Tradeoffs in childhood energy allocation and the impact of market integration on ontogeny and health

社会、行为和经济科学理事会提供博士后研究金，为最近的博士毕业生提供获得额外培训的机会，在知名科学家的赞助下获得研究经验，并在本科和研究生培训之外拓宽他们的科学视野。博士后奖学金还旨在帮助新的科学家指导他们的研究工作，跨越传统的学科领域，并利用独特的研究资源，地点和设施，包括在国外的地点。这个博士后奖学金支持在人类学，进化生物学和公共卫生领域的交叉点的年轻学者的跨学科培训和研究，以探索儿童能量分配的权衡和市场经济对健康的影响。儿童管理能量资源和应对不断变化的环境条件的方式仍不清楚。所有生命的基本任务--维持、生长、繁殖、免疫功能和身体活动--都需要能量（即，卡路里），并且通常认为生物体以最大化适应性的方式将资源分配给这些竞争需求。这种能量分配和权衡的框架已被广泛应用于理解人类生物学变异。然而，很少有研究在儿童中测试其有效性。为了解决这一限制，本项目整合了多个学科的方法和观点，通过分配权衡的透镜来调查儿童能源使用的性质。它还应用这种新的综合来探讨一个重要的真实的世界问题：市场一体化对儿童个体发育和健康的影响。利用亚马逊厄瓜多尔的Shuar之间的一个新的研究设计，我们追求两个主要的研究问题。(1)能量分配模型预测的儿童生长、体力活动和免疫功能之间是否存在能量权衡？(2)市场一体化是否与促进超重/肥胖和心血管健康不良的儿童能量分配变化有关？研究结果将对几个科学领域产生重大影响。这些资金还将用于制定有效的卫生政策和向厄瓜多尔和美国提供救济援助。促进培训机会，这项工作涉及许多土著教育健康论坛和重要的研究经验，少数民族美国本科生。重要的是，该项目还提供科学和专业培训，并为研究员，准备他的职业生涯作为一个独立的研究人员在最前沿的综合生物科学。尽管以前的研究成功调查人类生物变异使用进化生命史理论，重要的差距，我们的理解人类表型可塑性和能源使用仍然存在。很少有研究调查儿童之间的能量权衡，或探讨身体活动在儿童能量动力学中的潜在重要作用。没有以前的生活史研究纳入准确的测量总能量消耗（TEE）和静息能量消耗（REE）的研究设计，防止评估生活史权衡模型的几个关键假设。直接解决这些限制，本项目的目的是测试的有效性充满活力的权衡模型，并应用此框架来调查的作用，权衡Shuar市场整合，个体发育和儿童健康之间的关系。我们采用了一种新颖的为期两周的纵向研究设计，100名Shuar儿童（年龄5-10岁）生活在两个社区，在市场一体化水平，生活方式和饮食有很大的不同。儿童TEE的金标准代谢指标（双标记水），REE（间接测热法）和体力活动能量消耗（双标记水和加速度计），以及每周线性增长的稳健措施（流速测定法），免疫活性（指血C反应蛋白、总免疫球蛋白E和总免疫球蛋白G）、心血管健康（指尖血糖和血脂），以及能量摄入和市场整合（观察和采访），将对每位参与者进行评估，支持社区间、个体间和个体内对能量使用和权衡的分析。这项工作有能力解决许多未充分探索的研究领域，包括超重/肥胖和心血管疾病病因学中能量摄入与能量消耗的相对重要性，人类免疫激活的精确能量成本，以及重要的是，生活史权衡模型的整体有效性。

The Directorate of Social, Behavioral and Economic Sciences offers postdoctoral research fellowships to provide opportunities for recent doctoral graduates to obtain additional training, to gain research experience under the sponsorship of established scientists, and to broaden their scientific horizons beyond their undergraduate and graduate training. Postdoctoral fellowships are further designed to assist new scientists to direct their research efforts across traditional disciplinary lines and to avail themselves of unique research resources, sites, and facilities, including at foreign locations. This postdoctoral fellowship award supports the interdisciplinary training and research of a young scholar at the intersection of the fields of anthropology, evolutionary biology, and public health to explore the tradeoffs in childhood energy allocation and the impact of market economy on health. The way in which children manage energetic resources and respond to changing environmental conditions remains unclear. All of life's essential tasks -- maintenance, growth, reproduction, immune function, and physical activity -- require energy (i.e., calories), and it is often assumed that organisms allocate resources to these competing demands in a manner that maximizes fitness. This framework of energy allocation and tradeoffs has been widely applied to understand human biological variation. However, few studies have tested its validity among children. Addressing this limitation, the present project integrates methods and perspectives from multiple disciplines to investigate the nature of childhood energy use through the lens of allocation tradeoffs. It also applies this new synthesis to explore an important real world problem: the impact of market integration on child ontogeny and health. Utilizing a novel study design among the Shuar of Amazonian Ecuador, we pursue two primary research questions. (1) Do energetic tradeoffs exist between childhood growth, physical activity, and immune function as predicted by the energy allocation model? (2) Is market integration associated with changes in childhood energy allocation that promote overweight/obesity and poor cardiovascular health? Results will have significant implications for several scientific areas. They will also be used to develop effective health policy and relief aid in Ecuador and the United States. Promoting opportunity for training, this work involves numerous indigenous educational health forums and significant research experience for minority American undergraduates. Importantly, the project also provides scientific and professional training and for the Fellow, preparing him for a career as an independent researcher at the forefront of integrative biological science.Despite the success of previous studies investigating human biological variation using evolutionary life history theory, important gaps in our understanding of human phenotypic plasticity and energy use remain. Few studies have investigated energetic tradeoffs among children or have explored the potentially important role of physical activity in child energy dynamics. No previous life history research has incorporated accurate measurements of total energy expenditure (TEE) and resting energy expenditure (REE) into study designs, preventing assessment of several critical assumptions of the life history tradeoff model. Directly addressing these limitations, the present project aims to test the validity of the energetic tradeoff model and apply this framework to investigate the role of tradeoffs in relationships between Shuar market integration, ontogeny, and child health. We employ a novel two-week longitudinal study design among 100 Shuar children (age 5-10 years) living in two communities differing greatly in level of market integration, lifestyle, and diet. Gold standard metabolic measures of child TEE (doubly labeled water), REE (indirect calorimetry), and physical activity energy expenditure (doubly labeled water and accelerometry), as well as robust measures of weekly linear growth (knemometry), immune activity (finger-prick blood C-reactive protein, total Immunoglobulin E, and total Immunoglobulin G), cardiovascular health (finger-prick blood glucose and lipids), and energy intake and market integration (observation and interviews) will be made from each participant, supporting between-community, between-individual, and within-individual analyses of energy use and tradeoffs. This work has the ability to address many underexplored areas of research, including the relative importance of energy intake versus energy expenditure in the etiology of overweight/obesity and cardiovascular disease, the precise energetic costs of human immune activation, and, importantly, the overall validity of the life history tradeoff model.