Healthy Habits to Prevent Dementia
Although Alzheimer’s disease (AD) and related dementias have long been considered non-preventable and even an inevitable consequence of ageing, recent findings indicate a downtrend in the prevalence of dementia in Western countries. This might be the result of improved management of modifiable risk factors. This is hopeful as it indicates there are some things we can do to reduce our risk of dementia.
Dementia is likely to have multiple causes. Non-modifiable risk factors include age, genetics, sex, ethnicity, and family history. However, there are many risk factors that are modifiable. See blog posts Diet to Prevent Dementia and The Gut Microbiome and Alzheimer’s Disease for ideas on what to eat and how to alter the gut flora to prevent dementia.
A review of dietary and lifestyle factors that may be preventative or deleterious to the onset and progression of Alzheimer’s disease found the following modifiable risk factors (1):
Fewer Years of Education – particularly lack of secondary school education affects cognitive reserve. Higher educational level could have a direct effect on brain development and function as well as affecting other health behaviours. It is also likely to generate increased wealth and opportunities. Mid-life and late-life cognitive stimulation through leisure activities is also associated with a reduced risk of dementia.
Hearing Loss – hearing loss may be associated with an increased risk of dementia. Wearing a hearing aid has a protective effect against cognitive decline. Reduce the risk of hearing loss by avoiding loud noises, wearing noise cancelling headphones when necessary, and not listening to anything loud through ear buds or headphones.
Traumatic Brain Injury – traumatic brain injuries in non-veteran populations are often due to motor vehicle crashes or sports injuries. Use of seat belts and protective head gear where appropriate can reduce the risk.
Drinking more than 21 units of alcohol per week – the association between alcohol consumption and cognitive function depends on the frequency and amount of alcohol consumed. In 2015, a systematic review found that dementia risk might decrease with light drinking (1–2 drinks a day). The study also found that excessive late-life alcohol consumption did not affect the risk of AD and other dementias. It’s wise to have some alcohol free evenings each week and to avoid binge drinking.
Hypertension – Midlife hypertension (high blood pressure) has deleterious effects on brain health. This is defined as a BP over 140/90 between 40 and 65 years of age. Aim to keep systolic blood pressure below 130.
Obesity – midlife obesity, defined as having a BMI over 30 between the ages of 35 and 64 is associated with an increased risk of later life dementia. Obesity is linked to a decrease in brain tissue volume. BMI often decreases in the years preceding dementia diagnosis and is considered to be a predictive sign for dementia.
Smoking – the increased risk of Alzheimer’s disease in smokers may be due to the increased risk of cardiovascular disease caused by smoking as well as the neurotoxins in cigarette smoke and tobacco. Passive smoking also increases the risk of AD. Stopping smoking could reduce the risk of dementia to the same level as non-smokers so it’s worth taking steps to give up smoking whatever age you are. There is help available for those who want to give up smoking. Talk to your GP about what is available in your area.
Physical Inactivity – according to some studies, physical inactivity could explain the largest proportion of Alzheimer’s disease cases in Western countries. Physical activity increases blood flow to the brain, reduces insulin resistance, increases brain glucose metabolism, reduces cytokine levels in the brain and stimulates brain plasticity. Individuals with lifelong exercise routines have larger brain volumes and improved executive function than inactive, age-matched, older adults.
Depression – depression, especially during late life, is associated with an increased risk of dementia. It’s not clear whether it’s an early symptom or an accelerating factor.
Use of Anticholinergics – recent studies suggest that anticholinergics may be associated with an increased risk of developing dementia. Drugs with anticholinergic properties inhibit the action of acetylcholine, which is involved in learning and memory. Medications with anticholinergic properties are commonly used in older people and include antihistamines, sleep agents, and treatments for overactive bladder.
Loneliness – the association between social isolation and development of dementia is complex and interrelated with other risk factors. For example, decreased executive function and depression, which may be associated with subclinical dementia, feed into social isolation by limiting motivation and ability to make plans and participate in activities. A 3-year follow-up study suggests that feelings of loneliness, rather than social isolation, may predict dementia onset. Interventions to reduce social isolation for elderly people may act as a protective factor for dementia and other health problems.
Diabetes – both type 1 and type 2 diabetes are considered to be risk factors for Alzheimer’s disease. Chronic hyperglycaemia involves advanced glycation end product accumulation, impaired insulin receptivity and glucose neurotoxicity. Metformin, used to treat diabetes, may reduce cognitive impairment and dementia. Dietary changes can make a big difference to the risk and progression of type 2 diabetes. Avoiding sugar, refined carbohydrates, ultra processed foods and trans fats is recommended.
Conclusions
It is not known at which stage of life, and for how long, lifestyle interventions would need to be undertaken to address these risk factors. However, it is likely that adopting healthy dietary and lifestyle practices will most likely improve many aspects of mental and physical health and vastly improve the quality of life for older people and their families (1,2).
References
1. Clin Ther. 2021 Jun; 43(6): 953-965. Modifiable Risk Factors in Alzheimer Disease and Related Dementias: A Review. Litke R et al.
2. Alzheimers Dement (Amst). 2022 Jul 13;14(1):e12337. The adverse effect of modifiable dementia risk factors on cognition amplifies across the adult lifespan. LaPlume AA et al.