0721 GMT January 19, 2020
People who lose weight over decades appear to have an increased risk of losing memory and thinking skills, called mild cognitive impairment, which can lead to dementia, including Alzheimer's disease. A loss of 11 pounds every 10 years may indicate as much as a 24 percent higher risk for loss of mental ability, researchers found, livescience.com reported.
"Unintended weight loss may be a signal to examine whether to increase efforts to engage in lifestyle measures that are beneficial to mental function," said lead researcher Dr. Rosebud Roberts, a professor of epidemiology and neurology at the Mayo Clinic in Rochester, Minn.
About five percent to 15 percent of adults who show early loss of mental ability progress to dementia, Roberts said.
For the study, Roberts and colleagues collected data on almost 1,900 men and women 70 and older who took part in the Mayo Clinic Study of Aging, which started in 2004. Their height and weight readings at midlife were taken from medical records.
During an average of over four years of follow-up, 524 people developed memory and thinking problems (mild cognitive impairment). These folks were more likely to be older or carrying the APOE e4 allele, a gene mutation associated with an increased risk of Alzheimer's disease.
In addition, people who developed memory and thinking problems were more likely to have diabetes, high blood pressure, and to have had a stroke or heart disease, compared with those who stayed mentally fit, the researchers found.
Those who developed thinking and memory problems had a greater weight change per decade from midlife than those who remained mentally normal, a loss of 4.4 pounds versus 2.6 pounds, the study said.
Keith Fargo, director of scientific programs and outreach at the Alzheimer's Association, pointed out, "This study shows only an association between weight loss and a decline in mental ability, so you can't really say anything about cause."
In addition, Fargo said the weight loss seen in the study may not be significant. Losing 11 pounds over 10 years works out to about a pound a year, which may be just normal weight fluctuation, he said.