Impact of green/blue spaces on specific morbidity and cause-specific mortality in Belgium: the GRESP-HEALTH project protocol (2015-2019)

Abstract

Living in green/blue areas is associated with better health. This may be due to low air/noise pollution, opportunities for physical activity, facilitation of social contacts, and/or promotion of recovery from fatigue and stress. Yet, socio-economic (SE) factors also explain inequalities in both health and access to green/blue spaces. The GRESP-HEALTH (Impact of green/blue spaces on specific morbidity and cause-specific mortality in Belgium) project intends to evaluate the associations between living in/close to a green or a blue area on morbidity and mortality in Belgium, at different stages of life (infancy to elderly). It assesses all-cause and cause-specific mortality, specific morbidities and perceived health and takes into account environmental pollutants and SE factors at different levels of spatial aggregation. The project includes all individuals registered in the official Belgian censuses of 1991 and/or 2001. Three main levels of observation will be studied: individual, statistical sector and group of statistical sectors having similar characteristics in green/blue areas and air pollution. This allows to follow individual and ecological designs. Mortality will be based on the National Mortality Database (a linkage between cause-specific mortality and SE factors using the 1991 and 2001 censuses and cause-specific mortality for 2000-2010). Perceived health information is available from the 2001 census. Specific morbidity (2000-2010) will be derived from the IMA-AIM ("Intermutualistisch Agentschap-Agence Inter-Mutualiste") database, which contains reimbursement data of individual prescriptions. For green/blue spaces, the surface, shape, accessibility and type will be calculated for each statistical sector. Residential area-specific exposure to air pollutants will be obtained from satellite images (CORINE) and traffic noise databases are used whenever possible. Material deprivation, educational attainment, and professional status will be indicators of SE status (SES). The analyses will be conducted separately in different age specific populations (infants, children and adults). We will use multilevel models for clustered data within geographical areas (i.e. individuals, households, nested scales, statistical sectors/groups of statistical sectors and municipalities). When possible, the models will be controlled for SES, perceived environment, air/noise pollution, and type of area (urban, sub-urban, rural, etc.). Interactions of green/blue spaces with air pollution and SE factors will be evaluated and stratified analyses in areas with similar SE and environmental characteristics will be performed. Moreover, more specific population groups (elderly, gender, employment status) will be considered. The GRESP-HEALTH project will improve the scientific knowledge about the hitherto uncertain associations between living close to green/blue spaces and health.