Introduction
It is estimated that the first inhabitants of the Americas came from Asian populations in their early history, with their migratory separation dating back 23,000 years, presumably in Beringia, which lasted 10,000 years longer.(Reference Harris, Song and Shetty1) Subsequent population expansions took 1,000–2,000 years, during which time trans-Andean colonisation of settlers who formed various empires, including the Inca, was presumed to have occurred.(Reference Battaglia, Grugni and Perego2)
In America, the Spanish conquest in the 16th century determined the succession of ethnic mixtures, including Quechua with Europe in 25%, while this only occurred in 8% of Aymara,(Reference Hartinger, Tapia and Carrillo3) an indicative aspect of the genetic and linguistic flow of the population groups of interest in the dynamics of adaptation to high altitude.(Reference Harris, Song and Shetty1) Both Aymara and Quechua populations inhabit the South American highlands at altitudes exceeding 2,500 metres above sea level. They are considered ethnolinguistic groups with over 11,000 years of historical continuity, characterised by a slow process of adaptation due to their relatively shorter residence at high altitudes(Reference Rupert and Hochachka4) in contrast to the Han Chinese population, which exhibits greater genotypic adaptation, providing an evolutionary advantage for life at high altitude.(Reference Wang, Zhang and Zhang5)
Hypobaric and chronic hypoxia are determinants of bodily, physiological, and clinical adaptations associated with oxygen availability and the capacity to cope with habitation at high altitudes.(Reference Santos-Martínez, Gómez-Tejada and Murillo-Jauregui6) Knowledge of the extent of these adaptive processes in skeletal and bodily changes in these populations is scarce.
If these adaptation factors add to the changes in the epidemiological profile, characterised by an increase in overweight and obesity coexisting with malnutrition problems, and the influence of environmental factors, such as the westernisation of diet, changes in eating patterns, lifestyle, and certain habits, the impact they may have on the nutritional profile, biotype, and body proportionality must be significant, affecting the health of the population. Their study would allow the implementation of health and nutrition prevention mechanisms from an early age.(Reference Lizana, González and Lera7)
Considering the Quechua and Aymara ethnicities, this study aimed to evaluate and establish a relative comparison of nutritional status, body composition, somatotypic characteristics, proportionality, and bone morpho structure so that they can constitute baseline data to generate appropriate public health policies for populations with probable differences and similarities that are not considered within the framework of health and nutrition policies.
Methods
Two-stage probabilistic random cluster sampling was applied, and expert criteria were used to select six provinces and districts within Puno region, three from the Quechua area and three from the Aymara area. Simple stratified sampling by age was applied, with 1289 children of both sexes (608 Aymara children and 681 Quechua), who met the following inclusion criteria: age, Quechua or Aymara extending up to two generations; and being apparently healthy schoolchildren enrolled in the state education system.(8) Informed consent signed by parents and informed assent provided by the children were also required. Exclusion criteria also included children exhibiting any signs of pubertal development according to Tanner stages, participation in competitive sports, and the presence of physical abnormalities Figure 1.
Fig. 1. Sample selection flow chart. From the population of children aged 6 to 10 years enrolled in the school education system in 13 provinces of the Puno Region, two-stage cluster sampling was applied to select three provinces with predominantly Quechua-speaking ethnicity (Azángaro, Melgar, Lampa) and three Aymara-speaking ethnicity (Chucuito, El Collao, Puno) for a sample of 1289 children (608 Aymara and 681 Quechua). One of the inclusion criteria was Quechua or Aymara origin of the children up to two generations.
Anthropometric methods were used to obtain the data, measurements were taken with the child in the Frankfort plane, on the right side, and performed by trained and certified personnel according to the technical criteria of the International Society for the Advancement of Kinanthropometry (ISAK) for the measurement of eleven lengths (stature, sitting height, trunk height, acromial, radial, styloid, radial, iliospinal, trochanteric, tibial, and malleolar), five diameters (biiliocrestal, acromial, radioulnar, biepicondylar of the humerus and femur), eight circumferences (waist, hip, maximum thigh, mid-thigh, mid-calf, wrist, contracted and relaxed arm), and five skinfolds (subscapular, suprailiac, biceps, triceps and medial calf) (S1).
To determine nutritional status
The anthropometric method was applied to assess weight and height and to calculate the BMI/Age Z-score and Height-/Age Z-score according to WHO references(9) (S1). The results were processed using the WHO Anthro Plus program,(10) software proposed for monitoring the growth of children and adolescents between 5 and 19 years using three indicators: Weight/Age, Height/Age, and BMI/Age; the latter two were considered for the present study. A certified stadiometer(11) of 200 cm with 0.1 cm precision was used for height measurement.
To assess body composition
The electrical bioimpedance method, a lower limb technique using a standardised TANITA BF-350(12) scale, was applied to assess body weight and fat components. Participants stood barefoot on the scale, wearing sports clothing, without metal objects, and with prior instructions to evacuate urine or faeces.
To determine the bone, muscle, and residual components, equations proposed in the De Rose and Guimarães four-compartment model, accepted by the Spanish Group of Kinanthropometry for application in children, were used(Reference Agrasar13) Table 1.
Table 1. Equations and classifications for calculating indices, proportionality and body components
SD, Standard Deviation M, Men W, Women H, Height (m) RU, radio ulnar diameter (cm) F, femoral diameter We, weight (kg) F, fat mass (kg) BM, Bone mass (kg) VM, visceral mass (kg) RLUE, Relative Length Upper Extremity RLLE, Relative Length Lower Extremity.
To determine body indices and proportionality
An anthropometric method using techniques standardised by ISAK(Reference Sillero15) was applied. A 100 cm stadiometer with 0.1 cm precision was used to measure projected heights, a Cescorf Innovare anthropometer with 0.1 cm precision for diameters, a Lufkin W606PM anthropometric tape with 0.1 cm precision for circumferences, and a Harpenden skinfold caliper with +/– 0.2 mm precision for skinfolds (S1). Four equations were applied to assess body composition, two indices to assess nutritional status, and thirteen indices to characterise body proportions and standardised equations and classifications were used Table 1.
To determine somatotype
Anthropometric and standardised ISAK techniques were applied. Data were processed using the Heath and Carter equation method(Reference Norton and Olds21) which characterises three main somatotype types: mesomorphic, endomorphic, and ectomorphic Table 1.
Statistical treatment
Data were entered into the Excel program, and analysis was performed using STATA v17.0 software (SE-Standard Edition, College Station, Texas, USA). After prior evaluation of normality using the Kolmogorov-Smirnov test, and visually with box and whisker plots (SG1a–SG1e), continuous variables, such as anthropometric and nutritional parameters, did not have a normal distribution, so they were expressed as medians and interquartile ranges.
Different percentiles (5th, 10th, 25th, 50th, 75th, and 95th percentiles) were calculated for each parameter by ethnicity and sex. Subsequently, these parameters were categorised according to their respective physiological reference values and expressed as relative frequencies (%) and 95% CI. The comparison of continuous parameters by ancestry, as there were only two groups (Quechua and Aymara), was performed using the Mann-Whitney U test, and Pearson’s χ⊃ test and/or Fisher’s exact test were used, as appropriate, presented in contingency tables. Statistical significance was set at P < 0.05.
Disclosure of ethical standards
This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. All procedures involving human participants were approved by the Institutional Research Ethics Committee of the National University of the Altiplano (Certificate No. 022-2023/CIEI-UNA-Puno).
Written informed consent was obtained from the parents or legal guardians, who were fully informed about the nature and objectives of the study. The voluntary decision of children aged 6–10 years was respected through the administration of an informed assent prior to their participation.
Results
Of the 1,289 children, 47.2% were Aymara and 52.8% were Quechua. By sex, 48.7% of Aymara children and 49.6% of Quechua children were male, and 51.3% and 50.4% were female, respectively, with no statistical difference between them (P = 0.734). By age, the smallest number corresponded to 6-year-old children in both ethnicities; from 7 to 10 years, the percentage distribution was similar by age (P = 0.063). By educational grade, the largest proportion of students corresponded to Quechua children in the 3rd grade (P = 0.001) (S2).
Nutritional status
No significant differences were found between the Aymara and Quechua populations in terms of the BMI/age Z-score indicator (S3). Figure 2a shows a negative trend in normal nutritional status in the Aymara population, at 86.2% at 6 years and 61.1% at 10 years, while overweight and obesity showed a positive trend, jointly reaching 13.8% of children at 6 years and 39% at 10 years. In Quechua children, normal status reached 73.2% at 6 years and 71.6% at 10 years; together, overweight and obesity were present in 26.9% at 6 years and 28.4% at 10 years.
Fig. 2. (a) Nutritional status according to BMI/Age indicator in children aged 6 to 10 years in Aymara and Quechua high Andean areas. Children at 6 years of age show a predominance of normal nutritional status in both ethnic groups; at 10 years of age the percentage is lower in the Aymara. According to age, overweight and obesity is ascending in the Aymara, while in the Quechua, this state is expressed from the age of 6, increasing the obese state at the age of 10. (b) Nutritional status according to Height/Age indicator in children aged 6–10 years in Aymara and Quechua high Andean areas. The highest percentage of children show normal growth in both ethnic groups. Short stature is evident in both ethnicities.
According to the Height/age Z-score, no significant differences were found between ethnicities (S3). The Figure 2b shows that children present normal height in 93.1% (Aymara) and 97.6% (Quechua) at 6 years, and 97.4% (Aymara) and 90.8% (Quechua) at 10 years. The percentage of low stature reached 6.9% in Aymara children and 2.4% in Quechua at 6 years, and 2.6% (Aymara) and 7.3% (Quechua) at 10 years; the percentages of tall height was reduced in both ethnicities.
Body composition
Table 2a shows the percentile (P) distribution of body fat percentage (%BF), where differences by ethnicity are found at P5 (Aymara 13.7 95%CI [12.8–14.5] - Quechua 9.4 95%CI [4.6–12.3]), P10 (Aymara 15.6 95%CI [13.3–16.6] - Quechua 11.8 95%CI [9.23–12.8]), P50 (Aymara 20.3 95%CI [18.6–23.7] - Quechua 17.1 95%CI [15.5–18.4]), and P75 (Aymara 27.4 95%CI [24.5–31.9] - Quechua 20.5 95%CI [18.4–24.2]), where 10-year-old Aymara children present higher %BF than Quechua children. Aymara girls at P25 showed higher %BF at 9 years (Aymara 17.2 95%CI [16.7–18.7] - Quechua 13.4 95%CI [12.3–16.1]).
Table 2a. Percentiles of the percentage of fat mass by age group and sex in children aged 6 to 10 years from high Andean Aymara and Quechua areas
P, percentile.
According to %MM (Table 2b), Quechua boys presented higher muscle content than Aymara boys at P5 – 6 years (Aymara 21.5 95%CI [18.6–36.3] - Quechua 37.0 95%CI [36.8–37.3]) and 9 years (Aymara 17.0 95%CI [4.5–25.7] - Quechua 27.1 95%CI [16.1–32.5]), at P75 – 10 years (Aymara 41.2 95%CI [39.9–42.3] - Quechua 44.8 95%CI [42.9–46.7]), and P95 – 10 years (Aymara 44.8 95%CI [43.0–46.2] - Quechua 48.5 95%CI [46.7–52.5]). There were no differences in girls between ethnicities. At P5 – 7 years (boys 31.3 95%CI [30.3–34.6], - girls 23.8 95%CI [15.4–28.1]), Aymara boys presented higher %MM than girls, while at 10 years (boys 21.1 95%CI [11.8–24.8], -girls 27.0 95%CI [25.4–33.6]), girls reached higher %MM; the same behaviour was observed at the 50th, 75th, 90th, and 95th percentiles.
Table 2b. Percentiles of the percentage of muscular mass by age group and sex in children aged 6 to 10 years from high Andean Aymara and Quechua areas
P, percentile.
According to the %BM (Table 2c), no differences we are found between ethnicities. At P5, the minimum and maximum values were between 14.8% and 16.6%; at P50, 16% and 17.4%; and at P95, between 17.4% and 19.2%.
Table 2c. Percentiles of the percentage of bone mass by age group and sex in children aged 6 to 10 years from high Andean Aymara and Quechua areas
P, percentile.
Body proportionality indices
According to BS, Quechua children presented large (50.5%) and medium (43.3%) structures, with a similar distribution in Aymara children (P = 0.246). The RLUE index showed a brachybrachial (short legs) predominance in Quechua children (98.7%) compared with Aymara children (86.8%) (P = 0.029). According to the BI, Aymara (49.7%) and Quechua (47.3%) children showed brachypical characteristics. The lower extremity (RLLE) showed brachyskelic (short leg length) characteristics in Aymara children (44.7%) and mesoskelic (intermediate leg length) characteristics in Quechua children (41.7%) (P = 0.048).
According to SI, Aymara children (63.7%), unlike Quechua children (57.4%), presented with short lower limbs (brachyskelic) (P = 0.057). The CI showed that Aymara (71.9%) and Quechua (74%) children presented with an elongated/large trunk (macrocormic) (P = 0.687). According to the AII, the trunk was rectangular and intermediate in both ethnicities (P = 0.110). The RBI showed that the back was broad in Aymara (68.4%) and Quechua (57.3%) children (P = 0.001), with differences in pelvic breadth according to the BII (P = 0.037), with narrow and broad pelvis being proportionally higher in the Aymara population.
According to the WHI, body fat distribution was android (abdominal) (P = 0.163), with overweight and elevated overweight, together, in Aymara (18.1%) and Quechua (13.8%) children (P = 0.024) according to the WHeI Table 3.
Table 3. Body indices of children aged 6 to 10 years from high Andean Aymara and Quechua areas
a Fisher’s exact test.
b Pearson χ⊃ test; comparing the Aymara vs Quechua group.
Somatotype
The somatotype shows mesomorphic and endomorphic tendencies in both populations, according to sex and ethnicity. Aymara and Quechua boys presented mesomorphic characteristics (5.015 and 4.995, respectively) with an endomorphic tendency (3.725 and 3.458, respectively). Aymara and Quechua girls showed mesomorphic (4.601 and 4.762) and endomorphic characteristics (4.129 and 3.952) (P = 0.001) Table 4.
Table 4. Distribution of the Heath and Carter somatotype in children aged 6–10 years from high Andean Aimara and Quechua areas
Test U-Mann Whitney P < 0.005, comparing the Aymara vs Quechua group.
Figure 3a and b; illustrate the somatotype distribution using the Heath-Carter Somatochart. A greater concentration of data points is evident in the mesomorphic region, with an extension towards the endomorphic component. This clustering is more prominent among the Aymara population, suggesting a tendency in both ethnic groups towards increased adiposity, overweight, and obesity.
Fig. 3. (a) Heath-Carter Somatotype Chart of Quechua Children. The somatochart of Quechua children displays a point cloud predominantly located in the mesomorphic region, with a moderate endomorphic inclination relative to the Aymara, and reduced ectomorphic representation. (b) Heath-Carter Somatotype Chart of Aymara Children. The somatochart of Aymara children reveals a cluster of points predominantly within the mesomorphic component, exhibiting a marked endomorphic trend in comparison to the Quechua group, with lower ectomorphic distribution.
Discussion
The Quechua people are long-standing Andean populations, originally from Cusco who speak the Quechua language and constitute a majority of the indigenous or native populations of Peru, Bolivia, and Ecuador. The Aymara population is located in the high Andean areas of Peru, Bolivia, and Chile; their language is Aymara or Aru, which is older than Quechua.(Reference Palomino22) Historical events determine differences between ethnicities, not only in language and territory but also in attitudes, habits, and health practices.(Reference Mendoza-Mori23) Both represent an equivalent of 10 million people (30%) residing above an altitude of 2000 m.
Human growth and development are determined by genetic factors(Reference Watkins, Testa and Smith24) that can be modified by the effects of diverse environmental exposures.(Reference Julian25) In high-altitude dwellers, significant associations have been found between the methylation of Hypoxia-Inducible Factor (HIF1α, HIF-2α, and HIF-1β) and the SNP genotypes of Endothelial PAS Domain-Containing Protein 1 (EPAS1) that encodes HIF-2α, which induces the developmental plasticity required for adaptation to hypoxia at high altitudes.(Reference Wang, Zhang and Zhang5) This process is mediated by more than 100 genes and their regulatory variants, including those involved in vascular endothelial growth factor signalling, erythropoietin production, glycolytic enzymes,(Reference Basak and Thangaraj26) and bone mass modulators such as FAM213A.(Reference Valverde, Zhou and Lippold27) These adaptations manifest in distinct physiological, anatomical, morphological, and biochemical characteristics, as observed in Tibetan, Han, Andean, and other high-altitude populations.(Reference Storz28)
The expression of such traits is shaped by evolutionary processes,(Reference Harris, Song and Shetty1) the adaptive history of Andean natives,(Reference Bigham29) and the duration of residence in high-altitude environments marked by chronic environmental stress.(Reference Valverde, Zhou and Lippold27) Despite current knowledge of the genetic composition of high-altitude populations, there is still limited understanding of the extent of changes in skeletal characteristics and body composition among Andean populations.
Epigenetic factors have recently been incorporated into this knowledge. Differences have been found in the methylation processes of the LINE-1 promoter DNA that induce HIF in the high-altitude Quechua population in relation to Quechua migrants to low altitudes, which explains their dependence on the exposure factor.(Reference Basak and Thangaraj26) However, altitude may not exert the same effect on the expression of HIF-1α genes in native Aymara as sea-level residents.(Reference Lundby, Pilegaard and Andersen30) Despite the knowledge about the genetic composition of high-altitude populations, skeletal(Reference Pomeroy, Stock and Stanojevic31) and muscular(Reference Lundby, Pilegaard and Andersen30) characteristics of the Andean population are still scarce.
Nutritional status
A diversity of anthropometric studies shows that high altitude can determine restrictions in weight from the intrauterine and infant stages(Reference Julian, Galan and Wilson32) growth retardation in children aged 6–12 years between 1 and 4 cm, showing them to be smaller but heavier.(Reference Cossio-Bolaños, de Arruda and Álvarez33) Other studies hypothesised that at high altitudes, a greater capacity for adaptation is expressed,(Reference Hartinger, Tapia and Carrillo3) an aspect that includes pregnancy, where the child conceived and born at high altitude would have the same possibility of reaching an optimal weight as children at low altitude, an aspect that is dependent on the duration of habitation(Reference Wu, Liu and Chen34) and environmental conditions.
Secular trend studies over 50 years in Peruvian high Andean populations have demonstrated modifications in growth associated with improvements in socioeconomic status, with a secular increase in height of 7–8 cm and reduction in growth retardation rates attributed to improved conditions in infrastructure, social support, health care, and economic expansion, a situation that changes when these conditions are inadequate, determining alterations in growth due to reduced energy consumption, among other health conditions.(Reference Hoke and Leatherman35)
In the last three decades, Peru has undergone an epidemiological and demographic transition, with significant improvements in infant and overall survival, although the burden of child malnutrition and infectious disease is still maintained, with an increase in overweight, obesity, and chronic diseases. This situation has encompassed increasingly younger ages with increased morbidity and mortality, mainly in populations experiencing various types of economic inequality,(Reference Rios-Blancas, Pando-Robles and Razo36) such as the Andean population.
In the present study, a predominance of normal nutritional status was observed, with reduced percentages of thinness; short stature is still found, a product of the persistence of nutritional deficiencies and chronic malnutrition, which require public policies that improve education, maternal nutritional status and birth weight, with breastfeeding and care practices, better family incomes, availability of health services, family size, and even the kitchen area and fuel used.(Reference Katoch37) According to a national reference, short stature (chronic malnutrition) reaches 12.1% in children under 5 years, with rural areas being the most affected at 20.9%.(38)
Another characteristic that alarmingly affects these populations is the increase in the prevalence rates of overweight and obesity, which in Peru affects 38.4% of the population aged between 6 and 13 years.(39) In our study, it jointly reached 39% in Aymara and 28.4% in Quechua children. Research in Aymara children showed a greater increase in body weight compared to the non-Aymara population(Reference Barrio-Mateu, León-Valladares and de-Souza-Lima40); this characteristic was observed in the Quechua population by Frisancho et al., and was associated with the socioeconomic factors.(Reference Frisancho41)
The presence of overweight and obesity could signify an additional epidemiological burden in populations exposed to changing variables in their physical activity characteristics.(Reference Lan and Sulaiman42) The Aymara ethnicity had a significant dedication to agriculture and animal herding with a great deal of physical activity involved in moving to distant areas in search of food for the animals.(Reference Quispe-Martínez, Blanco-Gallegos and Huanca-Arohuanca43) These activities, which included children, have been reduced due to drastic changes in the areas of economic activity, generally directed towards mining and tourism with an emphasis on commerce.(44) People dedicated to commercial activities tend to eat outside the home,(Reference Ticona, Arocutipa and Alacona45) with preparations high in fat, carbohydrates, and sodium and poor in essential elements, an increase in industrialised foods,(Reference Godbharle, Jeyakumar and Giri46) and living in an obesogenic environment,(Reference Di Cesare, Sorić and Bovet47) all of which are associated with cardiometabolic risk in children and adults due to central abdominal fat disposition.(Reference Sijtsma, Bocca and L’Abée48)
The Quechua people share similar changes in their economic activities, although with greater development of agriculture, livestock farming, and trade of their products, an aspect that may be associated with predominant consumption of the foods they harvest and produce,(Reference Palomino22) which would explain the results.
Quechua communities have experienced similar shifts in their economic activities, although with a greater emphasis on agriculture, an aspect likely linked to their predominant consumption of locally harvested foods, particularly tubers such as potato (Solanum tuberosum), oca (Oxalis tuberosa), and olluco (Ullucus tuberosus).(49)
Dietary studies conducted in adult high-altitude populations have revealed a transition away from traditional eating patterns, marked by the growing inclusion of sugary beverages, carbonated drinks, processed meats, and industrially processed foods. These changes have resulted in a dietary profile dominated by carbohydrates (accounting for nearly 70% of total caloric intake) along with a high intake of saturated fats and a reduced intake of essential vitamins and minerals. This dietary transition represents a key factor associated with changes in nutritional status. Although the evidence stems from adult populations, it is particularly relevant given that food habits are typically shared within households and thus also affect children.(Reference Caballero Gutiérrez50)
Body composition
It is known that BMI is one of the most used indices because ease of its determination, but it has little sensitivity to define tissue composition; therefore, its evaluation is necessary to quantify body components such as adipose, muscle, bone, and visceral tissue.
As there are no references to define body composition in children, percentile distribution was applied. Aymara children presented with a higher %FM than Quechua children, gender differences are highlighted in P90 and P95, with girls achieving a higher fatty component than boys. Our findings are similar to those found in Aymara children in Chile at P50.(Reference Barrio-Mateu, León-Valladares and de-Souza-Lima40)
A normal growth process is accompanied by an increase in body fat mass with age, which is greater before puberty, with differences by gender.(Reference KOmiya, Eto and Otoki51) The characteristics of the fat component in Aymara boys these could be associated with a pubertal transition in progress, while girls could present this characteristic in higher percentiles (P90 and P95) associated with overweight and obesity. In this regard, the impact of body fat distribution mediated by genetic contribution and environmental circumstances, whether android or peripheral, developed from an early ages, has consequences on growth and adult health.(Reference Rogol, Roemmich and Clark52) Evidence suggests that approximately three-quarters of overweight or obese children remain in this state in adulthood, with risks in the expression of chronic diseases(Reference Di Cesare, Sorić and Bovet47) and early risks of diseases that require urgent intervention policies.(Reference Lan and Sulaiman42)
Muscle mass has a direct relationship with fat mass and a reduced muscle component (P10) can be associated with various states, including thinness due to illness. Children with a higher fat component tend to express lower values of muscle mass and vice versa, aspects related to the level and type of physical activity, lifestyle, and obesogenic environment of great influence on metabolic alterations due to the epidemic increase in overweight and obesity worldwide.(Reference Mager, Hager and Gilmour53)
The limited reference regarding %MM at altitude restricts comparisons regarding muscle content above P75 in girls; however, it may be associated with the practice of family work activities that include girls and boys. Various comparative studies on physical performance in adult native Aymara and Quechua have found genotypic associations with metabolic adaptation processes, quantity and types of muscle fibres that lead to better muscle performance and greater lean muscle area in the arms.(Reference Bailey, Xu and Feng54)
Regarding %BM, no significant differences were found; the values were between 15 and 20% (P5 to P95) in both ethnicities. Various studies in Latin athletes at low altitude found bone mass percentages between 12 and 13%(Reference Gajardo-Burgos, Barría-Vargas and Flández-Valderrama55); despite not being an equivalent reference to the study sample, the %BM in this study was higher, an aspect that may be associated with the large and medium bone structure, which represents having wider bones and probably with greater mineral density, in both ethnicities.
A study conducted in children between 6 and 12 years of high and moderate altitude in Peru found higher values of the Bone Quality Index.(Reference Fuentes-López, Vidal-Espinoza and Mamani-Luque56) The factors of importance in the variations of this component are the level of lean mass, which establishes a positive relationship with bone mass and its mineralisation, and the content of fat mass, which exerts a negative effect on bone mass acquisition in obese children and adolescents due to the inflammatory state associated with alterations in osteoclastic activity and therefore in cortical and trabecular bone microarchitecture.(Reference Emeriau, Amsellem-Jager and Bouhours-Nouet57)
Lifestyle, physical activity and diet(Reference Emeriau, Amsellem-Jager and Bouhours-Nouet57) can constitute potentiating and limiting factors of the extent of bone mass associated with sedentary behaviour, climate, calcium consumption, and vitamin D status, dependent not only on diet but also on UV-B intensity, solar zenith angle, aspects that affect cutaneous production of vitamin D, and children’s bone health.(Reference Mendoza and Ronco58) All these factors are important to the public health of these populations.
Body proportionality
Studies in Quechua and Aymara populations have focused on elucidating whether physiological, metabolic, and physical changes are associated with genetics or whether epigenetic responses influence the growth of segments and body proportions. The complexity of bone metabolism during growth determines that the skeleton changes in size, shape, length, width, and weight, with a rapid increase in bone mass towards adolescence, where the main characteristic is the longitudinal growth of long bones.(Reference Tau59) However, these characteristics are not fully understood in high-altitude populations.
In this study, Aymara and Quechua children showed a large and medium BS, with no difference between ethnicities. This characteristic of skeletal width and shape assumes a greater skeletal weight, not considered when evaluating nutritional status in these populations, characterised by greater robustness,(Reference Ortiz-Prado, Mendieta and Simbaña-Rivera60) probably associated with a genetic component.(Reference Basak and Thangaraj26)
In addition to bone structure, both ethnicities show a macrocormic trunk, with a slight predominance in Quechua, rectangular shape, and a predominance of broad back in Aymara. Similarly, studies in Quechua children found that macrocormic trunk and thoracic breadth were associated with better pulmonary compliance,(Reference De Meer, Bergman and Kusner61) unlike a smaller chest size in Aymara children.(Reference Rupert and Hochachka4) Thoracic size in both ethnicities is one of the most reported characteristics, and various authors associate these bodily changes with evolutionary adaptation to life at high altitudes.(Reference Bigham29) Observations in Tibetan children aged 6–11 years show greater proportions of thorax and short legs, a characteristic of incidence in final height at older ages.(Reference Weitz and Garruto62) However, in the Quechua and Aymara populations, these differences are not maintained into adulthood,(Reference Rupert and Hochachka4) possibly affecting growth velocity, being slow and prolonged with a greater probability of reaching a smaller body size in adulthood.(Reference De Meer, Bergman and Kusner61)
The brachyskelic characteristics Aymara and mesoskelic in Quechua indicate that Aymara children have a shorter leg length and a wider and longer trunk. Anthropological studies of ancient Peru describe variations in the body shape of Andeans, without defining ethnicities: “The body is stocky overall; the limbs underdeveloped, which contrast with the thorax, abdomen, and head, which are voluminous”.(Reference Ayala and Huarcaya63) Later studies reported morphological findings that showed differences in arm length, being shorter in natives at high altitudes.(Reference Ortiz-Prado, Mendieta and Simbaña-Rivera60) If we consider that the lower extremities present greater environmental sensitivity than the upper extremities, it could be considered that the bone length reached in both ethnicities is a response to a variety of factors,(Reference Pomeroy, Stock and Stanojevic31) which allows us to question the extent to which it could be a genetic background.(Reference Rupert and Hochachka4) These results indicate the importance of adequate standards for these populations.(Reference Weitz and Garruto62)
Somatotype
Somatotype describes the tendency to develop body tissues based on genetics and the impact of the environment in diverse populations.(Reference Lizana, González and Lera7) Our results show mesomorphic and endomorphic characteristics in both ethnicities, with a risk of being overweight and obese. Some studies have found a mesomorphic tendency in Quechua inhabitants of the Central Andes.(Reference Toselli, Tarazona-Santos and Pettener64)
The limited number of somatotype studies conducted in Aymara, non-Aymara, and other ethnic groups of children and adolescents consistently report a predominance of mesomorphic and endomorphic components,(Reference Barrio-Mateu, León-Valladares and de-Souza-Lima40) reflecting a notable accumulation of both muscle and fat mass. This pattern results in a characteristically broad and compact physique, rather than a linear build, due to the relatively low ectomorphic component.(Reference Toselli, Tarazona-Santos and Pettener64) These traits are further accentuated by a large-boned skeletal structure and a predominance of thoracic width and depth, which together contribute to a robust body morphology distinct from that of populations living at lower altitudes.
Although high-altitude populations have historically been characterised by muscularity, the increasing presence of adipose tissue may suggest the influence of additional factors, including environmental pressures.(Reference Bruneau-Chávez, Maldonado-Hernández and Lagos-Hernández65)
Somatotypes, which are markers dependent on genetic influence, can be modified by environmental factors (epigenetics) such as child nutrition, exercise, and climatic, cultural, economic, and other factors of incidence on health.(Reference Lizana, González and Lera7) Some reports indicate that the Quechua man was of medium build and short stature,(Reference Mendoza-Mori23) in reference to build, although reports vary, the impact of time and living conditions have determined secular changes(Reference Hoke and Leatherman35) that seem to be positive in reaching height in current populations, although negative due to the increase in fat mass. These aspects allow the identification of probable health risks throughout the life cycle,(Reference Lizana66) and aspects not considered in health systems for these populations.
Various studies have estimated evolutionary epigenetic differences in high-altitude ethnicities, which have transitioned from a state of reduced body fat and significant musculature, associated with the physical deployment of herding, agriculture, and hunting, to more endomorphic characteristics associated with reduced physical activity, globalisation of diet, and expression of risk predictors of diseases such as diabetes and cardiovascular disease in adulthood,(Reference Koleva, Nacheva and Boev67) with Nutritional stress in the factor with the greatest impact in high-altitude populations.(Reference Bailey, Xu and Feng54)
The increasing influence of economic and social globalisation is thought to be linked to a growing burden of malnutrition. Although its impact is well documented among the world’s poorest populations, evidence also points to its effects on households with higher income levels. These realities must be taken into account in national policy planning aimed at mitigating the potential adverse consequences and inequalities associated with globalisation—pressures to which we are not exempt, given the pace of modernity,(Reference Beall68) ongoing internal and international migration, and the resulting shifts in traditional lifestyles and patterns of exposure to a changing environment.(Reference Beall68)
Understanding the characteristics of growth, body composition, and proportionality, as well as somatotypic trends and behaviour, would allow for the formulation of public health policies consistent with the situation of the people, with better diagnostic criteria for nutritional status, effectiveness of preventive interventions, improvement of health conditions and quality of life of children and a high-altitude resident population, mainly in a context where the socioeconomic situation is difficult, with the presence of health problems and limited geographical access, which constitute extrinsic factors capable of determining intrinsic effects.
Strengths and weaknesses of the study
The study presents strengths associated with the methodology, where the set of techniques, equations, and classifications, carefully chosen and executed, have allowed the characterisation of the nutritional status, proportions, and somatotypic trends of the Quechua and Aymara populations, for which there are no evaluation references.
We found as weaknesses in the non-consideration of populations from other altitudes for comparative purposes; similarly, the study of the food situation, characteristics of physical activity and other factors of incidence on the health status of children has not been included. The study is framed in children aged 6–10 years, requiring the establishment of baseline data for children of other ages, which allows them to know their characteristics and design appropriate public policies for these populations.
Conclusions
Nutritional status normal was higher in Quechua and Aymara children, and both groups showed a tendency towards overweight and obesity, although the presence of short stature was verified, indicative of a double nutritional burden.
In study body composition, Aymara children present a higher percentage of body fat, mainly at 10 years, probably associated with a transitional phase prior to the pubertal growth spurt Quechua girls present higher body fat content from early ages and are tall up to 10 years, aspects that are associated with the endomorphic tendency, build, and differences in the proportionality of upper limbs in relation to lower limbs, could constitute conditioning characteristics of risk in child and adult health in these populations, aspects not considered in public health and nutrition policies, which allow for promotion, treatment, and follow-up interventions appropriate to the characteristics and requirements of their habitation at high altitude.
Supplementary material
The supplementary material for this article can be found at https://doi.org/10.1017/jns.2025.10026
Acknowledgements
Directors, parents, and students of primary educational institutions participated in this study. To the students of the Professional School of Human Nutrition for their participation in the collection of anthropometric data. Dr. Gustavo Gonzales Rengifo, for revising and contributing to this manuscript.
Author contributions
Caballero L is the lead author who conceptualised and, participated in data curation, writing, revision, editing, and visualisation of the manuscript; Begazo J conceptualised and participated in the research process, methodological design, and project management; Núñez R and Chávez J participated in the research process, obtaining funding, and supervision; and Tapia V performed the formal analysis and data validation. All the researchers approved the final version of the manuscript.
Financial support
This study received financial support from the Special Fund for University Development (FEDU) of the National University of Altiplano Puno, as part of its policy to support research. The National University of Altiplano Puno played no role in the design, analysis, or interpretation of results.
Competing interests
Each author declares that he/she has no conflicts of interest, financial or otherwise.
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