Hazel, Dr. Mary-Ashley, Stanford U., Stanford, CA - To aid research on 'Ecology, Mobility, and Sexually Transmitted Virus Burden in a Pastoralist Population'
Preliminary abstract: Migration and other forms of human mobility contribute to the global transmission dynamics of infectious diseases. The act of being mobile--of spending significant amounts of time in different locations and environments--influences the patterns of a person's social contacts. Although some pandemic disease spread is driven by mobility that spans vast distances and requires only brief and or even indirect contact (e.g. influenza spreading along airline routes), transmission of diseases that require intense and frequent contact, such as sexually transmitted diseases (STDs), usually occurs in the context of repetitive and local mobility. This issue is particularly important for rural populations with historically high rates of STDs that, due to recent changes in local mobility that increase contact with urban and novel populations, are at risk for introduction of HIV. One such high-risk context is Kaokoveld, Namibia, where traditional nomadic mobility (restricted mainly to rural areas) is merging with increased travel to growing urban areas and incoming mobility from adjacent regions with high HIV prevalence. This research will identify the major mobility patterns in Kaokoveld and how these mobility patterns shape structural determinants of risk in sexual contact networks for herpes simplex virus type 2. The outcomes of this study offer important insights into the underlying structural outcomes of diverse mobility in a pastoralist society and how social systems associated with a mobile lifestyle can drive epidemic spread.
Martin, Dr. Melanie, Yale U., New Haven, CT - To aid engaged activities on 'Targeting Early Life Health Risks Among the Tsimane Through Mixed Educational Outreach Modes,' 2016, Bolivia
Preliminary abstract: This project uses mixed modes of outreach to inform Tsimane families, affiliated government agencies, and local health care providers about specific early life health risks in this community. The Tsimane are a subsistence-scale population residing in the Bolivian Amazon. My dissertation research on variation in Tsimane infant feeding practices uncovered several areas of risk that may contribute to early life nutritional and infectious morbidity. Of primary concern, 28% of children were weaned before two years of age and only 44% achieved adequate dietary diversity. I also documented numerous instances of inappropriate antibiotic usage, and incomplete coverage of government-subsidized prenatal care and immunizations, particularly in more rural villages. This project will promote community awareness of these health risks through local radio programming and village meetings. These educational sessions will highlight current infant feeding recommendations, how to improve dietary diversity through locally available foods, and how to minimize risk of antimicrobial resistance through safe antibiotic usage. Formal reports documenting nutritional risks, antibiotic usage, and insufficient prenatal and immunization coverage will also be delivered to affiliated government and health care organizations. These reports may assist these agencies in better meeting the needs of the Tsimane community.
Quinn, Dr. Elizabeth Anne, Washington U., St. Louis, MO - To aid research on 'Milk with Altitude: Investigations Into Milk Composition and Physiology Among Tibetans'
DR. ELIZABETH A. QUINN, Washington University, St. Louis, Missouri, received funding in April 2013 to aid research on 'Milk with Altitude: Investigations into Milk Composition and Physiology among Tibetans.' This project was designed to specifically investigate the hypotheses that altitude would have an effect on milk composition among high altitude adapted ethnic Tibetans living in Nepal. Milk samples were collected from 130 mothers, with detailed anthropometrics collected on both mothers and infants. As predicted, there was no association between altitude and milk macronutrients or energy, although milk fat was much higher than reported by previous studies. Milk adiponectin did show a dose dependent association with altitude but not maternal body composition, while maternal body fat predicted milk leptin content. Older infants and toddlers in Nubri had significantly lower weight for age z-scores compared to toddlers in Kathmandu (-1.85 vs. -0.36). There were no associations between milk leptin or adiponectin and infant weight for age z-score in Nubri, but both leptin and adiponectin were inversely associated with weight for age z-score in Kathmandu. It appears that the ecological pressures of altitude (hypoxia, marginal nutrition, thermal stress, radiation stress) may have significantly stronger influences on infant weight among high altitude living populations than hormonal signals in milk. In Kathmandu, with many of these external stressors removed, the associations between these hormones and weight for age are present.
Bekelman, Traci Allison, U. of Colorado, Boulder, CO - To aid research on 'Using the Protein Leverage Hypothesis to Understand Socioeconomic Variation in Diet and Body Size,' supervised by Dr. Darna Dufour
TRACI A. BEKELMAN, while a graduate student at the University of Colorado, Boulder, Colorado, was awarded a grant in October 2013 to aid research on 'Using the Protein Leverage Hypothesis to Understand Socioeconomic Variation in Diet and Body Size,' supervised by Dr. Darna Dufour. Guided by the Protein Leverage Hypothesis the grantee examined an explanation for the inverse relationship between socioeconomic status (SES) and obesity: limited access to dietary protein among low-SES women leads to consumption of a lower proportion of protein in the diet, which in turn drives higher energy intake and hence obesity. The project examined the prevalence of obesity, diet, the perceived cost and desirability of different sources of protein and shopping habits in 140 women of low-, middle- and high-SES. As expected, high-SES women had the lowest obesity levels. Protein intake (as a proportion of energy intake) was positively associated with SES, and inversely associated with energy intake. Also as expected, protein intake (in grams) did not vary by SES. These finding are consistent with the Protein Leverage Hypothesis. Contrary to expectations, there was not an inverse relationship between SES and energy intake nor was there a difference in the frequency of desirable protein consumption across SES groups. These findings are inconsistent with the Protein Leverage Hypothesis. In conclusion, obesity is inversely associated with SES in Costa Rican women and protein intake may play a role in this relationship.
Fried, Ruby L., Northwestern U., Evanston, IL - To aid research on 'Intergenerational Impacts of Culture Change: Traditional Food and the Metabolic Functioning of Alaska Native Peoples,' supervised by Dr. Christopher Kawaza
Preliminary abstract: Anthropological studies conducted from Samoa to Siberia have demonstrated consequences of cultural change on human biological variation. Findings point to market integration, 'Westernization,' 'acculturation,' and other social transitions as determinants of changes in diet and lifestyle that lead to increased obesity and metabolic dysregulation in affected populations. While the majority of this research has focused on the direct impacts of such shifts on adult biology, recent work is focusing attention on early life critical periods when experiences can lead to durable biological changes that alter developmental biology and long-term health. As a recent manifestation of this idea, rising rates of maternal obesity, gestational weight gain (GWG), and high blood glucose and triglycerides may be creating an evolutionarily novel, gestational milieu that promotes faster fetal growth, higher birth weights, adiposity, and metabolic dysregulation in offspring. This emerging evidence supports a new hypothesis: the impacts of culture change on human biology do not end with the individual who directly experiences it, but may also be transmitted, via an altered in utero environment, to the next generation. The proposed study aims to test this model of an intergenerational impact of culture change among Alaska Native mother-infant dyads by comparing dietary intake (traditional vs. Western foods) with maternal obesity, GWG, pregnancy metabolism and fetal/infancy growth and adiposity in offspring. Recent and still ongoing cultural and dietary transitions among Alaska Native groups provide a valuable opportunity to evaluate maternal metabolism as a pathway linking rapid culture change with altered growth, body composition and health outcomes in offspring.
Hodges-Simeon, Carolyn Randolph, U. of California, Santa Barbara, CA - To aid research on 'Life History Trade-offs Affecting the Development of Human Sexual Dimorphism,' supervised by Dr. Steven J. Gaulin
CAROLYN R. HODGES-SIMEON, then a student at University of California, Santa Barbara, California, was awarded a grant in October 2010 to aid research on 'Life History Trade-Offs Affecting the Development of Human Sexual Dimorphism,' supervised by Dr. Steven J. Gaulin. The human vocal voice is sexually dimorphic in two primary ways: males have lower 'fundamental frequency' (F0, the perceptual correlate of which is 'pitch') and more closely spaced 'formant position' (Pf; also termed 'resonance'). These characteristics exhibit a pronounced and abrupt change during adolescence, marking the advancement of puberty. Research and data gathering target the developmental associations between dimorphic vocal characteristics (F0 and Pf), testosterone, immune functioning (secretory IgA and CRP), and energetic status (BMI and height) in adolescent boys in a non-industrialized population: the Tsimane' of lowland Bolivia. In doing so, this project uses the ontogeny of male vocal characteristics as a model system for examining two major theories in human evolutionary biology: 1) Life history theory (by examining trade-offs between reproductive and somatic investment); and 2) Immunocompetence handicap theory of sexual selection (by investigating whether sexually dimorphic signals are honest indicators of immunocompetence). Results indicate that males in better condition -- with better energetic and immune investment -- have higher testosterone levels, which are associated with lower voices. This research presents the first evidence that male vocal features are linked with condition, and that this association is mediated by testosterone.
Martin, Melanie Ann, U. of California, Santa Barbara, CA - To aid research on 'Maternal Factors Influencing Variation in Infant Feeding Practices in a Natural Fertility Population,' supervised by Dr. Michael Gurven
MELANIE A. MARTIN, then a student at University of California, Santa Barbara, California, was awarded funding in April 2012 to aid research on 'Maternal Factors Influencing Variation in Infant Feeding Practices in a Natural Fertility Population,' supervised by Dr. Michael Gurven. Exclusive breastfeeding for six months and continued breastfeeding for two years or longer promote optimal infant health and growth. Globally, however, many mothers introduce complementary foods and wean earlier than recommended. This study examined factors associated with variation in infant feeding practices in an indigenous population, the Tsimane of Bolivia. During 2012-2013, interviews and anthropometric measurements were collected from 147 Tsimane mothers and infants aged 0-36 months, with 47 mother-infant pairs visited repeatedly over eight months. Half of Tsimane infants were introduced to complementary foods by four months of age, although 75 percent were still breastfed at two years. On average, male infants were exclusively breastfed longer and weaned later than females. No other maternal, infant, or household factors measured influenced the duration of exclusive breastfeeding duration. Age at weaning, however, was increased by the number of family members over the age of 10, and decreased by a mother's subsequent pregnancy and total number of living offspring. Poor growth was evident in only two percent of infants aged 0-6 months, but increased markedly after twelve months. Earlier weaning and/or the quantity or quality of complementary foods may more significantly impact Tsimane infant growth and health outcomes than does early complementary feeding.
Robins, Tara C., U. of Oregon, Eugene, OR - To aid research on 'Social Change, Parasite Exposure, and Autoimmunity among Shuar Forager- Horticulturalists of Amazonia: An Evolutionary Medicine Approach,' supervised by Dr. J. Josh Snodgrass
TARA C. ROBINS, then a graduate student at University of Oregon, Eugene, Oregon, was awarded funding in April 2012 to aid research on 'Social Change, Parasite Exposure, and Autoimmunity among Shuar Forager-Horticulturalists of Amazonia: An Evolutionary Medicine Approach,' supervised by Dr. J. Josh Snodgrass. The Hygiene Hypothesis and the Disappearing Microbiota Hypothesis posit that decreases in parasite and bacterial exposure in developed nations are responsible for immune dysregulation associated with the development of allergies and autoimmune disorders. These hypotheses explore the co-evolutionary relationship between humans and pathogens that led to the development of the human immune system. While these hypotheses have been tested in clinical and laboratory settings in developed nations, very few studies have tried to capture these relationships among populations undergoing the transition from traditional to more market-based lifestyles. This study tests these hypotheses among the Shuar forager-horticulturalists of Amazonian Ecuador who are undergoing rapid (though varied) social and economic changes associated with increased market participation. Using stool samples to assess parasite and microbial diversity, blood spot markers of immune dysregulation, and interviews to evaluate level of market integration, this study documents a decrease in parasite exposure with market participation/increased hygiene and a related increase in inflammatory marker C-reactive protein. Findings suggest that parasites, specifically intestinal parasitic worms may provide immune stimulation necessary to decrease inflammation, suggesting that the altered intestinal microflora in developed nations may be, in part, responsible for the development of allergy and autoimmunity.
Betti, Lia, U. of Kent, Canterbury, United Kingdom - To aid research on 'Out of Africa and What Happened Next: Exploring the Origins of Human Pelvic Shape Variability,' supervised by Dr. Noreen von Cramon-Taubadel
LIA BETTI, then a student at University of Kent, Canterbury, United Kingdom, received a grant in April 2011 to aid research on 'Out of Africa and What Happened Next: Exploring the Origins of Human Pelvic Shape Variability,' supervised by Dr. Noreen von Cramon-Taubadel. The origin of human morphological diversification is one of the most intriguing questions in human evolution. Starting from a single origin of the species, how did the current pattern of morphological diversity between populations develop? Recent studies on cranial shape variation disclosed a very strong signature of the Out Of Africa expansion of our species on the global pattern of morphological diversity. This study builds upon this knowledge and explores the foundation of pelvic shape variation. Being involved in locomotion, childbirth, and potentially subject to climatic factors, the pelvis is a key anatomical region in studies of human biology and evolution. 3D pelvic morphometric data were collected from 27 globally distributed modern human populations. An explicit population genetic approach was used to explore the effect of different evolutionary factors on the global pattern of variation, revealing a strong signature of ancient demographic history on pelvic shape variation, with climatic adaptation and obstetrical constraints playing a secondary role.
Betti, Lia. 2014. Sexual Dimorphism in the Size and Shape of the Os Coxae and the Effects of Microevolutionary Processes. American Journal of Physical Anthropology 153(2):167-177.
Froehle, Andrew William, U. of California, San Diego, La Jolla, CA - To aid research on 'Physical Activity and Basal Metabolic Rate in Postmenopausal Women,' supervised by Dr. Margaret J. Schoeninger
ANDREW WILLIAM FROEHLE, then a student at University of California - San Diego, La Jolla, California, received a grant in October 2007 to aid research on 'Physical Activity and Basal Metabolic Rate in postmenopausal Women,' supervised by Dr. Margaret J. Schoeninger. The project investigated the relationship between age, exercise and basal metabolic rate (BMR) in postmenopausal women, comparing two subgroups: 'active' (>5 hours exercise/week) and 'training' (sedentary at baseline, completed four-month exercise program). Across the entire sample, BMR correlated significantly with fat free mass (FFM; P<0.001, R=0.862) and physical activity level (PAL; P=0.004, R=0.542), but not with age or maximal aerobic capacity (VO2MAX). At baseline, subgroups differed significantly for BMR (P=0.005) and VO2MAX (P=0.006); active women were also 4.9 kg heavier (FFM) than sedentary women (not significant: P=0.077). Within the active group, no variables changed significantly over the study period. Meanwhile, the training sample exhibited significant increases over baseline in VO2MAX (P=0.015) and BMR (P=0.002), despite no change in FFM (P=0.952). Controlling for effects of the covariate FFM, subgroups differed significantly for BMR at baseline (P=0.007), but not at the end of the study (P=0.089). Results suggest that in this population, both short- and long-term exercise associate similarly with elevations in BMR above sedentary levels. Contrary to some research, this may not be tied to increased FFM. These results have implications for preventative exercise prescription against age-related health risks, and will help refine models of metabolic physiology in active postmenopausal women.
Froehle, Andrew W., S.R. Hopkins, L Natarajan, and M.J. Schoeninger. 2013. Moderate to High Levels of Exercise are Associated with Higher Resting Energy Expenditure in Community-dwelling Postmenopausal Women. Applied Physiology, Nutrition, and Metabolism 38(11):1147-1153.