Glucose and the Slippery Slope Towards Dementia

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

With many tests, the results aren't always clear cut, black & white. There's often quite a bit of gray in between. For instance, normal fasting glucose is less than 100mg/dL while diabetes is greater than 125 mg/dL on two different occasions. But what about numbers from 100mg/dL up to 124mg/dL? They lay in that slippery slope that we now call impaired fasting glucose. So what. Why bother to care?

Turns out that in a longitudinal study published last week in the New England Journal of Medicine, the authors concluded that higher average glucose levels were linked to an increase risk of dementia, something that we've known about diabetes for quite some time. In this particular study, the authors followed for almost 7yrs 2,067 participants who were cognitively intact at baseline. In those w/diabetes, higher A1c values were linked to as much as 40% greater risk of developing dementia. In those w/o diabetes, even an average glucose of 115mg/dL was linked to 18% greater risk compared to average glucose of just 100mg/dL.

Now you have to understand that this study only proves a link. It doesn't demonstrate cause & effect. And it definitely doesn't say anything about what might happen if you actively lowered your glucose. That bit of information will hopefully come out of current/future studies. In the meantime, I think it's still reasonable to be as aggressive as possible and aim for fasting glucose less than 100mg/dL via healthy nutrition & regular physical activity. No harm in a healthy lifestyle, right?