With More Night Light Comes A Greater Risk of Leukemia

A group of international experts is considering evidence about a link between the rise in childhood leukemia and increased light at night (LAN). The concern: The incidence of childhood leukemia has increased dramatically over the 20th century, particularly the under 5 age group. From 1950-2000, the risk increased alone by more than 50 percent.

Although the causes of leukemia in children are poorly understood, researchers believe environmental factors play a major role in the rising incidence since changes in genetic makeup do not happen on this kind of timescale.

Compared with a century ago, people are exposed to considerable LAN during the natural hours of darkness, disrupting a person's natural circadian rhythm and suppressing the normal nocturnal production of the hormone melatonin. That reduction in melatonin has been linked to the beginning stages of cancer as well as its progression.

A number of studies have shown people in occupations that expose them to LAN experience a higher risk of breast cancer, but blind people, who are not vulnerable to reduced melatonin levels through LAN, have a lower incidence of cancer.

This link between light and leukemia isn't surprising to me because light exposure at night can reduce melatonin levels, which increases your risk of cancer. And getting young children to sleep can be problematic.

EurekAlert September 8, 2004

Post your comment
Click Here and be the first to comment on this article