Anna M. Colacicco

Vascular risk factors, incidence of MCI, and rates of progression to dementia.

Objective: To estimate prevalence, incidence, and rate of progression of mild cognitive impairment (MCI) to dementia and correlated vascular risk factors with incident MCI and its progression to dementia. Methods: The authors evaluated 2,963 individuals from the population-based sample of 5,632 subjects 65 to 84 years old, at the first (1992 to 1993) and second survey (1995 to 1996) of the Italian Longitudinal Study on Aging (ILSA), with a 3.5-year follow-up. Dementia, Alzheimer disease (AD), vascular dementia (VaD), other types of dementia, and MCI were classified using current clinical criteria. Results: Among the 2,963 participants, 139 MCI patients were diagnosed at the first ILSA survey. During the 3.5-year follow-up, 113 new events of MCI were diagnosed with an estimated incidence rate of 21.5 per 1,000 person-years. We found a progression rate to dementia (all causes) of 3.8/100 person-years. Specific progression rates for AD, VaD, and other types of dementia were 2.3, 1.3, and 0.3/100 person-years. Furthermore, age was a risk factor for incident MCI (RR: 5.93, 95% CI: 3.17 to 11.10), while education was protective (RR: 0.06, 95% CI: 0.03 to 0.10), and serum total cholesterol evidenced a borderline nonsignificant trend for a protective effect. There was a nonsignificant trend for stroke as a risk factor of progression of MCI to dementia. Conclusions: In this population, among those who progressed to dementia, 60% progressed to AD and 33% to VaD. Vascular risk factors influence incident mild cognitive impairment and the rate of progression to dementia.

Late-life depression, mild cognitive impairment, and dementia: possible continuum?

Clinical and epidemiologic research has focused on the identification of risk factors that may be modified in predementia syndromes, at a preclinical and early clinical stage of dementing disorders, with specific attention to the role of depression. Our goal was to provide an overview of these studies and more specifically to describe the prevalence and incidence of depression in individuals with mild cognitive impairment (MCI), the possible impact of depressive symptoms on incident MCI, or its progression to dementia and the possible mechanisms behind the observed associations. Prevalence and incidence of depressive symptoms or syndromes in MCI vary as a result of different diagnostic criteria and different sampling and assessment procedures. The prevalence of depression in individuals with MCI was higher in hospital-based studies (median: 44.3%, range: 9%-83%) than in population-based studies (median: 15.7%, range: 3%-63%), reflecting different referral patterns and selection criteria. Incidence of depressive symptoms varied from 11.7 to 26.6/100 person-years in hospital-based and population-based studies. For depressed normal subjects and depressed patients with MCI, the findings on increased risk of incident MCI or its progression to dementia were conflicting. These contrasting findings suggested that the length of the follow-up period, the study design, the sample population, and methodological differences may be central for detecting an association between baseline depression and subsequent development of MCI or its progression to dementia. Assuming that MCI may be the earliest identifiable clinical stage of dementia, depressive symptoms may be an early manifestation rather than a risk factor for dementia and Alzheimer disease, arguing that the underlying neuropathological condition that causes MCI or dementia also causes depressive symptoms. In this scenario, at least in certain subsets of elderly patients, late-life depression, MCI, and dementia could represent a possible clinical continuum.

Dietary intake of unsaturated fatty acids and age-related cognitive decline: A 8.5-year follow-up of the Italian Longitudinal Study on Aging

There is evidence from a population-based study of an inverse relationship between monounsaturated fatty acids (MUFA) energy intake and age-related cognitive decline (ARCD), while high polyunsaturated fatty acids (PUFA) intake was positively associated with cognitive impairment in elderly subjects. We investigated the possible role of MUFA and PUFA on age-related cognitive changes. A population-based, prospective study was carried out on 278, 186, and 95 nondemented elderly subjects (65-84 years) evaluated for global cognitive functions (Mini-Mental State Examination, MMSE) at the first (1992-1993), second (1995-1996), and third survey (2000-2001), respectively, from the randomized cohort of Casamassima, Bari, Italy (n=704), one of the eight centers of the Italian Longitudinal Study on Aging (ILSA). MUFA and PUFA intakes were assessed at baseline with a semi-quantitative food frequency questionnaire. High MUFA and PUFA energy intakes and total energy intake were significantly associated with a better cognitive performance in a 8.5-year follow-up. In this prospective population-based study on older nondemented subjects with a typical Mediterranean diet, high MUFA and PUFA intakes appeared to be protective against ARCD.

Mediterranean diet and cognitive decline

OBJECTIVE To investigate the possible role of diet in age-related cognitive decline (ARCD) and cognitive impairment of both degenerative (Alzheimers disease, AD) and vascular (vascular dementia, VaD) origin. DESIGN Literature review. RESULTS In an elderly population of southern Italy with a typical Mediterranean diet, high energy intake of monounsaturated fatty acids (MUFA) appeared to be associated with a high level of protection against ARCD. In addition, dietary fat and energy in the elderly seem to be risk factors, while fish consumption and cereals are found to reduce the prevalence of AD in European and North American countries. Finally, the relative risk of dementia (AD and VaD) was lower in the subjects of a French cohort who drank three or four glasses of red wine each day compared with total abstainers. CONCLUSION Essential components of the Mediterranean diet--MUFA, cereals and wine--seem to be protective against cognitive decline. As such, dietary antioxidants and supplements, specific macronutrients of the Mediterranean diet, oestrogens and anti-inflammatory drugs may act synergistically with other protective factors, opening up new therapeutic interventions for cognitive decline.

Lipid metabolism in cognitive decline and dementia

This review will focus on the current knowledge on circulating serum and plasma risk factors of cognitive decline of degenerative (Alzheimers disease, AD) or vascular origin (vascular dementia, VaD) linked to cholesterol homeostasis and lipoprotein disturbances, i.e. total cholesterol (TC), 24S-hydroxy-cholesterol, lipoprotein(a) (Lp(a)), or apolipoprotein E (APOE). These measures linked to lipoprotein metabolism appear to be altered in AD, VaD, or predementia syndrome relative to controls, but with contrasting results. At present, several studies have demonstrated the dependence of APOE serum levels upon the APOE genotype, nonetheless serum APOE levels seems not to be a credible risk factor or a biochemical marker for AD instead of APOE genotyping. In fact, there was no consistent association of serum or plasma apoE protein levels with the disease when controlled for APOE genotype. In addition, there are some evidence that higher Lp(a) levels could be linked with AD, although there are studies suggesting an increased presence of low molecular weight apo(a) in AD, VaD, and frontotemporal dementia, that are associated with elevated Lp(a) levels. In fact, the apo(a) gene is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 domain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. Furthermore, although serum/plasma levels of TC and 24S-hydroxycholesterol are not credible diagnostic markers for AD and cognitive decline, the current evidence suggests that they may be modifiable risk/protective factors. The prevailing wisdom is that high TC is a risk factor for dementia. However, the relationship between TC and dementia may vary considerably depending on when cholesterol is measured over the life course or, alternatively, in relation to the underlying course of the disease. Several observational studies have suggested that statins, which are effective in lowering cholesterol, may reduce the risk of dementia, but the results of these reports are inconclusive. Thus, more studies with long-term follow-up and serial assessments of TC are needed to further clarify the causal relationship between cholesterol and dementia.

Dietary fatty acids intake: possible role in cognitive decline and dementia

There is a recent increase in the level of interest in the possible role of dietary fatty acids in age-related cognitive decline, and cognitive impairment of both degenerative (Alzheimers disease, AD) or vascular origin. At present, several studies suggested that an increase of saturated fatty acids (SFA) could have negative effects on cognitive functions. Furthermore, a clear reduction of risk of cognitive decline has been found in a population sample with a high intake of polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA). These findings were confirmed by studies in which high intakes of n-6 PUFA, n-3 PUFA, MUFA, and weekly fish consumption, providing large amount of n-3 PUFA, appear to be protective against the risk of AD. In our elderly population from Southern Italy, elevated unsaturated fatty acids intake (MUFA and PUFA), high levels of antioxidant compounds, and very low SFA intake could act synergistically in improving cognitive performance. Epidemiological studies on the association between diet and cognitive decline suggested a possible role of fatty acids intake in maintaining adequate cognitive functioning and possibly in preventing or delaying the onset of dementia, both of degenerative or vascular origin. Appropriate dietary measures or supplementation with specific micro- and macronutrients might open new ways for the prevention and management of cognitive decline and dementia.

Lifestyle-related factors in predementia and dementia syndromes

Cognitive decline and dementia have a deep impact on the health and quality of life of older subjects and their caregivers. Since the therapeutic options currently available have demonstrated limited efficacy, the search for preventive strategies for cognitive decline and dementia are mandatory. A possible role of lifestyle-related factors was recently proposed for age-related changes of cognitive function, predementia syndromes and the cognitive decline of degenerative (Alzheimer’s disease [AD]) or vascular origin. At present, cumulative evidence suggests that vascular risk factors may be important in the development of mild cognitive impairment (MCI), dementia and AD. Moderate alcohol drinking has been proposed as a protective factor against MCI and dementia in several longitudinal studies, but contrasting findings also exist. The Mediterranean diet could therefore be an interesting model with which to further study the association between dietary patterns and cognitive functioning, given the suggested role of many components of this diet (monounsaturated fatty acids, polyunsaturated fatty acids, cereals and red wine) in contrasting cognitive impairment and dementia. The association between low education and predementia and dementia syndromes is supported by the majority of studies, but very few studies have investigated whether this association may be attributed with lifestyle factors that covary with education. Studies in the literature seem to identify in physical exercise one promising strategy in decreasing cognitive decline, but some of the limitations of these studies do not allow us to draw definite conclusions. At present, in older subjects, healthy diets, antioxidant supplements, the prevention of nutritional deficiencies, and moderate physical activity could be considered the first line of defense against the development and progression of predementia and dementia syndromes. However, in most cases, these were only observational studies, and results are awaited from large multicenter randomized clinical trials in older persons that may clarify the possible synergy, for example, between moderate exercise, physical activity and healthy Mediterranean diet on cognition in the elderly.

Cognitive frailty: Predementia syndrome and vascular risk factors.

With increasing emphasis on early diagnosis of Alzheimer disease (AD), clinical research has focused on the identification of risk factors that may be modified at a preclinical and early clinical stage of dementing disorders. Prevalence and incidence of different predementia syndromes vary as a result of different diagnostic criteria, as well as different sampling and assessment procedures. Particular interest in mild cognitive impairment (MCI) arises from the fact that MCI is thought to be a prodromal phase and therefore highly predictive of subsequent AD. Furthermore, many of the risk factors for cerebrovascular disease (CVD) and vascular dementia (VaD), including serum total cholesterol, hypertension, atherosclerosis, and apolipoprotein E (APOE) genotype have also been shown to increase the risk of AD. Both vascular factors and APOE epsilon4 allele have been associated with higher risk of AD. Some recent studies suggested further that CVD or vascular factors increased the risk of conversion of MCI to dementia. This review will focus on the possible role of vascular risk factors in modulating the risk of age-related cognitive decline, and the progression of predementia syndrome such as MCI to dementia.

Alcohol consumption, mild cognitive impairment, and progression to dementia

Objective: To estimate the impact of alcohol consumption on the incidence of mild cognitive impairment and its progression to dementia. Methods: We evaluated the incidence of mild cognitive impairment in 1,445 non–cognitively impaired individuals and its progression to dementia in 121 patients with mild cognitive impairment, aged 65 to 84 years, participating in the Italian Longitudinal Study on Aging, with a 3.5-year follow-up. The level of alcohol consumption was ascertained in the year before the survey. Dementia and mild cognitive impairment were classified using current clinical criteria. Results: Patients with mild cognitive impairment who were moderate drinkers, i.e., those who consumed less than 1 drink/day (approximately 15 g of alcohol), had a lower rate of progression to dementia than abstainers (hazard ratio [HR] 0.15; 95% CI 0.03 to 0.78). Furthermore, moderate drinkers with mild cognitive impairment who consumed less than 1 drink/day of wine showed a significantly lower rate of progression to dementia than abstainers (HR 0.15; 95% CI 0.03 to 0.77). Finally, there was no significant association between higher levels of drinking (≥1 drink/day) and rate of progression to dementia in patients with mild cognitive impairment vs abstainers. No significant associations were found between any levels of drinking and the incidence of mild cognitive impairment in non–cognitively impaired individuals vs abstainers. Conclusions: In patients with mild cognitive impairment, up to 1 drink/day of alcohol or wine may decrease the rate of progression to dementia.

Metabolic syndrome and the risk of vascular dementia: the Italian Longitudinal Study on Ageing

Objective The authors investigated the relationship of metabolic syndrome (MetS) and its individual components with incident dementia in a prospective population-based study with a 3.5-year follow-up. Methods A total of 2097 participants from a sample of 5632 subjects (65–84 years old) from the Italian Longitudinal Study on Ageing were evaluated. MetS was defined according to the Third Adults Treatment Panel of the National Cholesterol Education Program criteria. Dementia, Alzheimer disease (AD) and vascular dementia (VaD) were classified using current published criteria. Results MetS subjects (N=918) compared with those without MetS (N=1179) had an increased risk for VaD (1.63% vs 0.85%, adjusted hazard ratio (HR) 3.71, 95% CI 1.40 to 9.83). After excluding 338 subjects with baseline undernutrition, MetS subjects compared with those without MetS had an elevated risk of VaD (adjusted HR, 3.82; 95% CI 1.32 to 11.06). Moreover, those with MetS and high inflammation had a still further higher risk of VaD (multivariate adjusted HR, 9.55; 95% CI 1.17 to 78.17) compared with those without MetS and high inflammation. On the other hand, those with MetS and low inflammation compared with those without MetS and low inflammation did not exhibit a significant increased risk of VaD (adjusted HR, 3.31, 95% CI 0.91 to 12.14). Finally, a synergistic MetS effect versus its individual component effects was verified on the risk of VaD. Conclusion In our population, MetS subjects had an elevated risk of VaD that increased after excluding patients with baseline undernutrition and selecting MetS subjects with high inflammation.