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Multimorbidity accelerates cognitive decline in older adults

Multimorbidity using a validated index weighted to physical functioning was linked to faster decline in global cognition and verbal memory over time among U.S. middle-aged and older adults, according to data from a large nationally representative cohort study.

“Chronic conditions have a broad and far-reaching impact on individuals. We can most easily ‘see' the impact of multimorbidity on physical health, such as a slower walking speed and use of assistive devices like a cane or walker,” Melissa Wei, MD, MPH, from the division of general medicine, University of Michigan Medical School, told Healio Psychiatry. “It is harder to quickly recognize the effects on cognitive health. Basic cognitive screening tests do not easily pick up on subtle changes.”

Participants without dementia from the Health and Retirement Study underwent interviews regarding physician-diagnosed conditions. The researchers used their answers to compute their multimorbidity-weighted index (MWI) that weights diseases to physical functioning.

They examined global cognition using the modified Telephone Interview for Cognitive Status, 10-word immediate recall and delayed recall to determine memory, and serial 7s outcomes to determine information processing speed. More specific cognitive domains, including episodic memory and working memory, were also assessed.

Overall, 14, 265 participants (60% female) contributed 73,700 observations.

Analysis indicated that each point rise in MWI was linked to declines in global cognition (0.04; 95% CI, 0.030.04), immediate recall (0.01; 95% CI, 0.01-0.02), delayed recall (0.01; 95% CI, 0.01-0.02) and working memory (0.01; 95% CI, 0.010.02). However, multimorbidity was tied to accelerated declines in global cognition of 0.003 points per year faster (95% CI, 0.002-0.004), immediate recall of 0.001 words per year faster (95% CI, 0.001-0.002) and working memory of 0.006 incorrect serial 7s per year faster (95% CI, 0.004-0.009).

“The current study provides evidence that physical impairment and cognitive impairment frequently coexist in adults with multimorbidity, and further, multimorbidity worsens cognitive health and the rate of cognitive decline,” Wei told Healio Psychiatry. “Physical health and mental health are intricately linked. It is important for clinicians to ask their patients how multimorbidity is impacting their overall health and wellbeing, and what we can do better as a provider.” – by Savannah Demko

Disclosure: The authors reported no relevant financial disclosures.