RESUMEN
OBJECTIVES: Previous research has shown that indigenous circumpolar populations have elevated basal metabolic rates (BMRs), yet few studies have explored whether metabolic rates increase during the winter. This study addresses this gap by examining seasonal variation in BMR and its associations with thyroid function and lifestyle factors among the Yakut (Sakha) of Siberia. METHODS: Anthropometric dimensions, BMR, and thyroid hormone levels (free triiodothyronine [fT3], free thyroxine [fT4], thyroid-stimulating hormone [TSH]) were measured on two occasions (July/August, 2009 and January 2011) on a sample of 94 Yakut (Sakha) adults (35 men, 59 women) from the rural village of Berdygestiakh, Sakha Republic, Russia. RESULTS: Seasonal changes in BMR varied by age. Younger Yakut adults (19-49 years) showed significant elevations in winter-time BMR of 6% (P < 0.05), whereas older individuals (≥50 years) showed modest declines (2%; n.s.). Both younger and older Yakut men and women showed increased respiratory quotients during the winter. FT3 and fT4 levels significantly declined during the winter in both younger and older Yakut men and women (P < 0.05). Lifestyle factors were significant predictors of BMR variation, particularly among older men and women. CONCLUSIONS: Among the Yakut, increased wintertime BMR was observed among younger but not older adults, whereas all adults showed sharp reductions in free thyroid hormone levels during the winter. Among men, greater participation in subsistence activities was associated with increased BMRs and greater fat oxidation. Among women, variation in food use had the strongest impact on metabolic function.
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Metabolismo Basal , Estilo de Vida , Tiroxina/sangre , Adulto , Anciano , Regiones Árticas , Respuesta al Choque por Frío , Femenino , Humanos , Técnicas para Inmunoenzimas , Masculino , Persona de Mediana Edad , Estaciones del Año , Siberia , Triyodotironina/sangre , Adulto JovenRESUMEN
OBJECTIVES: Infectious disease and nutritional stress have both been associated with reductions in adult work productivity and work capacity in the context of wage labor, but less research has investigated their effects among groups relying on more traditional subsistence practices of horticulture and foraging. In this article, we examine the relations among measures of adult nutritional status (BMI, skinfold measurements, and fat-free mass) and infection (presence of soil transmitted helminth infections) and measures of adult work productivity. METHODS: As part of a larger panel study among Tsimane', a foraging-horticulturalist group in the Bolivian Amazon, health surveys, anthropometric information, and the quantity of products (both crops and game) brought into the household were collected for 320 Tsimane' adults over a four-month period in 2003. In addition, a single fecal sample was collected for a sub-sample of 86 adults. RESULTS: Our analysis shows mixed associations between either BMI or the presence of parasitism and reported adult productivity. Muscularity was not clearly related to adult productivity. In contrast, body fatness (Skinfold z-score) was inversely associated with the average quantity of fish and game brought into the household, especially for men. CONCLUSIONS: These findings suggest that the effects of adult infection and nutritional stress may be less clearly identified outside of the context of wage labor. Further research linking adult physical activity levels and metabolic rates to productivity in diverse contexts is needed.
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Eficiencia , Estado de Salud , Helmintiasis/complicaciones , Carne , Trabajo , Adulto , Agricultura , Animales , Índice de Masa Corporal , Bolivia , Heces/parasitología , Femenino , Peces , Helmintiasis/diagnóstico , Humanos , Indígenas Sudamericanos , Masculino , Manihot , Persona de Mediana Edad , Músculo Esquelético , Estado Nutricional , Plantago , Población Rural , Grosor de los Pliegues Cutáneos , Adulto JovenRESUMEN
Infectious disease, such as diarrheal disease, respiratory infections, and parasitic infections, are an important source of nutritional and energetic stress in many populations. Inspired by the research and methodological innovations of A. Roberto Frisancho, this work considers the impact of childhood environment and local disease ecology on child health and nutritional patterns among an indigenous group in lowland Bolivia. Specifically, we examine the association between soil-transmitted helminth infection, especially hookworm species, and anthropometric markers of short- and long-term nutritional status. Fecal samples, anthropometric dimensions, and health interviews were collected for 92 children ranging in age from 2.0 to 10.9 years. Microscopic examination revealed high levels of parasitic infection, with 76% of children positive for hookworm species infections (77% of girls and 74% of boys). Less common infections included Ascaris lumbricoides, Trichurius trichiura, and Strongyloides stercoralis with only 15% of children positive for multiple-species infections. After adjusting for sex and age, no statistically significant associations were observed between helminth infections and the frequency of reported illness or anthropometric measures of nutritional status. These data demonstrate the difficulty of assessing nutritional impacts of endemic infections.
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Pesos y Medidas Corporales , Trastornos de la Nutrición del Niño/etnología , Helmintiasis/complicaciones , Parasitosis Intestinales/complicaciones , Animales , Bolivia/epidemiología , Niño , Trastornos de la Nutrición del Niño/etiología , Preescolar , Femenino , Helmintiasis/etnología , Infecciones por Uncinaria/complicaciones , Infecciones por Uncinaria/etnología , Humanos , Indígenas Sudamericanos , Lactante , Parasitosis Intestinales/etnología , MasculinoRESUMEN
BACKGROUND: Global climate change and recent studies on early-life origins of well-being suggest that climate events early in life might affect health later in life. AIM: The study tested hypotheses about the association between the level and variability of rain and temperature early in life on the height of children and adolescents in a foraging-farming society of native Amazonians in Bolivia (Tsimane'). SUBJECT AND METHODS: Measurements were taken for 525 children aged 2-12 and 218 adolescents aged 13-23 in 13 villages in 2005. Log of standing height was regressed on mean annual level and mean intra-annual monthly coefficient of variation (CV) of rain and mean annual level of temperature during gestation, birth year, and ages 2-4. Controls include age, quinquennium and season of birth, parent's attributes, and dummy variables for surveyors and villages. RESULTS: Climate variables were only related with the height of boys age 2-12. The level and CV of rain during birth year and the CV of rain and level of temperature during ages 2-4 were associated with taller stature. There were no secular changes in temperature (1973-2005) or rain (1943-2005). CONCLUSION: The height of young females and males is well protected from climate events, but protection works less well for boys ages 2-12.
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Estatura , Indígenas Sudamericanos , Lluvia , Temperatura , Adolescente , Adulto , Factores de Edad , Estatura/fisiología , Bolivia/etnología , Niño , Preescolar , Estudios Transversales , Escolaridad , Femenino , Humanos , Masculino , Padres , Embarazo , Efectos Tardíos de la Exposición Prenatal/epidemiología , Pubertad/fisiología , Estaciones del AñoRESUMEN
Immune function is a central component of maintenance effort, and it provides critical protection against the potentially life threatening effects of pathogens. However, immune defenses are energetically expensive, and the resources they consume are not available to support other activities related to growth and/or reproduction. In our study we use a life history theory framework to investigate tradeoffs between maintenance effort and growth among children in a remote area of Amazonian Bolivia. Baseline concentrations of C-reactive protein (CRP) were measured in 309 2- to 10-year olds as an indicator of immune activation, and height was measured at baseline and three months later. Elevated CRP at baseline predicts smaller gains in height over the subsequent three months, with the costs to growth particularly high for 2- to 4-year olds and for those with low energy reserves (in the form of body fat) at the time of immunostimulation. These results provide evidence for a significant tradeoff between investment in immunity and growth in humans, and highlight an important physiological mechanism through which maintenance effort may have lasting effects on child growth and development.
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Crecimiento/fisiología , Sistema Inmunológico/fisiología , Agricultura , Estatura , Peso Corporal , Bolivia , Niño , Preescolar , Cultura , Femenino , Geografía , Estado de Salud , Humanos , Estilo de Vida , Masculino , Grosor de los Pliegues Cutáneos , Factores SocioeconómicosRESUMEN
Culture is a critical determinant of human behavior and health, and the intergenerational transmission of knowledge regarding the use of available plant resources has historically been an essential function of culture. Local ethnobotanical knowledge is important for health and nutrition, particularly in rural low-resource settings, but cultural and economic transitions associated with globalization threaten such knowledge. This prospective study investigates the association between parental ethnobotanical knowledge and child health among the Tsimane', a horticulturalist and foraging society in Amazonian Bolivia. Anthropometric data and capillary blood samples were collected from 330 Tsimane' 2- to 10-year-olds, and mothers and fathers were interviewed to assess ethnobotanical knowledge and skills. Comprehensive measures of parental schooling, acculturation, and economic activities were also collected. Dependent variables included three measures of child health: (i) C-reactive protein, assayed in whole-blood spots as an indicator of immunostimulation; (ii) skinfold thickness, to estimate subcutaneous fat stores necessary to fuel growth and immune function; and (iii) height-for-age, to assess growth stunting. Each child health measure was associated with maternal ethnobotanical knowledge, independent of a wide range of potentially confounding variables. Each standard deviation of maternal ethnobotanical knowledge increased the likelihood of good child health by a factor of >1.5. Like many populations around the world, the Tsimane' are increasingly facing the challenges and opportunities of globalization. These results underscore the importance of local cultural factors to child health and document a potential cost if ethnobotanical knowledge is lost.
Asunto(s)
Etnicidad/psicología , Etnobotánica , Conocimientos, Actitudes y Práctica en Salud , Indicadores de Salud , Adulto , Antropometría , Índice de Masa Corporal , Bolivia , Proteína C-Reactiva/análisis , Niño , Preescolar , Femenino , Humanos , Entrevistas como Asunto , Funciones de Verosimilitud , Masculino , Estudios Prospectivos , Factores SocioeconómicosRESUMEN
C-reactive protein (CRP), an acute-phase reactant and marker of inflammatory response, is known to be an important predictor of future cardiovascular mortality, independent of other risk factors. The purpose of this research was to investigate the association between CRP, adiposity, and blood pressure in the Yakut, an indigenous Siberian population undergoing rapid cultural change. We conducted a cross-sectional study of 265 healthy Yakut adults in six villages in rural northeastern Siberia. Plasma CRP was measured by high-sensitivity immunoturbidimetric assay. The median CRP value was 0.85 mg/l, with values for the 25th, 50th, and 75th percentiles of 0.30, 0.85, and 2.28 mg/l, respectively. CRP was positively associated with age (r = 0.19; P = 0.002), but not plasma lipids or smoking status. CRP was associated with measures of central adiposity and characteristics of the metabolic syndrome, particularly in women. We found significantly higher CRP across quintiles (Q) of waist circumference for women (difference = 0.7 mg/l; P = 0.035), but not men (difference = 0.36 mg/l; P = 0.515). CRP was significantly associated with systolic blood pressure in men (difference, Q1 vs. Q5 = 1.1 mg/l; P = 0.044) but not women (difference, Q1 vs. Q5 = 0.03 mg/l; P = 0.713) after adjusting for age, waist circumference, and smoking status. CRP in the Yakut was considerably lower than was reported for other populations. The low CRP levels may be explained in part by a low prevalence of abdominal obesity. Among the Yakut, the high physical-activity demands of a traditional herding lifeway likely play a role through high energy expenditure and maintenance of negative energy balance. Our findings underscore the need for further research on the metabolic activity of adipose tissue, blood pressure, and inflammatory activation in non-Western populations.
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Adiposidad , Presión Sanguínea , Proteína C-Reactiva/metabolismo , Adulto , Antropometría , Enfermedades Cardiovasculares/prevención & control , Estudios Transversales , Femenino , Humanos , Lípidos/sangre , Masculino , Síndrome Metabólico/etnología , Persona de Mediana Edad , Factores de Riesgo , Siberia/epidemiologíaRESUMEN
The rapid social and cultural changes introduced by the collapse of the Soviet Union have resulted in important differences in cardiovascular health for indigenous Siberians. This study investigated diet and lifestyle determinants of plasma lipids in the Yakut, an indigenous Siberian herding population. The study used a cross-sectional design with data on 201 subjects in three urbanized towns and three rural communities in northeastern Siberia. Data on sociodemographic characteristics, dietary intake, and material lifestyle were collected, and lipids were analyzed from venous whole blood. Diet was analyzed using patterns of dietary intake based on principal components analysis of a dietary intake (food frequency) questionnaire. We identified three diet patterns: a traditional subsistence diet, a market foods diet, and a mixed diet. The effect of lifestyle on cardiovascular risk factors was measured using an ethnographically defined lifestyle index, with two orthogonal dimensions: subsistence lifestyle and modern lifestyle. Total cholesterol (TC) and low-density lipoprotein (LDL) were significantly higher among those consuming a traditional subsistence diet of meat and dairy products. A modern lifestyle was associated with lower TC and LDL but higher adiposity and higher risk of obesity. LDL and TC were higher in rural communities and lower in urbanized towns. The significantly higher lipid levels associated with a subsistence diet and indirectly with a subsistence lifestyle indicate the emergence of a significant health problem associated with the social and cultural changes occurring in Yakutia today. These findings underscore the need for dietary modification and promotion of physical activity among those most at risk for cardiovascular disease (CVD). Moreover, these results differ from those commonly seen in "modernizing" populations, in that elements of subsistence lifestyle are associated with an elevated rather than reduced risk of CVD. Such variable responses to lifestyle change emphasize the need to better understand the distinct social and historical events that may influence health changes among populations in transition.
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Comunismo , Dieta/clasificación , Ingestión de Alimentos , Estado de Salud , Transición de la Salud , Estilo de Vida/etnología , Lípidos/sangre , Estado Nutricional , Grupos de Población , Adiposidad/etnología , Adulto , Crianza de Animales Domésticos , Antropología Cultural , Cultura , Dieta/efectos adversos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Siberia/epidemiología , Cambio SocialRESUMEN
AIM: The study analysed variability in physical stature, weight, and body mass index (BMI) in the USA during 1971-2002. SUBJECTS: Subjects were non-Hispanic Blacks and Whites, 2-74 years of age from the National Health and Nutrition Examination Surveys (NHANES I-III and 1999-2002). METHODS: The coefficient of variation and the standard deviation of the logarithm of stature, weight, and BMI were used to assess anthropometric variability for groups defined by age, race, sex, income, and survey year. Weighted ordinary least squares regressions were used to estimate the effect of socio-economic variables on anthropometric variability. RESULTS: (a) The relation between age and variability in weight or BMI resembles an inverted U, (b) men have lower variability in BMI than women, (c) Blacks and the poor have greater variability in weight and BMI than Whites or than the non-poor, and (d) variability in anthropometric indices increased during 1971-2002. Results were robust to the measure of variability used and to the use of the mean and mean square of the anthropometric indicators as explanatory variables. CONCLUSION: Since anthropometric indices correlate reliably with canonical indicators of well-being (e.g. income), growing variability in anthropometric indices, particularly among the Blacks and the poor, signals growing inequality in quality of life--a worrisome trend.
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Estatura/fisiología , Índice de Masa Corporal , Peso Corporal/fisiología , Adolescente , Adulto , Factores de Edad , Anciano , Algoritmos , Análisis de Varianza , Población Negra/estadística & datos numéricos , Estatura/etnología , Peso Corporal/etnología , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Encuestas Nutricionales , Factores Sexuales , Factores de Tiempo , Estados Unidos , Población Blanca/estadística & datos numéricosRESUMEN
Infectious disease is a major global determinant of child morbidity and mortality, and energetic investment in immune defenses (even in the absence of overt disease) is an important life-history variable, with implications for human growth and development. This study uses a biomarker of immune activation (C-reactive protein) to investigate an important aspect of child health among the Tsimane', a relatively isolated Amerindian population in lowland Bolivia. Our objectives are twofold: 1) to describe the distribution of CRP by age and gender in a cross-sectional sample of 536 2-15-year-olds; and 2) to explore multiple measures of pathogen exposure, economic resources, and acculturation as predictors of increased CRP. The median blood-spot CRP concentration was 0.73 mg/l, with 12.9% of the sample having concentrations greater than 5 mg/L, indicating a relatively high degree of immune activation in this population. Age was the strongest predictor of CRP, with the highest concentrations found among younger individuals. Increased CRP was also associated with higher pathogen exposure, lower household economic resources, and increased maternal education and literacy. The measurement of CRP offers a direct, objective indicator of immune activation, and provides insights into a potentially important pathway through which environmental quality may shape child growth and health.
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Proteína C-Reactiva/inmunología , Proteína C-Reactiva/metabolismo , Enfermedades Transmisibles/etnología , Enfermedades Transmisibles/inmunología , Indígenas Sudamericanos/estadística & datos numéricos , Aculturación , Adolescente , Distribución por Edad , Biomarcadores/sangre , Bolivia/epidemiología , Niño , Desarrollo Infantil , Preescolar , Enfermedades Transmisibles/sangre , Estudios Transversales , Ambiente , Femenino , Geografía , Humanos , Masculino , Distribución por Sexo , Factores SocioeconómicosRESUMEN
This study examines patterns of growth and nutritional status of indigenous Tsimane' children under 9 years of age (n = 199 boys and 210 girls), based on a cross-sectional sample from 58 villages from the Beni Deparment of lowland Bolivia. Compared with US children, Tsimane' children are quite short, with linear growth tracking at or below the US 5th centile in both sexes. The prevalence of low height-for-age ("stunting;" HA Z-scores =-2) is 52% in boys and 43% in girls. In contrast, weight-for-height in Tsimane' children approximates the US median, with the prevalence of low weight-for-height ("wasting"; WH Z-scores =-2) being only 4% and 6% in boys and girls, respectively. Tsimane' boys and girls are leaner than their US peers, but their levels of body fatness are not so low as to indicate severe energy stress. Arm muscularity of Tsimane' children is similar to that of their US age peers, and this suggests that they are not experiencing acute protein malnutrition. Variation in measures of nutritional status of Tsimane' children is modestly correlated with village-level differences. Degree of isolation, as measured by distance to urban centers or to primary forest, was not a strong predictor of children's anthropometric status. Rather, in both boys and girls, nutritional status was most strongly associated with number of teachers in the village, a measure of access to education. Comparative analyses indicate that high levels of statural growth stunting are common among indigenous populations throughout lowland South America. This problem appears to be largely attributable to poor dietary quality (diets low in key micronutrients) and high disease loads. Further research is needed to identify the specific causes and potential interventions for the high rates of childhood growth stunting in this region.
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Tamaño Corporal/etnología , Tamaño Corporal/fisiología , Desarrollo Infantil/fisiología , Fenómenos Fisiológicos Nutricionales Infantiles/fisiología , Indígenas Sudamericanos/estadística & datos numéricos , Distribución por Edad , Bolivia/epidemiología , Niño , Preescolar , Estudios Transversales , Femenino , Trastornos del Crecimiento/epidemiología , Humanos , Lactante , Recién Nacido , Masculino , Evaluación Nutricional , Estado Nutricional , Prevalencia , Distribución por Sexo , Delgadez/epidemiologíaRESUMEN
We use new data on the timing and extent of the early Pleistocene dispersal of Homo erectus to estimate diffusion coefficients of early Homo from Africa. These diffusion coefficients indicate more rapid and efficient dispersals than those calculated for fossil Macaca sp., Theropithecus darti, and Mesopithecus pentelicus. Increases in home range size associated with changes in ecology, hominid body size, and possibly foraging strategy may underlay these differences in dispersal efficiency. Ecological data for extant primates and human foragers indicate a close relationship between body size, home range size, and diet quality. These data predict that evolutionary changes in body size and foraging behavior would have produced a 10-fold increase in the home range size of H. erectus compared with that of the australopithecines. These two independent datasets provide a means of quantifying aspects of the dispersal of early Homo and suggest that rapid rates of dispersal appear to have been promoted by changes in foraging strategy and body size in H. erectus facilitated by changes in ecosystem structure during the Plio-Pleistocene.
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Conducta Alimentaria , Hominidae , Modelos Teóricos , Movimiento , Dinámica Poblacional , África , Animales , Antropología Física , Constitución Corporal , Dieta , Ecología , Fósiles , Humanos , PrimatesAsunto(s)
Evolución Biológica , Metabolismo Energético , Locomoción , Postura , Caminata , Adaptación Fisiológica , Animales , Antropología Física , Femenino , Hominidae , Humanos , Masculino , Factores SexualesRESUMEN
Increasing rates obesity and related chronic diseases in the United States and other parts of the world appear to be partly attributable to declining levels of physical activity. Given that adult obesity and chronic diseases often have their origins in childhood, there is a critical need to better understand how activity and fitness levels in childhood and adolescence shape health status in adulthood. The four papers in this series on physical activity draw on several longitudinal studies to examine the relationships between levels of physical activity and health-related fitness in childhood and adolescence to those in adulthood. These studies consistently demonstrate that adult activity levels and associated health outcomes are only modestly correlated with activity and fitness measures from childhood and adolescence. However, it appears that the methodological limitations in measuring activity levels may result in an underestimation of the importance of the influence of physical activity on health. Newer methods of measuring activity and energy expenditure offer to substantially improve our understanding of the influence of activity patterns on human health and fitness. Such information is necessary for promoting lifestyle changes that will reduce the risks of obesity and other chronic diseases.
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Ejercicio Físico , Estado de Salud , Aptitud Física , Adolescente , Adulto , Niño , Humanos , InvestigaciónRESUMEN
Mechanical interpretations of Neandertal skeletal robusticity suggest extremely high activity levels compared to modern humans. Such activity patterns imply high energy requirements; yet it has been argued that Neandertals were also inefficient foragers. The present study addresses this apparent conflict by estimating energy needs in Neandertals and then evaluating those estimates in the context of energetic and foraging data compiled for contemporary human foragers and nonhuman primates. Energy demands for Neandertals were determined by first predicting basal metabolic rates (BMR) from body weight estimates using human standards developed by the World Health Organization [FAO/WHO/UNU (1985) Energy and Protein Requirements. Report of the Joint FAO/WHO/UNU Export Committee, Geneva: WHO]. Total daily energy expenditure (kcal/day) was then estimated assuming high levels of physical activity (i.e., 2--3 x BMR), comparable to those observed among subsistence-level populations today. These estimates of energy requirements (ranging from 3000--5500 kcal/day) were then used to determine Neandertal foraging efficiency assuming (1) minimal survival-level foraging returns, and (2) daily foraging times longer than those observed among any contemporary foraging group and comparable to a nonhuman primate. Even with these extremely conservative parameters, estimates of Neandertal foraging efficiency (approximately 800--1150 kcal/h foraged) were comparable to those observed among living hunter-gatherers. These results indicate that if Neandertals did have heavy activity levels, as implied by their skeletal robusticity, they would have required foraging efficiencies within the range observed among modern groups. Thus, Neandertals could have been either highly active or poor foragers, but they could not have been both.
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Conducta/fisiología , Ingestión de Alimentos/fisiología , Metabolismo Energético/fisiología , Hominidae/fisiología , Adulto , Animales , Metabolismo Basal/fisiología , Peso Corporal , Europa (Continente) , Femenino , Hominidae/metabolismo , Humanos , MasculinoRESUMEN
Problems for child health have been attributed to child and sibling caretaking. Nevertheless, our data from highland Ecuador suggest an ambiguous relationship between growth failure and the practice of peer care. In a region where levels of chronic undernutrition as measured by stunting exceed 75 percent and fully one-quarter of children under five are underweight, analysis of structured observations of a sample of 28 children reveals no statistical association between growth indices and the practice of older children caring for younger children. Qualitative data, however, indicate that the practice can be a complication in specific cases where children already suffer compromised health. While the advantages or disadvantages associated with particular caretakers appear secondary to the risks attending inadequate diets or the broader environment of rural poverty, the potential for difficulties to emerge from peer care suggests that community day care provides a valuable alternative in this context.
Asunto(s)
Cuidado del Niño , Desarrollo Infantil , Adulto , Índice de Masa Corporal , Niño , Ecuador , Familia , Femenino , Humanos , Masculino , Política NutricionalAsunto(s)
Glucosa/análogos & derivados , Inhibidores de Hidroximetilglutaril-CoA Reductasas/síntesis química , Alcoholes del Azúcar/síntesis química , Glucosa/química , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Espectroscopía de Resonancia Magnética , Alcoholes del Azúcar/farmacologíaRESUMEN
A polymorphism with a variable number of tandem repeats (VNTR) found in the 3' untranslated region of the human dopamine transporter gene (DAT1) was scored in unrelated individuals drawn from 10 geographically widely dispersed populations in order to assess this marker's usefulness in human population genetics. The populations that were analyzed in this study included 4 indigenous groups of Siberia, natives of North and South America, as well as Caucasian and Oceanic groups, most of which represented small-scale societies. A total of 5 DAT1 alleles were seen overall, but only in one Siberian population, the Altai-Kizhi, were all 5 present, and in the Native Americans of Colombia the locus was monomorphic. The most common allele, DAT1*10, ranged in frequency from 52% in Greeks to 100% in South Americans. The high frequency of the DAT1*10 allele (approximately 90%) among Mongoloid groups of north and east Asia distinguishes them from most Caucasian groups. The presence of the rare DAT1*7 allele in relatively high frequency (approximately 5%) among all Siberian groups suggests a close affinity with north Asian groups, especially Mongolians. The presence of the even rarer DAT1*13 allele in one Siberian population, the Altai-Kizhi, reflects this group's long historical contact with Mongolians. The results demonstrated that the DAT1 VNTR polymorphism is useful in investigating population relationships, and that rare alleles at this locus may be particularly valuable in understanding the extent of genetic affinity between neighboring groups and in situations where admixture is suspected. However, because of both the association and linkage of this VNTR locus with attention-deficit hyperactivity disorder (ADHD) in children, and its highly restricted polymorphism (usually 3 alleles) in most human groups, the possibility of selection constraints on the DAT1 gene cannot be ignored.
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Pueblo Asiatico/genética , Proteínas Portadoras/genética , Glicoproteínas de Membrana , Proteínas de Transporte de Membrana , Nativos de Hawái y Otras Islas del Pacífico/genética , Proteínas del Tejido Nervioso , Polimorfismo Genético/genética , Población Blanca/genética , Alelos , Secuencia de Bases , ADN/análisis , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Europa (Continente) , Femenino , Genética de Población , Humanos , Masculino , Datos de Secuencia Molecular , Mutación , Islas del Pacífico , Reacción en Cadena de la Polimerasa , Vigilancia de la Población , Estados Unidos , Organización Mundial de la SaludRESUMEN
This study examines variation in dietary patterns and its influence on physical growth among children under 60 months of age from rural households of highland and coastal Ecuador. Differences in subsistence ecology between the regions appear to influence infant and early childhood feeding patterns. Coastal children are weaned significantly earlier than their highland counterparts (median +/- SE = 15.9 +/- 1.7 vs. 24.7 +/- 3.4 months) and have a weaning/supplemental diet that contains significantly more animal foods. In both regions, growth retardation is most severe among infants (<12 months), with growth rates being poorer in the highlands than on the coast. Linear growth rates among coastal infants are positively correlated with intakes of animal energy and animal protein, whereas among highland children energy intake from supplemental/weaning foods is negatively correlated with linear growth. These divergent patterns appear to be a consequence of the differences in nutrient density of the weaning/supplemental diets. Among the coastal infants, higher quality, nutrient dense foods augment breast milk and contribute to better growth rates. In contrast, among the highland infants the more filling, less nutrient dense foods appear to be replacing breast milk, and thus compromising growth status. In the older cohorts (i.e., "weaning age" children: 12.0-35.9 months, and completely weaned children: 36.0-59.9 months), linear growth rates stabilize with little evidence of "catch up" growth in either region. Improved weight gain, however, is seen among the highland children, and is correlated with the nutritional intake (i.e., energy, total protein, and animal protein) from weaning foods. Overall, marked growth stunting is seen in both regions, but is more pronounced in the highland children. These high levels of stunting are largely established in the first 12 months of life. Greater growth retardation among the highland children appears to reflect the influence of hypoxia as well as the lower nutrient density of weaning foods in that region. Am. J. Hum. Biol. 12:825-837, 2000. Copyright 2000 Wiley-Liss Inc.