Developmental, genetic, and environmental components of lung volumes at high altitude

Abstract

ABSTRACT Vital capacity and residual lung volume (in terms of 1/min or ml/m2 of body surface area) of 357 subjects (205 males, 152 females) was evaluated in La Paz, Bolivia, situated at 3,750 m. The sample included: (1) 37 high altitude rural natives (all male), (2) 125 high altitude urban natives (69 male, 58 female), (3) 85 Bolivians of foreign ancestry acclimatized to high altitude since birth (40 male, 45 female), (4) 63 Bolivians of foreign ancestry acclimatized to high altitude during growth (30 male, 33 female), and (5) 47 non-Bolivians of either European or North American ancestry acclimatized to high altitude during adulthood (24 male, 23 female). Results indicate that (1) all samples studied, irrespective of origin or acclimatization status, have larger lung volumes than those predicted from sea level norms; (2) the high altitude rural natives have significantly greater lung volumes (vital capacity and residual lung volume) than the high altitude urban natives and all the non-native high altitude samples; (3) males acclimatized to high altitude since birth or during growth attain similar lung volumes as high altitude urban natives and higher residual lung volumes than subjects acclimatized to high altitude during adulthood but lower than the high altitude rural natives; (4) females acclimatized to high altitude since birth or during growth attain similar lung volumes as subjects acclimatized to high altitude during adulthood; (5) age at arrival to high altitude is inversely related to residual lung volume but not vital capacity; (6) among subjects acclimatized to high altitude during growth, approximately 20–25% of the variability in residual lung volume can be explained by developmental factors; (7) among high altitude rural and urban natives, it appears that approximately 20–25% of the variability in residual lung volume at high altitude can be explained by genetic traits associated with skin reflectance and genetic traits shared by siblings; and (8) vital capacity, but not the residual lung volume, is inversely related to occupational activity level. Together these data suggest that the attainment of vital capacity at high altitude is influenced more by environmental factors, such as occupational activity level, and body composition than developmental acclimatization. On the other hand, the attainment of an enlarged residual volume is related to both developmental acclimatization and genetic factors.