Moving home is a common experience across the life course, yet it is a surprisingly underexplored factor in health research. Some relocations provide access to cleaner air, greener surroundings, or safer neighborhoods, which may have long-term benefits for physical and mental health. Others, however, may increase exposure to air pollution, noise, or socioeconomic disadvantages. Beyond environmental quality, moving home can also disrupt social ties, weaken community networks, and interrupt continuity of health and social care. These changes may be particularly relevant for brain health, where both biological and social factors shape the risk of decline. Although dementia is now one of the leading causes of mortality and disability worldwide, little is known about how residential mobility affects long-term brain health. The UK Biobank offers a unique opportunity to address this gap by linking detailed residential histories with rich environmental datasets on neighborhood characteristics as well as dementia incidence and structural changes in the brain. Therefore, the aim of this study is to investigate whether moving to more favorable or less favorable environments (defined by changes in exposures such as air quality and socioeconomic environment conditions) is related to subsequent dementia risk and markers of brain health. By studying both improvements and deteriorations in the living environment, this study can test whether relocation represents a critical turning point for long-term cognitive outcomes. The findings may shed light on how housing and neighborhood conditions influence dementia risk, and provide evidence that can inform housing strategies, urban planning, and public health policies designed to support healthier aging.
