International Mind, Activities and Urban Places (iMAP) study: Methods of a cohort study on environmental and lifestyle influences on brain and cognitive health

Abstract

Introduction Numerous studies have found associations between characteristics of urban environments and risk factors for dementia and cognitive decline, such as physical inactivity and obesity. However, the contribution of urban environments to brain and cognitive health has been seldom examined directly. This cohort study investigates the extent to which and how a wide range of characteristics of urban environments influence brain and cognitive health via lifestyle behaviours in mid-aged and older adults in three cities across three continents. Methods and analysis Participants aged 50 79 years and living in preselected areas stratified by walkability, air pollution and socioeconomic status are being recruited in Melbourne (Australia), Barcelona (Spain) and Hong Kong (China) (n=1800 total; 600 per site). Two assessments taken 24 months apart will capture changes in brain and cognitive health. Cognitive function is gauged with a battery of eight standardised tests. Brain health is assessed using MRI scans in a subset of participants. Information on participants' visited locations is collected via an interactive web-based mapping application and smartphone geolocation data. Environmental characteristics of visited locations, including the built and natural environments and their by-products (e.g., air pollution), are assessed using geographical information systems, online environmental audits and self-reports. Data on travel and lifestyle behaviours (e.g., physical and social activities) and participants' characteristics (e.g., sociodemographics) are collected using objective and/or self-report measures. Ethics and dissemination The study has been approved by the Human Research Ethics Committee of the Australian Catholic University, the Institutional Review Board of the University of Hong Kong and the Parc de Salut Mar Clinical Research Ethics Committee of the Government of Catalonia. Results will be communicated through standard scientific channels. Methods will be made freely available via a study-dedicated website. trial registration number ACTRN12619000817145. IntroduCtIon Dementia prevention is a global health priority. Around 40 50million people suffer from dementia worldwide and these figures are expected to almost double by 20301 2 due to population ageing.3 Mild cognitive impairment (MCI) that is not severe enough to meet strengths and limitations of this study ? By recruiting participants from residential areas stratified by walkability, air pollution and socioeconomic status from three cities varying in exposures and lifestyle behaviours, this study will allow a robust estimation of dose response relationships of urban design and the relevant by-products (e.g., pollution) with brain and cognitive health. ? This study will provide a comprehensive assessment of multiple environmental factors and multiple lifestyle behaviours by which environments may affect brain and cognitive health. This will allow improved understanding of which environmental characteristics are related to brain and cognitive outcomes and by which mechanisms. ? The focus on locations visited for daily activities rather than only residential neighbourhoods will enable a more accurate estimation of individual exposure to features of the urban environment. ? The comprehensive assessment of lifestyle behaviours and individual-level moderators (apolipoprotein E genotype, physical health and personality traits) will assist the identification of optimal patterns of lifestyle activities that can be integrated in individually tailored lifestyle interventions, taking into account individual genetic factors and environmental living conditions. ? Current resources can support only two assessments, 24 months apart. This may not be a sufficiently long period to detect changes in certain exposures and/or outcomes. by copyright. BMJ Open: first published as 10.1136/bmjopen-2019-036607 on 18 March 2020. Downloaded from http://bmjopen.bmj.com/ on June 6, 2020 at Elsevier Bibliographic Database