The effects of obesity on cognitive decline in middle-aged and older African Americans

Obesity has the potential to raise an older adult's risk for having difficulty thinking and making decisions (also known as "cognitive decline" or dementia). It is a complex health concern. Body mass index (BMI) is a scale that measures a person's weight in relationship to their height. Research shows that older adults who have an elevated BMI are at lower risk for dementia than people with lower BMIs.

However, BMI may not be the best measure for obesity's effect on dementia. For example, signs such as carrying excess weight in the abdomen (also known as "belly fat"), and having a larger waist size, may better indicate whether a person is at higher risk for problems such as dementia.

Despite the fact that more African Americans are affected by obesity and dementia than other individuals, few studies have examined the link between obesity and dementia among African Americans. Recently, a team of researchers examined this link, and published their findings in the Journal of the American Geriatrics Society.

The researchers used information from the GENOA study. The GENOA study was conducted in Jackson, Mississippi, between 1997 and 1999. It enrolled African Americans with high blood pressure and their siblings (at least one of whom also had high blood pressure). People in the study ranged in age from 35- to 86-years-old. 78% were women and most were obese.

Participants in the study took detailed tests to measure how well they could think and make decisions. Researchers noted participants' body weight, height, waist measurements, and BMI. The researchers assessed the participants a second time between 2001 and 2006, and conducted a final visit between 2009 and 2011.

These key findings resulted from their study, said the researchers:

  • Having too much abdominal (belly) fat in mid- or late life was linked to a much higher risk of mental decline.
  • Weight loss, weight gain, maintaining a stable weight, and overall obesity were not linked to mental decline.
  • Among middle-aged participants, losing weight was linked to higher scores on cognitive tests. Gaining weight was linked to lower scores among middle-aged participants.
  • On the other hand, losing weight in later life was linked to lower scores on cognitive tests. Gaining weight in later life was linked to higher scores on cognitive tests.
  • Having the combination of a smaller waist measurement and a higher BMI appears to be linked to higher scores on those tests.

The researchers suggest that combining waist measurements with BMI in future studies might be a more accurate way to predict how well a person will retain the ability to think and make decisions in later life.


This summary is from "Adiposity, Change in Adiposity, and Cognitive Decline in Mid- and Late-Life." It appears online ahead of print in the February 2017 issue of the Journal of the American Geriatrics Society. The study authors are Nancy A. West, PhD; Seth T. Lirette, MS; Victoria A. Cannon, MD; Stephen T. Turner, MD; Thomas H. Mosley, Jr., PhD; and Beverly G. Windham, MD.

About the Health in Aging Foundation

This research summary was developed as a public education tool by the Health in Aging Foundation. The Foundation is a national non-profit established in 1999 by the American Geriatrics Society to bring the knowledge and expertise of geriatrics healthcare professionals to the public. We are committed to ensuring that people are empowered to advocate for high-quality care by providing them with trustworthy information and reliable resources. Last year, we reached nearly 1 million people with our resources through We also help nurture current and future geriatrics leaders by supporting opportunities to attend educational events and increase exposure to principles of excellence on caring for older adults. For more information or to support the Foundation's work, visit

About the Journal of the American Geriatrics Society

Included in more than 9,000 library collections around the world, the Journal of the American Geriatrics Society (JAGS) highlights emerging insights on principles of aging, approaches to older patients, geriatric syndromes, geriatric psychiatry, and geriatric diseases and disorders. First published in 1953, JAGS is now one of the oldest and most impactful publications on gerontology and geriatrics, according to ISI Journal Citation ReportsĀ®. Visit for more details.

About the American Geriatrics Society

Founded in 1942, the American Geriatrics Society (AGS) is a nationwide, not-for-profit society of geriatrics healthcare professionals that has — for 75 worked to improve the health, independence, and quality of life of older people. Its nearly 6,000 members include geriatricians, geriatric nurses, social workers, family practitioners, physician assistants, pharmacists, and internists. The Society provides leadership to healthcare professionals, policymakers, and the public by implementing and advocating for programs in patient care, research, professional and public education, and public policy. For more information, visit

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