Comorbid diabetes and multiple sclerosis negatively affect cognitive functioning in older adults

Area of Science:

• Neuroscience
• Gerontology
• Endocrinology

Background:

• Multiple sclerosis (MS) and diabetes mellitus are chronic conditions impacting cognitive function.
• Limited research exists on the combined cognitive effects of MS and diabetes in older adults.
• Cognitive deficits in processing speed, executive function, learning, and memory are common in both conditions.

Purpose of the Study:

• To evaluate the cumulative impact of diabetes and MS on cognitive functioning in older adults.
• To determine if comorbid diabetes and MS result in greater cognitive impairment than either condition alone.

Main Methods:

• Cross-sectional study comparing individuals with MS (n=108) to healthy controls (n=114).
• Cognitive assessment included tests of fluency, processing speed, and learning/memory (e.g., TMT, SDMT, HVLT-R).
• Linear regression models analyzed the association of diabetes and MS, individually and combined, with overall cognitive z-scores, adjusting for covariates.

Main Results:

• Both diabetes and MS were independently associated with poorer overall cognitive performance.
• The combination of diabetes and MS demonstrated a significant negative effect on overall cognition (b = -0.67, p < .001).
• Comorbid diabetes and MS were specifically linked to deficits in semantic fluency and verbal learning/recall.

Conclusions:

• Having both diabetes and MS significantly impairs cognitive functioning in older adults.
• Comorbidities like diabetes can exacerbate cognitive difficulties in individuals with MS.
• Clinicians should assess and consider the role of comorbidities in cognitive decline among older MS patients.