Table 4 Summary of reviews examining whether physical activity in healthy older adults is associated with a reduced risk of developing Alzheimer’s disease and related dementias

Beckett et al. 2015 [4]

7

MA

9

Prospective cohort studies

Cognitively healthy older adults, ≥65 years

Any PA

PA is associated with a ↓ risk of developing AD in adults 65 years and older. RR of .61, 95% CI 0.52-0.73 for physically active older adults compared to non-active counterparts.

Barnes et al., 2011 [5]

4

NR

2

Prospective cohort studies

No dementia diagnosis at baseline

Any PA

Of seven potentially modifiable risk factors examined, physical inactivity contributed to the largest proportion of AD cases in the US and a substantial proportion of cases globally.

Beydoun et al., 2014 [6]

7

MA

8

Cohort studies with sample size > 300

Generally healthy older adults

Any PA

RR of AD = 0.58 (0.49,0.70) for the group reporting the highest PA versus the lowest PA. PAR% = 31.9%, 95% CI 22.7–41.2%.

Daviglus et al., 2011 [7]

9

NR & MA

12

Cohort studies with sample size ≥ 300

General population in developed countries, ≥50 year

Self-reported PA.

NR: 8/12 studies reported a protective effect of moderate to high levels of PA on risk of AD; however, the associations were not always significant after adjusting for confounding factors or when looking across high and moderate activity levels.

MA: Across 9 cohort studies, higher PA associated with ↓risk of incident AD (HR = 0.72); however, substantial heterogeneity among studies.

Hamer et al., 2009 [8]

11

MA

5

Prospective cohort studies

Diagnosis of dementia/AD

Any PA

PA ↓risk of AD by 45%. RR of AD = 0.55 for the group reporting the highest PA versus the lowest PA

Patterson et al., 2007 [10]

6

NR

3

Longitudinal cohort studies

Representative of Canadian demographic, exclusion of dementia at baseline

Any PA or energy expenditure

3/3 studies provided evidence that regular physical activity is associated with a reduced risk for AD.

Rolland et al., 2008 [11]

5

NR

24

Longitudinal epidemiological studies

No dementia diagnosis at baseline, ≥60 year

Any PA or energy expenditure

20/24 studies suggested a significant and independent preventive effect of physical activity on cognitive decline, or dementia, or AD risk. Physical activity could reduce the incidence of AD.