Doctoral Dissertation Improvement: Deciduous tooth emergence, nutritional status, and weaning and feeding decisions in the Brazilian Amazon

这项研究调查了产前和出生后营养与牙萌出的关系，以及发育中的牙列在母亲断奶和喂养决策中的作用。断奶年龄是一个关键的生活史特征，因为母乳喂养和两次生育间隔之间的关系已被公认，并最终决定了母亲一生的生殖成功。在非人类灵长类动物和人类身上，都发现了断奶年龄、母体状况以及婴儿营养和生长之间的联系。此外，人类母亲在做出断奶和喂养决定时，会将婴儿的生长和发育状况作为线索。这项研究由来自俄亥俄州立大学的博士生Jennifer Spence在Guatelli-Steinberg博士的指导下，解决了一个相对未知但意义重大的问题：发育中的牙列如何参与这些关系。这项研究利用人体测量和人种学方法，1)使用可靠的孕期测量技术来准确评估产前母亲的营养状况和出生后婴儿营养状况以及乳牙出现的时间之间的关系；2)确定乳牙出现的时间与断奶过程开始的年龄相关的程度；3)调查乳牙的存在如何影响母亲的断奶和喂养决定。据推测，母亲和婴儿的营养都与乳牙出现的时间有关，而乳牙的出现反过来又被预测会影响断奶和喂养决定。该项目以巴西亚马逊东部的Ribeirinho人口为背景，该地区的特点是营养压力大，断奶和喂食做法多种多样。这项研究是STEM计划的一部分，该计划旨在让服务不足的公立学校的学生熟悉社会科学，特别是人类学。该项目通过吸收当地妇女参与数据收集，并通过大学研讨会促进与巴西非学术界人士的合作。计划在当地社区创建和传播非技术材料，以鼓励良好的营养和牙齿健康。

This research investigates how prenatal and postnatal nutrition relate to dental eruption and, in turn, the role of the developing dentition in mothers' weaning and feeding decisions. Weaning age is a critical life history characteristic because of the recognized relationship between breastfeeding and inter-birth intervals, and, ultimately, mothers' lifetime reproductive success. Links among weaning age, maternal condition, and infant nutrition and growth have been found in both non-human primates and humans. In addition, human mothers use infants' growth and developmental status as a cue when making weaning and feeding decisions. This research, by doctoral student Jennifer Spence (Ohio State University), under the guidance of Dr. Guatelli-Steinberg, addresses a relatively unexplored yet significant question: how the developing dentition is involved in these relationships.Using anthropometric assessment and ethnographic methods, this research 1) employs a reliable technique of gauging gestation duration to accurately evaluate the association between prenatal maternal nutritional status and postnatal infant nutritional status, and the timing of deciduous (primary) tooth emergence; 2) determines the extent to which the timing of deciduous tooth emergence is related to the age at which the weaning process begins; and 3) investigates how the presence of deciduous teeth affects mothers' weaning and feeding decisions. It is hypothesized that both maternal and infant nutrition are associated with the timing of deciduous tooth emergence, which is in turn predicted to influence weaning and feeding decisions. This project is set among Ribeirinho populations in the eastern Brazilian Amazon, an area characterized by nutritional stress and with variation in weaning and feeding practices.This research is part of a STEM initiative familiarizing underserved public-school students with the social sciences, particularly anthropology. The project promotes collaboration with Brazilian non-academics through inclusion of local women in data collection and academics through a university seminar. A campaign is planned to create and disseminate nontechnical material in local communities to encourage good nutrition and dental health.