Evolution of dementia diagnosis over time (1988–2013): Evidence from French and English cohorts. Implication for secular trends analyses. Issue 1 (9th August 2018)

• Record Type: Journal Article
• Authors: Grasset, Leslie; Matthews, Fiona E.; Pérès, Karine; Foubert‐Samier, Alexandra; Helmer, Catherine; Dartigues, Jean‐François; Brayne, Carol
• Is Part Of: Alzheimer's & dementia. Volume 10:Issue 1(2018)
• Page Start: 490
• Page End: 497
• Publication Date: 2018-08-09
• Subjects: Dementia -- Secular trends -- Diagnosis -- Incidence -- Prevalence; Alzheimer's disease -- Periodicals; Alzheimer's disease -- Diagnosis -- Periodicals; Dementia -- Periodicals; Dementia -- Diagnosis -- Periodicals; 616.831
• DOI: 10.1016/j.dadm.2018.07.005
• Languages: English
• ISSNs: 2352-8729

Abstract

Abstract: Introduction: The aims of this study are to examine the evolution of clinical dementia diagnosis over 3 decades and to investigate secular trends of dementia. Methods: Four cohorts covering a period from 1988 to 2013 were used: the Personnes Agées Quid and Three‐City‐Bordeaux studies, and the Cognitive Function and Aging Study (CFAS) I and II. Mini–Mental State Examination scores at clinical diagnosis were evaluated over a 24‐year follow‐up period in French studies. An algorithmic approach was applied to CFAS I and II to provide dementia prevalence and incidence estimates. Results: A significant increase of the Mini–Mental State Examination score at diagnosis was observed until 2000 and a significant decrease after. We reported a prevalence of 8.8% for CFAS I (1990–1993) compared with a prevalence of 6.5% in CFAS II (2008–2011). The 2‐year incidence rate was estimated at 31.2/1000 (95% confidence interval = 28.0–34.8) for CFAS I and 15.0/1000 (95% confidence interval = 13.5–16.7) for CFAS II. Discussion: Applying a stable algorithm to different cohorts across time can provide a robust method for time trends estimation. Highlights: Secular trends of dementia are important to research and policy, yet studies exploring this face methodological challenges. This work reveals changes in characteristics of those diagnosed with dementia over time in France. Applying an algorithmic approach confirmed the prevalence and incidence decrease already published in the CFAS studies in UK. It is critical to account for changes in diagnostic practices when studying secular trends, using stable definitions.