Greater Weight Loss in Old Age Linked With MCI, Dementia

Findings reported in the Journal of the American Geriatrics Society show that women with a greater rate of weight loss in old age are more likely to develop mild cognitive impairment (MCI) or dementia.¹

While an association has been observed between cognitive decline and weight loss in late life, it is unclear whether the overall trajectory of weight in late life is linked with cognitive function.^2-4 Elucidating this relationship could inform interventions aimed at preserving cognitive health. To that end, researchers from multiple US universities and the Center for Health Research at Kaiser Permanente Northwest investigated the association in a cohort of 1289 community-dwelling women aged 65 years and older.

They used data from the Study of Osteoporotic Fractures (SOF), which recruited women from several regions of the United States from 1986 to 1988. Each participant’s weight was recorded at clinic visits every 2 to 4 years and at a 20-year follow-up examination between 2006 and 2008. The women also underwent complete cognitive testing at the 20-year session. Of the total sample, 514 women were determined to have MCI or dementia (both diagnoses were combined to ensure that the study would be sufficiently powered) based on case reviews by a team of expert physicians, and the remaining sample was considered cognitively normal.

According to the results, women who were cognitively normal at the 20-year exam weighed more, walked faster, consumed more alcohol, and had lower scores on the 15-item geriatric depression scale (GDS). After adjustments for age, education, clinic, walking speed, and depressive symptoms, the following significant associations were found:

• For each 0.5-kg/y weight loss, there was a 17% increase in the odds of developing MCI/dementia (odds ratio [OR] = 1.17; 95% CI, 1.02-1.35)
• Women with a moderate negative slope of weight change (indicating a rate of loss greater than the standard deviation [SD] for the population rate [slope <1 SD]) had greater odds of developing MCI/dementia (OR = 1.46; 95% CI, 0.98-2.17)
• Women with a higher rate of weight loss over the 20-year period had worse cognitive performance on the California Verbal Learning Test-II, Short Form, Immediate and Delayed (CVLT-I and CVLT-D) (P =.001 and P =.03, respectively)
• Women with a greater absolute weight loss over the 20-year period had worse cognitive performance on the CVLT-I (P =.002)
• Women with greater weight variability had worse performance on the Modified Mini-Mental State Examination (3MS), Verbal Associative Fluency, and Category Fluency (Ps =.05, .03, and .03, respectively)

The finding that normal cognitive function is associated with a more stable weight trajectory in older women “could be of importance given the high prevalence of cognitive decline and dementia with aging, and because weight is a potentially modifiable risk factor in older age,” wrote the investigators. “Future research should target nutritional status, social-environmental factors, and/or adipose tissue function and structure as methods for preserving cognitive function into old age.”

References

1. LeBlanc ES, Rizzo JH, Pedula KL, et al. Weight trajectory over 20 years and likelihood of mild cognitive impairment or dementia among older women [published online December 19, 2016]. J Am Geriatr Soc. 2016; doi: 10.1111/jgs.14552
2. Johnson DK, Wilkins CH, Morris JC. Accelerated weight loss may precede diagnosis in Alzheimer disease. Arch Neurol. 2006;63:1312-1317.
3. Knopman DS, Edland SD, Cha RH et al. Incident dementia in women is preceded by weight loss by at least a decade. Neurology. 2007;69:739-746.
4. Hughes TF, Borenstein AR, Schofield E, et al. Association between late-life body mass index and dementia: The Kame Project. Neurology. 2009;72:1741-1746.