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.
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.
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.
Masterson, Erin Elizabeth, U. of Washington, Seattle, WA - To aid research on 'Putting Teeth into the Developmental Origins Hypothesis: Early Childhood Ecology, Enamel Defects and Adolescent Growth,' supervised by Dr. Daniel Eisenberg
Preliminary abstract: Like a window into the past, adult teeth may reflect early childhood ecology. Dental enamel on the permanent maxillary incisors calcifies incrementally during early childhood (0-5 years of age), is highly-sensitive to biological stress, and doesn't repair over the life course. Developmental defects in the enamel (DDE) are caused by metabolic disruption during development, including micronutrient deficiency, gastrointestinal disturbance, and bacterial and viral infections. According to developmental origins of health and disease (DOHaD) research findings and evolutionary theory, these factors may also influence chronic disease risk later in life. Bioarcheological findings have indicated an association exists between DDEs in the permanent dentition and increased morbidity and early mortality among skeletal remains, suggesting that dental enamel may be a retrospective marker of early childhood ecology. However, the association between DDEs and long-term health consequences has never been tested in a contemporary population. The purpose of the proposed project is to assess whether DDEs -- developed during the first five years of life -- is a marker of early childhood ecology and predictor of adolescent growth in a contemporary population. Based on evolutionary theory, we hypothesize that enamel defects mark a physiologically-stressful early childhood that predicts unhealthy growth in adolescence. We expect our study to provide the scientific community more confidence in interpretations of DDEs, and to introduce a new measure of early childhood ecology that may enable widespread study of the DOHaD and improve the sensitivity of these studies.
Rosinger, Asher Yoel, U. of Georgia, Athens, GA - To aid research on 'Hydration Strategies, Nutrition, and Health During a Lifestyle Transition in the Bolivian Amazon,' supervised by Dr. Susan Tanner
ASHER Y. ROSINGER, then a student at University of Georgia, Athens, Georgia, received a grant in April 2013 to aid research on 'Hydration Strategies, Nutrition, and Health during a Lifestyle Transition in the Bolivian Amazon,' supervised by Dr. Susan Tanner. Currently, many Amazonian populations are undergoing a period of rapid change in lifestyle through increased market participation and dietary changes, yet the search for clean water remains a critical problem facing many of these populations. The social sciences emphasize that when populations undergo lifestyle transitions, health, disease patterns, and body composition are affected. Lifestyle transitions may create a mismatch between hydration strategies and the nutritional landscape. This research found that Tsimane' have flexible hydration strategies that rely on their environment for water. Increased water intake from foods was associated with a decreased risk of diarrheal illness among adults, which may represent a nutritional adaptation to an environment with limited access to clean water. Tsimane' who lived in a market integrated community were significantly more dehydrated than Tsimane' living in a traditional community. These findings contribute to human biology theory by suggesting that lifestyle transitions may create conditions that increase vulnerability to dehydration among rural populations. Additionally, lactating women were significantly more dehydrated than non-lactating women controlling for environmental and lifestyle factors. This work illustrates the nutritional challenges lactating women face in stressful physical environments and raises evolutionary questions dealing with maternal buffering during chronic dehydration.
Rosinger, Ascher. 2015. Heat and Hydration Status: Predictors of Repeated Measures of Urine Specific Gravity Among Tsimane' Adults in the Bolivian Amazon. American Journal of Physical Anthropology 158(4):696-707
Rosinger, Asher. 2014. Water from Fruit or the River? Examining Hydration Strategies and Gastrointestinal Illness among Tsimane' Adults in the Bolivan Amazon. Public Health Nutrition. (Published Online, DOI 10.1017/s1368980014002158)
Rosinger, Asher. 2014. Dehydration among Lactating Mothers in the Amazon: A Neglected Problem. American Journal of Human Biology. (Published Online.DOI 10.1002/ajhb.22672)