New Study Explores How Nighttime Light Affects Biological Aging Markers - Video

Your streetlights might be keeping more than just the darkness away-they could also be influencing how your body ages.

Could living in brighter neighborhoods at night affect biological aging? A large UK study published in Scientific Reports suggests the answer may be more complicated than expected.

Researchers analyzed data from 296,372 adults in the UK Biobank to explore whether long-term exposure to residential night-time light (NTL) was linked to biological aging. Instead of relying on chronological age, they used two established measures—Klemera-Doubal Method (KDM) and PhenoAge—which estimate how “old” the body is based on clinical biomarkers.

Participants’ outdoor night-time light exposure was estimated using satellite data collected over five years and matched to their home addresses. Scientists also accounted for several factors, including age, education, income, smoking, diet, physical activity, sleep, obesity, diabetes, and hypertension.

The results revealed a surprising contradiction. After adjusting for these factors, people living in brighter areas appeared to have lower biological age according to the KDM measure. However, the PhenoAge algorithm showed the opposite, linking greater night-time light exposure with higher biological age and accelerated aging. Adults in the brightest areas had 5% lower odds of accelerated aging using KDM, but 3% higher odds using PhenoAge.

Researchers also found that the relationship was nonlinear, meaning the effects did not increase steadily with higher light exposure. Age, obesity, and smoking also influenced some of the associations.

The team cautioned that the study does not prove cause and effect. Because it was cross-sectional, it cannot determine whether artificial night-time light actually speeds up or slows down aging.

The findings highlight that biological aging is complex, and different aging algorithms may capture different aspects of health. Researchers say long-term studies are now needed to understand whether our increasingly illuminated nights truly influence how our bodies age.

REFERENCE: Liu, X. et al. (2026) Residential-area nighttime light exposure and biological aging patterns in the UK Biobank. Scientific Reports. DOI: 10.1038/s41598-026-65071-w