Examination of potentially modifiable dementia risk factors across the adult life course: The Framingham Heart Study

Abstract

Introduction: We examined for associations between potentially modifiable risk factors across the adult life course and incident dementia.

Methods: Participants from the Framingham Heart Study were included (n = 4015). Potential modifiable risk factors included education, alcohol intake, smoking, body mass index (BMI), physical activity, social network, diabetes, and hypertension. Cox models were used to examine associations between each factor and incident dementia, stratified by early adult life (33-44 years), midlife (45-65 years), and late life (66-80 years).

Results: Increased dementia risk was associated with diabetes (hazard ratio [HR] = 1.62; 95% confidence interval [CI] = 1.07-2.46) and physical inactivity (HR = 1.57; 95% CI = 1.12-2.20) in midlife, and with obesity (HR = 1.76; 95% CI = 1.08-2.87) in late life. Having multiple potential modifiable risk factors in midlife and late life was associated with greater risk.

Discussion: Potentially modifiable risk factors individually have limited impact on dementia risk in this population across the adult life course, although in combination they may have a synergistic effect.

Highlights: Diabetes and physical inactivity in midlife is associated with increased dementia risk. Obesity in late life is associated with increased dementia risk. Having more potentially modifiable risk factors in midlife and late life is associated with greater dementia risk.

Keywords: Framingham Heart Study; dementia; epidemiology; life course; modifiable risk factors.

Figure 1.

Study design and flow diagram.

Figure 2.

Associations between each potentially modifiable risk factor (less education, obesity, physical inactivity, high alcohol intake, smoking, social isolation, diabetes, and hypertension) in early adult life, midlife, and late-life with incident all-cause dementia. CI, Confidence interval *Adjusted for age (years), sex (female vs. male), history of cardiovascular disease (yes vs. no), and ApoE genotype (0 ε4 vs. ≥1 ε4 allele).