A population-based cohort study examined the cardiac consequences of nighttime light exposure using cardiac MRI.Brighter nighttime light exposure was linearly associated with adverse cardiac remodeling and subclinical functional decline, followed by excess cardiovascular events within a decade.The observational study precluded claims of causation, however, and the findings were mediated in part by shorter sleep duration.
The concept that there are cardiovascular harms of nighttime light exposure gained greater credence with a large new study.
Based on the U.K. Biobank cohort, people with more light exposure (>3 lux) during normal sleep hours typically showed worse cardiac structure and function on cardiac MRI scans 3 years later. Imaging findings showed left ventricular (LV) concentric hypertrophy and subclinical functional decline, impaired myocardial deformation, adverse changes in the right ventricle, and adverse changes in the left atrium in these individuals compared with peers having no nighttime light exposure, according to Lu Qi, MD, PhD, of Tulane University in New Orleans, and colleagues.
This ultimately translated into worse clinical outcomes over 8-10 years of follow-up. Participants with brighter nighttime light exposure had 29% higher risk of heart failure, 15% higher risk of atrial fibrillation, 24% higher risk of myocardial infarction, 33% higher risk of stroke, and 26% higher risk of cardiovascular disease (CVD) mortality, study authors reported in European Heart Journal.
