Diabetes not related to abnormal biomarkers of Alzheimer’s disease

An analysis of clinical data from over 4,000 people demonstrated that diabetes is not related to underlying Alzheimer’s disease (AD) brain pathology. Therefore, diabetes and AD appear to affect cognition differently and independently of each other.

Diabetes is common in people with AD and having diabetes in midlife is a risk factor for being diagnosed with AD later in life [1]. In addition, similar patterns of glucose dysregulation in the brain are observed across the 2 disorders [2]. However, as previous research mainly focused on the relationship between diabetes and clinical AD diagnosis, the question remains whether diabetes is related to underlying AD brain pathology, and whether AD biomarkers and diabetes are synergistically associated with cognitive decline. PhD student Veerle van Gils (Maastricht University, the Netherlands) aimed to answer these questions and analysed clinical data from over 4,000 people with either normal cognition or mild cognitive impairment (MCI) from multiple European memory clinics [3]. Available data included diabetes diagnosis, AD biomarkers (amyloid and tau in liquor), and cognition (at baseline and at least at 1 follow-up).

In people with normal cognition (n=2,678), no correlation was found between diabetes diagnosis or abnormal blood glucose and either abnormal amyloid or tau. In people with MCI (n=1,494), there was a significant correlation between diabetes diagnosis and abnormal levels of amyloid (P=0.04). However, this correlation was the opposite of what was expected, as having a diagnosis of diabetes was a negative predictor for having abnormal amyloid.

As expected, both abnormal amyloid and abnormal tau levels were associated with memory dysfunction at baseline and a decline of memory over time. The AD biomarker levels were also associated with a decline in attention and in executive function over time. Diabetes diagnosis was only associated with attention dysfunction and executive dysfunction at baseline.

Based on these results, Ms van Gils concluded that “there are no synergistic effects of AD biomarkers and diabetes on cognitive functioning and decline. Thus, diabetes and AD affect cognition differently and independently of each other.”

1. Chatterjee S, Mudher A. Front Neurosci. 2018;12:383.
2. Shieh JC-C, et al. Mol Neurobiol. 2020;57:1966–1977.
3. Van Gils V, et al. Insulin signalling and cognitive decline in elderly: a relation to Alzheimer’s disease pathophysiology? Abstract S12.02, ECNP Congress 2022, 15–18 October, Vienna, Austria.

 

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Posted on 28 November, 202225 March, 2024