Sex differences in dementia risk and risk factors: Individual‐participant data analysis using 21 cohorts across six continents from the COSMIC consortium
Jessica Gong, Katie Harris, Darren M. Lipnicki, Erico Castro‐Costa, Maria Fernanda Lima‐Costa, Breno S. Diniz, Shifu Xiao, Richard B. Lipton, Mindy J. Katz, Cuiling Wang, Pierre‐Marie Preux, Maëlenn Guerchet, Antoine Gbessemehlan, Karen Ritchie, Marie‐Laure Ancelin, Ingmar Skoog, Jenna Najar, Therese Rydberg Sterner, Nikolaos Scarmeas, Mary Yannakoulia, Mary H. Kosmidis, Antonio Guaita, E Rolandi, Annalisa Davin, Oye Gureje, Stella Trompet, Jacobijn Gussekloo, Steffi G. Riedel‐Heller, Alexander Pabst, Susanne Röhr, Suzana Shahar, Devinder Kaur Ajit Singh, Nurul Fatin Malek Rivan, Martin P.J. van Boxtel, Sebastian Köhler, Mary Ganguli, Chung‐Chou H. Chang, Erin Jacobsen, Mary N. Haan, Ding Ding, Qianhua Zhao, Zhenxu Xiao, Kenji Narazaki, Tao Chen, Sanmei Chen, Tze Pin Ng, Xinyi Gwee, Katya Numbers, Karen A. Mather, Márcia Scazufca, António Lobo, Concepción De‐la‐Cámara, Elena Lobo, Perminder S. Sachdev, Henry Brodaty, Maree L. Hackett, Sanne A. E. Peters, Mark Woodward
Abstract
INTRODUCTION: Sex differences in dementia risk, and risk factor (RF) associations with dementia, remain uncertain across diverse ethno-regional groups. METHODS: A total of 29,850 participants (58% women) from 21 cohorts across six continents were included in an individual participant data meta-analysis. Sex-specific hazard ratios (HRs), and women-to-men ratio of hazard ratios (RHRs) for associations between RFs and all-cause dementia were derived from mixed-effect Cox models. RESULTS: Incident dementia occurred in 2089 (66% women) participants over 4.6 years (median). Women had higher dementia risk (HR, 1.12 [1.02, 1.23]) than men, particularly in low- and lower-middle-income economies. Associations between longer education and former alcohol use with dementia risk (RHR, 1.01 [1.00, 1.03] per year, and 0.55 [0.38, 0.79], respectively) were stronger for men than women; otherwise, there were no discernible sex differences in other RFs. DISCUSSION: Dementia risk was higher in women than men, with possible variations by country-level income settings, but most RFs appear to work similarly in women and men.