Objectives: Mild Cognitive Impairment (MCI) constitutes a pre-stage of dementia in many cases.
The aims of the present study were to estimate age- and gender-specific incidence
of MCI and to identify risk factors for incident MCI in a population-based sample
of cognitively healthy subjects aged 75 years and older. Methods: Data were derived from the Leipzig Longitudinal Study of the Aged (LEILA75+), a population-based
study of individuals aged 75 years and older. Incidence was calculated according to
the 'person-years-at-risk' method. Cox proportional hazards models were used to identify
risk factors for incident MCI. Results: During the 8-year follow-up period, roughly one fourth (n=137; 26.4%) of the population
at risk developed MCI. The overall incidence of MCI for subjects aged 75 years and
older was 76.5 (95%-PCI=64.7–90.4) per 1,000 person-years (overall person-years=1,791.08).
The incidence rate was highest in age group 85+ years and higher in women than men
(80.8, 95%-PCI=66.6–98.0 vs. 65.8, 95%-PCI=47.0–92.1). Cox proportional hazards model
identified older age, subjective memory complaints, impairment in instrumental activities
of daily living, and lower cognitive performance as significant risk factors for incident
MCI. Conclusions: MCI has high incidence in the elderly population. The inclusion of restrictions in
instrumental activities of daily living in the criteria of MCI particularly might
be useful to improve the prediction of dementia. Subjective memory complaints in previously
cognitively healthy individuals should be taken seriously as a possible pre-stage
of MCI. Declaration of Interest: The field work was supported by the Interdisciplinary
Centre for Clinical Research Leipzig (project C07). Further work was supported by
the Leipzig Interdisciplinary Research Cluster of Genetic Factors, Clinical phenotypes
and Environment (LIFE) that is financed by means of the European Union (European Regional
Development Fund; ERDF) and the Free State of Saxony.
