Ventilatory capacity and productive cough in a rural community.

The wider adoption of the Medical Research Council's questionary on respiratory symptoms has been an important step in enabling more accurate comparisons of pulmonary morbidity and risk factors between various environments. Objective evidence of respiratory function also forms an essential part of these epidemiological studies if confident conclusions are to be established. In this regard, the study by Lowe, Pelmear, Campbell, Hitchens, Khosla, and King (1968) of steel workers in South Wales has established criteria for ventilatory function of value for objective comparisons with other populations. Hong, Gandevia, and Lovell (1967) assessed the presence of phlegm by listening for audible loose cough in their subjects, and con sidered this test to be a reliable and simple measure of sputum production suitable for a variety of clinical and epidemiological purposes. In 1966, a longitudinal study in the rural popula tion of Busselton, Western Australia, was com menced and one of its aims was to assess the predic tive validity of various measurements relating to subsequent pulmonary and cardiovascular mor bidity. This population was known to have a low incidence of respiratory disorders (Cullen, Sten house, Welborn, McCall, and Curnow, 1968). The study aimed to establish for Busselton norms of ventilatory capacity, to assess the empirical value of the productive cough test of Hong et al. (1967) and to make comparisons between South Wales and Busselton of the effect of age on ventilatory capacity.