Systematic review finds wide variation in neurodegenerative disease prevalence among older Russian adults

Purpose: To systematically review population-based studies reporting the prevalence and incidence of neurodegenerative diseases among adults aged 50 and older in Russia Methods: We searched Medline, Scopus, Embase, and eLibrary from inception to January 2025. Cross-sectional and cohort studies were eligible if they reported community-based prevalence or incidence of dementia, cognitive impairment, or Parkinson's disease in adults aged 50 and older in Russia. Healthcare and institutionalised populations were excluded. Risk of bias was assessed using the RoB-PrevMH tool, and dementia prevalence from screening tools was adjusted for test sensitivity and specificity. Prevalence estimates were pooled using random- and fixed-effects meta-analysis, stratified by age group and assessment method. Results: Twenty studies met the inclusion criteria. Dementia prevalence ranged from 0.5% to 81.6%, with the lowest estimates from administrative data and the highest from Mini-Cog screening in adults aged 85 and older. Cognitive dysfunction was reported in 12 studies (prevalence 3.1-81.5%). Nine studies reported Parkinson's disease prevalence (0.017-0.31%), with the highest estimate from the only neurologist-assessed population-based study. Conclusion: Prevalence of dementia and Parkinson's disease in Russia varies widely depending on diagnostic method, age group, and study design. Most studies lacked representative sampling and used non-standardised diagnostic criteria. Population-based longitudinal research using validated tools is urgently needed to support public health planning in Russia.