The multinational andean genetic and health program-IV. Altitude and the blood pressure of the aymara

Of 2096 surveyed males and females of all ages living at three altitudes (coastal < 3000 m, sierra ~ 3000 m, and altiplano * > 4000 m), 759 were included in a study of blood pressure. Twelve groups are defined (male and female adults and children at each of three altitudes) and within each, systolic and diastolic pressures were regressed stepwise on age, ethnicity, height, weight and wt ht² (relative weight: adults only). Results show that in children, blood pressures depend mostly on weight or height. In male adults no consistent dependency could be found except for diastolic pressure on wt ht² on the coast. Female adults showed strong regressions of both blood pressures on wt ht² in the sierras and altiplano while age was most important on the coast. Except for persons residing near sea level, these populations do not show the 'usual' pattern of increased blood pressure with age. When pressures are plotted against weight, however, most of the differences between altitudes and even between sexes disappear (except, perhaps, for systolic pressure in females). We conclude that the lower blood pressures found in populations at high altitudes in this and other studies are ascribable at least partially to lower body weights due to the harshness of high altitude environments.