Greater weight loss during aging associated with increased risk for mild cognitive impairment

MCI is a prodromal (early) stage of dementia with about 5 percent to 15 percent of people with MCI progressing to dementia per year. Changes in body mass index (BMI) and weight are associated with increased risk of dementia but overall study findings have been inconclusive. An association of declining weight and BMI with MCI could have implications for preventive strategies for MCI.

Rosebud O. Roberts, M.B., Ch.B., of the Mayo Clinic, Rochester, Minn., and coauthors studied participants 70 or older from the Mayo Clinic Study of Aging, which started in 2004. Height and weight in midlife (40 to 65 years old) were collected from medical records.

During an average of 4.4 years of follow-up, the authors identified 524 of 1,895 cognitively normal participants who developed MCI (about 50 percent were men and their average age was 78.5 years). Those who developed MCI were older, more likely to be carriers of the APOE*E4 allele and more likely to have diabetes, hypertension, stroke or coronary artery disease compared with study participants who remained cognitively normal.

Participants who developed MCI had a greater average weight change per decade from midlife than those who remained cognitively normal (-4.4 lbs vs. -2.6 lbs). A greater decline in weight per decade was associated with an increased risk of incident MCI, with a weight loss of 11 pounds per decade corresponding to a 24 percent increased risk of MCI, according to the results.

The authors note it was not possible to determine whether weight loss was intentional or unintentional.

"In summary, our findings suggest that an increasing rate of weight loss from midlife to late life is a marker for MCI and may help identify persons at increased risk of MCI," the study concludes.