JAMA Netw Open

Nighttime light exposure linked to higher cardiovascular risk

October 28, 2025

Avoiding nighttime light exposure may be a novel, actionable strategy to reduce cardiovascular disease risk, supplementing current lifestyle recommendations. This study positions night light as an important environmental risk factor for cardiovascular disease prevention.

Study details: This prospective cohort study analyzed 88,905 U.K. Biobank participants (mean age, 62.4 years; 56.9% female) who wore wrist-worn light sensors for one week to objectively measure personal light exposure. Participants were followed for 9.5 years (2013–2022) for incident cardiovascular disease outcomes, including coronary artery disease (CAD), MI, heart failure, afib, and stroke. Light exposure at night was categorized into percentiles, and risks were assessed using Cox proportional hazards models adjusted for established cardiovascular risk factors.

Results: Individuals in the highest night light exposure group (91st–100th percentile) had significantly increased risks of CAD (adjusted hazard ratio [aHR], 1.32), MI (aHR, 1.47), heart failure (aHR, 1.56), afib (aHR, 1.32), and stroke (aHR, 1.28) compared with those with the darkest nights. Associations were independent of physical activity, smoking, alcohol, diet, sleep duration, socioeconomic status, and polygenic risk. Stronger associations were observed for females and younger individuals for certain outcomes.

Source:

Windred DP, et al. (2025, October 1). JAMA Netw Open. Light Exposure at Night and Cardiovascular Disease Incidence. https://pubmed.ncbi.nlm.nih.gov/41129148/