People with a genetic predisposition to dementia can reduce their risk by up to 35 percent by increasing their fitness, according to a study published in the British Journal of Sports Medicine. High levels of fitness are also linked to better cognitive ability, according to the study by researchers from Karolinska Institutet.
Cardiorespiratory fitness is the body's ability to deliver oxygen to the muscles and declines with age as skeletal muscle is lost. Fitness declines by about three to six percent per decade when people are in their 20s and 30s, but this accelerates to more than 20 percent per decade when people reach their 70s.
Most previous studies that have examined the effect of fitness on cognitive function and dementia risk have included small numbers of participants. For this study, the researchers examined a much larger group, using data from 61,214 dementia-free people aged 39 to 70 years from the UK Biobank database.
At enrolment, a six-minute cycle test was carried out to assess fitness, cognitive function was assessed using neuropsychological tests and genetic susceptibility to dementia was assessed using a genetic risk score for Alzheimer's disease. During the follow-up period of up to 12 years, 553 people, corresponding to 0,9 percent, were diagnosed with dementia.
"Our study shows that higher fitness is linked to better cognitive function and reduced dementia risk. In addition, high fitness could attenuate the effect of genetic risk for all dementias by up to 35 percent," says Weili Xu , professor of Geriatric Epidemiology at the Department of Neurobiology, Care Sciences and Society , Karolinska Institutet and the study's last author, and continues:
"Our findings suggest that maintaining good fitness may be a strategy to prevent dementia, even among people with high genetic susceptibility."
This is an observational study and therefore cannot establish cause and effect, and the researchers cite various limitations to their findings. Most importantly, the number of dementia cases may have been underestimated because UK Biobank participants are generally healthier than the general population.
The study was funded by the Swedish Research Council, the Swedish Research Council for Health, Working Life and Welfare and the Karolinska Institutet Research Foundation.
This news article is based on a press release from the British Journal of Sports Medicine.
Publikation
"Association of cardiorespiratory fitness with dementia risk across different levels of genetic predisposition: a large community-based longitudinal study", Shuqi Wang, Liyao Xu, Wenzhe Yang, Jiao Wang, Abigail Dove, Xiuying Qi, Weili Xu, British Journal of Sports Medicine, online 20 november 2024, doi: 10.1136//bjsports-2023-108048.
