Environmental contaminants and psychological stress as predictors of cognitive decline during aging: a cohort study

• Grant number: 15/22792-1
• Support type: Scholarships abroad - Research
• Effective date (Start): May 13, 2016
• Effective date (End): May 27, 2016
• Field of knowledge: Health Sciences - Nursing - Medical-Surgical Nursing
• Principal researcher: Juliana Nery de Souza Talarico
• Grantee: Juliana Nery de Souza Talarico
• Host: Sonia J. Lupien
• Home Institution: Escola de Enfermagem (EE). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: Université de Montréal, Canada

Abstract

Recently, in a cross-sectional study, we demonstrated that individuals 50 years older with increased levels of environmental contaminants (EC) such as lead (Pb), polychlorinated biphenyls (PCBs) and organochlorides (OC) in blood show altered levels of cortisol (hyper and hipocortisolemia), the main mediator of the stress neuroendocrine response, as well as poor cognitive performance compared to individuals with lower levels of EC. Altogether, these findings suggest that the exposure to heavy metals, PCBs and OC, even under levels recommended by the Center for Disease Control and Prevention (CDC), may be a factor of vulnerability to the development of cognitive disorders. Hence, wonders whether individuals with previous exposure to increased levels of Pb, PCBs, OC and altered cortisol develop cognitive decline over time. The current proposal aims to analyze whether EC and the biological mediators of stress response as well as the interaction between them are predictors of cognitive decline during aging. The 129 participants included in our previous study "Environmental contaminants exposure and cognitive decline in healthy elderly: influence of psychological and oxidative stress (FAPESP 2009/13911-6), as described, individuals 50 years older, residents in the metropolitan area of São Paulo, with cognitive and functional abilities preserved, will be recruited to reassessment of cognitive performance, stress and EC evaluation. Salivary samples to determine the diurnal pattern of cortisol as well as blood samples to the EC will be analyzed. Attentional, working memory, declarative memory and executive function tasks will assess the cognitive performance. It is hypothesized that individuals with previous exposure to high levels of EC and poor stress response develop cognitive decline. The hypothesis assert may contribute to identify risk factors related to cognitive decline during aging and to support public policies of EC exposure control and monitoring to prevent health problems and to maintain physical and emotional well-being in the elderly. The current study has been developed in collaboration with the Centre d'étude sur le stress humain of Centre de Recherche Fernand-Seguin, Hôpital Louis-H. Lafontaine of Université de Montréal, em Montreal, Quebec, Canadá, supervised by Dra. Sonia J. Lupien, in the study "Environmental contaminants and cognitive decline in aging people: the stress hypothesis" (Canadian Institutes of Health Research - CIHR # 62434). (AU)