Study: Melatonin May Lower Prostate Cancer Risk
Findings support importance of maintaining stable sleep–wake cycle (January 19)
Higher levels of melatonin, a hormone involved in the sleep–wake cycle, may be associated with a decreased risk of developing advanced prostate cancer, according to a study presented at the American Association for Cancer Research (AACR)–Prostate Cancer Foundation Conference on Advances in Prostate Cancer, held Jan. 18–21 in San Diego, California.
Melatonin is a hormone that is produced exclusively at night in the dark and is an important output of the circadian rhythm, or the body’s inherent 24-hour clock. Many biological processes are regulated by the circadian rhythm, including the sleep–wake cycle. Melatonin may play a role in regulating a range of other hormones that influence certain cancers, including breast and prostate cancers.
To investigate the association between urine levels of the main breakdown product of melatonin, 6-sulfatoxymelatonin (6-SMT), and the risk of prostate cancer, Sarah C. Markt, MPH, and colleagues conducted a case-cohort study of 928 Icelandic men from the AGES-Reykjavik cohort between 2002 and 2009.
Of the study participants, 111 men were diagnosed with prostate cancer, including 24 with advanced disease. The researchers found that men whose 6-SMT levels were higher than the median value had a 75% decreased risk of advanced prostate cancer. An overall 31% decreased risk of prostate cancer was observed as well, but this finding was not statistically significant.
“Our results require replication but support the public health implication of the importance of maintaining a stable light–dark and sleep–wake cycle,” Markt said. “Because melatonin levels are potentially modifiable, further studies of melatonin and prostate cancer risk and progression are warranted.”
Source: AACR; January 19, 2014.