Summary of the Article: Artificial Light at Night and Heart disease Risk
This article discusses a preliminary study presented at the American Heart Association’s Scientific Sessions 2025, which suggests a link between exposure too artificial light at night (light pollution) and an increased risk of heart disease.
Key Findings:
* Higher Light Exposure = Higher Risk: The study of 466 adults found a nearly linear relationship between nighttime artificial light exposure and heart disease risk – the more light, the higher the risk. Even modest increases in light were linked to increased stress in the brain and inflammation in arteries.
* Brain & Vessel Impact: Artificial light at night was associated wiht higher brain stress activity and inflammation of blood vessels. This stress response can lead to hardening of the arteries and increased risk of heart attack and stroke.
* Compounding Factors: The risk was amplified for those already facing other stressors like traffic noise and lower income.
* Potential solutions: Reducing needless external city lighting and limiting indoor light exposure (especially from screens) before bed could mitigate the risk.
Study Details:
* Observational Study: Researchers analyzed data from patients who underwent PET/CT scans (to measure brain stress and artery inflammation) and correlated it with their exposure to artificial nighttime brightness based on satellite data.
* Data Source: Data was collected between 2005-2008 for scans and 2016 for light exposure assessment. Follow-up data showed 17% of participants experienced notable heart problems by 2018.
Limitations:
* Limited diversity: The study population was drawn from a single hospital system, potentially limiting the generalizability of the findings.
* Correlation, Not Causation: As an observational study, it cannot definitively prove that light pollution causes heart disease, only that there is a strong association.
Expert Commentary: Experts agree the study sheds light on how artificial light at night might harm health, specifically by triggering a stress response in the brain. Further research is needed with larger, more diverse populations and interventions to reduce light exposure.
