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Gene helps predict time of death

Filed in
  • mortality
  • Circadian rhythms

American Academy of Sleep Medicine  |  Nov 19, 2012
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Researchers have identified the gene that helps determine the time of day a person is most likely to die. Researchers at Beth Israel Deaconess Medical Center (BIDMC) say this gene can also determine if you’re an early bird or night owl.

This information could help in planning medical treatments and monitoring the conditions of vulnerable patients.

“Virtually all physiological processes have a circadian rhythm, meaning that they occur predominantly at certain parts of the day,” says the study’s co-author Dr. Clifford Saper. “There’s even a circadian rhythm of death, so that in the general population people tend on average to be most likely to die in the morning hours. Sometime around 11 a.m. is the average time.”

The study appears in the November 2012 issue of the Annals of Neurology. The study originated several years ago while first author, Andrew Lim, and others were working in the lab of BIDMC studying why older people have trouble sleeping. The study intended to identify precursors to Parkinson’s or Alzheimer’s disease. Participants underwent various sleep-wake analyses using a wrist actigraph. The device records activity patterns to identify sleep and wakefulness. Subjects also agreed to donate their brains after they died. The group also had their DNA genotyped and compared to their wake-sleep behavior.

People with the A-A gene variation woke up about an hour earlier than did the people with the G-G gene variation. Those with the A-G gene variation woke up almost exactly in the middle.

When the investigators went back and looked at the people in the study (many of whom had enrolled more than 15 years ago at age 65) who had died, they found that this same gene variation predicted six hours of variation in the time of death: Those with the A-A or A-G gene variation died just before 11 a.m., like most of the population, but those with the G-G gene variation on average died at just before 6 p.m.

“So there is really a gene that predicts the time of day that you’ll die. Not the date, fortunately, but the time of day, says Saper.

The authors of the study said that additional work is needed to determine the mechanisms by which this and other gene variations influence the body’s biological clock. In addition to helping people optimize their schedules, the research could eventually lead to novel therapies to treat disturbances of this clock as seen in jet lag or shift work.

“Also, working out which causes of death are influenced by gene variations like the one we identified may eventually lead to rational timed interventions – such as taking heart medications at particular times depending on which version of the gene variation one carries – to provide protection during an individuals’ period of greatest risk,” says Lim. The potential clinical applications may be as diverse as the many processes that the circadian clock controls.