Prediction equation for lung functions in South Indian children

Lung functions including VC, IVC, FVC, FEV0.5, FEV1, PEF, FEF0.2-1.2, FEF25-75%, FEF75-85%, PIF, FMFT, MVV(IND), peak expiratory flow at 25%, 50% and 75% of FVC, peak inspiratory flow at 75%, 50%, 25% and the ratio between different lung volumes were measured with Vitallograph Compact-II spirometer on 109 South Indian school boys in the age group of five to sixteen years. The results show an increase in "lung volumes" and "flow rates" with increase in age, height and weight. FMFT and MVV(IND) also increase with increase in anthropometric measurements. All the lung functions except FEF75-85% and the ratio between different lung volumes show significant positive correlation with age, height and weight. Regression equations were derived for predicting normal lung functions for healthy South Indian boys. Lung volumes and flow rates were lower than North Indian and foreign boys. The decrease in lung functions in South Indian boys were due to their sea level dwelling, dietary habits and comparatively lower anthropometric measurements.