CIND and MCI in the Italian elderly: frequency, vascular risk factors, progression to dementia.

OBJECTIVE: To estimate prevalence and progression to dementia of cognitive impairment, no dementia (CIND), mild cognitive impairment (MCI), and relative subtypes, evaluating the relationships with daily functioning, cardiovascular diseases and vascular risk factors.

METHODS: We evaluated CIND and MCI in the Italian Longitudinal Study on Aging. The neuropsychological battery assessed global cognitive function, memory and attention. Two thousand eight hundred thirty participants were examined at baseline and after a mean follow-up of 3.9 +/- 0.7 years.

RESULTS: The prevalence was 9.5% for CIND and 16.1% for MCI. Prevalence rates for CIND subtypes were 1.8% for amnestic, 2.3% for single nonmemory, 1.5% for multidomain, and 3.9% for CIND defined only on global cognitive function. The prevalence was 7.0% for amnestic, 7.8% for single nonmemory, and 1.3% for multidomain MCI. Incidence of dementia (per 1,000 person-years) was 7.63 in the total sample, 21.37 in CIND, and 13.59 in MCI. In MCI, rates ranged from 8.74 in amnestic to 40.60 in multidomain subtype. The highest incidence of 56.02 per 1,000 person-years was found in multidomain CIND. Both CIND and MCI increased by almost three times the risk of dementia at follow-up. Among baseline variables, only previous stroke and impairment in instrumental activities of daily living significantly increased the risk of dementia at follow-up.

CONCLUSIONS: Both cognitive impairment, no dementia and mild cognitive impairment are frequent in the Italian elderly (2,955,000 prevalent cases expected) and significantly predict progression to dementia. Individuation of subgroups with different risk factors and transition rates to dementia is required to plan early and cost-effective interventions.