Exercise of Any Level Linked to Reduced All-Cause Mortality in Individuals with Dementia

Following a diagnosis of dementia of any cause, initiating physical activity (PA) of any intensity was associated with a significantly lower risk for all-cause mortality of at least 20% in a cohort of more than 60 000 Korean adults, according to new research findings published in the British Journal of Sports Medicine.

Yong-Moon Park, MD, MS, PhD

Courtesy of Fay W. Boozman College of Public Health

Physical activity of any intensity after a diagnosis of dementia is associated with a significantly lower risk for all-cause mortality.

Higher levels of PA were linked to a dose-dependent decrease in mortality risk (P <.001) and, after multivariable adjustment, participants who remained physically active both before and after a diagnosis of dementia compared with those who did not engage at all, had the lowest risk of mortality, at 29% (HR 0.71, 95% CI, 0.65-0.79).

When they evaluated the effects on mortality risk of sustained PA across levels of intensity, study authors reported an average risk reduction of 30%:

• Light: HR 0.70, 95%CI 0.67 to 0.75
• Moderate: HR 0.74, 95%CI 0.64 to 0.86
• Vigorous: HR 0.70, 95%CI 0.61 to 0.79

In particular, among the small group of study participants with vascular dementia (VaD), risk of mortality was reduced by 36% among the those who maintained regular PA compared with those who had never engaged, reported the research team led by Yong-Moon Park, MD, MS, PhD, assistant professor, department of epidemiology, Fay W Boozman College of Public Health at the University of Arkansas or Medical Sciences in Little Rock, AK. The team observed that the association between PA and reduced mortality risk was consistent across types of dementia, including Alzheimer disease (AD) and VaD.

When PA was treated as a continuous variable, Park and colleagues observed a significant 3% reduction in mortality risk for every 100 metabolic equivalent of task (MET)-min/week increase in PA after a dementia diagnosis; the finding was consistent across all-cause dementia and subgroups, they wrote.

“As dementia cannot be reversed with any medications, a nonpharmacologic approach, such as lifestyle modification, is considered important to modify the progression of dementia. Our study has important public health implications, highlighting the significance of continuous engagement in regular physical activity both before and after the diagnosis of dementia among individuals with all dementia subtypes," the authors wrote.

The existing data on the association between remaining physically active and reduced risk of mortality in individuals with dementia comes from studies that were limited to measuring PA at a single point in time, according to the researchers. This study is the first to investigate whether changes in PA are associated with mortality risk, including the amount and the intensity of PA, both before and after a dementia diagnosis.

Study Details, Findings

For the retrospective cohort study, Park et all tapped data from the Korean National Health Insurance Service Database, including 60 252 individuals (mean age 74 years, 39% men) newly diagnosed with dementia between 2010 and 2016 who underwent health examinations both before and after diagnosis. PA was assessed via self-report, using the International Physical Activity Questionnaire–Short Form. The cohort was grouped based on changes in regular PA before and after a dementia diagnosis and were followed for all-cause mortality for an average of 3.7 years, according to the study.

There were 16 431 (27.3%) deaths during the follow-up. Park et al reported that survival probabilities increased in individuals who maintained regular PA before and after their dementia diagnosis (log-rank P <.001). After adjusting for confounding variables, they observed a gradually decreasing risk of mortality as the amount of PA after the diagnosis of dementia increased from 1 to 499 MET-min/week (HR 0.82, 95% CI 0.79 to 0.85) to ≥1000 MET-min/week (HR 0.66, 95% CI 0.62 to 0.70), compared no exercise at all (P_trend <.001), The trends were similar among study participants with AD (HR 0.65, 95% CI 0.61 to 0.70; P_trend <.001) and in those with VaD (HR=0.65, 95% CI 0.55 to 0.77; P_trend <.001) in the groups engaging in the most vigorous PA (≥1000 MET-min/week.)

Forty-two percent of the study participants were sedentary and only 11.8% reached the recommended level of PA for adults of more than 1000 MET-min/min, according to the study. Recent guidelines from the World Health Organization recommend minimum PA levels for older adults and state that engagement in some PA is better than none at all and that sedentary behavior should be limited.

Unfortunately, fewer than one-third of older adults meet recommended PA levels, Park and colleagues wrote, and those with dementia likely fall below those already diminished levels. The authors believe their results have parallel implications, that their findings “suggest even a small amount of PA could be beneficial in decreasing the risk of mortality in patients with dementia.”

Among the study's limitations the authors cite the drawbacks of the retrospective cohort design, including the potential for reverse causality. They also point to the reliance on administrative data for a dementia diagnosis and use of self-report for PA and lifestyle data. The homogeneity of the study population naturally limits the generalizability of the results to other groups.

Source: Park K-Y, Huh Y, Nam GE, et al. Changes in physical activity and all-cause mortality among individuals with dementia: a cohort study using the National Health Insurance Service Database in Korea. Br J Sports Med. 2024;58(21):1258-1266. https://bjsm.bmj.com/content/58/21/1258