Leisure Time Physical Activities’ Association With Cognition and Dementia: A 19 Years’ Life Course Study

Abstract

IntroductionCognitive impairment is one of the main disabilities in dementia. Physical activity (PA) has been suggested as protective for dementia. However, the findings are disparate in studies, and the question of whether this is because of reverse causality is still open. We aimed to explore the association of PA with cognition in people who later developed dementia compared to those who did not.MethodSince 2001, 11,512 (55% women) participants over the age of 50 years had taken at least one cognitive test in the Tromsø Study. Of these, 1,123 (58% women) later developed dementia. The cases were extracted from hospital journals and entered into an endpoint registry. Leisure time PA (LTPA) was self-reported. Multilevel mixed-effects linear regression was used to address whether LTPA was associated with cognition, stratified by those later developing dementia, and dementia-free in a separate analysis.ResultsLeisure time PA was associated with scores in cognitive tests that were 55% (z-score 0.14) higher in those who did not develop dementia. For those in a preclinical phase of dementia, there was no association with LTPA on global cognitive scores. However, in a multifactorial test on processing speed and memory, women had a positive association with processing speed and memory.ConclusionLeisure time PA had a positive association with global cognition function only for those who did not develop dementia. In women who were developing dementia, LTPA had a positive association with processing speed and memory, while in men, there were no such associations.

Perimenopausal Physical Activity and Dementia Risk: A Systematic Review

“…Study sample size ranged from 191 to 1,136,846. 13 of the 14 studies included were longitudinal cohort studies 9 12 13 14 15 16 17 18 19 20 21 22 23 with one additional case-control study 24 . Data from large-scale cohort studies were included, including the CADIE cohort study from Finland 17 20 21 ; Swedish PPSW cohort study 9 13 18 ; Swedish national march cohort study 22 ; Danish national hospital register and Danish central population register 24 ; Copenhagen city heart study and Copenhagen general population study 19 ; the Million women Study 12 ; UK Bio-bank 23 ; Tromsø 15 ; Japan Public health center-based prospective disabling dementia study 14 and the Murakami cohort study 16 .…”

“…Physical activity was predominantly assessed via the use of self-perceived questionnaires, including the Saltin-Grimby physical activity level scale 9 15 ; Japan public health center-based prospect study-physical activity questionnaire 16 ; international physical activity questionnaire 23 , and Likert scale style questionnaires 12 14 17 18 19 20 21 22 24 . An objective assessment of physical fitness using a stepwise-increased maximal ergometer cycling test was utilized in one study 13 .…”

“…Hence suggesting that LTPA must reach a certain intensity before a significant relationship can be found with dementia risk reduction. Johnsen et al also displayed that high LTPA resulted in improved scoring in cognitive tests in both dementia-free participants and those who later developed dementia (▶table 3 [15]). In summary, three studies provided evidence for a dose-response relationship between LTPA and dementia risk, where a higher exercise intensity, frequency, or both, related to a greater decrease in dementia risk.…”

“…and dementia risk despite statistical adjustments for cardiovascular co-variables [9,[13][14][15][16]19,23], hence suggesting that mid-life physical activity contributes independently, as a modifiable risk factor, to reducing dementia risk [5,20]. Indeed, it has been shown that the increased risk of dementia in females is not explained by risk-factor accumulation, nor by greater longevity [28,29].…”

Incidence of dementia over a period of 20 years in a Norwegian population

“…25,26 Forecasts may be complicated as the modifiable risk factors for dementia also affects the estimates. 15 Though some of the risk factors, such as hypercholesterolemia, 27 hypertension, and smoking prevalence, are decreasing 13,15,28 and protective factors such as physical activity in leisure time 12,29,30 and education levels are increasing, 31 other risk factors such as the prevalence of diabetes and obesity are increasing. 29,32 However, overall improved risk factor levels in the population have already been shown to cause a decrease in incidence of stroke and myocardial infarction, and could also have contributed to the decrease in the incidence of dementia.…”