Physical Activity Over the Adult Life Course and Risk of Dementia in the Framingham Heart Study

 

3 years post stroke at a physical I had a resting heart rate of 54 at age 53, level of an athlete. My doctor asked what exercises I was doing, 'I've done no exercises for the past 3 years'. So now after 19 years of little exercise I'm no longer that athlete. Hopefully that physical activity in my midlife is enough to prevent dementia

Physical Activity Over the Adult Life Course and Risk of Dementia in the Framingham Heart Study

Francesca R. Marino, PhD¹ Chenglin Lyu,MS¹ Yuqing Li,MPH² Author Affiliations  

1 Department of Anatomy and Neurobiology, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts 

2 Department of Medicine, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts 

3 Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts 

4 Department of Neurology, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts 

5 Slone Epidemiology Center, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts 

6 The Framingham Heart Study, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts 

7 Boston University Alzheimer’s Disease and Chronic Traumatic Encephalopathy Center, Department of Neurology, Boston University Chobanian and Avedisian School of Medicine, Boston, Massachusetts 

Key Points

 Question When during the adult life course is physical activity most associated with risk of incident dementia? 

Findings

 In this cohort study of 1526 early adult–life, 1943 midlife, and 855 late-life participants in the Framingham Heart Study, individuals with the highest levels of physical activity at midlife and late life had 41% and 45% lower risk of all-cause dementia, respectively, compared with those with the lowest levels of physical activity, a statistically significant difference. Early adult–life physical activity was not associated with dementia risk. 

Meaning

  These findings suggest that timing efforts to promote physical activity during midlife or late life may be warranted to help delay or prevent dementia. 

Importance

 Being physically active is protective against dementia. Yet, it is unknown when during the adult life course physical activity is most associated with dementia risk. 

Objective

 To determine whether higher physical activity levels in early adult life, midlife, or late life are associated with lower risk of all-cause or Alzheimer disease (AD) dementia. 

Design, Setting, and Participants

 This prospective cohort study used data from the Framingham Heart Study Offspring cohort. The offspring of participants in the original Framingham Heart Study cohort who were dementia free and had physical activity measured at baseline (early adult life [1979-1983], midlife [1987-1991], or late life [1998-2001]) were followed up for a mean (SD) of 37.2 (7.1), 25.9 (8.5), or 14.5 (6.6) years for the development of incident all-cause or AD dementia until December 31, 2023. 

Exposure

 Physical activity was self-reported using the physical activity index, a composite score weighted by hours spent sleeping and in sedentary, slight, moderate, or heavy activities. Physical activity was divided into quintiles (Q). 

Main Outcome and Measure

 All-cause and AD dementia were classified by expert consensus based on established diagnostic criteria. 

Results

 This study included 1526 early adult–life (mean [SD] age, 36.7 [4.7] years; 821 [53.8%] female), 1943 midlife (mean [SD] age, 54.0 [5.8] years; 1010 [52.0%] female), and 885 late-life (mean [SD] age, 71.0 [4.5] years; 473 [53.4%] female) participants. There were 567 cases of incident all-cause dementia during follow-up. Higher levels of midlife and late-life physical activity were associated with lower risk of all-cause dementia. Midlife and late-life physical activity levels in Q4 or Q5 were associated with lower risk of all-cause dementia compared with Q1 (midlife Q4: HR, 0.60; 95% CI, 0.41-0.89; midlife Q5: HR, 0.59; 95% CI, 0.40-0.88; late-life Q4: HR, 0.64; 95% CI, 0.42-1.00; late-life Q5: HR, 0.55; 95% CI, 0.35-0.87). There were no associations between early adult–life physical activity and dementia risk. Findings were similar for incident AD (369 cases). 

Conclusions and Relevance

 In this cohort study of adults in the Framingham Heart Study Offspring cohort, higher levels of midlife and late-life physical activity were associated with similar reductions in risk of all-cause and AD dementia. These findings may inform future efforts to delay or prevent dementia through timing interventions during the most relevant stages of the adult life course.