Variable description Variable name Variable code Population group of the study participant propgrp "0 = black"; "1 = coloured" and "3 = white" and "4 = indian" Sex of the study participant sex "0 = Female" and "1 = Male" Age group of the study participant agegrp "0 = 55 to 65 years" and "1 = older than 65 years" The highest level of education attained by the study participant edulev "0 = no education"; "1 = primary education"; "2 = secondary education" and "3 = tertiary education" Type of the community where the study participant resides com "0 = unexposed" and "1 = exposed" Type of fuel used for cooking fuelcook "0 = electricity"; "1 = gas"; "2 = paraffin" and "4 = coal" Smoking habits of the study participants smokcig "0 = non-smoker" and "1 = smoker Have you ever had hay fever? heyfever "0 = no" and "1 = yes" Was your asthma diagnosed by the doctor? drasthma "0 = no" and "1 = yes" Have you ever had a chronic cough? chroncough "0 = no" and "1 = yes" Have you ever worked in a dusty dustywork "0 = no" and "1 = yes" environment