Shirley, Meghan, U. College London, London, UK - To aid research on 'Body Composition and the Brain: Investigating Life History Trade-offs in Living Humans,' supervised by Dr. Jonathan Wells
Preliminary abstract: Energy resources in any given environment are finite. Life history theory examines trade-offs between competing functions such as maintenance and reproduction across an organism's life course. For early humans, the evolution of a metabolically expensive brain was likely associated with reorganized energy investment and/or alterations in life history strategy and behavior. Insight into how the human brain was afforded may be most readily achieved with attention directed to investment 'decisions' at the level of organs and tissues. For example, Aiello and Wheeler's (1995) 'expensive tissue' hypothesis proposed that a reduction in the size of the human gut enabled encephalization. Research has demonstrated tissue trade-offs in a range of animals, yet empirical studies of human investment strategies remain rare. With the collection of MRI and body composition data from healthy adults, this project will investigate trade-offs between the human brain and other 'expensive' tissues of the body, trade-offs between the brain and adipose tissue, and also positive brain-body phenotype associations. Further, the study will examine the effect of early life experience on phenotype. This data will add to knowledge of the variability with which modern humans 'strategically' manage energy investment and lead to more robust inferences concerning hominin life history evolution.
Dufour, Dr. Darna L., U. of Colorado, Boulder, CO - To aid research on 'Work Efficiency in Lactating Women'
DR. DARNA L. DUFOUR, University of Colorado, Boulder, Colorado, was awarded a grant in July 2004 to aid research on 'Work Efficiency in Lactating Women.' Lactation is the most costly phase of reproduction for human females and can increase a women's energy needs by 30 percent. Women can potentially meet this increase in energy needs by increasing their food energy intake, decreasing their physical activity and/or utilizing their body fat stores. This study examined a fourth way women can potentially meet their increased energy needs in lactation, that is by an increase in work (metabolic) efficiency in exercise. A sample of exclusively breastfeeding women was recruited and their work efficiency in exercise measured at peak lactation (3-4 months postpartum) and then again after weaning. Work efficiency in exercise was measured as delta efficiency (the ratio of work accomplished to energy needed to accomplish that work) using a submaximal exercise test on a cycle ergometer. The results demonstrated that delta efficiency is significantly higher at peak lactation than after weaning. Further, delta efficiency at peak lactation was significantly higher than in a control sample of non-pregnant, non-lactating women. These findings suggest that in addition to increased food energy intake, decreased physical activity and the utilization of fat stores, women can compensate for the extra energy demands of lactation through increases in work efficiency.
Hoke, Morgan Kathleen, Northwestern U., Evanston, IL - To aid research on 'Changing Economic Activity, Infant Feeding, and Early Growth among the Quechua of Nuñoa, Peru,' supervised by Dr. William Leonard
Preliminary abstract: This biocultural research project examines the changing practices of infant feeding and the emergence of early growth inequalities in Nuñoa, Peru in light of ongoing political and economic changes, specifically the emergence of a new dairy industry and an increasing reliance on wage labor. Infancy is a critical period in which environmental and social inputs can have a significant effect on both health and socioeconomic outcomes later in life. Early nutrition has been shown to be particularly important. Drawing on anthropological and health literature on infant feeding, scholarship on the developmental origins of health and disease, and biocultural anthropology to inform research questions, this study represents a work of 'ethnographic human biology' (Wiley 2004). Previous anthropological research in Nuñoa dating to the 1960's allows findings to be contextualized within the political-economic and biological history of the region. Research methods include both ethnographic and biological approaches such as participant observation, interviews, infant nutritional assessment, anthropometric measurements, and infant focal follows. Original data will be analyzed to compare infant nutrition and growth between contemporary communities participating in different economic activities. Additional comparisons will be made with data collected in previous waves of research to identify dietary changes and highlight key changes in the growth process in the face of fifty years of economic changes.
McCabe, Collin Michael, Harvard U., Cambridge, MA - To aid research on 'Unwelcome Guests: Human-rodent Cohabitation and its Implications for Disease Transfer in Sedentary Agricultural Populations,' supervised by Dr. Richard Wrangham
Preliminary abstract: Rodents have inhabited human settlements since at least the advent of agriculture and sedentary lifestyles. This close contact between humans and rodents has been, and still is, a source of many emerging zoonotic diseases. However, little is known about what drives species to commensal lifestyles, and even less is known about whether these commensal species are more likely than non-commensal rodents to carry novel zoonotic pathogens. The aim of this study is to investigate certain behavioral and ecological factors that favor commensal living and pathogen burdens in East African rodents. I hypothesize that more exploratory rodent species with broader diets will more likely be commensal, and will likely have higher pathogen burdens. I plan to live-trap rodents in central Kenya from a community of 25 wild species, in both recently settled human agricultural villages and adjacent, undisturbed habitats to determine each species' level of commensality and the features of these wild rodents that favor commensal living. I will also obtain biological samples from these rodents to determine the zoonotic pathogen burdens. By enriching knowledge of rodent disease ecology, this project will provide data to hone or even transform our understanding of selective pressures of zoonotic pathogens on early agriculturalists.
Leidy Sievert, Dr. Lynnette, U. of Massachusetts, Amherst, MA - To aid research on 'Do Women Who Think They Know Really Know? Validating Signals of Ovulation'
DR. LYNNETTE LEIDY SIEVERT, of the University of Massachusetts in Amherst, Massachusetts, received funding in November 2002 to aid research on signals of ovulation in women who believe they know when they ovulate. Sievert tested whether or not women who think they know when they ovulate really do know, by assessing the concordance between perceived signals of ovulation and an elevated level of urinary LH, a biological indicator of ovulation. Participants were ages 18 to 46, had regular menstrual periods, were using no form of hormonal contraception, and believed they knew when they ovulated. Fifty-three women began the study. Signals of ovulation reported at initial interview included cervical discharge (68%), abdominal pain (64%), increased libido (30%), changes in mood or energy (25%), basal body temperature (17%), and other, infrequently reported symptoms (45%). Signal reporting varied in relation to smoking habits, body mass index, and health status. Thirty-six women provided a total of 87 urine specimens for LH testing. Thirty-seven of the specimens tested positive for an LH surge, for a concordance rate of 43%. Using the first tested cycle from the 36 women who provided urine specimens, 13 demonstrated an LH surge, for a concordance rate of 36%. The mean level of accuracy among the 15 women who contributed three to six urine specimens was 49%. It appeared, then, that between one-third and one-half of women who thought they knew when they ovulated were correct.
Abrams, Elizabeth T., U. of Michigan, Ann Arbor, MI - To aid research on 'Variability in Birth Outcome following Malaria during Pregnancy,' supervised by Dr. A. Roberto Frisancho
ELIZABETH T. ABRAMS, while a student at the University of Michigan in Ann Arbor, Michigan, was awarded a grant in September 2001 to aid research on variability in birth outcomes following malaria during pregnancy, under the supervision of Dr. A. Roberto Frisancho. Malaria infections during pregnancy are associated with a number of poor birth outcomes, including intrauterine growth retardation, preterm delivery, and fetal death. Previous researchers had identified malaria-induced immune responses and birth outcomes, but the immune response to malaria could not fully account for the variation in birth outcomes. Abrams focused on a second potential determinant of poor birth outcomes: maternal and fetal iron status. She examined umbilical-cord hemoglobin levels in 33 malaria-infected and 57 uninfected women delivering in Blantyre, Malawi, in relation to maternal hemoglobin levels, malaria status, neonatal inflammation, and birth outcome. Although, as expected, maternal hemoglobin levels were significantly decreased by malaria infection during pregnancy, there was no reduction in cord levels, nor was there any significant relationship between the two. Nevertheless, cord ferritin levels were elevated in the neonates of malaria-infected mothers in relation to increased parasitemia, suggesting fetal immune activation to maternal malaria. Increased cord ferritin was associated with significantly decreased birth weight and gestational length, although maternal and cord hemoglobin levels and malaria status had no effect on birth outcome. The markers of fetal hypoxia that were examined, including erythropoietin, cortisol, and corticotrophin-releasing hormone, were not altered in malaria-infected versus uninfected women. In sum, in this population, cord hemoglobin levels were buffered from the effects of maternal malaria. However, elevated cord ferritin levels suggested fetal immune activation to malaria, which appeared to influence birth outcomes.
Abrams, Elizabeth T., and Julienne N. Rutherford. 2011. Framing Postpartum Hemorrhage as a Consequence of Human Placental Biology: An Evolutionary and Comparative Perspective. American Anthropologist 113(3):417-430.
Abrams, Elizabeth T. and Elizabeth M. Miller. 2011. The Roles of the Immune System in Women's Reproduction: Evolutionary Constraints and Life History Trade-Offs. Yearbook of Physical Anthropology 54:134-154.
Abrams, Elizabeth T., et al 2005. Malaria during Pregnancy and Fetal Haematological Status in Blantyre, Malawi. Malaria Journal 4(39):1-8.
Eaves-Johnson, K. Lindsay, U. of Iowa, Iowa City, IA - To aid research on 'A Spirometric and Geo-Morphometric Baseline for the Study of Thoracic Patterning in Fossil Homo,' supervised by Dr. Robert Gary Franciscus
Preliminary abstract: Due to a general, though undocumented, sense that little diagnostic information can be gleaned from them, ribs and overall thoracic morphology have been comparatively understudied relative to other anatomical regions in human paleontology. This study tests the influence of skeletal thoracic shape on respiratory variables (e.g., total lung capacity, functional residual capacity, etc.) using computed tomography (CT), to expand our understanding of modern and Neandertal thoracic patterning. The mixed-sex CT sample consists of 50 respiratorily normal subjects and 10 subjects with chronic obstructive pulmonary disorder (COPD), all between the ages of 20 and 60 (IRB: 199708651). This homogenous, living CT sample is compared with a regionally heterogeneous, mixed-sex skeletal sample from the extremes of human variation (n=134), as well as the Neandertal specimens Kebara 2, Tabun C1, Shanidar 3, and La Chapelle. Preliminary results suggest that, while gross spirometric measures, such as total lung capacity agree well with the predicted model, further study is needed to delineate the skeletal parameters most amenable to comparison for such variables as functional residual capacity. Additionally, comparisons of the Levantine Neandertals with the modern sample fail to demonstrate any significant temporal excursion from the range of modern variability with respect to these parameters.
Houck, Kelly Marie, U. of North Carolina, Chapel Hill, NC - To aid research on 'A New Dual Burden Life History Theory Application Exploring Childhood Gut Immune Function and Overnutrition,' supervised by Dr. Amanda Thompson
Preliminary abstract: The emerging field of gut microbiota contributes to anthropological concerns by providing a new pathway to examine the effects of pathogenic, nutritional and social environments on human physiology and consequently human variation. The bacterial components and metabolites of gut microbial communities are vital factors in the regulation of the immune system and in providing energy processing. This project develops and tests a new application of childhood life history theory tradeoffs in maintenance and growth for the dual burden environment through a focus on gut immune function. This framework incorporates the increased energetic cost of both dietary- and pathogenic-induced immune activation and models the influence of gut immune function on diverting resources from linear bone growth towards adiposity. Children will be sampled from the three populated islands of the Galapagos and detailed survey data will be collected on their diet, symptom history, sociodemographics and household sanitation, along with anthropometric assessments, household water quality tests, and blood spot and fecal analyses of gut immune function biomarkers. Data will be used to test for the relationship between overnutrition and infection on gut immune activation and to determine the cost of pathogenic and dietary immune activation on tradeoffs in adiposity and linear growth.
Melby, Dr. Melissa Kathleen, National Institute of Health and Nutrition, Tokyo, Japan - To aid research on 'Developmental Origins of Metabolic Syndrome: Study Utilizing the Japanese Maternal and Child Health Handbook'
DR. MELISSA K. MELBY, National Institute of Health and Nutrition, Tokyo, Japan was awarded a grant in October 2008 to aid research on 'Developmental Origins of Metabolic Syndrome: Study Utilizing the Japanese Maternal and Child Health Handbook.' The 'Developmental Origins of Health and Disease' hypothesis posits that in utero stress such as nutritional restriction resulting in low birth weight (LBW) increases later life risk of metabolic-syndrome related disease. Understanding risk factors for LBW thus has implications for later life health. Among singleton full-term births (N~437) in Japan, females were three times more likely to be born at LBW than males. For males, gestational length was the biggest predictor of LBW, but gestational length was not a significant predictor of female LBW. Instead maternal weight at first prenatal exam, and total gestational weight gain after that exam, were most predictive. For girls only, primiparity and maternal history of LBW babies also increased risk, while maternal height decreased risk. If given adequate time in the womb, male babies appear largely immune to early pre-natal or pre-conception maternal condition and low maternal gestational weight gain. Female babies appear to be very sensitive to maternal condition, particularly early/initial weight and weight gain, as well as reproductive history. BMI at age 6-7 appears independent of birth weight and maternal gestational weight gain for boys, while girls' age 6-7 BMI appears more dependent on reproductive history, gestational weight gain, and resulting birth weight.
Middleton, Emily Ruth, New York U., New York, NY - To aid research on 'Ecogeographical Influences on Trunk Modularity in Recent Humans: Colonization and Morphological Integration,' supervised by Dr. Susan C. Anton
EMILY R. MIDDLETON, then a student at New York University, New York, New York, received funding in April 2013 to aid research on 'Ecogeographical Influences on Trunk Modularity in Recent Humans: Colonization and Morphological Integration,' supervised by Dr. Susan C. Antón. The ribcage, vertebral column, and pelvis have undergone numerous shape changes throughout hominin evolutionary history, responding to a wide suite of locomotor, obstetric, and climatic selective pressures. The degree to which morphological elements are integrated, or covary, has important implications for the way body form evolves, and this project seeks to understand the pattern of morphological integratio