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
Preliminary abstract: Exposure to parasites is hypothesized to decrease the risk of autoimmune disorders by regulating immune activity. Termed the Hygiene Hypothesis, this suggests that exposure to certain microbes helps organize immune function and prevents immune response to harmless stimuli. The Disappearing Microbiota Hypothesis takes this a step further, suggesting that recent changes in human ecology are altering the composition of our intestinal bacteria, thereby reducing vital immune programming. Existing research suffers from two weaknesses. First, almost all studies of these relationships have been conducted in Western clinical settings among populations with low infection rates, limiting our knowledge of the contextual factors that affect immune regulation. Second, there is very little anthropological research that explores the co-evolutionary relationship between humans and microbes. The proposed study uses evolutionary medicine and biocultural frameworks to further test these hypotheses among the indigenous Shuar forager-horticulturalists of Ecuador, who are currently experiencing rapid social change resulting in pronounced intra-population variation in parasite exposure. Avoidance behaviors, intestinal parasite composition, and autoimmune disease prevalence will be examined among Shuar at different levels of market integration. This project is the first population-based study to examine relationships between microbe exposure and autoimmunity among an indigenous population transitioning to a market-based economy.
Gettler, Lee Thomas, Northwestern U., Evanston, IL - To aid research on 'Longitudinal Perspectives on Paternal Socioendocrinology in the Philippines,' supervised by Dr. Christopher Kuzawa
LEE T. GETTLER, then a student at Northwestern University, Evanston, Illinois, was awarded funding in May 2010 to aid research on 'Longitudinal Perspectives on Paternal Socioendocriniology in the Philippines,' supervised by Dr. Christopher Kuzawa. Much prior research has been conducted on the neuroendocrine underpinnings of maternal care, but much less is known about paternal socioendocrinology, particularly among human males. This research is the first to demonstrate that fatherhood causally decreases testosterone in human males. The finding that fathers involved in high levels of childcare have lower testosterone also adds to the growing body of evidence suggesting that suppression of testosterone by fatherhood is potentially mediated through paternal care. Finally, these data represent one of the few evaluations of human paternal prolactin, especially in the context of short-term, father-child interaction. Prolactin is likely an important hormone influencing expression of paternal care behaviors in men, but it has been given substantially less attention in studies of male socioendocrinology, relative to, for example, testosterone. The findings that first-time fathers and those who feel support by their wives show greater declines in prolactin when interacting with their children provide important insights on the plasticity of human male physiology as men move through different life history stages and priorities shift. In total, this research presents multiple lines of evidence that behavior/personality influence biology and vice versa, reflecting the mutually-regulatory, interactive relationship between behavior and biology.
Gettler, Lee T., Sonny S. Agustin, and Christopher W. Kuzawa. 2010. Testosterone, Physical Activity, and Somatic Outcomes Among Filipino Males. American Journal of Physical Anthropology 142(4):590-599.
Gettler, Lee T., Thomas W. McDade, Sonny S. Agustin, and Christopher W. Kuzawa. 2011. Short-Term Changes in Fathers' Hormones during Father-Child Play: Impacts of Paternal Attitudes and Experience. Hormones and Behavior 60(5):599-606.
Gettler, Lee T., Thomas W. McDade, Alan B. Feranil, and Christopher W. Kuzawa. 2011. Longitudinal Evidence that Fatherhood Decreases Testosterone in Human Males. Proceedings of the National Academy of Science, USA 108(39):16194-16199.
Gettler, Lee T., Thomas W. McDade, Alan B. Feranil, and Christopher W. Kuzawa. 2012. Prolactin, Fatherhood, and Reproductive Behavior in Human Males. American Journal of Physical Anthropology 148(3):362-370.
Gettler, Lee T., James J. McKenna, Thomas W. McDade, et al. 2012. Does Cosleeping Contribute to Lower Testosterone Levels in Fathers? Evidence from the Philippines. PLOS One 7(9):1-11,
Madimenos, Felicia Chrisafo, U. of Oregon, Eugene, OR - To aid research on 'Lifestyle and Reproductive Effects on Bone Mineral Density in an Ecuadorian Forager-Horticulturalist Population,' supervised by Dr. James Josh Snodgrass
FELICIA C. MADIMENOS, then a student at University of Oregon, Eugene, Oregon, received funding in April 2009 to aid research on 'Lifestyle and Reproductive Effects on Bone Mineral Density in an Ecuadorian Forager-Horticulturalist Population,' supervised by Dr. James Josh Snodgrass. Bone mineral density (BMD) is the primary diagnostic parameter of bone health and a predictor of future fracture risk. The mechanisms and life history trade-offs affecting bone integrity evolved under conditions quite different from those experienced by industrialized populations, yet minimal data on bone health are available from non-Western, subsistence populations. Such data are particularly important because people in subsistence-based populations have dietary, reproductive, and activity patterns more like those of our evolutionary past. Using calcaneal ultrasound, this study presents the first available data on bone health among the Shuar, an indigenous Ecuadorian Amazonian population, and non-Shuar colonists (colonos) from the same area. Results show that among colonos, BMD is positively correlated with the consumption of fish and greens but not other food categories. Among Shuar, no such relationship is found but BMD is negatively associated with greater ownership of market goods. Further analyses considering the effects of reproductive history show that in both populations multiparity provides a protective effect on BMD but this protection is lost with increased duration of lactation per child (> 24 months). The most protective effect on bone health is realized when mothers breastfeed multiple children for shorter durations.
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
Preliminary abstract: Currently, many Amazonian populations are undergoing a period of rapid change in lifestyle through increased market exposure and market participation, including wage labor, surplus production, selling, and buying items. The social sciences emphasize that when populations undergo lifestyle transitions (i.e., changes to dietary, economic, and cultural activities), health, disease patterns, and body composition are affected. A common explanation points to changes in energetic inputs and outputs, while higher population density increases susceptibility to infectious diseases. However, hydration strategies, or how people meet their dietary water needs, may serve as dietary adaptations that balance hydration, pathogen exposure, and nutritional status. Furthermore, lifestyle transitions may create a mismatch between hydration strategies and the nutritional landscape. The proposed study will assess the relationships between hydration strategies and hydration, nutritional status, pathogen exposure, and immune activation, and evaluate how market participation is related to water consumption patterns among Tsimane' Amerindians in Lowland Bolivia. This study will expand our understanding of variation and consequences of hydration needs and contribute to literatures on nutritional anthropology, life history theory, and lifestyle transitions. Responses to lifestyle transitions are important to anthropology because they provide insight into both past and future trends of human variation in nutrition and health.
Crews, Dr. Douglas Earl, Ohio State U., Columbus, OH - To aid conference on 'Evolution Theory, Life History, and Human Longevity,' 2009, Ohio State U.
'Evolution Theory, Life History, and Human Longevity'
February 5-7, 2009, Ohio State University, Columbus, Ohio
Organizer: Douglas E. Crews (Ohio State University)
This conference brought together a diverse group of researchers, representing anthropology, medicine and biology, to link their research programs into the broad theme of human life history (LH) evolution. The multi-disciplinary perspective was crucial to examining how LH characteristics link diverse species such as fruit flies and rodents to primate and human
LH evolution. Crosscutting anthropological, biocultural, biomedical, and gerontological interests, this conference focused upon similarities of systems in biology and LH. Papers addressing such issues as reproductive costs, evolutionary pressures, and longevity in fruit flies and humans set the stage for an interdisciplinary exchange of concepts and methodologies. Reports on LH of non-human primates and among fossil hominins explored how modern human life histories and longevities may have developed. Concluding papers examined how modern humans senesce and experience frailty and late-life due to
biocultural forces acting over a 70+-year lifespan. This integrative conference ranged from senescent alterations in fruit flies to the trade-offs encountered by humans as they have evolved.
Gray, Dr. Peter Bard, U. of Nevada, Las Vegas, NV - To aid research on 'Fathers in Jamaica: Longitudinal Changes, Biological and Stepparenting, and Testosterone'
DR. PETER B. GRAY, University of Nevada, Las Vegas, Nevada, was awarded funding in April 2012 to aid research on 'Fathers in Jamaica: Longitudinal Changes, Biological and Stepparenting, and Testosterone.' What are the impacts of fatherhood on Jamaican men? The project addresses this wider question in several ways. Fathers of children aged approximately 18-24 months were asked about their paternal attitudes, relationship dynamics, sexual function, and health, enabling testing for effects of fatherhood on such outcomes as relationship quality and depression. The potential moderating effects of socioeconomic status on these changes are also addressed, since the variable resources available to men may also influence the quality of their partnerships and availability to meet paternal expectations. In a context of variable male parental involvement and many families with mixed parentage, paternal outcomes of biological and stepfathers are compared. Existing cross-cultural studies suggests that biological fathers tend to be more invested in their children, a proposition also tested here. Last, the project tests the hypothesis that biological fathers have lower testosterone levels than stepfathers. Altogether, findings from this study enhance an understanding of the changes fathers of young children undergo; the different experiences of biological and stepfathers; and one of the possible physiological mechanisms differentiating the experiences of biological and stepfathers. Since these areas are of interest and relevance not just in Jamaica, this project contributes to wider discussions of fatherhood.
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.
Rowe, Elizabeth Jane, Temple U., Philadelphia, PA - To aid research on 'The Role of the Progesterone Receptor in the Menstrual Cycle,' supervised by Dr. L. Christie Rockwell
ELIZABETH JANE ROWE, then a student at Temple University, Philadelphia, Pennsylvania, was awarded a grant in May 2008, to aid research on 'The Role of the Progesterone Receptor in the Menstrual Cycle,' supervised by Dr. L. Christie Rockwell. Much of the work in Physical Anthropology related to variation in women's reproductive function has been heavily focused on evolutionary models to explain the responsiveness of ovarian steroid production to ecological conditions. Underlying functionally significant, genetic variation that also likely impacts reproductive phenotypes has seldom been investigated. This project addressed this problem by investigating the impact of a common, functionally significant variant of the progesterone receptor gene on uterine function and the menstrual cycle among women in the Philadelphia area. Women who carried the variant differed from women who did not with regard to menstrual cycle characteristics. Furthermore, the variant was found to modify the impact of life history and ecological variables on both uterine function and the menstrual cycle. These findings indicate that genetic variation should be considered in future models for women's reproduction in Physical Anthropology. Additionally, uterine function and menstrual cycle characteristics did not reflect ovarian hormone levels, but instead were significantly predicted by ecological variables that indicated energetic status. These findings, coupled with results of other work, indicate that the uterus responds directly to environmental cues, and therefore suggest that it plays an active role in the maternal decision to commit resources to gestation.
Crews, Dr. Douglas Earl, Ohio State U., Columbus, OH - To aid research on 'Frailty and Allostatic Load among Aging Japanese'
DR. DOUGLAS EARL CREWS, Ohio State University, Columbus, Ohio, was awarded a grant in May 2008, to aid research on 'Frailty and Allostatic Load among Aging Japanese.' Residents of Sakiyama City were chosen for this study of how allostatic load and frailty are related to health and morbidity among elderly residents of a more traditional and isolated community. The study obtained sufficient data to examine allostatic load and frailty as correlates of morbidity, physiological function, fertility and aging in elderly Japanese samples living more traditional and less traditional life styles within Sakiyama City. Detailing cross-cultural variation in allostatic load and frailty enhances our interpretations of how biological aspects of senescence may structure health at the latest ages of human life. Determining allostatic load and frailty in an age-stratified sample of Japanese elders also aids in resolving the female-male health paradox, wherein elderly women frequently report poorer health than same-aged men, while same-age men suffer higher mortality. These data allow us to determine whether fertility significantly burdens women's health outcomes. By working directly with physicians engaged in providing health care to participants, the benefits of ongoing research on biomarkers of stress, function, and somatic abilities to clinical interventions and health maintenance setting is directly tested.