Reproductive inequality in humans and other mammals.

To address claims of human exceptionalism, we determine where humans fit within the greater mammalian distribution of reproductive inequality. We show that humans exhibit lower reproductive skew (i.e., inequality in the number of surviving offspring) among males and smaller sex differences in reproductive skew than most other mammals, while nevertheless falling within the mammalian range. Additionally, female reproductive skew is higher in polygynous human populations than in polygynous nonhumans mammals on average. This patterning of skew can be attributed in part to the prevalence of monogamy in humans compared to the predominance of polygyny in nonhuman mammals, to the limited degree of polygyny in the human societies that practice it, and to the importance of unequally held rival resources to women's fitness. The muted reproductive inequality observed in humans appears to be linked to several unusual characteristics of our species-including high levels of cooperation among males, high dependence on unequally held rival resources, complementarities between maternal and paternal investment, as well as social and legal institutions that enforce monogamous norms.

Body norms, body image, and media in a market-integrating indigenous population in Argentina: A mixed-methods investigation.

OBJECTIVE: The aim of this study was to investigate the relationship between media, body norms, and body image among the Qom, a market-integrating indigenous population in Argentina that has historically idealized larger body sizes. METHODS: With men and women (n = 87), we measured frequency of media/technology use through a Likert-type questionnaire. Using the Stunkard Figure Rating Scale, we asked participants to select the most healthy and ideal body size for their gender, as well as their own body size. We calculated body dissatisfaction as the difference between ideal and own body size. We conducted semi-structured interviews to describe the role of media in body norms and body image. RESULTS: Media exposure was not significantly associated with perceptions of the "healthiest" or most "ideal" body sizes, nor body dissatisfaction. Men and women perceived categorically "middle-range" body sizes as both healthy and ideal, differing from a similar study in 2010, where larger bodies were favored. Interviews revealed that: media is not recognized as affecting body norms and body image, but is conceptually associated with cultural loss (Theme 1); a "dual stigma" of fatness and thinness is perpetuated by peers, family, and healthcare providers (Theme 2); and body acceptance is highly valued (Theme 3). CONCLUSION: In this context, while some body norms have changed over time, the impact of media on body norms and image may be secondary to influences from individuals' social networks, and may be occluded by norms favoring body acceptance.

Human Milk Oligosaccharide Compositions Illustrate Global Variations in Early Nutrition.

BACKGROUND: Human milk oligosaccharides (HMOs) are an abundant class of compounds found in human milk and have been linked to the development of the infant, and specifically the brain, immune system, and gut microbiome. OBJECTIVES: Advanced analytical methods were used to obtain relative quantitation of many structures in approximately 2000 samples from over 1000 mothers in urban, semirural, and rural sites across geographically diverse countries. METHODS: LC-MS-based analytical methods were used to profile the compounds with broad structural coverage and quantitative information. The profiles revealed their structural heterogeneity and their potential biological roles. Comparisons of HMO compositions were made between mothers of different age groups, lactation periods, infant sexes, and residing geographical locations. RESULTS: A common behavior found among all sites was a decrease in HMO abundances during lactation until approximately postnatal month 6, where they remained relatively constant. The greatest variations in structural abundances were associated with the presence of α(1,2)-fucosylated species. Genomic analyses of the mothers were not performed; instead, milk was phenotyped according to the abundances of α(1,2)-fucosylated structures. Mothers from the South American sites tended to have higher proportions of phenotypic secretors [mothers with relatively high concentrations of α(1,2)-fucosylated structures] in their populations compared to the rest of the globe, with Bolivia at ∼100% secretors, Peru at ∼97%, Brazil at ∼90%, and Argentina at ∼85%. Conversely, the cohort sampled in Africa manifested the lowest proportion of secretors (South Africa ∼ 63%, the Gambia ∼ 64%, and Malawi ∼ 75%). Furthermore, we compared total abundances of HMOs in secretors compared with nonsecretors and found that nonsecretors have lower abundances of HMOs compared to secretors, regardless of geographical location. We also observed compositional differences of the 50+ most abundant HMOs between milk types and geographical locations. CONCLUSIONS: This study represents the largest structural HMO study to date and reveals the general behavior of HMOs during lactation among different populations.

Demystifying mentorship: Tips for successfully navigating the mentor-mentee journey.

BACKGROUND: Quality mentorship is crucial for long-term success in academia and overall job satisfaction. Unfortunately, formal mentorship training is lacking, and there is little recourse for failed mentor-mentee relationships. METHODS: We performed a literature review to understand the current state of mentorship research with a focus on: (1) what mentorship is and why it is important for success; (2) establishing mentor-mentee relationships; and (3) the role of diversity, equity, and inclusion. RESULTS: From the literature review, we compiled a number of mentorship recommendations for individuals, departments, institutions, and professional associations. These recommendations focus on building a mentorship network, establishing formalized mentorship training, how to build a productive and mutually beneficial mentor-mentee relationship, and instituting a system of mentorship accountability. CONCLUSION: We hope that by centralizing this information and providing a list of resources and actionable recommendations we inspire and encourage others to make meaningful changes in their approach to mentorship to create a more kind, caring, and equitable environment in which to conduct our work.

C-reactive protein in adult Samoans: Population variation and physiological correlates.

OBJECTIVES: C-reactive protein (CRP) has been associated with adiposity and cardiometabolic disease risk in many populations but remains remarkably understudied in Pacific Islander populations. Here, we provide the first examination of correlates of CRP in adult Samoans (n = 108, ages 35-55 years) to test the hypotheses that CRP exhibits sex-dependent associations with measures of BMI, adiposity, and cardiometabolic disease risks. METHODS: We analyzed associations between measures of adiposity (total fat mass, visceral fat mass, percent total body fat), body mass index (BMI), cardiometabolic risks, behaviors, demographics, and CRP. Unadjusted analyses of CRP were undertaken using Pearson's pairwise, and Spearman's rank correlations; one-way analysis of variance and Kruskal-Wallis tests assessed variables by CRP quartiles. Adjusted analyses of CRP correlates were examined using generalized linear regression. RESULTS: Serum CRP ranged from 0.08 to 13.3 mg/L (median 1.4 mg/L) and varied significantly by sex t (108) = -2.47, p = .015. CRP was weakly to moderately associated with measures of adiposity and BMI (r and ρ ranged between 0.25 and 0.50, p < .05) and some cardiometabolic markers (including HbA1c, fasting insulin, and insulin resistance). CRP was significantly associated with percent body fat in women and men, adjusting for other variables. CONCLUSIONS: These data are among the first to demonstrate CRP correlates in a sample of adult Samoans. CRP differed by sex and was associated with BMI, adiposity, and some cardiometabolic risk markers. These data align with findings in other populations.

Comparison of two human infant urine collection methods for measuring estrone-3-glucuronide.

OBJECTIVES: Current human infant urine collection methods for the field are problematic for the researcher and potentially uncomfortable for the infant. In this study, we compared two minimally invasive methods for collecting infant urine: organic cotton balls and filter paper. MATERIALS AND METHODS: We first collected urine from infants using the clean catch method. We then used those samples to compare the performance of filter paper and cotton ball collection protocols. We analyzed the clean catch and cotton samples using commercial estrone-3-glucuronide (E1G) kits and tried two different extraction methods for the filter paper. Using a paired t-test (n = 10), we compared clean catch and cotton samples. We also compared effect sizes within and between methods. RESULTS: We were unable to extract enough urine from the filter paper to successfully assay the samples for E1G. The paired t-test revealed a statistically significant difference between the clean catch and cotton methods (t = 2.63, p-value = 0.03). However, the effect size was small (5.91 µg/ml, n = 10, 95% CI = 3.80, 8.02) and similar to or larger than the difference seen between duplicate wells for clean catch and cotton values. DISCUSSION: While this study is limited by sample size, our results indicate that filter paper is not a field-friendly method for collecting infant urine. However, we found that organic cotton balls showed similar values to the clean catch method, and we propose this method as an alternative, minimally invasive method for study of E1G in human infant urine.

Associations between fecal cortisol and biparental care in a pair-living primate.

OBJECTIVES: We quantified variation in fecal cortisol across reproductive periods in Azara's owl monkeys (Aotus azarae) to examine physiological mechanisms that may facilitate biparental care. Specifically, we evaluated evidence for the explanation that owl monkeys have hormonal mechanisms to mobilize energy during periods when each sex is investing heavily in reproduction, that is, the gestation period for females and the infant care period for males. MATERIALS AND METHODS: Between 2011 and 2015, we monitored 10 groups of Azara's owl monkeys from a wild population in Formosa, Argentina and collected fecal samples from 26 adults (13 males, 13 females). Using enzyme-linked immunosorbent assays, we quantified fecal cortisol as a proxy for evaluating stress responses, including energetic demands, on both sexes during periods of reproduction and parental care. RESULTS: Male cortisol was lowest during periods when they were caring for young infants (<3 months) compared with periods with older infants or no infant. Female cortisol was elevated during gestation compared with other periods. Mean fecal cortisol in both males and females was lower when an infant was present compared with when females were gestating. DISCUSSION: Our results do not support the hypothesis that owl monkey males have elevated fecal cortisol during periods when they need to mobilize energy to provide intensive infant care. Our findings are also inconsistent with the Maternal Relief hypothesis. However, results from studies measuring fecal cortisol must be interpreted with care and alternative explanations, such as seasonal fluctuations in diet and thermoenergic demands, should be considered when drawing conclusions.

Postpartum amenorrhea duration by sex of the newborn in two natural fertility populations.

OBJECTIVES: Postpartum amenorrhea (PA) affects the length of interbirth intervals and thus is intimately related to human life history strategies. PA duration appears to be influenced by maternal energetic status. In humans, as in other mammals, sons are costlier than daughters. Thus, we hypothesize that, in energetically constrained environments, a newborn's sex should be associated with PA duration. METHODS: We analyzed data from two natural fertility populations in which mothers have differing energy budgets: Qom women (n = 121) from a periurban village in Argentina, who have a comparatively calorically dense diet and are sedentary (prepregnancy mean BMI = 24.8 ± 4.5 kg/m2 in 1997), and agropastoral Kaqchikel Maya women (n = 88), who have a comparatively calorically restricted diet and high physical activity levels (mean BMI = 21.8 ± 3.7 kg/m2 ). We predict that (a) mothers of sons exhibit longer PA duration than mothers of daughters and (b) this association between offspring sex and PA duration is stronger in the Maya, who have smaller energy budgets. RESULTS: Maya mothers with sons exhibited estimated mean and median PA durations that were 1.34 times the estimated mean and median PA duration of mothers with daughters (p = 0.02). Among the Qom, mean, and median PA duration did not differ significantly in relation to offspring sex (p = 0.94). CONCLUSIONS: Maya mothers with sons exhibited longer PA duration than those with daughters. This phenomenon was not observed in the well-nourished Qom, possibly due to "buffering" effects from larger energy budgets. Offspring sex may influence birth spacing and maternal life history strategies in energetically constrained environments.

Access to electric light is associated with delays of the dim-light melatonin onset in a traditionally hunter-gatherer Toba/Qom community.

Key to the transition of humans from nomadic hunting-gathering groups to industrialized and highly urbanized societies was the creation of protected and artificially lit environments that extended the natural daylight hours and consolidated sleep away from nocturnal threats. These conditions isolated humans from the natural regulators of sleep and exposed them to higher levels of light during the evening, which are associated with a later sleep onset. Here, we investigated the extent to which this delayed timing of sleep is due to a delayed circadian system. We studied two communities of Toba/Qom in the northern region of Argentina, one with and the other without access to electricity. These communities have recently transitioned from a hunting-gathering subsistence to mixed subsistence systems and represent a unique model in which to study the potential effects of the access to artificial light on sleep physiology. We have previously shown that participants in the community with access to electricity had, compared to participants in the community without electricity, later sleep onsets, and shorter sleep bouts. Here, we show they also have a delayed dim-light melatonin onset (DLMO). This difference is present during the winter but not during the spring when the influence of evening artificial light is likely less relevant. Our results support the notion that the human transition into artificially lit environments had a major impact on physiological systems that regulate sleep timing, including the phase of the master circadian clock.

Perceptions of the healthiest body in a market-integrating indigenous population in Argentina: Fat idealization and gendered generational differences.

OBJECTIVES: Market integration seems to induce gender-specific generational change in health-related perceptions of body size. We predicted that among the Qom of Argentina, younger women would perceive comparatively thinner bodies as healthiest, demonstrating thin-idealizing body norms, and older women would retain culturally rooted perceptions of heavier bodies as healthiest. As traditional and globalized body size ideals are different for men, we predicted that men would perceive normal bodies as healthiest and would not exhibit generational differences. METHODS: We asked Qom adults (n = 273) residing in Namqom, Argentina to choose the healthiest body size from the Stunkard Figure Rating Scale (FRS). We performed multiple linear regression with age, gender, and body mass index (BMI) predicting healthy-body perception score. RESULTS: A majority of women chose overweight bodies as healthiest. As predicted, older women preferred heavier bodies compared to their younger peers; this generational effect was stronger among women clinically defined as underweight (BMI ≤19.99 kg/m2 ), and "normal" weight (20.00 kg/m2 ≤ BMI ≤24.99 kg/m2 ), as compared to women clinically defined as overweight (25.00 kg/m2 ≤ BMI ≤29.99 kg/m2 ) or obese (≥30.00 kg/m2 ). Men exhibited no generational effects and largely perceived bodies corresponding to a "normal" BMI as healthiest. CONCLUSIONS: Among Qom women, there is evidence for the adoption of the idealization of thinness as healthy alongside traditional perceptions that fat bodies are healthy.

Incipient Neighborhood and Socioeconomic Stratification Associated to Nutritional Status in Indigenous Qom Preschoolers from Formosa, Argentina.

Indigenous populations in Latin America are among the most socially vulnerable groups and their children often suffer severe deprivation in terms of access to proper nutrition, water, and shelter. This study describes the nutritional status of Qom preschoolers in general, and by neighborhood area and family's socioeconomic characteristics in a peri-urban village of Formosa, Argentina. Across-sectional study was carried out between January and December 2016, with 160 Qom children between 2 and 5 years of age. Interviews and anthropometric measures were conducted at the children's homes. Nutritional status was determined by body mass index. The prevalence of excess weight (overweight + obesity) and of stunting were associated with neighborhood area and socioeconomic level. The overall prevalence of stunting was 15.6% and it was found to be higher (25.8%) in areas of relatively lower access to material resources. The overall prevalence of excess weight reached 25%; however, neighborhood areas with greater access to material resources had a significantly higher prevalence of children with excess weight (41.2%). Despite the entire community living under the line of poverty, we found differences in nutritional status by neighborhood areas, suggesting an incipient social stratification and a deepening of inequalities in access to resources.

Cesarean birth and the growth of Yucatec Maya and Toba/Qom children.

OBJECTIVE: Cesarean delivery is often epidemiologically associated with childhood obesity. However, little attention is paid to post-birth modulatory environments, and most studies are conducted in settings where obesity arises for a number of reasons in addition to birth mode. We therefore assess population differences in the relationship between birth mode and childhood growth using data from rural and peri-urban Latin American indigenous populations, and test predictions developed using life history theory. METHODS: Child height and weight were measured monthly in 80 Yucatec Maya and 58 Toba/Qom children aged 1-48 months (2007-2014, 3812 observations). Random-effects linear mixed models were used to compare children's growth by population, sex, and birth mode, accounting for potential confounders. RESULTS: Cesarean delivery rates were 47% (Toba/Qom) and 20% (Yucatec Maya). Childhood obesity and overweight rates were low in both populations. Cesarean-delivered children had significantly greater weight gain (but similar height grain) compared to vaginally-delivered children. By age 4, cesarean delivered Yucatec Maya girls and boys, and Toba/Qom boys (not girls), had significantly higher weight-for-age compared to vaginally-delivered children from their own sex and population. CONCLUSIONS: This provides one of the first attempts to document differences in children's growth patterns according to mode of birth in modernizing indigenous populations. Cesarean delivery is associated with young children's growth patterns, even in the absence of many obesity-inducing factors. There are also population, age, and sex differences in the relationship between birth mode and childhood weight trajectories that warrant future investigation.

Birth mode and infectious morbidity risks in Qom children of Argentina.

OBJECTIVES: Cesarean delivery may increase childhood infectious morbidity risks via altered birth exposures and subsequent immune, microbial, and epigenetic development. Many Latin American indigenous populations experience dual burdens of infectious and chronic diseases, and are particularly vulnerable to rising rates of cesarean delivery and associated adverse outcomes. The Qom/Toba are an indigenous population in Argentina experiencing rapid lifestyle transitions. We hypothesized that cesarean delivery would be associated with increased risk of infectious symptoms in Qom children after adjusting for gestational and nutritional factors. METHODS: We conducted a secondary analysis of birth records and monthly anthropometric and illness data collected previously from 90 Qom children (aged 1-55 months). We tested for additive effects of birth mode on risk of gastrointestinal (GI) and respiratory illness (RI) in mixed-effects logistic regression models adjusting for child weight-for-age (WAZ), weaning, and gestational and maternal age. RESULTS: Cesarean deliveries accounted for 46% of births and were associated with maternal age < 20 and ≥ 30 years, gestational age < 39 weeks, and prenatal complications. GI and RI risks were reduced in association with cesarean delivery, greater WAZ, weaning, maternal age ≥ 30 years, and gestational age < 39 weeks. CONCLUSIONS: The relationship between cesarean delivery and reduced infectious risks may reflect statistical confounding with relatively rapid postnatal growth and greater adiposity. Postnatal growth trajectories may be important mediators of long-term morbidity risks associated with cesarean delivery. The frequency of cesarean deliveries among the Qom remains concerning given traditionally high rates of fertility and adolescent pregnancy.

A time to be born: Variation in the hour of birth in a rural population of Northern Argentina.

OBJECTIVES: The present study aimed at investigating the timing of birth across the day in a rural population of indigenous and nonindigenous women in the province of Formosa, Argentina in order to explore the variation in patterns in a non-Western setting. MATERIALS AND METHODS: This study utilized birth record data transcribed from delivery room records at a rural hospital in the province of Formosa, northern Argentina. The sample included data for Criollo, Wichí, and Toba/Qom women (n = 2421). Statistical analysis was conducted using directional statistics to identify a mean sample direction. Chi-square tests for homogeneity were also used to test for statistical significant differences between hours of the day. RESULTS: The mean sample direction was 81.04°, which equates to 5:24 AM when calculated as time on a 24-hr clock. Chi-squared analyses showed a statistically significant peak in births between 12:00 and 4:00 AM. Birth counts generally declined throughout the day until a statistically significant trough around 5:00 PM. DISCUSSION: This pattern may be associated with the circadian rhythms of hormone release, particularly melatonin, on a proximate level. At the ultimate level, giving birth in the early hours of the morning may have been selected to time births when the mother could benefit from the predator protection and support provided by her social group as well as increased mother-infant bonding from a more peaceful environment.

Timing of pubertal growth and menarche in indigenous Qom girls of Argentina.

BACKGROUND: Pubertal timing is in part mediated by environmental factors, with greater energy availability often associated with earlier or more rapid development. Many indigenous populations are undergoing socioeconomic change that may affect pubertal development and related health risks, necessitating fundamental longitudinal research on growth and development in these populations. AIM: Growth velocity and time to menarche among peri-urban indigenous Qom (Toba) girls in Argentina are described. SUBJECTS AND METHODS: From 2011-2015, monthly anthropometrics and menstrual status were collected from 61 Qom girls aged 7-14. Growth velocity curves were generated using the 'Super-imposition by translation and rotation' (SITAR) method. Median time to menarche was estimated by Kaplan-Meier survival analysis. RESULTS: Mean ages at peak height, weight and BMI velocity were estimated at 10.8, 10.5 and 10.7 years and median age at menarche at 11.6 years (95% CI = 11.4-11.9). At menarche, 45% of girls were overweight or obese and only one participant was short-statured by international standards. CONCLUSION: Qom participants in this study exhibit relatively fast pubertal development as compared to other Latin American indigenous populations studied previously by others. Genetic and environmental factors influencing body size, diet and/or activity levels should be investigated further in this population.

Aged Black-and-Gold Howler Monkey Female (Alouatta caraya): A Sign of Reproductive Senescence?

Reproductive senescence patterns have been scarcely studied in Neotropical primates. The few studies available on the hormonal profiles of aging female monkeys indicate that the decline of ovarian function in nonhuman primates may resemble the hormonal events associated with the perimenopause in women. In this study, we explore a reproductive hormone profile of an aged black-and-gold howler monkey female (Alouatta caraya) from a wild population in northeastern Argentina and compare this profile with that of a cycling female in the same population. As part of a larger study, we recorded sociosexual behaviors in adult and subadult females belonging to two groups, and we collected urine (n = 877) to determine the sex hormone profile of each female. These samples were analyzed using enzyme immunoassays for estrone conjugates and pregnanediol-3-glucuronide (PdG). We found differences in mean values of PdG between the younger (cycling) and the older female. These hormone values were lower in the older female, and she did not show any signs of cyclicity for either reproductive hormone. Our results show that the aging female in this wild population shows signs of ovarian senescence, indicated by low, acyclic levels of progesterone metabolites.

Hormonal correlates of development and natal dispersal in wild female owl monkeys (Aotus azarae) of Argentina.

Pair-living and socially monogamous primates typically do not reproduce before dispersing. It is currently unclear whether this reproductive suppression is due to endocrine or behavioral mechanisms. Cooperatively breeding taxa, like callitrichids, may forego reproduction in natal groups because they reap inclusive fitness benefits and/or they are avoiding inbreeding. However, neither of these benefits of delayed reproduction appear to adequately explain the lack of reproduction prior to leaving the natal group in pair-living monogamous species. In this study, we determined whether wild Azara's owl monkeys (Aotus azarae) in the Argentinean Chaco establish reproductive maturity prior to dispersing. We utilized 635 fecal extracts to characterize reproductive hormone profiles of 11 wild juvenile and subadult females using enzyme immunoassays. Subadult females showed hormone profiles indicative of ovulatory cycling and had mean PdG and E1G concentrations approximately five times higher than juveniles. Contrary to expectations from the inbreeding avoidance hypothesis, female owl monkeys do not delay puberty, but rather commence ovarian cycling while residing in their natal group. Still, subadults appear to have a period during which they experience irregular, non-conceptive cycles prior to reproducing. Commencing these irregular cycles in the natal group may allow them to develop a state of suspended readiness, which could be essential to securing a mate, while avoiding costs of ranging solitarily. Our results indicate that reproductive suppression in female owl monkeys is not due to endocrine suppression. We suggest that adults likely use behavioral mechanisms to prevent subadults from reproducing with unrelated adult males in their natal group.

The ecology of anemia: Anemia prevalence and correlated factors in adult indigenous women in Argentina.

OBJECTIVES: The Toba/Qom of Namqom are an indigenous community native to the Gran Chaco region of northern Argentina. Historically seminomadic foragers, the diet of peri-urban community members has rapidly changed from high-protein, high-fiber to hypercaloric, processed. This study aims to understand the impact of this nutritional transition on aspects of women's health by exploring the relationship between prevalence of anemia and current diet composition, place of birth, and reproductive history. METHODS: We measured the capillary hemoglobin (Hb) levels of 153 adult women. Each participant was also given two interviews characterizing reproductive history and a 24-hour food recall. RESULTS: The average Hb level was 12.6 g/dL (range 5.8-15.7 g/dL). In our sample, 28% of participants were anemic and 31% were borderline anemic. Iron and vitamin C consumption were negatively associated with Hb levels. Body mass index was marginally associated with Hb levels. Being born in a peri-urban setting, a proxy for early Westernized diet was associated with higher risk of anemia, suggesting developmental experience may play a role. Pregnant and lactating women had lower Hb levels than menstruating and menopausal women. Age, height, parity, and age at first pregnancy were not found to be statistically significant predictors of anemia. CONCLUSIONS: Iron deficiency represents a serious health concern for women, particularly pregnant ones. Our results suggest that both past and current nutritional ecology variables may be associated with the risk of anemia. These findings inform public health interventions, since reproductive history may be more difficult to modify than current diet.

Impact of Universal Health Coverage on Child Growth and Nutrition in Argentina.

OBJECTIVES: To estimate trends of undernutrition (stunting and underweight) among children younger than 5 years covered by the universal health coverage programs Plan Nacer and Programa Sumar. METHODS: From 2005 to 2013, Plan Nacer and Programa Sumar collected high-quality information on birth and visit dates, age (in days), gender, weight (in kg), and height (in cm) for 1.4 million children in 6386 health centers (13 million records) with broad coverage of vulnerable populations in Argentina. RESULTS: The prevalence of stunting and underweight decreased 45.0% (from 20.6% to 11.3%) and 38.0% (from 4.0% to 2.5%), respectively, with differences between rural versus urban areas, gender, regions, age, and seasons. CONCLUSIONS: Undernutrition prevalence substantially decreased in 2 programs in Argentina as a result of universal health coverage.

Growth patterns among indigenous Qom children of the Argentine Gran Chaco.

OBJECTIVES: This study describes and compares the growth strategies of rural (Western) and peri-urban (Eastern) Qom indigenous children from Argentina. METHODS: Height and weight were cross-sectionally assessed in Western (n = 263) and Eastern Qom (n = 512) individuals aged 0-18.9 years. Height-for-age (HAZ), weight-for-age (WAZ), and BMI-for-age (BMIZ) z-scores were calculated with an LMS software. Results were organized into four age categories: infancy, childhood, juvenility, and adolescence. Between-group comparisons of HAZ, WAZ, and BMIZ were carried out by age and sex categories and compared with Student's t or Mann Whitney tests. Nutritional status was classified based on BMIZ following WHO recommendations and was compared with x2 tests. RESULTS: In both groups, height and weight followed the typical human growth curve. Mean HAZ scores in both groups were within two standard deviations from the international reference, and increased from infancy to juvenility. WAZ and BMIZ scores were high during infancy and showed a general declining trend with age. Overall, Western Qom had higher HAZ scores. WAZ and BMIZ score comparisons showed only a handful of statistically significant differences, which, along with the analysis of BMI categories, indicated an association between peri-urban environments and a higher prevalence of overweight and obese individuals (P < 0.01). CONCLUSION: Among the Qom, low HAZ and high WAZ scores during the early years of development allow for the attainment of a relatively high adult stature. Their adaptive life-history strategy seems to be to divert energy toward body mass during early development, and catch-up with linear growth at a later stage of development. Am. J. Hum. Biol. 28:895-904, 2016. © 2016Wiley Periodicals, Inc.