Spirometric reference values for an east-African population

Background: Accurate interpretation of lung function testing requires appropriate reference values. Unfortunately, few African countries have produced spirometric reference values for their populations. Objectives: The present study was carried out in order to establish normal lung function values for subjects living in Rwanda, East Africa. Methods: The study was conducted in Kigali, capital of Rwanda, and in the rural district of Huye in southern Rwanda. The variables studied were forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and peak expiratory flow. Multiple regression analysis was performed using age, height, weight and BMI as independent variables to obtain predicted equations for both sexes. Results: Predicted equations for normal lung functions were obtained from 740 healthy nonsmoking subjects; 394 were females and 346 were males. Minor differences in FEV1 and FVC were observed in comparison with other studies of Africans, African-Americans (difference in FEV1 and FVC of less than 5%), Chinese and Indians. When compared with selected studies from Caucasians and white Americans, our results for FEV1 and FVC were 9-12% and 16-18% lower in men and 12-23% and 17-28% lower in women, respectively. Conclusions: This study provides reference values for pulmonary function in a healthy, nonsmoking Rwandan population and enables comparisons to be made with other prediction equations from other populations. Spirometric reference values in our study were similar to those obtained in a study of black Americans by Hankinson et al.