history of chest illness and history of allergy, after adjusting for standing height, age and sex. Exposure to kerosene stove was significantly associated with reduced FVC and FEV1 indicating that environmental factors may impair lung function in symptomless children. Prediction equations were derived for each ethnic group and sex. Comparison with data from the literature showed that Malaysian children had lower lung function values than Caucasian children. Generally, Chinese children had higher FEV1, FVC and FEF25-75 than Malay and Indian children. Indian children consistently had the lowest lung function values. Since these ethnic differences were independent of environmental and other host factors, anthropometric variations could be an explanation.