A Twin Study of Chronic Fatigue Syndrome in Sweden

尽管进行了大量的研究，但关于慢性疲劳综合症的基本问题最多只能得到部分回答。这些问题包括其定义、有效性、由遗传因素与环境因素导致的程度、观察到的与其他条件的大量共病的性质以及女性优势的基础。这个项目的首要目标是通过一个大型的、基于人群的经典双胞胎研究来阐明关于慢性疲劳综合症的一些基本问题。首先，我们将收集大约32000名42-65岁的成年人（13000对完整的双胞胎）的数据，这些人是瑞典双胞胎登记处的成员，他们有持续性疲劳、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）和详细的病史。第二，将通过一个有效的国家检索系统查询所有患有类似慢性疲劳综合症疾病的双胞胎的医疗记录，以及部分患有“解释性慢性疲劳综合症”的双胞胎的医疗记录。经专家审查后，这些人将根据疾病预防控制中心和疾病安全中心的标准进行分类。获得这些独特的数据将使我们能够解决关于慢性疲劳综合症的一系列关键问题。首先，我们将估算CFS的患病率及其常见合并症（纤维肌痛、肠易激综合征、紧张性头痛、过敏/湿疹、广泛性焦虑障碍和重度抑郁症），这是迄今为止研究的最大样本之一。其次，我们将使用各种多变量技术来得出长时间疲劳的经验类型，并评估这种类型与CFS定义的比较。第三，我们将量化CFS及其合并症变异的遗传和环境来源。第四，至关重要的是，我们将研究性别对这些变异来源的影响。最后，我们将分析CFS与纤维肌痛、肠易激综合征、紧张性头痛、过敏/湿疹、广泛性焦虑障碍和重度抑郁症的共病模式，使用多变量双胞胎分析，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，我们希望通过在多个人群中进行平行研究来加快了解CFS病因的进展。目前的建议有几个独特的目标，代表了一种具有成本效益的方法，可以在流行病学样本中扩展这项工作，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.