The prevalence of dementia varies substantially worldwide. This is partially attributed to the lack of methodological uniformity among studies, including diagnostic criteria and different mean population ages. However, even after considering these potential sources of bias, differences in age-adjusted dementia prevalence still exist among regions of the world. In Latin America, the prevalence of dementia is higher than expected for its level of population aging. This phenomenon occurs due to the combination of low average educational attainment and high vascular risk profile. Among developed countries, Japan seems to have the lowest prevalence of dementia. Studies that evaluated the immigration effect of the Japanese and blacks to USA evidenced that acculturation increases the relative proportion of AD cases compared to VaD. In the Middle East and Africa, the number of dementia cases will be expressive by 2040. In general, low educational background and other socioeconomic factors have been associated with high risk of obesity, sedentarism, diabetes, hypertension, dyslipidemia, and metabolic syndrome, all of which also raise the risk of VaD and AD. Regulating these factors is critical to generate the commitment to make dementia a public health priority.

Cognitive dysfunction and dementia have recently been proven to be common (and underrecognized) complications of diabetes mellitus (DM). In fact, several studies have evidenced that phenotypes associated with obesity and/or alterations on insulin homeostasis are at increased risk for developing cognitive decline and dementia, including not only vascular dementia, but also Alzheimer's disease (AD). These phenotypes include prediabetes, diabetes, and the metabolic syndrome. Both types 1 and 2 diabetes are also important risk factors for decreased performance in several neuropsychological functions. Chronic hyperglycemia and hyperinsulinemia primarily stimulates the formation of Advanced Glucose Endproducts (AGEs), which leads to an overproduction of Reactive Oxygen Species (ROS). Protein glycation and increased oxidative stress are the two main mechanisms involved in biological aging, both being also probably related to the etiopathogeny of AD. AD patients were found to have lower than normal cerebrospinal fluid levels of insulin. Besides its traditional glucoregulatory importance, insulin has significant neurothrophic properties in the brain. How can clinical hyperinsulinism be a risk factor for AD whereas lab experiments evidence insulin to be an important neurothrophic factor? These two apparent paradoxal findings may be reconciliated by evoking the concept of insulin resistance. Whereas insulin is clearly neurothrophic at moderate concentrations, too much insulin in the brain may be associated with reduced amyloid-beta (Abeta) clearance due to competition for their common and main depurative mechanism - the Insulin-Degrading Enzyme (IDE). Since IDE is much more selective for insulin than for Abeta, brain hyperinsulinism may deprive Abeta of its main clearance mechanism. Hyperglycemia and hyperinsulinemia seems to accelerate brain aging also by inducing tau hyperphosphorylation and amyloid oligomerization, as well as by leading to widespread brain microangiopathy. In fact, diabetes subjects are more prone to develop extense and earlier-than-usual leukoaraiosis (White Matter High-Intensity Lesions - WMHL). WMHL are usually present at different degrees in brain scans of elderly people. People with more advanced WMHL are at increased risk for executive dysfunction, cognitive impairment and dementia. Clinical phenotypes associated with insulin resistance possibly represent true clinical models for brain and systemic aging.

A finalidade deste estudo foi identificar a dependência funcional de idosos e a sobrecarga do cuidador. Trata-se de estudo epidemiológico e transversal realizado em 2009 com 574 idosos e 124 cuidadores em Ribeirão Preto-SP, por meio dos instrumentos MIF e Escala de Sobrecarga de Zarit. Entre os idosos, a maioria era do sexo feminino (67,8%), com média de 76,6 anos, baixa escolaridade (54,7%) e renda individual mensal de R$ 942,20. Apenas 15,7% foram identificados como dependentes. Dos cuidadores, 85,6% era do sexo feminino, com média de 56,5 anos e 90,3% eram familiares (filhas ou esposas). A média de sobrecarga dos cuidadores foi de 27,8 (±17,5). A dependência do idoso foi fator de risco para sobrecarga do cuidador (p<0,05). A abordagem preventiva e a intervenção precoce devem ser prioritárias para essa população. São necessárias a vigilância de uma equipe multidisciplinar de saúde, a aplicação de instrumentos de avaliação do comprometimento da funcionalidade e a intervenção para prevenção da sobrecarga dos cuidadores.

Met.S was significantly associated with functional dependence, depression, cognitive impairment, and low HRQoL, and its effects were independent of clinical stroke, IHD, and its own individual components.