In a large population-based study, researchers have found a link between poor cardiovascular and cognitive function at age 18 and early-onset dementia.
The lead researcher was Jenny Nyberg, Ph.D., of the Center for Brain Repair and Rehabilitation at the University of Gothenburg in Sweden. Study results were published March 6 in Brain.
The researchers noted that since individuals with early-onset dementia—that is, before age 65—are an underrecognized patient group, and since modifiable risk factors for the illness are unknown, they wanted to assess whether physical fitness might be such a factor.
Their study included more than 1 million Swedish men. At age 18, the men had mental and physical exams as part of their military conscription process. They were then followed for up to 42 years (26 years on average) to see which ones developed early-onset dementia. Such information was available via the Swedish National Hospital Discharge Register. The researchers then used the data to see if there was any association between cardiovascular and cognitive function at age 18 and early-onset dementia.
The researchers found that such an association was evident, with their data showing that poor cardiovascular function as well as poor cognitive performance at age 18 were associated with an increased risk of early-onset dementia, but the highest risks were found for individuals who had both. The men with poor performance in both realms were seven times more likely to develop early-onset dementia than men who had neither.
A surprising finding, they noted, was that high cardiovascular fitness in individuals with low cognitive performance reduced the risk of early-onset dementia by 48 percent. And high cognitive performance in individuals with low cardiovascular fitness reduced the risk of early-onset dementia by 74 percent.
The researchers also assessed whether one domain of cognitive performance correlated more with early-onset dementia than others did. They found, however, that low performance in all four domains of interest—logic cognition, verbal cognition, visuospatial cognition, and technical cognition—resulted in a significantly increased risk for early-onset dementia.
But how might cardiovascular fitness at a young age influence the risk for early-onset dementia? By enhancing neuroplasticity in the young brain, the researchers speculated, and this neuroplasticity in turn might have a protective or disease-slowing effect on dementia.
“This technically well-executed study is among the first to link cardiovascular fitness and cognitive functioning at a young age with early-onset dementia,” Constantine Lyketsos, M.D., chair of psychiatry at Johns Hopkins Bayview Medical Center and a geriatric psychiatrist, told Psychiatric News. “As the study is observational, high confidence in a causal link is not possible. However, the findings are consistent with other research linking cardiovascular health or disease and cognitive functioning or reserve with late-onset dementia decades later. Much research is needed to translate this finding into a specifically actionable preventative intervention. For now, active efforts to maintain cardiovascular and cognitive fitness through the lifespan, starting at a young age, offer some promise at preventing or delaying the onset of dementia at mid or later life.”
The research was funded by several Swedish foundations and research organizations. ■