WHO 预测,到 2020 年全球将有 2,900 万人患痴呆,其中阿尔茨海默病 (AD) 占大多数。[3]Qiu C, De Ronchi D, Fratiglioni L. The epidemiology of the dementias: an update. Curr Opin Psychiatry. 2007;20:380-385.http://www.ncbi.nlm.nih.gov/pubmed/17551353?tool=bestpractice.com非洲 65 岁及以上人群的阿尔茨海默病和血管性痴呆患病率是 1.6%,东欧是 3.9%,中国是 4.0%,西欧是 5.4%,北美是 6.4%。[3]Qiu C, De Ronchi D, Fratiglioni L. The epidemiology of the dementias: an update. Curr Opin Psychiatry. 2007;20:380-385.http://www.ncbi.nlm.nih.gov/pubmed/17551353?tool=bestpractice.com在整个欧洲,6% 的 65 岁以上人群和 30% 的 90 岁以上人群患某种类型的痴呆。[4]Lobo A, Launer LJ, Fratiglioni L, et al; Neurologic Diseases in the Elderly Research Group. Prevalence of dementia and major subtypes in Europe: a collaborative study of population-based cohorts. Neurology. 2000;54(11 Suppl 5):S4-S9.http://www.ncbi.nlm.nih.gov/pubmed/10854354?tool=bestpractice.com据估计,阿尔茨海默病占老年人痴呆病因的 35%-50%,该比例因地理位置、文化及种族而异。
在美国,AD 是最常见的痴呆类型,约占 60%-70%,70 岁以下人群中约 5% 会患 AD。80 岁以上人群中,患病率增加至 30%。目前美国有 450 万人患有此病。[5]Brookmeyer R, Gray S, Kawas C. Projections of Alzheimer's disease in the United States and the public health impact of delaying disease onset. Am J Public Health. 1998;88:1337-1342.http://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.88.9.1337http://www.ncbi.nlm.nih.gov/pubmed/9736873?tool=bestpractice.com[6]Kelley BJ, Petersen RC. Alzheimer's disease and mild cognitive impairment. Neurol Clin. 2007;25:577-609.http://www.ncbi.nlm.nih.gov/pubmed/17659182?tool=bestpractice.com预计到 2050 年,美国的 AD 患病数将达到约 1,400 万。[7]Bachman DL, Wolf PA, Linn R, et al. Prevalence of dementia and probable senile dementia of the Alzheimer type in the Framingham Study. Neurology. 1992;42:115-119.http://www.ncbi.nlm.nih.gov/pubmed/1734291?tool=bestpractice.com[8]Demirovic JA, Prineas R, Loewenstein D, et al. Prevalence of dementia in three ethnic groups: the South Florida program on aging and health. Ann Epidemiol. 2003;13:472-478.http://www.ncbi.nlm.nih.gov/pubmed/12875807?tool=bestpractice.com女性的AD患病率高于男性。[9]Ferri CP, Prince M, Brayne C, et al. Global prevalence of dementia: a Delphi consensus study. Lancet. 2005;366:2112-2117.http://www.ncbi.nlm.nih.gov/pubmed/16360788?tool=bestpractice.com相对于白人,黑人患痴呆的风险更高。[3]Qiu C, De Ronchi D, Fratiglioni L. The epidemiology of the dementias: an update. Curr Opin Psychiatry. 2007;20:380-385.http://www.ncbi.nlm.nih.gov/pubmed/17551353?tool=bestpractice.com早发型 AD(年龄<60 周岁)通常为常染色体显性遗传,所占比例<1%。AD 是全球最常见的痴呆类型。