Author:
Roehr Susanne,Pabst Alexander,Riedel-Heller Steffi G.,Jessen Frank,Turana Yuda,Handajani Yvonne S.,Brayne Carol,Matthews Fiona E.,Stephan Blosso C.M.,Lipton Richard B.,Katz Mindy J.,Wang Cuiling,Guerchet Maëlenn,Preux Pierre-Marie,Mbelesso Pascal,Ritchie Karen,Ancelin Marie-Laure,Carrière Isabelle,Guaita Antonio,Davin Annalisa,Vaccaro Roberta,Kim Ki Woong,Han Ji Won,Suh Seung Wan,Shahar Suzana,Din Normah C.,Vanoh Divya,van Boxtel Martin,Köhler Sebastian,Ganguli Mary,Jacobsen Erin P.,Snitz Beth E.,Anstey Kaaren J.,Cherbuin Nicolas,Kumagai Shuzo,Chen Sanmei,Narazaki Kenji,Ng Tze Pin,Gao Qi,Gwee Xin Yi,Brodaty Henry,Kochan Nicole A.,Trollor Julian,Lobo Antonio,López-Antón Raúl,Santabárbara Javier,Crawford John D.,Lipnicki Darren M.,Sachdev Perminder S.
Abstract
Subjective cognitive decline (SCD) is recognized as a risk stage for Alzheimer`s disease (AD) and other dementias, but its prevalence is not well known. We aimed to use uniform criteria to better estimate SCD prevalence across international cohorts. Therefore, we combined individual participant data for 16 cohorts from 15 countries (members of the COSMIC consortium) and used qualitative and quantitative (Item Response Theory/IRT) harmonization techniques to estimate SCD prevalence. The sample comprised 39,387 cognitively unimpaired individuals above age 60. The prevalence of SCD across studies was around one quarter with both qualitative harmonization/QH (23.8%, 95%CI=23.3%-24.4%) and IRT (25.6%, 95%CI=25.1%-26.1%); however, prevalence estimates varied largely between studies (QH: 6.1%, 95%CI=5.1%-7.0%, to 52.7%, 95%CI=47.4%-58.0%; IRT: 7.8%, 95%%CI=6.8%-8.9%, to 52.7%, 95%CI = 47.4%-58.0%). Across studies, SCD prevalence was higher in men than women, in lower levels of education, in individuals with Asian and African ancestry compared to European ancestry, in lower- and middle-income countries compared to high-income countries, and in studies conducted in later decades. Data harmonization and application of uniform criteria across diverse cohorts yielded more accurate estimates of SCD prevalence. Having a quarter of older individuals with SCD warrants further investigation of its significance, as a risk stage for AD and other dementias, and of ways to help individuals with SCD who seek medical advice.
Publisher
Cold Spring Harbor Laboratory