Dementia Risk Reduction and Prevention

Introduction

Dementia is a collective name for progressive brain syndromes which affect memory, thinking, behaviour and emotion. There are currently almost 50 million people affected by Alzheimer’s disease (AD) and other dementias worldwide, and this number is projected to double approximately every 20 years. Approximately 60% of patients with dementia are estimated to be living in low- and middle-income countries (LMIC) with almost 8 million people over the age of 60 years with dementia estimated to be living in India alone according to the first and largest nationwide dementia prevalence study – the Longitudinal Ageing Study of India, 2020. While age is the strongest known risk factor for cognitive decline, dementia is not a natural or an inevitable consequence of ageing.

Types of Dementia

There are many different causes and types of dementia. Primary dementias include: dementia due to Alzheimer disease (AD), vascular dementia, dementia with Lewy bodies and frontotemporal dementia (in which the decline in cognitive abilities itself is mostly due to an underlying neurodegenerative process and not directly caused by other aetiologies). Alzheimer disease is the most common, followed by vascular dementia and dementia with Lewy bodies. Mixed dementia with features of more than one type is also common, especially in older adults, while frontotemporal dementia is a less common form but relatively more frequent before old age. Secondary dementias are those caused by, or closely related to, some other recognizable disease, such as HIV, head injury, multiple sclerosis, thyroid disorders or vitamin B12 deficiency.

Studies have shown a relationship between the development of cognitive impairment and dementia with lifestyle-related risk factors, such as physical inactivity, tobacco use, unhealthy diets and harmful use of alcohol. Certain medical conditions are associated with an increased risk of developing dementia, including hypertension, diabetes, hypercholesterolemia, obesity and depression. Other potentially modifiable risk factors include social isolation and cognitive inactivity.

There is currently no cure for dementia, with some limited symptomatic treatment options, and emerging disease modifying treatments. Medical advances aimed at delaying disease onset for 5 years or longer would result in a 41% lower prevalence and 40% lower cost of AD in 2050. Modifying 12 risk factors - less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, low social contact, excessive alcohol consumption, traumatic brain injury (TBI), and air pollution might prevent or delay up to 40% of dementias.

Studies suggest that personalized multidomain interventions may offer the greatest opportunity to decrease the incidence of, delay, or prevent AD and other dementias.

Good for the Heart, Good for the Brain

Cardiovascular risk factors, or those that affect the heart and blood vessels such as hypertension, diabetes mellitus and high cholesterol are linked to a higher risk of developing dementia later in life. These should be managed optimally with medications if needed or non-pharmacologically as follows:

• Hypertension: High blood pressure has been associated with an increased risk of late life dementia. In particular, a pattern of increased blood pressure during mid-life followed by a rapid decrease in blood pressure later in life has been found in individuals who go on to develop dementia. Individuals should aim to maintain systolic BP of 130 mm Hg or less in midlife from around age 40 years (antihypertensive treatment for hypertension is the only known effective preventive medication for dementia).
• Diabetes: The presence of late life diabetes has been linked to an increased risk of dementia. In addition, the complications associated with diabetes, such as nephropathy (kidney damage), retinopathy (eye damage), hearing impairment and CVD, have all been found to increase the risk of dementia. Aiming for optimal control of diabetes, in form of a Glycosylated Haemoglobin [HbA1C] level less than 7 % is recommended as a dementia prevention measure.
• Hyperlipidemia: A large body of observational evidence has linked high blood lipids/cholesterol to an increased risk of dementia and/or cognitive decline and found an association between control of dyslipidaemia and reduction of dementia and/or cognitive decline risk. Overall, indirect evidence suggests that managing dyslipidaemia in mid-life can help reduce the risk of cognitive decline and/or dementia.
• Smoking: Smoking or tobacco use in any form causes brain damage, underpinning subsequent cognitive decline and dementia. Mid-life smoking is especially correlated to a higher risk of late life dementia. Cessation of tobacco use and smoking should be the goal for dementia risk reduction and prevention.
• Alcohol Use: There is extensive evidence on excessive alcohol as a risk factor for dementia and cognitive decline. The most consistent pattern is that of a U-shaped relationship between alcohol consumption and dementia and/or cognitive impairment, which clearly links excessive alcohol consumption to a significantly increased risk. Guidelines recommend limiting alcohol use to less than 21 units weekly [males <65 years] and 14 units of alcohol [females <65 years] and less than 14 units per week for both males and females >65 years.
• Obesity: Obesity (Body Mass Index ≥30) is associated with late-life dementia. In individuals with BMI greater than 25, even a modest weight loss of 2 kg or more was associated with a significant improvement in attention and memory even over short follow up intervals such as 8-24 weeks. Overweight patients should attempt to reduce weight by following a balanced diet, give preference to low glycaemic-index foods (beans, lentils, oats and unsweetened fruit) as the source of carbohydrates in their diet and reduce sedentary behaviour and practise regular daily physical activity appropriate for their physical capabilities (e.g. walking).      

Look after the body

Being fit and healthy is important for the brain. One can maintain body health and reduce the risk of developing dementia by:

Increasing physical activity: A physically active lifestyle is linked to brain health. Physically active people seem less likely to develop cognitive decline, all-cause dementia, vascular dementia and Alzheimer disease when compared with inactive people. Physical activity seems to have beneficial effects on brain structures. Other potential mechanisms underlying the association are most likely indirect, such as the positive effects of physical exercise on other modifiable cardiovascular risk factors (CVRFs), including hypertension, insulin resistance and high cholesterol levels as well as other biological mechanisms. Cardiovascular exercises - 150 minutes [2½ hours] per week of moderate intensity physical activity aimed at achieving 65–70% of maximum heart rate or breaking into a sweat such as brisk walking, running, swimming, and cycling are recommended. Develop a plan using a safe, gradual approach that starts with moderate-intensity physical activity that fits within a person’s lifestyle (e.g., walking, gardening, dancing, calisthenics) and is culturally acceptable – such as Yoga or Tai Chi.

Maintaining healthy sleep patterns: Sleep disturbances can increase the risk of developing depression, cognitive problems and dementia later in life. Various factors can affect the quality of our sleep. These include:

• medical conditions
• depression or anxiety
• substance and medication use
• irregular sleep habits
• breathing problems

Encourage getting 7 to 8 hours of sleep in a 24-hour period, including naps. Those with severe sleep complaints which may indicate sleep apnoea (e.g., snoring with stops of breathing or excessive daytime sleepiness), should get referred to a sleep clinic for diagnosis and treatment.

Checking your hearing and other senses: People with mild hearing loss are twice more likely to develop dementia than those with normal hearing, while people with severe hearing loss are five times more likely.

To prevent or minimise hearing loss:

• avoid loud noise
• quit smoking
• remove ear wax properly
• have your hearing tested regularly

Protecting your head: Moderate to severe head injuries, or repeated blows to the head, may increase the risk of developing dementia in later life.

Protect your head and avoid injury in the first place:

• Wear a helmet and appropriate safety gear during sporting or recreational activities, including riding bicycles, scooters or motorbikes
• Wear a seatbelt when travelling in any motor vehicle
• Obey road rules, including not driving after using drugs or alcohol
• Take extra care on slippery surfaces
• Minimise your risk of trips or falls inside and outside the home

Maintain a healthy, balanced diet: The best diet for minimising the risk of cognitive decline or dementia is the “MIND Diet - Mediterranean-DASH Intervention for Neurodegenerative Delay” which combines foods from the Mediterranean and DASH diets. The ‘Mediterranean diet’ is based off the lifestyle and eating patterns of those that live in the Mediterranean area of the world. The ‘DASH diet’ was originally established to lower blood pressure. The MIND diet recommends the following:

Increase the intake of:

• leafy green and cruciferous vegetables (cabbage, broccoli, brussels sprouts, turnip)
• beans, legumes
• berries (blueberries, blackberries, raspberries, and strawberries)
• high-fibre nuts (walnuts, almonds, cashews, Brazil nuts, etc)
• whole grains and cereals
• non-red meats like fish or chicken

Decrease the intake of following foods:

• high-fat dairy products (e.g., butter, cheese)
• red meat
• fried foods and fast foods
• processed food
• pastries and sweets

Foods provide a much more diverse nutrient and bioactive profile than vitamin and supplements and should be prioritized.

Look after the mind

Keeping the brain stimulated and active is extremely important for our cognitive health as such stimulating activities lead towards building up two important brain capacities – cognitive reserve and neuroplasticity. Cognitive reserve refers to the brain’s ability to cope with or compensate for neuropathology or damage. Studies have shown that increased cognitive activity may stimulate (or increase) cognitive reserve and have a buffering effect against rapid cognitive decline. Building the brain’s neuroplasticity, through the growth of new brain cells, improves connections between existing brain cells and improves support networks surrounding brain cells which in turn protect against cognitive decline and dementia.

Here are some of the ways to build brain reserve and neuroplasticity:

Cognitive Stimulation: Consistent cognitive engagement throughout life is associated with improved cognitive function. Mental stimulation and new learning are linked to a reduced risk of dementia.

Some activities that exercise the brain are:

• reading, watching documentaries or news
• crossword puzzles, sudoku
• card/board games [chess, bridge, dominoes]
• learning a new language
• painting, sewing, cooking, woodwork
• playing an instrument
• using technology [smart phone, computer]

Social activity: Social interaction helps to improve our wellbeing, reduce feelings of loneliness or depression as well as reduce our risk of cognitive decline. All forms of relationships and support can be meaningful in building a sense of connection, better they can handle stress, make individuals better at handling stress and serve as a protective factor to brain health.

Examples to suggest for improving social connections may include:

• Meeting new people by joining clubs or organizations, such as a book club, a local sports team, a civic organization, or a political or religious group
• Volunteering at a pet shelter, the library, hospital, school, or senior centre
• Staying connected to family and friends by phone and video conferencing.

Mental Health and Stress: Numerous studies suggest that depression, anxiety, and chronic stress are associated with the development of dementia and Alzheimer’s Disease. The presence of depression nearly doubles the risk of developing dementia. The following are the symptoms of depression:

• Persistent low mood or severe feelings of sadness
• loss of enjoyment in usual activities
• fatigue
• difficulty sleeping
• appetite changes
• cognitive problems (forgetfulness or poor concentration)

If any of these symptoms are present, it is advisable to seek professional help from your doctor or psychologist and get them addressed appropriately without delay.

Risk reduction for dementia focuses on being brain healthy. This can be done by creating a healthier heart, body, and mind. The earlier and the greater number of these changes are adopted, the better but please remember that it is never too early or too late to start these measures. Start gradually, safely in keeping with your lifestyle, adopting culturally acceptable methods.

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