Laura Maclachlan

Research problem and specific questions: Strong evidence links high outdoor temperatures to increased population morbidity, but little is known about the relationship between heat exposure indoors and its impact on health. Presently, no empirically supported recommendations regarding an upper indoor temperature threshold for health exist. Defining such a threshold is important as without this it will be difficult to establish any regulatory requirements that ensure that future buildings are sufficiently resilient to warmer summers. As the frequency of heat waves increases, understanding the sensitivity of different dwellings to outdoor temperature, especially in homes occupied by the elderly, is critical. This collaboration programme between six Swedish Universities aims to establish an evidence-based upper indoor temperature threshold for wellbeing

identify dwelling-specific characteristics that are most likely to increase the risk of heat-related illness, develop a temperature sensitivity regression model for indoor temperature prediction, and visualise area-level heat-vulnerability of the buildings on interactive maps, made available for a wide variety of endusers.Data and method: We aim to collect indoor temperature and humidity data, self-reported information about sleep quality, mental and physical health, as well as dwelling-specific characteristics from 4,000 adults across Sockholm, Malmö, Göteborg and Umeå during summer months, 2024-2027, by using temperature loggers, automatic text messages and electronic questionnaires. Physiological health data will be collected from 400 senior citizens by using Actiheart-5, activity, heart rate and sleep monitors. The associations between indoor temperatures and physical and mental health outcomes will be examined by multiple regression models. A model for prediction of indoor temperatures in different types of buildings will be developed by fitting the collected indoor temperature data to a modified energy balance model.Relevance and utilisation: The sustainability of housing policy includes ensuring access to a healthy indoor environment for all socio-economic groups. Being able to predict how different buildings are likely to respond to high outdoor temperatures is important for mitigating their potentially harmful impact. The present programme aims to fill the gaps in knowledge regarding the role that different building characteristics play in personal temperature exposure and visualise these problems on interactive maps for wider public, which is important for improving heat epidemiology, preparing prevention programmes.Plan for programme realisation: The data will be collected during four summers, after which model development and data analyse will be conducted. Regular research group and stakeholder meetings will be held. Programme costs include salaries for a research assistant and statistician, costs for technical devices, as well as postal costs for the distribution of temperature loggers.

Research problem and specific questionsUrban living environments challenge the individual’s capacity to maintain a good health throughout the course of life. In Sweden, current trends in housing and neighborhood conditions tend to further increase disparities in health. The rapid urbanization and densification of Stockholm County makes it an optimal setting for studying health effects of urban living, for example in relation to air quality, transportation noise, urban greenness, climate change and overcrowded housing. In this program, we aim to assess and develop strategies for building a sustainable city promoting equitable public health among inhabitants of urbanized areas.Data and methodsThe program will use a variety of different data materials and methods. To map environmental hazards in Stockholm County, a new GIS-based tool aimed at regional stakeholders will be developed. A new cohort, based on the National Environmental Health Survey 2023, will form the basis for analyses of environmental health associations and estimates of disease burden. Furthermore, the effects on children’s development, education and health from overcrowded housing will be investigated in a nation-wide cohort study and in an intervention setting. In a literature review, we will summarize evidence on environmental interventions which can guide stakeholders in implementing planning and mitigation measures.Relevance and utilizationThe national Commission for Equity in Health listed 7 key areas of life which determine health inequalities. Among these, the intended program has a focus on Housing and neighborhood conditions but is also of relevance for aspects of Early life development, Health behavior, and Control, influence and participation. By this program, we aim to establish a strong research infrastructure for monitoring and assessing the impact of the built environment on public health and for the promotion of environmental health equity. This is in line with several other initiatives and governing documents within Sweden, e.g. “Health as a driving force for the environmental goals and sustainable development”, initiated by Miljömålsrådet.Plan for program realizationThe program will be carried out at the Institute of Environmental Medicine, Karolinska Institutet, in collaboration with the Center for Occupational and Environmental medicine, Region Stockholm, and builds on six different work packages, each with its specific aims, activities, and deliverables. The researchers of the program represent many different disciplines, spanning from environmental medicine, public health and epidemiology to GIS, nursing and multicultural psychiatry, and will work closely together in the different work-packages. To ensure a good dialogue with end-users of our research, we will host, and take part in, an array of activities throughout the program progression, e.g. via reference groups, seminars, workshops, regional networks and other applied activities.