Multiple Chronic Conditions Up Risk for Memory Decline

Megan Brooks

September 28, 2015

Having multiple chronic conditions increases the risk for mild cognitive impairment (MCI) and dementia in older adults, according to new data from the Mayo Clinic Study of Aging.

"The tendency has been to look at a single disease and its association with cognitive impairment. Here, we provide new information that indicates that having multiple chronic medical conditions should be recognized as a risk factor for developing MCI," senior author Rosebud Roberts, MB, ChB, professor of epidemiology and neurology, Mayo Clinic, Rochester, Minnesota, told Medscape Medical News.

She said the implications for clinicians are clear.

"They need to educate patients about prevention of medical conditions, and for those who already have the conditions, to ensure that patients do what is needed to ensure that the condition is under control. It also suggests that it is important for doctors to take the total burden of disease into account in treating patients and not look at one disease in isolation," said Dr Roberts.

Dr Rosebud Roberts

The study is published in the September issue of the Journal of the American Geriatrics Society.

The cohort included 2176 elderly adults (mean age, 78.5 years; 50.6% male) with normal cognitive function at baseline. Most (n = 1884 [86.6%]) had multiple chronic conditions, including but not limited to hyperlipidemia, hypertension, diabetes, depression, and coronary artery disease (CAD).

During a median follow-up of 4 years, 583 patients developed incident MCI or dementia. Those with two or more chronic conditions were 38% more likely to develop MCI/dementia; those with four or more conditions had a 61% increased risk, compared with those with none or one chronic condition. In addition, men were at higher risk than women.

Table. Risk for MCI/Dementia With Multimorbidity (95% Confidence Interval)

No. of Conditions Total Sample Men Women
Two or more 1.38 (1.05 - 1.82) 1.53 (1.01 - 2.31) 1.20 (0.83 - 1.74)
Four or more 1.61 (1.21 - 2.13) 1.75 (1.15 - 2.66) 1.43 (0.98 - 2.10)


"We were not able to investigate the specific mechanisms by which multimorbidity contributes to cognitive impairment; however, our findings are consistent with the hypothesis that multiple etiologies may contribute to late-life cognitive decline and thus emphasize the importance of prevention," Dr Roberts said in a news release. "They also emphasize that chronic diseases, once diagnosed, should be efficiently managed."

Big Picture

"This study provides more evidence that multiple chronic conditions are a contribution to MCI and memory complaints and that they do need to be controlled," Jessica Leigh Zwerling, MD, director of the Memory Disorders Center at Montefiore Health System and associate director of the Montefiore Einstein Center for the Aging Brain, in New York City, noted in an interview with Medscape Medical News.

"This contributes to the bigger picture of needing a multidisciplinary team with coordinated care to make sure that our patients age well and that we control their vascular risk factors," added Dr Zwerling, who was not involved in the study.

"Although the current study has several strengths, it's important to realize that the effects of risk factors (including heterogeneous chronic diseases) on dementia are complex," Jin-Tai Yu, MD, PhD, from the Memory and Aging Center, Department of Neurology, University of California, San Francisco, who was not involved in the study, told Medscape.

However, these "interesting findings seem to be consistent with our study, which validated several modifiable risk factors for Alzheimer's disease. Both studies highlight the potential for delaying or preventing MCI and dementia," Dr Yu said.

It is also worth noting, he said, that the most frequent co-occurring pairs of chronic conditions in individuals with multimorbidity were hypertension and hyperlipidemia (50.4%), hypertension and arthritis (32.9%), hyperlipidemia and arthritis (30.7%), CAD and hyperlipidemia (27.5%), and hypertension and CAD (25.5%).

"Several previous studies have shown that these vascular risk factors are associated with the risk of MCI and dementia, especially for vascular cognitive impairment and vascular dementia. Hence, there's not a lot of surprise here," Dr Yu said.

The study had no commercial funding. Dr Roberts has disclosed no relevant financial relationships. The original article contains a complete list of author disclosures.

J Am Geriatr Soc. 2015;63:1783-1790. Abstract


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