Physical Performance vs Dementia in Oldest Old

Alvin B. Lin, MD, FAAFP
 
Dr. Lin is an associate professor of family and community medicine at University of Nevada School of Medicine and an adjunct professor of family medicine and geriatrics at Touro University Nevada College of Medicine. He also serves as an advisory medical director for Infinity Hospice Care and as medical director of Lions HealthFirst Foundation. Dr. Lin maintains a small private practice in Las Vegas, NV. The posts represent the views of Dr. Lin, and in no way are to be construed as representative of the above listed organizations. Dr. Lin blogs about current medical literature and news at http://alvinblin.blogspot.com/.

In the geriatric kingdom, there's old, and then there's old. Roughly speaking, we categorize 65-75yo as young old, 75-85yo as middle old, and >85yo as old old. UC Irvine has had a population-based, longitudinal, epidemiologic study, The 90+ Study, running for the past decade looking at the effects of aging in these oldest of old. In an article published last month in JAMA Neurology, the authors noted an association between physical performance and dementia: poor performance was associated w/greater odds of dementia.

This cross-sectional analysis was performed on 629 participants, three-fourths of whom were female with an average age of 94 years, followed for 6+ years. Physical performance was measured in 4 ways: 4 meter timed walk, 5 timed chair stands, standing balance, & grip strength. Points were allotted based upon performance quartile w/4 points going to those in the top 25% of performance scores, 3 points to those in the 50-75% and so on & so forth. No points were given to those who were unable to perform the specific activity.

Now think about this for a minute. We're not even talking about aerobic fitness as measured by VO2max or METs. Sure, a chair stand is a semi-squat and grip strength is well, strength. But hey, we didn't even assess push-ups, pull-ups, or even plank time. So we're not even talking about "truly fit", but rather just enough to perform one's activities of daily living.

Of course, due to the nature of this (observational) study, we can't prove whether lack of physical performance caused dementia or whether dementia caused loss of physical performance. Perhaps the two are unrelated? Doubtful, especially in light of my previous post regarding mid-life fitness' link to dementia later on in life. So the bottom line hasn't changed: don't just sit there, do something!