“Currently, there is little information about death and the types of memory loss that affect many millions of Americans,” said study author Maria Vassilaki, MD, of the Mayo Clinic in Rochester, Minnesota. “Exploring how memory may or may not be linked with the length of life a person has is of tremendous significance as the population ages.” For the study, 862 people with thinking problems and 1,292 with no thinking problems between the ages of 70 and 89 were followed for nearly six years. Participants were from Olmsted County, Minnesota, and were given tests at the start of the study and every 15 months to assess their thinking abilities.
After six years, 331 of the group with MCI and 224 of the group without MCI died. Those who had MCI had an 80% higher death rate during the study than those without MCI. People with MCI and no memory loss had more than twice the death rate during the study than those without MCI, while people with MCI with memory loss had a 68% higher death rate during the study than those without MCI.
Low Tolerance for Pain? The Reason May Be Genetic
Researchers may have identified genes that affect individuals’ tolerance for pain. “Our study is quite significant because it provides an objective way to understand pain and why different individuals have different pain tolerance levels,” said study author Tobore Onojjighofia, MD, MPH, who is affiliated with Proove Biosciences. “Identifying whether a person has these four genes could help doctors better understand a patient’s perception of pain.”
Researchers evaluated 2,721 people diagnosed with chronic pain for the genes COMT, DRD2, DRD1, and OPRK1. Participants, all of whom were taking prescription opioid pain medications, were asked to rate their perception of pain on a scale from 0 to 10. People who rated their pain as 0 were excluded from further study. Low pain perception was defined as a score of 1, 2, or 3; moderate pain perception as a score of 4, 5, or 6; and high pain perception as a score of 7 or higher. Approximately 9% of the participants had low pain perception, 46% had moderate pain perception, and 45% had high pain perception. The researchers found that the DRD1 gene variant was 33% more prevalent in the low pain group than in the high pain group. Among people with a moderate pain perception, the COMT and OPRK variants were found 25% and 19% more often, respectively, than in individuals with a high pain perception. The DRD2 variant was 25% more common among people with a high pain perception, compared with people with moderate pain.
“Chronic pain can affect every other part of life,” said Dr. Onojjighofia. “Finding genes that may play a role in pain perception could provide a target for developing new therapies.