Physical activity of any intensity is linked to a lower risk of death after a dementia diagnosis
Physical activity of any intensity after a diagnosis of dementia is associated with around a 30 per cent lower risk of death, according to a research study published online in the British Journal of Sports Medicine last week (30 October).
The researchers conclude that those with a diagnosis of dementia should be encouraged to keep up or start an exercise routine, especially as average life expectancy after a diagnosis of dementia may be only around four to five years.
The article's first author is Kye-Yeung Park, who is based at the Department of Family Medicine, Hanyang University College of Medicine, Seoul, Korea. There are eight co-authors, all of whom are based in Seoul or at the University of Arkansas for Medical Sciences in the USA.
Previous researchers have linked physical activity with a lower risk of death in people with the disease, but these studies have focused on a single point in time. As a result, it’s not clear if changes in the amount or intensity of physical activity before and after diagnosis might be influential, say the researchers.
To explore this further, Kye-Yeung Park and colleagues drew on data from the Korean National Health Insurance Service Database, involving 60,252 people newly diagnosed with dementia between 2010 and 2016 who had undergone health check-ups two years before and after their diagnosis. The average age of the participants was 74, and 43,276 (72 per cent) of them had Alzheimer’s disease and 7,536 (12.5 per cent) had vascular dementia.
Physical activity was assessed at each of the check-ups using the International Physical Activity Questionnaire–Short Form (IPAQ-SF).
Three types of exercise levels
- exercise, such as running, aerobics, fast cycling and climbing for more than 20 minutes was defined as vigorous intensity
- moderate intensity included fast walking, doubles tennis, and cycling at a regular pace for more than 30 minutes; light intensity included activities, such as walking for more than 30 minutes.
- regular physical activity was defined as vigorous intensity exercise three or more times a week, for at least 20 minutes, or moderate intensity exercise five or more times a week, for at least 30 minutes
Participants were categorised according to the changes in regular physical activity in the two years before and after their diagnosis: non-exercisers (78 per cent; 47,050); quitters (just over 10 per cent; 6,212); starters (8 per cent; 4,801); and maintainers (just over 3.5 per cent; 2,189).
During an average monitoring period of nearly four years to the end of 2019, 16,431 (27 per cent) of the study participants died.
Sustained engagement in regular physical activity before and after the diagnosis of dementia was associated with the greatest reduction in the risk of death, irrespective of dementia type.
Quantity of activities appears to be a key factor
Higher physical activity levels after diagnosis were associated with a decrease in the risk of death that was dependent on quantity, but not on intensity.
Compared with remaining inactive, maintaining an exercise routine was associated with a 29 per cent lower risk of death. If this was of light intensity, the risk was 30 per cent lower. The reductions in risk for moderate and vigorous intensity activity were, respectively, 26 per cent and 30 per cent. And taking up exercise of any intensity after diagnosis was associated with at least a 20 per cent lower risk of death.
When considering physical activity as a continuous variable, the risk of death fell by 3 per cent for every 100 MET weekly increase – equivalent to adding five minutes of brisk walking on five days of the week – in physical activity after diagnosis for all types of dementia. METs express the amount of energy (calories) expended per minute of physical activity, relative to energy expended at rest.
Our study highlights the potential clinical value of encouraging people with dementia to maintain or start physical activity, regardless of its intensity, after their dementia diagnosis [Kye-Yeung Park et al]
Caveats and conclusions
As the study is observational in nature, Kye-Yeung Park and colleagues acknowledge that cause cannot be established. Their findings might have been due to reverse causality, they say, whereby those with less severe dementia and fewer functional limitations might have been more likely to remain physically active. Information on the type of physical activity participants said they did wasn’t available either.
Nevertheless, Kye-Yeung Park and colleagues say: ‘Building on the established protective effect of [physical activity] against all-cause mortality, our study suggests that even at low levels, [physical activity] might significantly diminish mortality risk in individuals with dementia.’
They conclude: ‘Our study highlights the potential clinical value of encouraging people with dementia to maintain or start physical activity, regardless of its intensity, after their dementia diagnosis.’
To access the full version of the article – titled Changes in physical activity and all-cause mortality among individuals with dementia: a cohort study using the National Health Insurance Service Database in Korea Doi: 10.1136/bjsports-2024-108264 – click
Author: Ian A McMillan
Share it with
