Lung function of healthy young men in India: contributory roles of genetic and environmental factors

Abstract

The forced expiratory volume and vital capacity, the total lung capacity and sub-divisions and the lung transfer factor for carbon monoxide and its sub-divisions have been measured on 122 young men living near Delhi, including Servicemen from Gurkha, Rajput and south Indian regiments and civilians mainly from north India. The findings, standardized for age and stature and in the case of the transfer factor the smoking habits, the haemoglobin concentration and the tension of oxygen in the alveolar capillaries, have been compared with those for European and New Guinea men studied by similar methods and with data reported in the literature for other inhabitants of the Indian sub-continent. The lung function of the present Gurkha highlanders is superior to that of the Indian lowlanders and resembles that of both New Guinea highlanders living at an altitude of approximately 1800 m and men from Bhutan (altitude 3100 m). The Rajputs and other north Indians have slightly larger lungs than the men from south India; the lung function of the latter subjects resembles that of the New Guinea coastal dwellers. All these lowland subjects have lungs which are materially smaller than those of Europeans. The observed differences may be explained in terms of a genetic factor which contributes to the relatively large lung of people of European descent and an environmental factor, probably related to physical activity during childhood, which contributes to the superior lung function of hill people. The possible survival value in an inhospitable environment of large and permeable lungs may also have contributed to the difference, but the magnitude of this effect is probably small.