Association of road traffic noise exposure with dementia or cognitive impairment – a systematic review of longitudinal cohort studies

Background Road traffic noise is a major public health concern that is associated with various cardiometabolic and neurological disorders. Dementia poses a significant health and socioeconomic burden. Existing systematic reviews have not explored the link between road traffic noise exposure alone, and risk of dementia or cognitive impairment. This review aims to identify and summarise available evidence linking road traffic noise exposure with risk of dementia or cognitive impairment. Methods MEDLINE, EMBASE, CINAHL Plus and GreenFile were searched for studies on road traffic noise exposure and the risk of dementia or cognitive impairment among adults from inception to July 2025 without restrictions on setting or geographical location. Studies were identified using strict inclusion and exclusion criteria. Two independent reviewers conducted screening, data extraction, and quality assessment. A narrative synthesis was conducted. Results 3296 studies were retrieved from the searches, of which 3264 were excluded and 32 underwent full text screening. 8 studies were narratively synthesised. Quality assessment of the studies revealed that they were good quality and only one study was prone to a high risk of bias. The findings suggest that adults exposed to high levels of road traffic noise exposure, particularly >50 dB, compared to those exposed to lower levels of road traffic noise are at higher risk of developing dementia or cognitive impairment. Conclusion There is a positive association between road traffic noise and dementia or cognitive decline. However, the amount of good-quality evidence is low and larger longitudinal studies using robust methods are needed. Such research could have significant implications on infrastructure planning and development of regulations to prevent adverse health effects due to road traffic noise.