THURSDAY, June 12 (HealthDay News) -- A new study suggests that older men with abnormal sleeping patterns may face a higher risk of death.

The findings aren't conclusive, and they don't indicate why unusual sleep patterns could be unhealthy. Still, they're food for thought, especially for older men, said study author Misti Paudel.

"If people think they have disruptions in their sleep, they really do need to see their physician and try to find potential causes or treatment options," said Paudel, a sleep researcher at the University of Minnesota-Twin Cities in Minneapolis.

The study, the first of its kind, sought to determine whether sleep patterns in older men had anything to do with their mortality rates, Paudel said.

She and her colleagues recruited 3,053 men aged 67 and older. They told the men to wear wrist actigraphs, wristwatch-like devices that measure body movement and allow researchers to analyze when people are awake or sleeping.

The participants wore the devices for up to 13 nights. "Over the course of a few days, we can see the activity patterns and compare them with other men in the group, start to look at what's normal and not normal," Paudel explained.

The researchers then followed the participants for about six years, checking to see if and when they died.

The researchers released the findings Wednesday at the annual meeting of the Associated Professional Sleep Societies, in Baltimore.

"What we found was that men who had [sleeping patterns] that were shifted either earlier or later in the day had an increased risk of mortality," Paudel said.

Even after researchers adjusted their findings to lessen the effect of factors like poor health, race and alcohol use, the differences in mortality rates remained. The men who hit their peaks of activity at the earliest and latest times of day were 80 percent more likely to die than the others, Paudel said.

The researchers didn't calculate how many years earlier the subjects died if they had abnormal sleeping patterns. The study also doesn't make it clear if night owls or early birds are at risk, although that could explain why some of the men were active at early or late times of day, Paudel said.

Why would abnormal sleep patterns make death more likely? "We don't really know how this is related to mortality," Paudel said. "It could be that there is some other medical condition that wasn't accounted for."

Sleep researcher Dr. Daniel Kripke said early or late sleep patterns may disrupt the body's metabolism or reflect cases of Alzheimer's disease. It's also possible that unusual sleep patterns could reflect problems in the body's genes, said Kripke, a professor of psychiatry at the University of California at San Diego, who plans to collaborate on future research with one of the study's authors.

Kripke isn't ready to advise older men to adjust their sleep patterns. "As yet, there is no evidence in this type of person that changing a person's hours would improve survival," he said. "It means it is not a bad idea to have normal hours, but we cannot yet say that not having them is a willful mistake."

More information

Learn more about sleep from the National Sleep Foundation.

SOURCES: Misti Paudel, M.P.H., research fellow, University of Minnesota-Twin Cities, Minneapolis; Daniel Kripke, M.D., professor, psychiatry, University of California, San Diego; June 11, 2008, presentation, Associated Professional Sleep Societies annual meeting, Baltimore

Copyright © 2008 ScoutNews, LLC. All rights reserved.