Incidence and Risk Factors for Mild Cognitive Impairment: A Population-Based Three-Year Follow-Up Study of Cognitively Healthy Elderly Subjects

Abstract

Background: Mild cognitive impairment (MCI) has attracted considerable interest as a potential predictor of Alzheimer’s disease (AD). Both the apolipoprotein E (ApoE) Ε4 allele and vascular factors have been associated with a higher risk for AD, recently they have also been linked to the risk of MCI. Objectives: To estimate the incidence of MCI among cognitively healthy elderly subjects during a 3-year follow-up, and to evaluate the impact of demographic and vascular factors as well as the ApoE Ε4 allele on the conversion to MCI. Methods: At baseline, the cognitive abilities of 806 out of 1,150 eligible subjects (aged 60–76 years) from a population-based sample were examined. Cognitively intact subjects (n = 747) were followed for an average of 3 years. Results: 66 subjects (8.8%) had converted to MCI. The global incidence rate of MCI was 25.94/1,000 person-years. Persons with higher age (OR 1.08, 95% CI 1.01–1.16), ApoE Ε4 allele carriers (OR 2.04, 95% CI 1.15–3.64) and persons with medicated hypertension (OR 1.86, 95% CI 1.05–3.29) were more likely to convert to MCI than those individuals of lower age and without an ApoE Ε4 allele or medicated hypertension. Persons with high education (OR 0.79, 95% CI 0.70–0.89) were less likely to convert to MCI than persons with low or no education. In subjects with both the ApoE Ε4 allele and medicated hypertension, the crude OR for conversion was 3.92 (95% CI 1.81–8.49). In subjects with cardiovascular disease, the crude OR for conversion was 2.13 (95% CI 1.26–3.60). Gender, elevated blood pressure, diabetes or cerebrovascular disease had no significant effect on the conversion to MCI. Conclusion: Higher age, the presence of at least one ApoE Ε4 allele and medicated hypertension are independent risk factors, but high education is a protective factor for MCI. The results suggest that vascular factors may have an important role in the pathogenesis of MCI.

Association between the rs189037 single nucleotide polymorphism in the ATM gene promoter and cognitive impairment

“…Recent long-term population-based studies have suggested that vascular risk factors and vascularrelated diseases were risk factors for vascular dementia, and also have an important role in the pathogenesis of cognitive impairment (Tervo et al, 2004). The present study showed that elderly people living in rural areas have a high prevalence of cognitive impairment (32.7%).…”

“…Accumulated evidence from epidemiological research strongly supports roles for lifestyle and cardiovascular risk factors in the pathogenesis and development of cognitive impairment (Qiu et al, 2010). These factors include increasing age, low education, smoking, living alone, poor living conditions (Cervilla et al, 2000;Frisoni et al, 2000;Verghese et al, 2003;Tervo et al, 2004), and vascular-related diseases such as hyperlipidemia, hypertension, heart disease, diabetes mellitus, and cerebrovascular disease or stroke (Elias et al, 1997;Kilander et al, 1998;Kivipelto et al, 2001;Ballard et al, 2003).…”

Less Atherosclerosis and Lower Blood Pressure for a Meaningful Life Perspective With More Brain

“…Differences in the definition of the cognitive end point, the wide range of age at baseline and duration of follow-up, varying sampling frames, and adjustment for different sets of covariates or effect modifiers, such as the apolipoprotein E 4 polymorphism, 35,79 made the computation of a pooled association size impossible. Nevertheless, of the 10 studies (Table 4), 35,[71][72][73][74][75][76][77][78][79] 8 reported that antihypertensive drug treatment lowered the risk of cognitive decline, the reduction being significant in 5 reports, 71,72,75,77,78 and proportional to duration of treatment. 80 No single study observed a multivariate-adjusted significantly elevated risk in treated hypertensive patients.…”

Altered Brain Activation During a Verbal Working Memory Task in Subjects with Amnestic Mild Cognitive Impairment

“…Within the MCI group there are various subgroups, with the amnestic Mild Cognitive Impairment (aMCI) group characterized by a single memory disorder [2]. This group is at higher risk for converting to AD compared to healthy subjects and other MCI subtypes such as non-amnestic MCI [2][3][4][5][6][7].…”