Data on physical growth were obtained for a sample of 1202 Quechua subjects, aged 2 to 35 years from the district of Nuiioa, Puno, located in the southe m highlands (altitude 4000-5500m) of Peru. These data were supplemented by a three-year longitudinal study of 300 subjects, aged 1 to 22 years.
The patterns of physical growth of members of the indigenous population of Nufioa are characterized by (1) late sexual dimorphism, (2) slow and prolonged growth in body size, (3) late and poorly defined adolescent stature spurt in both males and females, and ( 4 ) accelerated development in chest size. The socio-economic factors associated with urban-rural and altitude differences appear to be reflected in greater deposition of subcutaneous fat and increased weight but do not seem to influence the development of stature. We suggest the pattern of growth of this population is related to the hypoxic effects of high altitude, and/or reflects a genetic adaptation to such stress. The anthropometric and physiological studies conducted during this and previous studies and the comparative data from Peruvian populations situated at lower altitudes document the specific adaptive response of the chest wall to the hypoxic effects of high altitude.
Experimental studies on animals have demonstrated that high altitude hypoxia slows growth, The earlier investigations of Gordon and associates (Gordon, Zornetta, DAngelo and Charipper '43) and Moore and Price ('48) indicate that rats raised under hypoxic conditions on adequate diets show marked retardation in normal body growth. Recent studies by Timeras and coworkers (Timeras, Krum and Pace, '57; Krum, '57) point out that the inhibition in body growth becomes progressively more accentuated in successive generations. Further, the subnormal rate of growth in size in the animals born at high altitude appears to be irreversible even after prolonged soujourn at sea level (Timeras, '64). Despite these indications, there is insufficient information on the effects of high altitude on human growth to reach any definite conclusions. This fact led the authors to conduct an intensive cross-sectional and semi-longitudinal investigation of human growth of a high altitude native Peruvian Quechua population.
The present article is a detailed followup of previous preliminary reports (Fris-