Midlife Obesity Linked to Earlier Alzheimer's

Jigsaw puzzlie, of senior man, falling apart
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Obesity has been linked to a whole host of diseases, including cancer, cardiovascular disease, and diabetes, among others. Now researchers have linked it to Alzheimer disease as well.

When and How

Researchers have specifically found that obesity in middle age predicts an earlier onset of Alzheimer disease—and a higher burden of disease (meaning that the disease will be more severe when it hits).

In an analysis of the Baltimore Longitudinal Study of Aging, researchers looked at the relationship between midlife body mass index (BMI) and the time of onset of Alzheimer disease as well as the severity of the disease.

The study authors found that higher BMI in middle age (50 years of age) was associated with an earlier onset of Alzheimer disease as well as higher measures of disease severity.

The researchers found that there was more amyloid deposition (a defining factor of Alzheimer disease) in the brain of patients with a higher midlife BMI, as compared with those who had a healthy BMI at age 50. This indicates a more severe form of the disease.

The researchers concluded that a healthy BMI at midlife may thus delay the onset of Alzheimer disease.

Obesity and Dementia

Earlier studies have consistently shown that obesity is associated with dementia. In another study similar to the one above, but conducted in eastern Finland, researchers followed patients for a total of 26 years, measuring their BMI at an average age of 50 as well as later, at an average age of 71. The researchers observed which patients developed dementia later in life, and found that, again, higher midlife BMI was associated with a higher risk of dementia and Alzheimer disease.

An analysis of the Swedish Twin Registry by researchers concluded that “both overweight and obesity at midlife independently increase the risk of dementia [and Alzheimer disease].”

Others have found that diabetes, which is an obesity-related disorder, may lead to an earlier onset of dementia.

Stave Off Weight Gain in Middle Age

The evidence seems clear at this point: overweight and obesity at midlife puts one at a higher risk of developing dementia as well as an earlier onset of Alzheimer disease.

Unfortunately, midlife is also a time at which many individuals tend to gain weight, as metabolism slows down a bit and many become more sedentary.

Knowing this, however, should lead to greater vigilance in middle age to keep up an active lifestyle and eat healthfully.


Chuang YF, An Y, Bilgel M, et al. Midlife adiposity predicts earlier onset of Alzheimer’s dementia, neuropathology and presymptomatic cerebral amyloid accumulation. Mol Psychiatry 2015 Sep 1. [Epub ahead of print]

Tolpannen AM, Ngandu T, Kareholt I, et al. Midlife and late-life body mass index and late-life dementia: results from a prospective population-based cohort.

Whitmer RA, Gunderson EP, Quesenberry CP Jr, et al. Body mass index in midlife and risk of Alzheimer disease and vascular dementia. Curr Alzheimer Res 2007;4:103-9.

Diabetes in midlife may hasten dementia in later life. Harv Health Lett 2015;40:8.

Xu WL, Atti AR, Gatz M, Pedersen NL, et al. Midlife overweight and obesity increase late-life dementia risk: a population-based twin study. Neurology 2011;76:1568-74.

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