Table 2.
Selected risk factors for dementia
| Comments | |
|---|---|
| Non-modifiable risk factors | |
| Demographic factors | |
| Age | Dementia prevalence increases exponentially with age8 |
| Sex | Dementia prevalence greater in women than men7 |
| Ethnicity | VaD risk greater in blacks than whites9 |
| Genetic factors | Genetic alterations may affect cognitive function, e.g. apolipoprotein E ε4 allele and ABCA7 are associated with increased risk of AD; C9ORF72, MAPT, GRN gene mutations associated with frontotemporal dementia; rs12007229 is associated with VaD10 |
| Lifestyle factors | |
| Education | Lower education is associated with higher VaD risk11 |
| Physical activity | Increased physical activity is associated with lower risk of general dementia, Alzheimer’s dementia, and VaD risk, which was attenuated with further adjustment for baseline cognitive, psychosocial, and vascular factors. Review reported that seven out of eight studies found an association between increased physical activity and lower risk of cognitive decline12 |
| Body mass index | U-shaped association between body mass index and dementia, with dementia risk higher in individuals who were obese or underweight13 |
| Smoking | Meta-analysis reported that current smokers have higher risk of cognitive decline and dementia over follow-up, than non-smokers or former smokers14 |
| Social support and networks | Compared with small social networks, larger social networks were associated with a lower risk of incident dementia over time.15 |
| Cardiovascular risk factors | |
| Blood pressure | Higher mid-life blood pressure was associated with higher dementia risk16 and cognitive decline17 |
| Blood glucose | Diabetes was associated with increased dementia risk18 and cognitive decline19 |
| Lipids | Higher total serum cholesterol was associated with higher VaD and AD risk20,21 |
| Clinical cardiovascular or cerebrovascular disease | |
| Stroke | Stroke is associated with increased dementia risk22,23 |
| AF | AF is associated with increased dementia risk24,25 |
| Vascular/peripheral arterial disease | Carotid arterial disease is associated with incident dementia risk and cognitive decline26,27 Lower ankle brachial index is associated with increased dementia risk28 |
| Sleep apnoea | Sleep-disordered breathing is associated with an increased risk of cognitive impairment and a small worsening in executive function.29 |
ABCA7, ATP-binding cassette transporter A7; AD, Alzheimer’s disease; AF, atrial fibrillation; C9ORF72, chromosome 9 open reading frame 72; GRN, granulin; MAPT, microtubule-associated protein tau; VaD, vascular dementia.