The physical growth of high altitude Bolivian Aymara children

This study describes the growth characteristics of Aymara children living in Ancoraimes, Bolivia at altitudes between 3800 and 4000 meters. Anthropometric measurements were made on 510 children between the ages of 6. 0 and 20. 9 years, 360 males and 150 females. The growth pattern of Ancoraimes Aymara children is very similar to that of other high altitude Andean populations. They are greatly delayed in height and weight, exhibit little sexual dimorphism in body size and relative to stature, have larger chest dimensions than U.S. children. Compared to Quechua children living at higher altitudes in Peru, Ancoraimes children tend to be taller and heavier but have significantly smaller chest dimensions. Although the causes of the size differences between these two groups are not entirely clear, they may be due to the different altitudes at which the groups reside.     

Differences in physical growth of Aymara and Quechua children living at high altitude in Peru

Physical growth of Amerindian children living in two Aymara and three Quechua peasant communities in the Andean highlands of southern Peru (altitude 3,810–3,840 m) was studied, taking into account differences in the microclimate, agronomic situation, and sociodemographic variables. Anthropometric measurements were taken in 395 children aged under 14 years of age in a sample of 151 families in these communities, who were surveyed for sociodemographic variables as well. Data on the land system were available for 77 families. In comparison with reference populations from the United States (NCHS) and The Netherlands, stature, weight, head circumference, and midupper arm circumference (but not weight for stature) in the sample children were reduced. Growth retardation increased after the age of 1 year. Stature and weight in the present sample were very similar compared with previously published data on growth of rural Aymara children living near Lake Titicaca in Bolivia. Head circumference, midupper arm circumference, and weight for stature were significantly larger in Aymara children compared with Quechua children. Land was significantly more fragmented in Aymara compared with Quechua families, but amount of land owned was not different. Perinatal and infant mortality was elevated in Aymara vs. Quechua communities. Most families in Aymara communities used protected drinking water. One Quechua community had a severe microclimate, grim economic outlook, and weak social cohesion. Children in this community showed significant reductions in weight and midupper arm circumference compared with their peers in the other communities. We conclude that (presumably nutritionally mediated) intervillage and Aymara-Quechua differences in childhood physical growth existed in this rural high-altitude population in Peru and were associated with microclimate and the village economy, sociodemographic factors, and differences in the land system. © 1993 Wiley-Liss, Inc.     

Altitude,heredity and body proportions in northern Chile

Recent studies of the effects of hypoxia on human growth and adult size have focused mainly on the variability of single measurements. In this paper we explore changes with altitude and ethnicity (Spanish-Aymara ancestry) in body proportions of permanent residents of an altitudinal gradient (0–4000 meters) in northern Chile. Body proportion or shape is assessed by anthropometric indices and principal components of 14 bone measurements. Ethnicity independent of altitude had its major effect on proportions and a lesser effect on size. Aymara had larger relative sitting heights, broader builds and prominent facial development as compared to non-Aymara (Spanish). Altitude also affected head and chest proportions during growth. On the whole, the effects of altitude and Aymara ancestry on the measurements and indices were independent (not necessarily of similar direction or magnitude), in spite of a correlation of ethnicity and altitude in Andean populations.     

The effects of high altitudes on child growth and development

This study compares the growth characteristics of populations of Tibetan origin living in Nepal to high altitude populations of Peru and Ethiopia. Measurements were made on two groups of children, a sample of Sherpas living in the Everest region of northeast Nepal at elevations in excess of 3500 m, and a sample of Tibetan children living in Kathmandu at an altitude of 1000 m. Although the Tibetan children showed some growth advancement over the highland sample of Sherpas, the differences were less than might have been expected on the basis of work carried out in Peru, where long established high altitude populations live at similar elevations to those of Himalayan populations. In particular, some growth trends seen in Andean populations, such as the increased diameter of the chest wall, are not seen in populations of Tibetan origin. It is suggested that genetic influences may exert a stronger effect on the growth of high altitude populations than hitherto believed.Presented the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA.     

Developmental components of resting ventilation among high- and low-altitude Andean children and adults

This paper evaluates the age-associated changes of resting ventilation of 115 high- and low-altitude Aymara subjects, of whom 61 were from the rural Aymara village of Ventilla situated at an average altitude of 4,200 m and 54 from the rural village of Caranavi situated at an average altitude of 900 m. Comparison of the age patterns of resting ventilation suggests the following conclusions: 1) the resting ventilation (ml/kg/min) of high-altitude natives is markedly higher than that of low-altitude natives; 2) the age decline of ventilation is similar in both lowlanders and highlanders, but the starting point and therefore the age decline are much higher at high altitude; 3) the resting ventilation that characterizes high-altitude Andean natives is developmentally expressed in the same manner as it is at low altitude; and 4) the resting ventilation (ml/kg/min) of Aymara high-altitude natives is between 40–80% lower than that of Tibetans. Am J Phys Anthropol 109:295–301, 1999. © 1999 Wiley-Liss, Inc.     

Ventilation and hypoxic ventilatory response of Tibetan and Aymara high altitude natives

Newcomers acclimatizing to high altitude and adult male Tibetan high altitude natives have increased ventilation relative to sea level natives at sea level. However, Andean and Rocky Mountain high altitude natives have an intermediate level of ventilation lower than that of newcomers and Tibetan high altitude natives although generally higher than that of sea level natives at sea level. Because the reason for the relative hypoventilation of some high altitude native populations was unknown, a study was designed to describe ventilation from adolescence through old age in samples of Tibetan and Andean high altitude natives and to estimate the relative genetic and environmental influences. This paper compares resting ventilation and hypoxic ventilatory response (HVR) of 320 Tibetans 9–82 years of age and 542 Bolivian Aymara 13–94 years of age, native residents at 3,800–4,065 m. Tibetan resting ventilation was roughly 1.5 times higher and Tibetan HVR was roughly double that of Aymara. Greater duration of hypoxia (older age) was not an important source of variation in resting ventilation or HVR in either sample. That is, contrary to previous studies, neither sample acquired hypoventilation in the age ranges under study. Within populations, greater severity of hypoxia (lower percent of oxygen saturation of arterial hemoglobin) was associated with slightly higher resting ventilation among Tibetans and lower resting ventilation and HVR among Aymara women, although the associations accounted for just 2–7% of the variation. Between populations, the Tibetan sample was more hypoxic and had higher resting ventilation and HVR. Other systematic environmental contrasts did not appear to elevate Tibetan or depress Aymara ventilation. There was more intrapopulation genetic variation in these traits in the Tibetan than the Aymara sample. Thirty-five percent of the Tibetan, but none of the Aymara, resting ventilation variance was due to genetic differences among individuals. Thirty-one percent of the Tibetan HVR, but just 21% of the Aymara, HVR variance was due to genetic differences among individuals. Thus there is greater potential for evolutionary change in these traits in the Tibetans. Presently, there are two different ventilation phenotypes among high altitude natives as compared with sea level populations at sea level: lifelong sustained high resting ventilation and a moderate HVR among Tibetans in contrast with a slightly elevated resting ventilation and a low HVR among Aymara. Am J Phys Anthropol 104:427–447, 1997. © 1997 Wiley-Liss, Inc.     

Effect of altitude on the lung function of high altitude residents of European ancestry

The forced vital capacity (FVC), forced expiratory volume in one second (FEV), and ratio of FEV to FVC (%FEV) of 161 male and 158 female youths of European ancestry who were born at high altitudes and who were residing in La Paz, Bolivia (average altitude of 3,600 m) were examined and compared with those for lowland Europeans and highland Aymara Amerindians. FVC and FEV were significantly larger (p less than .001) in the La Paz Europeans than in two lowland control samples of European ancestry, with the relative differences between samples varying from small (1.5-4.1%) to moderate (7.7-11.9%). It could not be determined whether the enhanced lung volumes of the La Paz European children were acquired through an accelerated development of lung volumes relative to stature during adolescence, as is the case for Amerindian highlanders. After controlling for body and chest size, FVC and FEV were significantly smaller in the La Paz Europeans than in highland Aymara (p less than .001), suggesting that the lung volumes of the Aymara are influenced by factors other than simply growth and development at high altitude. Finally, as found in Amerindians, chest size is an important determinant of intra-individual variation in lung function among highland Europeans.     

Surnames as indicators of European admixture in Andean Indians

The goal of the present report was to determine how well surnames assess the degree of European admixture in urban Aymara. Reflectances, which were measured at three wavelengths (425 nm, 545 nm, and 685 nm) and on two sites (the medial surface of the upper arm and the forehead), were used as genetic markers. The sample consisted of 556 Andean Indians of Aymara ancestry (305 males, 251 females; 10.0–29.9 yr) residing in La Paz, Bolivia (average altitude of about 3600 m). The first component from a principal components analysis was demonstrated to assess the underlying genetics of pigmentation, after controlling for tanning and vascularity, the two primary environmental modifiers of skin color. The scores associated with the first principal component were there-force entered into a discriminant function analysis, which indicated that surnames provide a useful indirect index of the degree of European admixture in urban Aymara. However, these results also suggested that the relationship between, surnames and ethnicity is not equally strong across all surname categories. In particular, the likelihood of correctly predicting surname category from reflectances was about twice that expected by chance alone in individuals with two Aymara or two Spanish surnames but was slightly less than would be expected by chance alone in those with mixed surnames. In addition, the findings of this study suggested that there may be significant genetic differences between rural and urban Aymara.     

Mitochondrial DNA analysis of ancient Peruvian highlanders

Ancient DNA recovered from 57 individuals excavated by Hiram Bingham at the rural communities of Paucarcancha, Patallacta, and Huata near the famed Inca royal estate and ritual site of Machu Picchu was analyzed by polymerase chain reaction, and the results were compared with ancient and modern DNA from various Central Andean areas to test their hypothesized indigenous highland origins. The control and coding regions of the mitochondrial DNA (mtDNA) of 35 individuals in this group were sequenced, and the haplogroups of each individual were determined. The frequency data for the haplogroups of these samples show clear proximity to those of modern Quechua and Aymara populations in the Peruvian and Bolivian highlands, and contrast with those of pre-Hispanic individuals of the north coast of Peru that we defined previously. Our study suggests a strong genetic affinity between sampled late pre-Hispanic individuals and modern Andean highlanders. A previous analysis of the Machu Picchu osteological collection suggests that the residents there were a mixed group of natives from various coastal and highland regions relocated by the Inca state for varied purposes. Overall, our study indicates that the sampled individuals from Paucarcancha and Patallacta were indigenous highlanders who provided supportive roles for nearby Machu Picchu.     

Haematology and erythrocyte metabolism in man at high altitude: an Aymara-Quechua comparison

In the course of haematological and biological investigations among Aymara and Quechua populations in Bolivia, an anthropological study of the erythrocytary respiratory function was carried out on the two groups at two altitudes: 3,600 m and 450 m. A difference in the intensity of the biological variations of the two populations is observed at high altitude. In the Quechuas, as in any lowland native, the adaptative phenomena are totally and quickly reversible. In the Aymaras, we detected the existence of more marked haematological and biochemical characters: moderate polycythemia, hyperhaemoglobinemia, microcytosis, metabolical hyperactivity with accumulation of 2-3 di-phosphoglycerate and ATP, and methaemoglobinemia with a drop in the activity of the methaemoglobin reductases. The Aymaras preserve some of those characters (methaemoglobinemia excepted) when they settle in lowlands.     

A Novel Candidate Region for Genetic Adaptation to High Altitude in Andean Populations

Humans living at high altitude (≥2,500 meters above sea level) have acquired unique abilities to survive the associated extreme environmental conditions, including hypoxia, cold temperature, limited food availability and high levels of free radicals and oxidants. Long-term inhabitants of the most elevated regions of the world have undergone extensive physiological and/or genetic changes, particularly in the regulation of respiration and circulation, when compared to lowland populations. Genome scans have identified candidate genes involved in altitude adaption in the Tibetan Plateau and the Ethiopian highlands, in contrast to populations from the Andes, which have not been as intensively investigated. In the present study, we focused on three indigenous populations from Bolivia: two groups of Andean natives, Aymara and Quechua, and the low-altitude control group of Guarani from the Gran Chaco lowlands. Using pooled samples, we identified a number of SNPs exhibiting large allele frequency differences over 900,000 genotyped SNPs. A region in chromosome 10 (within the cytogenetic bands q22.3 and q23.1) was significantly differentiated between highland and lowland groups. We resequenced ~1.5 Mb surrounding the candidate region and identified strong signals of positive selection in the highland populations. A composite of multiple signals like test localized the signal to FAM213A and a related enhancer; the product of this gene acts as an antioxidant to lower oxidative stress and may help to maintain bone mass. The results suggest that positive selection on the enhancer might increase the expression of this antioxidant, and thereby prevent oxidative damage. In addition, the most significant signal in a relative extended haplotype homozygosity analysis was localized to the SFTPD gene, which encodes a surfactant pulmonary-associated protein involved in normal respiration and innate host defense. Our study thus identifies two novel candidate genes and associated pathways that may be involved in high-altitude adaptation in Andean populations.     

Effect of developmental and ancestral high-altitude exposure on VO(2)peak of Andean and European/North American natives

Peak oxygen consumption (VO(2)peak) was measured in 150 adult males (18-35 years old) in Bolivia, using a complete migrant study design to partition developmental from ancestral (genetic) effects of high-altitude (HA) exposure. High-altitude natives (HANs, Aymara/Quechua ancestry, n = 75) and low-altitude natives (LANs, European/North American ancestry, n = 75) were studied at high altitude (3,600-3,850 m) and near sea level (420 m). HAN and LAN migrant groups to a nonnative environment were classified as: multigeneration migrants, born and raised in a nonnative environment; child migrants who migrated to the nonnative environment during the period of growth and development (0-18 years old); and adult migrants who migrated after 18 years of age. Variability in VO(2)peak due to high-altitude adaptation was modeled by covariance analysis, adjusting for fat-free mass and physical activity (training) differences between groups. A trend for increased VO(2)peak with increasing developmental high-altitude exposure in migrant groups did not reach statistical significance, but low statistical power may have limited the ability to detect this effect. HANs and LANs born, raised, and tested at high altitude had similar VO(2)peak values, indicating no genetic effect, or an effect much smaller than that reported previously in the literature. There was no functional correlation between forced vital capacity and VO(2)peak, within or across groups. These results do not support the hypothesis that Andean HANs have been selected to express a greater physical work capacity in hypoxia.     

Percent of oxygen saturation of arterial hemoglobin among Bolivian Aymara at 3,900–4,000 m

A range of variation in percent of oxygen saturation of arterial hemoglobin (SaO₂) among healthy individuals at a given high altitude indicates differences in physiological hypoxemia despite uniform ambient hypoxic stress. In populations native to the Tibetan plateau, a significant portion of the variance is attributable to additive genetic factors, and there is a major gene influencing SaO₂. To determine whether there is genetic variance in other high-altitude populations, we designed a study to test the hypothesis that additive genetic factors contribute to phenotypic variation in SaO₂ among Aymara natives of the Andean plateau, a population geographically distant from the Tibetan plateau and with a long, separate history of high-altitude residence. The average SaO₂ of 381 Aymara at 3,900–4,000 m was 92 ± 0.15% (SEM) with a range of 84–99%. The average was 2.6% higher than the average SaO₂ of a sample of Tibetans at 3,800–4,065 m measured with the same techniques. Quantitative genetic analyses of the Aymara sample detected no significant variance attributable to genetic factors. The presence of genetic variance in SaO₂ in the Tibetan sample and its absence in the Aymara sample indicate there is potential for natural selection on this trait in the Tibetan but not the Aymara population. Am J Phys Anthropol 108:41–51, 1999. © 1999 Wiley-Liss, Inc.     

Altitude and growth: a study of the patterns of physical growth of a high altitude Peruvian Quechua population

Data on physical growth were obtained for a sample of 1202 Quechua subjects, aged 2 to 35 years from the district of Nuñoa, Puno, located in the southern 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 Nuñoa 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.     

Growth of Qinghai Tibetans living at three different high altitudes

This study compares the stature, weight, skinfolds, upper arm muscle area, and chest dimensions of Tibetan children, adolescents, and young adults who were born and raised, or who had lived from infancy, at 3,200 m, 3,800 m, and 4,300 m in Qinghai Province, People's Republic of China. While the individuals measured in Qinghai are among the tallest and heaviest Tibetans reported in the literature, they are nevertheless smaller and lighter than well-off children living at low altitude. The pattern of size variation among Tibetan males and females measured at the three high altitudes, along with evidence of a secular trend at 4,300 m, suggests that nutrition may significantly effect growth at high altitude. Only minor differences in thorax dimensions exist between Tibetan males and females measured at 3,200 m and 3,800 m. However, Tibetan males at 4,300 m possess slightly narrower and deeper chests (during and after adolescence) than males at 3,200 m and 3,800 m. Since individuals from 3,800 m and 4,300 m belong to the same local populations, this characteristic is unlikely to be genetically determined. However, it may be related to differences in the degree of hypoxia or to the influences of other environmental conditions.     

Growth trends among male Bods of Ladakh--a high altitude population

A random sample of 274 native male Bods of Ladakh ranging in age from 11 to 19 years, living in Leh (Ladakh) at mean altitude of 3,514 metres, was studied. The pattern of growth of this sample was compared with the sea level Indians. The results indicate that: (1) The so called adolescent spurt is not well defined among Bod highlanders. (2) Bods grow faster than plain dwelling Indians and are taller and heavier at the age of 19 years. (3) The highlanders exhibit greater chest circumference than the lowland norms. This finding, similar to those among Andean natives, supports high altitude hypoxia's role in human growth and morphology.     

Neonatal Variables,Altitude of Residence and Aymara Ancestry in Northern Chile

Studies performed in the Andean plateau, one of the highest inhabited areas in the world, have reported that reduced availability of oxygen is associated to fetal growth retardation and lower birth weight, which are established predictors of morbidity and mortality during the first year of life. To test this hypothesis, perinatal variables of neonates born at the Juan Noé Hospital of Arica, Chile, were analyzed in relation to altitude of residence and Aymara ancestry of their mothers. The study population comprised the offspring of 5,295 mothers born between February 2004 and August 2010. Information included birth weight, height, head circumference, gestational age, altitude of residence and socioeconomic status, and was obtained from medical records. Mother´s ancestry was assessed based on surnames which were linked to percentages of Aymara admixture estimates relying on 40 selected ancestry informative markers. After correcting for the effect of multicollinearity among predictor variables, neonates born to mothers with an increased component of Aymara ancestry showed significantly higher birth weight and height at sea level, a marginally significant (p-value 0.06) decrease of birth weight and a significant decrease of height with altitude in comparison with the offspring of mothers with low Aymara ancestry. Since observed tendencies are suggestive of a possible genetic adaptation to hypoxia of the Chilean Aymara, we discuss briefly preliminary evidence related to fetal oxygen transport, particularly polymorphisms in the promoters of the HBG1 and HBG2 genes that are modulators of HbF synthesis, obtained in this ethnic group.     

Growth profile of rural Meitei children of Manipur state of India

Patterns of growth in 10 anthropometric measurements among the rural Manipuri children (N=425), aged 5 to 14 years, with poor socio-economic backgrounds are reported. The anthropometric dimensions include weight, stature, sitting-height, head, chest and midupper-arm circumferences, biepicondylar widths of humerus and femur, and triceps and biceps skinfolds. Except skinfolds, the boys measured more than the girls in all measurements at all ages, except from 10 to 12 years in weight, stature, sitting-height, and chest and mid-upper-arm circumferences. Across all ages, the girls had thicker fat folds. Up to 12 years, the children lie approximately on the 10th centile of NCHS in stature and weight. The arm circumferences was below the 3rd centile of the Dutch children, until 11 years. The triceps fat fold fluctuated between 10th and 25th centiles of US whites. The rural Meiteis were taller and heavier than rural Burmese and urban Meiteis. The overall growth performance of the rural Meitei children was poor as compared to US, Urban Chinese, and well-nourished Indian children.     

Growth characteristics of populations of Tibetan origin in Nepal.

Previous growth studies of highland-dwelling populations in the ecologically diverse areas of Peru and Ethiopia have yielded highly varied results: the retarded growth of the Peruvian sample was attributed to the effects of hypoxia, while the increased height and weight of the highland Ethiopian sample could be traced to better health conditions in the highland village than in the lowland village studied. In an attempt to provide a basis for evaluating studies of growth at high altitude, the present study compared Sherpa children living in the Everest region of Nepal with Tibetan children living in Kathmandu. It was found that: (1) the growth of Sherpa and Tibetan children is considerably retarded compared to other high altitude populations; (2) despite conditions favorable for optimum growth among the Tibetans, their growth resembled that of the Sherpas and (3) increased chest circumference, which seems to reflect a developmental acclimatization to hypoxia among Peruvian high-altitude natives, was not seen among the Sherpas.     

Increased vital and total lung capacities in Tibetan compared to Han residents of Lhasa (3,658 m).

Larger chest dimensions and lung volumes have been reported for Andean high-altitude natives compared with sea-level residents and implicated in raising lung diffusing capacity. Studies conducted in Nepal suggested that lifelong Himalayan residents did not have enlarged chest dimensions. To determine if high-altitude Himalayans (Tibetans) had larger lung volumes than acclimatized newcomers (Han "Chinese"), we studied 38 Tibetan and 43 Han residents of Lhasa, Tibet Autonomous Region, China (elevation 3,658 m) matched for age, height, weight, and smoking history. The Tibetan compared with the Han subjects had a larger total lung capacity [6.80 +/- 0.19 (mean +/- SEM) vs 6.24 +/- 0.18 l BTPS, P less than 0.05], vital capacity (5.00 +/- 0.08 vs 4.51 +/- 0.10 1 BTPS, P less than 0.05), and tended to have a greater residual volume (1.86 +/- 0.12 vs 1.56 +/- 0.09 1 BTPS, P less than 0.06). Chest circumference was greater in the Tibetan than the Han subjects (85 +/- 1 vs 82 +/- 1 cm, P less than 0.05) and correlated with vital capacity in each group as well as in the two groups combined (r = 0.69, P less than 0.05). Han who had migrated to high altitude as children (less than or equal to 5 years old, n = 6) compared to Han adult migrants (greater than or equal to 18 years old, n = 26) were shorter but had similar lung volumes and capacities when normalized for body size. The Tibetans' vital capacity and total lung capacity in relation to body size were similar to values reported previously for lifelong residents of high altitude in South and North America. Thus, Tibetans, like North and South American high-altitude residents, have larger lung volumes. This may be important for raising lung diffusing capacity and preserving arterial oxygen saturation during exercise.