Sometimes it pays to keep yourself in the dark.

According to a new study, the amount of artificial light a man is exposed to at night might be linked to a risk of developing prostate cancer. No, there’s no need to switch off the lamps and sit in a darkened house: It’s the disruption to the body’s natural rhythms that researchers believe may be the real culprit.

The findings come from an international study that compared satellite measurements of nighttime light emissions with cancer rates in one-hundred-and-sixty-four countries. The research showed that nations that emitted the most light at night tend to have the highest prostate cancer rates.

While scientists stress they haven’t pinpointed an actual cause and effect relationship, they say there’s enough evidence to look into ways to reduce unnecessary exposure to light at night.

The problem centers around melatonin, a hormone that plays an important role in regulating the body’s natural rhythms. When people are exposed to too much artificial light, it causes melatonin levels to plunge. This is harmful because when melatonin drops, other hormones such as testosterone and estrogen may also be disturbed. This can lead to breast or prostate cancer.

So what can be done? Doctors recommend taking simple steps, such as sleeping in a fully darkened room and minimizing light exposure if you’re up in the middle of the night. Some people even take melatonin supplements, although many health providers say it’s better if you just try to get a good night’s sleep.