Dementia Risk Escalates When Both Gait and Memory Falter

— Parallel declines in walking speed and memory increase dementia risk sixfold

MedpageToday
A senior couple out for a walk

Older adults who had declines in both walking speed and memory abilities had a higher risk of dementia than people who declined in only one of those domains, a meta-analysis showed.

By itself, slower gait roughly doubled the risk of developing dementia in pooled analyses, while memory problems tripled it. But people who experienced parallel declines in gait and memory had more than six times higher risk of incident dementia than people who had no decline in memory or walking speed, reported Qu Tian, PhD, MS, of the National Institute on Aging in Baltimore, and co-authors, in JAMA Network Open.

This work has clinical implications and provides important contributions to research about early signs of underlying dementia, Tian said.

"Older persons with dual decline in memory and gait speed should receive further attention to address issues that may increase dementia risk, such as cardiovascular and metabolic risk factors," she told MedPage Today. "They may be a group to target for preventive or therapeutic interventions."

The findings echoed those seen in the Gait and Brain cohort study led by Manuel Montero-Odasso, MD, PhD, of the University of Western Ontario in Canada, which showed that decline in both gait velocity and cognition over time carried a higher risk for incident dementia than motor decline or cognitive decline alone.

"Importantly, the identification of dual decliners in clinical practice will help point to a subgroup of patients that may benefit most for intensive prevention strategies," Montero-Odasso told MedPage Today. "In light of emerging evidence that lifestyle interventions -- such as physical exercise, incorporating Mediterranean diets, or intensive blood pressure control -- may help delay progression to dementia in older adults at risk, knowing which individuals are at higher risk to progress becomes capital."

In their meta-analysis, Tian and her team evaluated six prospective cohort studies spanning 8,699 participants that were conducted from 1997 to 2018 in the U.S. and Europe.

Study participants were at least age 60, had an initial gait speed over 0.6 m/s (no overt mobility limitations) and no prevalent baseline cognitive impairment, and had repeated measures of gait speed and memory before being diagnosed with dementia. Mean follow-up ranged from 6.6 to 14.5 years.

The researchers classified participants in each study into four groups:

  • Memory decline only
  • Gait speed decline only
  • Dual decline
  • No decline (referred to as "usual agers")

The investigators defined gait decline as loss of 0.05 m/s or more per year and memory decline as being in the lowest tertile of annualized change. Across the six studies, they focused on verbal episodic memory when available, especially immediate recall.

Mean participant age ranged from 70 to 74 and mean gait speed ranged from 1.05 to 1.26 m/s. Incident dementia ranged from 5 to 21 per 1,000 person-years.

Compared with usual agers, people with dual decline had 5.2 to 11.7 times the risk of developing dementia, after adjusting for demographics and baseline memory and gait speed (pooled HR 6.28, 95% CI 4.56-8.64).

People with memory decline alone had 2.2 to 4.6 times higher risk of incident dementia (pooled HR 3.45, 95% CI 2.45-4.86) and those with gait decline alone had 2.1 to 3.6 times higher risk (pooled HR 2.24, 95% CI 1.62-3.09).

Zeroing in on verbal episodic memory and immediate recall allowed the analysis to capture early decline in Alzheimer's-related cognitive measures, the researchers noted. "Focusing on memory, rather than executive function or processing speed, also allows us to better differentiate phenotypic groups because gait speed is associated with executive function within cognitive domains."

Dual decline can be captured early by routinely administering gait speed assessments and free recall memory tests, Tian and co-authors added. "At this stage, this group should be carefully evaluated for potentially reversible risk factors for dementia. However, research focusing on biological and physiological characteristics that explain why individuals with dual decline are at such high risk of developing dementia may lead to new opportunities for prevention."

Memory measures and dementia diagnosis procedures varied across studies, which is a limitation of this meta-analysis, the researchers noted. Another potential limitation is possible regression to the mean. In some studies, participants with dual decline had higher baseline gait and memory performance than usual agers and more room to decline than people with lower baseline performance, though the researchers minimized this possibility by adjusting for baseline measurements.

Disclosures

Tian reported no disclosures. One co-author reported receiving grants from the National Institutes of Health/National Institute on Aging during the conduct of the study and receiving grants from Biogen outside the submitted work; another co-author reported receiving grants from the Italian Ministry of Health during the conduct of the study; and another reported serving as a consultant on research design for Merck and Biophytis.

Primary Source

JAMA Network Open

Source Reference: Tian Q, et al "Association of Dual Decline in Memory and Gait Speed With Risk for Dementia Among Adults Older Than 60 Years: A Multicohort Individual-Level Meta-analysis" JAMA Netw Open 2020; 3(2): e1921636.