Doctoral Dissertation Research: Socioeconomic and Environmental Determinants of Birth Defects in North Carolina

虽然出生缺陷的一些原因是已知的（即，染色体损伤），研究人员认为，不明的环境因素也可能有助于他们的发展。 在北卡罗来纳州，出生缺陷率表现出显着的空间变化。 传统的环境健康研究假设，这些模式是由于母亲的环境因素，如接近危险废物场，导致出生缺陷的发生。 然而，也有证据表明，出生缺陷与行为和经济风险因素有关，如吸烟和产前护理不良。 因此，出生缺陷的空间模式可能是由于具有相似背景和风险因素的个人生活在同一地理区域，从而产生更大的区域水平疾病模式。 传统的环境健康研究忽略了具有相似风险因素的人群的地理聚集，并使用非常简单的方法来确定暴露于环境污染物。 因此，他们可能错误地将出生缺陷的空间模式归因于环境危害，而不是社会经济因素。 这项研究将开发新的理论和方法，以检查这些因素中的哪些是最重要的，在解释地理变异的两个出生缺陷在北卡罗来纳州：口面裂和腹裂。 具体的研究问题包括：1）出生缺陷的聚集是组成因素的结果（即具有相似社会经济背景的人生活在一起）？ 2)如果控制了成分因素，还有哪些环境因素可以解释出生缺陷的空间变异性（即接近危险废物）？ 3)使用水文地理学定义高污染风险区域的模型是否比使用欧几里得距离的模型更好地估计出生缺陷的风险？ 来自NC出生缺陷监测计划和生命统计办公室的七年数据将用于检查这些问题。 将利用地理信息系统，将个人出生数据与地区社会经济数据和环境危害位置相结合。 分析方法包括统计聚类分析和病例对照研究与空间多层次回归模型，以确定哪些社会经济和环境因素解释出生缺陷结果的变化。 环境污染物和社会经济特征的存在或不存在以及这些因素的地理范围可以提供对出生缺陷原因的重要见解。 然而，人与环境之间复杂的相互作用使得很难确定不同的社会、经济和环境因素的相对重要性。 这项研究提供了一个跨学科的机会，合并地理和流行病学的理论和方法，出生缺陷的研究。 它将地理学理论和方法（即疾病生态学，水文建模和空间统计学）应用于传统的流行病学研究，以进一步了解人与环境的相互作用如何影响出生缺陷等慢性疾病。 所采用的方法是创新的;它们以前从未在这一主题领域使用过，将为今后的环境研究提供一个模式。 最终，这项研究将提供有关口面裂和腹裂的环境和社会经济决定因素的新发现。 这些发现具有重要的政策意义，可以整合到健康促进计划，以防止出生缺陷。

While some causes of birth defects are known (i.e., chromosomal damage), researchers believe that unidentified environmental factors may also contribute to their development. In North Carolina, birth defect rates exhibit a significant amount of spatial variation. Traditional environmental health studies assume that these patterns are due to factors in a mother's environment, such as proximity to a hazardous waste site, that cause birth defects to occur. However, there is also evidence that birth defects are related to behavioral and economic risk factors, such as smoking and poor prenatal care. Spatial patterns of birth defects may therefore be due to the fact that individuals with similar backgrounds and risk factors live in the same geographic area, producing larger area-level patterns of disease. Traditional environmental health studies ignore geographic clustering of people with similar risk factors and use very simple methods to determine exposure to an environmental contaminant. Thus, they may incorrectly attribute spatial patterns of birth defects to environmental hazards rather than socioeconomic factors. This study will develop new theories and methods for examining which of these factors are most important in explaining the geographic variation of two birth defects in North Carolina: orofacial clefts and gastroschisis. Specific study questions include: 1) Is the clustering of birth defects a consequence of compositional factors (i.e. people with similar socioeconomic backgrounds living near each other)? 2) If compositional factors are controlled for, what additional environmental factors explain spatial variability in birth defects (i.e. proximity to hazardous waste)? 3) Do models using hydrogeography to define areas of high contamination risk estimate the risk of birth defects better than models using Euclidean distance? Seven years of data from the NC Birth Defects Monitoring Program and Office of Vital Statistics will be used to examine these questions. Individual-level birth data will be integrated with area-level socioeconomic data and the location of environmental hazards using a Geographic Information System (GIS). Analytical methods include a statistical cluster analysis and a case-control study with spatial multi-level regression models to determine which socioeconomic and environmental factors explain variation in birth defect outcomes. The presence or absence of environmental contaminants and socioeconomic characteristics and the geographic extent of such factors can offer important insights into the causes of birth defects. However, the complex interactions between people and their environment make it difficult to determine the relative importance of different social, economic and environmental factors. This study offers an interdisciplinary opportunity to merge geographic and epidemiological theories and methods for birth defects research. It applies geographical theories and methods (i.e. disease ecology, hydrological modeling and spatial statistics) to traditional epidemiological research in order to further our understanding of how human-environment interactions affect chronic conditions such as birth defects. The methodologies employed are innovative; they have not been used in this subject area before and will provide a model for conducting future environmental research. Ultimately, this study will provide new findings about the environmental and socioeconomic determinants of orofacial clefts and gastroschisis. Such findings have important policy implications and can be integrated into health promotion programs seeking to prevent birth defects.