Associação entre marcadores de adiposidade, resistência à insulina, intolerância à glicose, diabetes e função cognitiva: Estudo Longitudinal de Saúde do Adulto-ELSA-Brasil

Abstract

The demographic, nutritional and technological transition phenomena that have been taking place in the last 30 years led to a dramatic increase in the number of individuals with diabetes mellitus (diabetes), overweight and obesity, in the most of countries. At the same time, the aging of the diabetic population around the world raises concerns about the prevalence of cognitive dysfunction in these individuals. There are not many researches about early markers for alterations in cognitive performance in adult populations. Several risk factors are modifiable and can offer a valuable opportunity to preventive approaches. Some authors suggest that the interventions could be more effective if they were implemented at the outset of cognitive decline. Delaying the decline of cognitive function in a few years could have a great impact on the prevalence of the problem in the future generations. This thesis will be presented as two manuscripts, and their aims were: i) to investigate whether diabetes mellitus is associated to early alterations in cognitive function; ii) to investigate whether adiposity, insulin resistance markers and pre-diabetes are associated to cognitive performance in middle aged non-diabetic men and women. Our hypothesis is that the increased adiposity, insulin resistance, and prediabetes and diabetes are associated to worse cognitive performance. First article: It is a cross-sectional study with participants aged between 35 and 74 years old, from Estudo Longitudinal de Saúde do Adulto (ELSA- Brasil), a baseline of a large cohort in a developing country, from the years 2008 to 2010. In order to assess the cognitive domains, we used word-list learning, word-list delayed recall, word recognition tests, verbal fluency (semantic and phonemic) tests and trail making test B. The exposition interest variable was diabetes. Second article: Cross-sectional study with 11,115 adults (34-64 years old at the baseline), recruited between 2008 and 2010 in the Brazilian Longitudinal Study of Adult Health (ELSA- Brasil). Cognitive performance was tested by word-list learning, word-list delayed recall, word recognition tests, verbal fluency (semantic and phonemic) tests and trail making test B. The indicators (Body Mass Index- BMI and waist), insulin resistance (Homeostatic Model Assessment Insulin Resistance (HOMA-IR) and prediabetes (reduced glucose tolerance) were stratified by sex.. The models were adjusted for age, schooling, comorbidities, health behaviours and lipids. In the final model, were only included variables p<0,05, in both articles. xi In the final conclusions of the two published articles, we found a significant association between diabetes and decreased memory, language and executive function (attention, concentration and psychomotor speed) performance in this population from a country with a distinct epidemiological profile, even after adjusting for the main intervening variables. There weres also an association of BMI and HOMA-IR with cognitive performance in young and middle aged adult women without diabetes. In men, we found an association between HOMA-IR and prediabetes and poorer performance on memory tests. Recognizing early changes in the tests of the cognition in association with metabolic disorders may be important for potential future interventions that help mitigate the unfavorable consequences, thereby improving the management of these problems.