Variation in diurnal cortisol patterns among the Indigenous Shuar of Amazonian Ecuador.

OBJECTIVES: The hypothalamic-pituitary-adrenal (HPA) axis and its primary end product, the glucocorticoid cortisol, are major components of the evolved human stress response. However, most studies have examined these systems among populations in high-income settings, which differ from the high pathogen and limited resource contexts in which the HPA axis functioned for most of human evolution. METHODS: We investigated variability in diurnal salivary cortisol patterns among 298 Indigenous Shuar from Amazonian Ecuador (147 males, 151 females; age 2-86 years), focusing on the effects of age, biological sex, and body mass index (BMI) in shaping differences in diurnal cortisol production. Saliva samples were collected three times daily (waking, 30 minutes post-waking, evening) for three consecutive days to measure key cortisol parameters: levels at waking, the cortisol awakening response, the diurnal slope, and total daily output. RESULTS: Age was positively associated with waking levels and total daily output, with Shuar juveniles and adolescents displaying significantly lower levels than adults (p < .05). Sex was not a significant predictor of cortisol levels (p > .05), as Shuar males and females displayed similar patterns of diurnal cortisol production across the life course. Moreover, age, sex, and BMI significantly interacted to moderate the rate of diurnal cortisol decline (p = .027). Overall, Shuar demonstrated relatively lower cortisol concentrations than high-income populations. CONCLUSIONS: This study expands the documented range of global variation in HPA axis activity and diurnal cortisol production and provides important insights into the plasticity of human stress physiology across diverse developmental and socioecological settings.

Pathogen disgust sensitivity protects against infection in a high pathogen environment.

Disgust is hypothesized to be an evolved emotion that functions to regulate the avoidance of pathogen-related stimuli and behaviors. Individuals with higher pathogen disgust sensitivity (PDS) are predicted to be exposed to and thus infected by fewer pathogens, though no studies have tested this directly. Furthermore, PDS is hypothesized to be locally calibrated to the types of pathogens normally encountered and the fitness-related costs and benefits of infection and avoidance. Market integration (the degree of production for and consumption from market-based economies) influences the relative costs/benefits of pathogen exposure and avoidance through sanitation, hygiene, and lifestyle changes, and is thus predicted to affect PDS. Here, we examine the function of PDS in disease avoidance, its environmental calibration, and its socioecological variation by examining associations among PDS, market-related lifestyle factors, and measures of bacterial, viral, and macroparasitic infection at the individual, household, and community levels. Data were collected among 75 participants (ages 5 to 59 y) from 28 households in three Ecuadorian Shuar communities characterized by subsistence-based lifestyles and high pathogen burden, but experiencing rapid market integration. As predicted, we found strong negative associations between PDS and biomarkers of immune response to viral/bacterial infection, and weaker associations between PDS and measures of macroparasite infection, apparently mediated by market integration-related differences. We provide support for the previously untested hypothesis that PDS is negatively associated with infection, and document variation in PDS indicative of calibration to local socioeconomic conditions. More broadly, findings highlight the importance of evolved psychological mechanisms in human health outcomes.

Bringing the lab bench to the field: Point-of-care testing for enhancing health research and stakeholder engagement in rural/remote, indigenous, and resource-limited contexts.

Point-of-care testing (POCT) allows researchers and health-care providers to bring the lab bench to the field, providing essential health information that can be leveraged to improve health care, accessibility, and understanding across clinical and research settings. Gaps in health service access are most pronounced in what we term RIR settings-rural/remote regions, involving Indigenous peoples, and/or within resource-limited settings. In these contexts, morbidity and mortality from infectious and non-communicable diseases are disproportionately higher due to numerous geographic, economic, political, and sociohistorical factors. Human biologists and global health scholars are well-positioned to contribute on-the-ground-level insights that can serve to minimize global health inequities and POCT has the potential to augment such approaches. While the clinical benefits of POCT include increasing health service access by bringing testing, rapid diagnosis, and treatment to underserved communities with limited pathways to centralized laboratory testing, POCT also provides added benefits to both health-focused researchers and their participants. Through portable, minimally invasive devices, researchers can provide actionable health data to participants by coupling POCT with population-specific health education, discussing results and their implications, creating space for participants to voice concerns, and facilitating linkages to treatment. POCT can also strengthen human biology research by shedding light on questions of evolutionary and biocultural importance. Here, we expand on the epidemiological and research value, as well as practical and ethical challenges of POCT across stakeholders (i.e., participant, community, health researcher, and trainee). Finally, we emphasize the immense opportunities of POCT for fostering collaborative research and enhancing access to health delivery and information and, by extension, helping to mitigate persistent global health inequities.

After Theranos: Using point-of-care testing to advance measures of health biomarkers in human biology research.

OBJECTIVES: The rise and fall of the health technology startup Theranos is emblematic of the promise and peril of point-of-care testing (POCT). Instruments that deliver immediate results from minimally invasive samples at the location of collection can provide powerful tools to deliver health data in clinical and public health contexts. Yet, POCT availability is driven largely by market interests, which limits the development of inexpensive tests for diverse health conditions that can be used in resource-limited settings. These constraints, combined with complex regulatory hurdles and substantial ethical challenges, have contributed to the underutilization of POCT in human biology research. METHODS: We evaluate current POCT capabilities and limitations, discuss promising applications for POCT devices in resource-limited settings, and discuss the future of POCT. RESULTS: As evidenced by publication trends, POCT platforms have rapidly advanced in recent years, gaining traction among clinicians and health researchers. We highlight POCT devices of potential interest to population-based researchers and present specific examples of POCT applications in human biology research. CONCLUSIONS: Several barriers can limit POCT applications, including cost, lack of regulatory approval for non-clinical use, requirements for expensive equipment, and the dearth of validation in remote field conditions. Despite these issues, we see immense potential for emerging POCT technology capable of analyzing new sample types and used in conjunction with increasingly common technology (e.g., smart phones). We argue that the fallout from Theranos may ultimately provide an opportunity to advance POCT, leading to more ethical data collection and novel opportunities in human biology research.

Age-related patterns of cytomegalovirus antibodies accompanying Epstein-Barr virus co-infection.

OBJECTIVE: Cytomegalovirus (CMV) infection is associated with age-related chronic disease, and co-infection with Epstein-Barr virus (EBV) may compound disease risk. We aimed to assess the frequency of CMV infection and its relationship with age among EBV seropositive individuals in an Indigenous Amazonian population. METHODS: We report concentrations of CMV and EBV antibodies in dried blood spot samples collected from 157 EBV positive Shuar participants aged 15-86 years (60.5% female) to assess CMV infection rate. We used logistic and linear regression models to examine associations among CMV, EBV, and age, adjusting for sex, geographic region, and body mass index. RESULTS: Nearly two-thirds (63.1%) of EBV seropositive participants were also CMV seropositive. A 1-year increase in age was associated with 3.4% higher odds of CMV infection (OR [95% CI]: 1.034 [1.009-1.064], p = .012), but CMV antibody concentration was not significantly associated with age or EBV antibody concentration among co-infected individuals. CONCLUSIONS: Herpesvirus-related immunosenescence may be important to understanding chronic disease risk among Shuar. Future studies should further explore the role of co-infection in shaping age-related changes in immune function.

Low prevalence of anemia among Shuar communities of Amazonian Ecuador.

OBJECTIVE: Anemia is an important global health challenge. We investigate anemia prevalence among Indigenous Shuar of Ecuador to expand our understanding of population-level variation, and to test hypotheses about how anemia variation is related to age, sex, and market integration. METHODS: Hemoglobin levels were measured in a total sample of 1650 Shuar participants (ages 6 months to 86 years) from 46 communities between 2008 and 2017 to compare anemia prevalence across regions characterized by different levels of market integration. RESULTS: Shuar anemia rates among children under 15 years (12.2%), adult women (10.5%), and adult men (5.3%) were less than half of those previously documented in other neo-tropical Indigenous populations. Anemia prevalence did not vary between more traditional and market integrated communities (OR = 0.47, p = .52). However, anemia was negatively associated with body mass index (OR = 0.47, p = .002). CONCLUSIONS: Compared to other South American Indigenous populations, anemia prevalence is relatively low among Shuar of Ecuador and invariant with market integration. Understanding this pattern can provide valuable insights into anemia prevention among at-risk populations.

Childhood Daily Energy Expenditure Does Not Decrease with Market Integration and Is Not Related to Adiposity in Amazonia.

BACKGROUND: Childhood overweight and obesity (OW/OB) is increasingly centered in low- and middle-income countries (LMICs) as rural populations experience market integration and lifeway change. Most explanatory studies have relied on imprecise estimates of children's energy expenditure, restricting understanding of the relative effects of changes in diet and energy expenditure on the development of OW/OB in transitioning contexts. OBJECTIVES: This study used gold-standard measurements of children's energy expenditure to investigate the changes that underlie OW/OB and the nutrition/epidemiologic transition. METHODS: Cross-sectional data were collected from "rural" (n = 43) Shuar forager-horticulturalist children and their "peri-urban" (n = 34) Shuar counterparts (age 4-12 y) in Amazonian Ecuador. Doubly labeled water measurements of total energy expenditure (TEE; kcal/d), respirometry measurements of resting energy expenditure (REE; kcal/d), and measures of diet, physical activity, immune activity, and market integration were analyzed primarily using regression models. RESULTS: Peri-urban children had higher body fat percentage (+8.1%, P < 0.001), greater consumption of market-acquired foods (multiple P < 0.001), lower concentrations of immune activity biomarkers (multiple P < 0.05), and lower REE (-108 kcal/d, P = 0.002) than rural children. Despite these differences, peri-urban children's TEE was indistinguishable from that of rural children (P = 0.499). Moreover, although sample-wide IgG concentrations and household incomes predicted REE (both P < 0.05), no examined household, immune activity, or physical activity measures were related to children's overall TEE (all P > 0.09). Diet and energy expenditure associations with adiposity demonstrate that only reported consumption of market-acquired "protein" and "carbohydrate" foods predicted children's body fat levels (multiple P < 0.05). CONCLUSIONS: Despite underlying patterns in REE, Shuar children's TEE is not reliably related to market integration and-unlike dietary measures-does not predict adiposity. These findings suggest a leading role of changing dietary intake in transitions to OW/OB in LMICs.

Disparities in bone density across contemporary Amazonian forager-horticulturalists: Cross-population comparison of the Tsimane and Shuar.

OBJECTIVES: This study investigates bone density across the life course among Bolivian Tsimane and Ecuadorian Shuar of Amazonia. Both groups are rural, high-fertility forager-horticulturalists, with high lifetime physical activity levels. We test whether Tsimane and Shuar bone density patterns are different from each other, and if both groups are characterized by lower osteoporosis risk compared to U.S. references. METHODS: Anthropometric and calcaneal bone density data, obtained via quantitative ultrasonometry (QUS), were collected from 678 Tsimane and 235 Shuar (13-92 years old). Population and sex differences in QUS values (estimated bone mineral density, speed of sound, broadband ultrasound attenuation) by age group were assessed using Mann-Whitney U tests. Age-related change and age at peak QUS value were determined using polynomial regressions. One-way analyses of covariance assessed population-level differences in QUS values by age group adjusting for body mass index. Participants aged 50+ years at elevated osteoporosis risk were identified using a T score < -1.8; binomial tests assessed risk compared to U.S. references. RESULTS: Shuar males and females <50 years old have QUS values 3-36% higher than Tsimane, with differences evident in adolescence. Among Tsimane and Shuar, 49 and 23% of participants aged 50+ years old, respectively, are at high risk for osteoporosis, compared to 34% of Americans; Shuar osteoporosis risk is comparable to Americans, while Tsimane risk is elevated. CONCLUSIONS: Disparate patterns in QUS values are documented for Tsimane and Shuar, with pronounced differences early in life. Potential explanations for differences include gene-environment interactions and/or degree of market integration, which influences diet, activity profiles, pathogen exposures, and other lifestyle covariates. As Tsimane osteoporosis risk is greater than in the United States, findings point to alternative risk factors for low bone density that are not readily discernible in industrialized populations.

Validation of an enzyme-linked immunoassay assay for osteocalcin, a marker of bone formation, in dried blood spots.

OBJECTIVES: Investigating factors that contribute to bone loss and accretion across populations in remote settings is challenging, particularly where diagnostic tools are scarce. To mitigate this challenge, we describe validation of a commercial ELISA assay to measure osteocalcin, a biomarker of bone formation, from dried blood spots (DBS). METHODS: We validated the Osteocalcin Human SimpleStep ELISA kit from Abcam (ab1951214) using 158 matched plasma and DBS samples. Passing-Bablok regression analysis assessed the relationships between plasma and DBS osteocalcin concentrations. Dilutional linearity and spike and recovery experiments determined if the DBS matrix interfered with osteocalcin measurement, and intra- and inter-assay coefficients of variation (CVs) were calculated. Limit of detection, analyte stability, and specific forms of osteocalcin measured by the kit were also investigated. RESULTS: Mean plasma osteocalcin value was 218.2 ng/mL (range 64.6-618.1 ng/mL). Linear relationships existed between plasma and DBS concentrations of osteocalcin, with no apparent bias in plasma vs DBS concentrations. There was no apparent interference of the DBS matrix with measurement of osteocalcin in DBS. Intra-assay CV for DBS was ~8%, while average inter-assay CV was 14.8%. Limit of detection was 0.34 ng/mL. Osteocalcin concentrations were stable in DBS stored at -28°C and room temperature, but not those stored at 37°C. This ELISA kit detects total osteocalcin. CONCLUSIONS: Osteocalcin, a bone formation biomarker, can be measured from DBS. Combined with a previously validated DBS assay for TRACP-5b, a bone resorption biomarker, these assays have the potential to help researchers disentangle the many factors contributing to bone strength.

Soil-transmitted helminth infection and intestinal inflammation among the Shuar of Amazonian Ecuador.

OBJECTIVES: Little research exists documenting levels of intestinal inflammation among indigenous populations where exposure to macroparasites, like soil-transmitted helminths (STHs), is common. Reduced STH exposure is hypothesized to contribute to increased prevalence of elevated intestinal inflammation in wealthy nations, likely due to coevolutionary histories between STHs and human immune systems that favored anti-inflammatory pathways. Here, we document levels of intestinal inflammation and test associations with STH infection among the Shuar of Ecuador, an indigenous population undergoing socioeconomic/lifestyle changes that influence their hygienic environment. We predict that fecal calprotectin (FC; a measure of intestinal inflammation) will be lower in STH infected individuals and that FC will be negatively associated with infection intensity. METHODS: Stool samples to analyze FC levels and STH infection were collected from 69 Shuar participants (ages 5-75 years). Children (<15 years) and adults (15+ years) were analyzed separately to understand the role of exposure in immune system development and the intestinal inflammatory response. RESULTS: Two species of STH were present: Ascaris lumbricoides and Trichuris trichiura. The relationships between infection and intestinal inflammation were age- and species-specific. While no significant relationships were found among adults, children who were singly infected with T. trichiura had lower FC levels than uninfected children. Infection intensity was not significantly associated with FC in children or adults. CONCLUSIONS: These preliminary results provide limited support for our hypotheses, documenting tentative age- and species-specific associations between FC and infection status. Findings may point to the importance of species-specific STH exposure during immune system development.

High energy requirements and water throughput of adult Shuar forager-horticulturalists of Amazonian Ecuador.

OBJECTIVES: We measured total energy expenditure (TEE; kcal/d) and water throughput (L/d) among Shuar forager-horticulturalists from Amazonian Ecuador to compare their daily energy and water demands to adults in other small-scale and industrialized populations. METHODS: TEE and water throughput were measured using the doubly labeled water method among 15 Shuar adults (eight women, seven men; age range 18-60 years) living in a relatively remote village. We used multiple regression to assess the effects of anthropometric variables (body size, fat free mass, age, and sex) on TEE and water throughput. We also compared Shuar TEE and water throughput to those of other small-scale and industrialized societies. RESULTS: TEE among Shuar adults (men: 4141 ± 645 kcal/d, women: 2536 ± 281 kcal/d) was most strongly correlated with fat free mass. Estimated physical activity levels (PAL) calculated as (TEE/estimated BMR), were greater for men (2.34 ± 0.29) than women (1.83 ± 0.14, P < 0.001). Water throughput was also greater among Shuar men (9.37 ± 2.34 L/d) than women (4.76 ± 0.36 L/d, P < 0.001). Shuar TEE and water throughput were elevated compared to adults in industrialized populations. DISCUSSION: TEE and PAL of Shuar men are among the highest recorded during normal daily life, and likely reflect both high levels of physical activity and cultural dietary practices. Drinking large amounts of chicha, a traditional carbohydrate-rich drink made from manioc, likely contributes to the high levels of water throughput among Shuar men, and may contribute to elevated TEE.

Physical growth of the shuar: Height, Weight, and BMI references for an indigenous amazonian population.

OBJECTIVES: Information concerning physical growth among small-scale populations remains limited, yet such data are critical to local health efforts and to foster basic understandings of human life history and variation in childhood development. Using a large dataset and robust modeling methods, this study aims to describe growth from birth to adulthood among the indigenous Shuar of Amazonian Ecuador. METHODS: Mixed-longitudinal measures of height, weight, and body mass index (BMI) were collected from Shuar participants (n = 2,463; age: 0-29 years). Centile growth curves and tables were created for each anthropometric variable of interest using Generalized Additive Models for Location, Scale, and Shape (GAMLSS). Pseudo-velocity and Lambda-Mu-Sigma curves were generated to further investigate Shuar patterns of growth and to facilitate comparison with United States Center for Disease Control and Prevention and multinational World Health Organization growth references. RESULTS: The Shuar are small throughout life and exhibit complex patterns of growth that differ substantially from those of international references. Similar to other Amazonians, Shuar growth in weight compares more favorably to references than growth in height, resulting in BMI curves that approximate international medians. Several additional characteristics of Shuar development are noteworthy, including large observed variation in body size early in life, significant infant growth faltering, extended male growth into adulthood, and a markedly early female pubertal growth spurt in height. Phenotypic plasticity and genetic selection in response to local environmental factors may explain many of these patterns. CONCLUSIONS: Providing a detailed reference of growth for the Shuar and other Amazonian populations, this study possesses direct clinical application and affords valuable insight into childhood health and the ecology of human growth.

Heterogeneous effects of market integration on sub-adult body size and nutritional status among the Shuar of Amazonian Ecuador.

BACKGROUND: Market integration (MI)-increasing production for and consumption from a market-based economy-is drastically altering traditional ways of life and environmental conditions among indigenous Amazonian peoples. The effects of MI on the biology and health of Amazonian children and adolescents, however, remain unclear. AIM: This study examines the impact of MI on sub-adult body size and nutritional status at the population, regional and household levels among the Shuar of Amazonian Ecuador. SUBJECTS AND METHODS: Anthropometric data were collected between 2005-2014 from 2164 Shuar (aged 2-19 years) living in two geographic regions differing in general degree of MI. High-resolution household economic, lifestyle and dietary data were collected from a sub-sample of 631 participants. Analyses were performed to investigate relationships between body size and year of data collection, region and specific aspects of household MI. RESULTS: Results from temporal and regional analyses suggest that MI has a significant and overall positive impact on Shuar body size and nutritional status. However, household-level results exhibit nuanced and heterogeneous specific effects of MI underlying these overarching relationships. CONCLUSION: This study provides novel insight into the complex socio-ecological pathways linking MI, physical growth and health among the Shuar and other indigenous Amazonian populations.

Low mineral density of a weight-bearing bone among adult women in a high fertility population.

Evolutionary theories of aging posit that greater reproductive effort causes somatic decline given a fundamental trade-off between investing energy in reproduction and repair. Few studies in high fertility human populations support this hypothesis, and problems of phenotypic correlation can obscure the expected trade-off between reproduction and somatic condition. This cross-sectional study investigates whether greater reproductive effort is associated with reduced calcaneal bone mineral density (BMD) among female Tsimane forager-farmers of lowland Bolivia. We also investigate whether female Tsimane BMD values are lower than sex- and age-matched US reference values, despite the fact that Tsimane engage in higher physical activity levels that can increase mechanical loading. To measure calcaneal BMD, quantitative ultrasonography was performed on 130 women (mean ± SD age = 36.6 ± 15.7, range = 15-75) that were recruited regardless of past or current reproductive status. Anthropometric and demographic data were collected during routine medical exams. As predicted, higher parity, short inter-birth interval, and earlier age at first birth are associated with reduced BMD among Tsimane women after adjusting for potential confounders. Population-level differences are apparent prior to the onset of reproduction, and age-related decline in BMD is greater among Tsimane compared with American women. Greater cumulative reproductive burden may lower calcaneal BMD individually and jointly with other lifestyle and heritable factors. Fitness impacts of kin transfers in adulthood may determine the value of investments in bone remodeling, and thus affect selection on age-profiles of bone mineral loss.

Determining osteoporosis risk in older Colono adults from rural Amazonian Ecuador using calcaneal ultrasonometry.

OBJECTIVE: Low bone density and osteoporosis prevalence, while well-documented in wealthy nations, are poorly studied in rural, non-clinical contexts in economically developing regions such as Latin America. This study contributes preliminary osteoporosis risk data for a rural Colono (mestizo) population from Amazonian Ecuador. METHODS: Anthropometrics were collected for 119 adult participants (74 females, 45 males [50-90 years old]). Heel bone density and T-scores were recorded using calcaneal ultrasonometry RESULTS: Approximately, 33.6% of the participants had low bone density and were at high-risk for osteoporosis. Four times as many females as males were considered high-risk. Consistent with epidemiological literature, advancing age was significantly associated with lower bone density values (P = 0.001). CONCLUSIONS: Low bone density and osteoporosis prevalence are expected to increase in this and other economically transitioning populations, yet infrastructure to monitor this changing epidemiological landscape is almost non-existent. Human biologists are uniquely positioned to contribute data from remote populations, a critical step toward initiating increased resource allocation for diagnosis and prevention.

Implications of market integration for cardiovascular and metabolic health among an indigenous Amazonian Ecuadorian population.

BACKGROUND: Market integration (MI), the suite of social and cultural changes that occur with economic development, has been associated with negative health outcomes such as cardiovascular disease; however, key questions remain about how this transition manifests at the local level. AIM: The present paper investigates the effects of MI on health among Shuar, an indigenous lowland Ecuadorian population, with the goal of better understanding the mechanisms responsible for this health transition. SUBJECTS AND METHODS: This study examines associations between measures of MI and several dimensions of cardiovascular and metabolic health (fasting glucose, lipids [LDL, HDL and total cholesterol; triglycerides] and blood pressure) among 348 adults. RESULTS: Overall, Shuar males and females have relatively favourable cardiovascular and metabolic health. Shuar who live closer to town have higher total (p < 0.001) and HDL cholesterol (p < 0.001), while Shuar in more remote regions have higher diastolic blood pressure (p = 0.007). HDL cholesterol is positively associated with consumption of market foods (r = 0.140; p = 0.045) and ownership of consumer products (r = 0.184; p = 0.029). CONCLUSIONS: This study provides evidence that MI among Shuar is not a uniformly negative process but instead produces complex cardiovascular and metabolic health outcomes.

Reproductive effects on skeletal health in Shuar women of Amazonian Ecuador: a life history perspective.

OBJECTIVE: Clinical and epidemiological research suggest that bone mineral density (BMD) in women is shaped by various reproductive factors such as parity and lactation patterns. However, the extent of these effects on BMD remains unclear because of contradictory findings and a focus on industrialized populations. Because fertility patterns in these groups are vastly different than those of women from non-Western, subsistence populations, our current understanding of the reproductive effects on skeletal health is incomplete. Using a life history perspective, this study examines the relationship between reproductive factors and bone density among women from the Indigenous Shuar population, an Amazonian Ecuadorian forager-horticulturalist group. METHODS: This preliminary, cross-sectional study included 130 premenopausal and postmenopausal women (14-86 years old) from the Morona-Santiago region of Ecuador. Anthropometrics were recorded, as was estimated BMD using a calcaneal ultrasonometer. A reproductive history questionnaire was administered that included questions regarding menarche, parity, lactation patterns, and menopause. RESULTS: Among postmenopausal women, early menarche and greater stature were significantly associated with higher bone density values. Among premenopausal women, few significant relationships between bone values and reproductive variables were documented; effects of lactation appeared to be transient and restored following weaning. CONCLUSIONS: Although preliminary and not based on longitudinal data, these findings suggest that the effects of reproduction are transient as the system of calcium homeostasis in premenopausal women efficiently restores the bone loss that results from metabolically active reproductive states. Further, this research suggests that the timing of early life history events may canalize bone density phenotype.

Analysis of variability of high sensitivity C-reactive protein in lowland Ecuador reveals no evidence of chronic low-grade inflammation.

OBJECTIVES: C-reactive protein (CRP) is a central component of innate immune defenses, and high sensitivity CRP has emerged as an important biomarker of chronic inflammation and cardiovascular disease risk. Prior analyses of CRP variability have reported stable between-individual differences in CRP over time, but a limitation of current knowledge is that it is based on research conducted in post-epidemiologic transition populations. METHODS: This study evaluated CRP variability among adults in the southeastern region of the Ecuadorian Amazon where rates of infectious diseases remain high. Blood samples were collected from 52 adults at four weekly sampling intervals and were quantified using a high-sensitivity immunoassay. RESULTS: Median CRP concentration was 0.52 mg/l. About 34.6% of participants had CRP >3 mg/l at one time point, but no individuals had CRP >3 mg/l across two or more sampling intervals, and within-individual correlations revealed low levels of stable, between-individual differences in CRP. The application of current guidelines for the assessment of chronic inflammation failed to detect a single case of "high risk" CRP. CONCLUSIONS: This study is the first to investigate CRP variability in a nonindustrialized, high infectious disease environment. It documents a pattern of variation over time that is distinct from prior research, with no evidence for chronic low-grade inflammation. These results may have substantial implications for research on inflammation and diseases of aging globally, as well as for scientific understandings of the regulation of inflammation.

Physical activity in an indigenous Ecuadorian forager-horticulturalist population as measured using accelerometry.

OBJECTIVE: Minimal information on physical activity is available for non-Western populations undergoing the transition to a market economy. This is unfortunate given the importance of these data for understanding health issues such as the global obesity epidemic. We consider the utility of using accelerometry technology to examine activity patterns and energy use regulation among indigenous Shuar, an Ecuadorian forager-horticulturalist population undergoing economic and lifestyle change. We investigate sex differences in Shuar activity patterns and the effects of reproductive status on activity. Finally, we discuss the potential of accelerometry use in human biology research. METHODS: Physical activity levels were measured using Actical accelerometers in 49 indigenous Shuar adults (23 males, 26 females) from a rural Ecuadorian community. Female participants were in various reproductive states including pregnant, lactating, and nonpregnant/nonlactating. RESULTS: Activity counts (AC), activity energy expenditure (AEE), and physical activity levels (PAL) were significantly higher (P < 0.05) in males than females. Significant differences in energy expenditure were found among pregnant or lactating females and males with pregnant or lactating partners (P < 0.001). Males with pregnant or lactating partners also had significantly higher activity levels than did other men (P < 0.01). CONCLUSIONS: Shuar activity levels are relatively low compared to other non-Western populations. Despite increasing market integration, pregnant and lactating females seem to be adopting a strategy noted in other subsistence populations where male participation in subsistence activities increases to compensate for their partners' elevated reproductive costs. Despite certain limitations, use of accelerometry in human biology research shows promise.

Obelionic cranial deformation in the Puebloan Southwest.

As a form of cranial deformation, obelionic flattening is rare. Originally named and described by Stewart (J Wash Acad Sci 29 (1939) 460-465), based on a small sample from Florida, it has been little noted since. Previously [Nelson and Madimenos, Paper presented at the Paleopathology Association annual meeting (2007)], we reported the discovery of two individuals from the Pueblo III Gallina site of Cañada Simon I who exhibit flattening of this type. Although technically undescribed in the Southwest before now, there are tantalizing clues in the literature that it occurred in low frequencies throughout the Ancestral Pueblo world. To determine whether the obelionic flattening found at Cañada Simon I was isolated or an indication of a more widespread phenomenon, we undertook a survey of crania from other Gallina sites, Chaco Canyon, and the literature (type of deformation can be determined on lateral photographs of crania properly positioned along the Frankfort Horizontal). We examined 146 crania (78 firsthand) of which seven exhibit obelionic flattening. Our results indicate that obelionic flattening should be added to the suite of cranial deformations that occur in the Southwest. Here, we propose parameters by which obelionic flattening can be described and differentiated from the more common lambdoidal and occipital forms and suggest that the three types of flattening form a continuum of cradleboard induced deformation, although the exact mechanism for obelionic flattening remains elusive. Am J Phys Anthropol, 2010. © 2010 Wiley-Liss, Inc.