Cycling may lower dementia risk, study finds
Cycling instead of driving or taking public transport is linked to a 19 per cent lower risk of developing dementia.
An analysis of nearly 480,000 people in Great Britain also found regular cyclists had a 22 per cent lower risk of Alzheimer’s disease compared with those using cars, buses or trains.
More than 55m people worldwide currently live with dementia, with numbers predicted to almost triple by 2050.
Physical activity has been identified as one of 14 factors that could prevent or delay about 45 per cent of cases.
Researchers from the UK Biobank study tracked the health of more than 500,000 people aged 40 to 69, recruited between 2006 and 2010.
Participants, who were aged 56.5 on average, answered questionnaires about which transport modes they used most often for non-work journeys.
Over a median follow-up of 13.1 years, 8,845 developed dementia and 3,956 developed Alzheimer’s disease.
The study examined nonactive travel (car, bus, train), walking, mixed walking (walking with nonactive modes), cycling, and mixed cycling (cycling with other modes).
Brain scans showed that cycling and mixed cycling were most strongly linked to greater hippocampal volumes.
The hippocampus is the part of the brain responsible for memory and learning.
Walking and mixed walking were associated with a 6 per cent lower dementia risk but, unexpectedly, a 14 per cent higher Alzheimer’s risk.
Dr Joe Verghese, professor and chair of neurology at Stony Brook University in New York, who was not involved in the study, said: “This study is the first to show that cycling is linked not only to a lower risk of dementia but also to a larger hippocampus.”
The APOE ε4 gene, the strongest genetic risk factor for Alzheimer’s, also influenced outcomes.
Participants without this gene variant had a 26 per cent lower dementia risk, while carriers had a 12 per cent lower risk.
“Travel modes were self-reported at a single time point, so we don’t know how people’s habits changed over time,” said Dr Sanjula Singh, instructor of neurology at Harvard Medical School.
Singh was not involved in the study.
“Most participants were White and healthier at baseline, so the results may not apply to all communities.
“And, most importantly, as this is an observational study, it cannot prove that cycling directly prevents dementia.
“It only shows an association.”
Older adults who cycle regularly are likely a healthier subgroup, and cycling may also reflect favourable genetics, with risk lowest among those without genetic susceptibility, Verghese said.
Participants choosing active travel were more often women, nonsmokers, more educated, more physically active overall, with lower body mass index and fewer chronic conditions.
Those in the cycling groups were more often men with healthier lifestyles.
The higher Alzheimer’s risk linked with walking could reflect participants already having balance or driving issues, said Dr Glen Finney, behavioural neurologist and director of the Memory and Cognition Program at Geisinger Health System in Pennsylvania.
Walking pace matters too, Finney added. Leisurely walking, especially for short distances, may not give the same benefit as brisker, longer walks.
The study did not report frequency, pace or duration of walking or cycling.
