Lopez Oscar L, Kuller Lewis H
Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States; Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
Graduate School of Public Health, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
Handb Clin Neurol. 2019;167:139-148. doi: 10.1016/B978-0-12-804766-8.00009-1.
The study of the incidence and prevalence of dementia is important to understand the distribution of dementing illness among age and sex groups, and for the detection of possible causes of these disorders. A variation in the incidence or prevalence of dementia, especially Alzheimer's disease (AD) by region or specific populations can be because of greater or lesser exposure to the causal agents of dementia. For example, in the past the striking differences in the incidence of coronary heart disease (CHD) led to the understanding of the relationship between dietary factors, such as saturated fat and dietary cholesterol, and the incidence of CHD. However, there is a high prevalence of dementia in elderly individuals around the world, and multiple studies conducted in industrialized and nonindustrialized countries have shown an age-standardized prevalence of dementia ranging from 5% to 7% in most countries. Dementia is not a specific disease but rather a constellation of cognitive changes and disability due to several "causes," i.e., AD, Lewy bodies, vascular disease, drugs, and alcohol. Whether there is a trend for reduced incidence of dementia has to be further evaluated. It is possible that the improvement in the treatments of risk factors, especially vascular disease, has resulted in decreased incidence. However, this could result in an increase in prevalence, since the improved therapies for risk factors will lead to increased longevity in patients with dementia.
痴呆症发病率和患病率的研究对于了解痴呆症在不同年龄和性别群体中的分布情况以及发现这些疾病的可能病因非常重要。痴呆症，尤其是阿尔茨海默病（AD）在不同地区或特定人群中的发病率或患病率存在差异，可能是由于接触痴呆症致病因素的程度不同。例如，过去冠心病（CHD）发病率的显著差异促使人们了解了饮食因素，如饱和脂肪和膳食胆固醇与冠心病发病率之间的关系。然而，全球老年人中痴呆症的患病率很高，在工业化国家和非工业化国家进行的多项研究表明，大多数国家痴呆症的年龄标准化患病率在5%至7%之间。痴呆症不是一种特定的疾病，而是由多种“病因”，即AD、路易体、血管疾病、药物和酒精引起的一系列认知变化和残疾。痴呆症发病率是否有下降趋势还有待进一步评估。有可能对危险因素，尤其是血管疾病的治疗改善导致了发病率的降低。然而，这可能会导致患病率上升，因为针对危险因素的改进疗法将使痴呆症患者的寿命延长。
