This article is from the WSSF 2017 AFRMA Rat & Mouse Tales news-magazine.

Did You Know?  Rats kept in continuous light from the age of 1 month had an accelerated spontaneous growth of tumors (benign fibroadenomas in females, testicular Leydig cell tumors in males, and malignant lymphomas). Both male and female rats also had a shortened life span. However, in rats 14 months old when the constant light was started, there was no change in life span.

Study Circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in young but not in old rats Aging (Albany NY). 2010 Feb; 2(2): 82–92.