Healthy BMI at middle age could delay onset of Alzheimer’s

by TMP Editor on September 8, 2015


If you’re on the young side of age 50 and you need to lose weight, new research on the relationship between obesity and Alzheimer’s could motivate you to get started now. Scientists from the National Institute on Aging have produced evidence that excess weight at midlife accelerated the onset of Alzheimer’s. What’s more, they found that as body mass index (BMI) increased, cognitive ability declined at increasingly earlier ages.

Obesity and Alzheimer’s

Obesity has long been associated with dementia later in life, but this study, published in Molecular Psychiatry, is the first to investigate the question of exactly when obesity could trigger the onset of debilitating cognitive decline.

The NIA researchers analyzed data from the Baltimore Longitudinal Study of Aging. A longitudinal study gathers data from a group of people as they are observed for many years. This particular study tracked people to monitor their health as they got older for as long as 35 years. Records of about 1,400 people who underwent regular cognitive testing showed that 142 were diagnosed with Alzheimer’s.

Alzheimer’s timeline

An analysis of BMI at age 50 of those who developed Alzheimer’s showed that each increase in BMI predicted that Alzheimer’s would emerge six and a half months earlier in life. For example, someone with a BMI of 30, the threshold for obesity, would be stricken with Alzheimer’s four years sooner than someone with a BMI of 26, which is in the overweight category (25-29.9). A BMI in the range of 18.5 to 24.9 is considered healthy.

Tangled brain

The NIA study was also unique in that it linked midlife obesity directly to the brain damage inflicted by Alzheimer’s. Autopsies on 191 participants and brain imaging on 75 of them showed that high BMIs at age 50 predicted the occurrence of neurofibrillary tangles in the brain. In the brain, protein structures called microtubules transport nutrients in brain cells. These microtubules become twisted and collapse into neurofibrillary tangles when Alzheimer’s attacks.

A sense of urgency

It’s estimated that about 5 million Americans are suffering from Alzheimer’s. That number is expected to more than double by 2050. The NIA study suggests that by losing weight enough to lower your BMI by 10 points, you could delay the onset of Alzheimers by about five and a half years.

There is no cure for Alzheimer’s. The disease does its damage undetected for a decade or more before its diagnosed. That fact alone could give someone contemplating weight loss a renewed sense of urgency.


MedPage Today

U.S. News & World Report

Bright Focus Foundation

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