A Twin Study of Chronic Fatigue Syndrome in Sweden

尽管进行了大量研究，但有关CFS的基本问题充其量只能部分回答。 这些问题包括它的定义，有效性，在何种程度上，它导致遗传与环境因素，观察到与其他条件的实质性comorbance的性质，以及女性优势的基础。 该项目的总体目标是通过一项大型的、基于人群的经典双胞胎研究来阐明有关CFS的一些基本问题。 首先，我们将收集大约32，000名42-65岁的成年人（13，000对完整的双胞胎）的数据，这些人是基于人群的瑞典双胞胎登记处的成员，用于持续性疲劳、几种重叠疾病（纤维肌痛、肠易激综合征、紧张性头痛、过敏/湿疹、广泛性焦虑症和重度抑郁症）以及详细的病史。 第二，通过一个有效的国家检索系统，将要求所有似乎患有CFS样疾病的双胞胎和一部分患有“CFS解释”的双胞胎的医疗记录。 经过专家审查，这些人将根据CDC CFS标准进行分类。获得这些独特的数据将使我们能够解决有关CFS的一系列关键问题。 首先，我们将在迄今为止研究的最大样本中估计CFS及其常见合并症（纤维肌痛、肠易激综合征、紧张性头痛、过敏/湿疹、广泛性焦虑症和重度抑郁症）的患病率。 其次，我们将使用各种多变量技术，得出一个经验类型的长期疲劳，并评估如何比较这种类型的CFS定义。 第三，我们将量化CFS及其共病条件的遗传和环境变异来源。 第四，批判性地，我们将研究性别对这些变异来源的影响。 最后，我们将使用多变量双生子分析来分析CFS与纤维肌痛、肠易激综合征、紧张性头痛、过敏/湿疹、广泛性焦虑症和重度抑郁症之间的共病模式，从而估计共享和独特的遗传和环境变异源之间的重叠程度。与研究者及其合作者正在进行的其他双胞胎研究相一致，我们希望通过多人群的平行研究来加速理解CFS病因的进展。 目前的建议有几个独特的目标，并代表了一个具有成本效益的手段，以扩大这项工作的流行病学样本，可以说是世界上最好的双胞胎登记。

Despite considerable research, fundamental questions about CFS remain at best partially answered. These questions include its definition, validity, the degree to which it results from genetic versus environmental factors, the nature of the substantial comorbidity observed with other conditions, and the basis of the female preponderance. The overarching aim of this project is to shed light on a number of basic questions about CFS via a large, population-based classical twin study. First, we will collect data on approximately 32,000 adults aged 42-65 years (13,000 complete twin pairs) who are members of the population- based Swedish Twin Registry for persistent fatigue, several overlapping conditions (fibromyalgia, irritable bowel syndrome, tension headache, allergy/eczema, generalized anxiety disorder, and major depression), and a detailed medical history. Second, the medical records of all twins who appear to have CFS-like illness and a subset of those with "CFS-explained" will be requested via an efficient national retrieval system. Following expert review, these individuals will be classified in regard to the CDC CFS criteria. Obtaining these unique data will allow us to address a set of critical questions regarding CFS. First, we will estimate the prevalence of CFS and its common comorbidities (fibromyalgia, irritable bowel syndrome, tension headache, allergy/eczema, generalized anxiety disorder, and major depression) in one of the largest samples yet studied. Second, we will use a variety of multivariate techniques to derive an empirical typology of prolonged fatigue and to assess how this typology compares to the CFS definition. Third, we will quantify the genetic and environmental sources of variation for CFS and its comorbid conditions. Fourth, critically, we will examine the influence of gender on these sources of variation. Finally, we will analyze the patterns of comorbidity between CFS and fibromyalgia, irritable bowel syndrome, tension headache, allergy/eczema, generalized anxiety disorder, and major depression using multivariate twin analyses and thereby to estimate the extent of overlap between the shared and unique genetic and environmental sources of variation. In concert with other twin studies being conducted by the investigators and their collaborators, we hope to hasten progress in understanding the etiology of CFS by parallel studies in multiple populations. The current proposal has several unique aims and represents a cost-effective means to extend this work in an epidemiological sample that is arguably the best twin registry in the world.