Dementia is a group of diseases that affect cognitive skills, causing a loss of memory, motor skills, reasoning and problem solving. Like most diseases, dementia has risk factors. Some risk factors such as age and family history are unavoidable. But there are contributing factors you can focus on to help reduce your risk for dementia. Here is a list of well-known risk factors.
The leading risk factor for dementia, although dementia can occur at any age. For most, the risk of getting dementia increases significantly after 65. Dementia isn’t a normal part of aging. One in 20 Canadians over age 65 has Alzheimer’s disease. After 65, the risk of developing Alzheimer’s disease doubles approximately every five years, with one in four Canadians over 85 having Alzheimer’s disease.
Sex and gender:
Women have a higher risk of developing Alzheimer’s disease than men.
While the reasons for this are still unclear, some of the potential contributors include women living longer on average than men and changes in estrogen levels over a woman’s lifetime. For types of dementia other than Alzheimer’s, men and women have the same risk.
Family history and genetics:
Researchers have discovered a number of genes that increase the risk of developing Alzheimer's disease. Although people with a family history of Alzheimer's disease are generally considered to be at a heightened risk of developing the disease themselves, many people who have relatives with Alzheimer's disease never develop the disease, and many without a family history of the disease do get it.
A cardiovascular disease caused by the buildup of fatty plaques on the lining of arteries. It can decrease in blood flow to the brain, eventually impairing cognitive health and increasing stroke risk. Since high cholesterol and high blood pressure contribute to atherosclerosis, they also raise your risk for dementia.
Having a body mass index of at least 30, which increases risks for health problems. Older obese adults, particularly women, have a 31 percent increased risk for dementia compared to their normal weight counterparts.
Research has shown that a higher-than-average blood level of homocysteine, a type of amino acid, is a strong risk factor for the development of Alzheimer's disease and vascular dementia.
Excessive alcohol and smoking:
Both are associated with dementia. Excessive alcohol can damage the brain, while smoking damages the vascular system, increasing your chances for cardiovascular disease (including atherosclerosis) and cerebrovascular disease, which contribute to dementia.
A lifestyle with little to no formal exercise or casual physical activity.
Includes nutritional deficiencies and unhealthy food choices. Studies suggest low levels of folate and vitamins D, B-6 and B-12 increase dementia risk. A diet high in saturated fat may raise your cholesterol levels and your risk for atherosclerosis, a known risk factor of dementia. And a diet high in trans fats is linked to an increased risk for dementia. Adopting a Mediterranean style diet or the MIND diet – a combination of a Mediterranean style diet and the DASH diet has been advocated.
Mild Cognitive Impairment (MCI) After 65:
The stage between age-related cognitive decline and dementia. MCI symptoms -- loss of memory, thinking and problem-solving skills – are more advanced than those associated with normal aging, but not as severe as dementia. Research has found that 40 percent of people over 65 with mild cognitive impairment develop dementia within three years.
A disorder in which your breathing stops and starts during the night as you sleep which can deprive the body (including the brain) of oxygen. Researchers have found that people with sleep apnea were almost twice as likely to become cognitively impaired.
Mechanisms by which sleep might affect dementia remain unclear, but sleep disturbance has been linked with β-amyloid (Aβ) deposition, reduced glymphatic clearance pathways activation, low grade inflammation, increased Tau, hypoxia and cardiovascular disease. Sleep disturbance is hypothesised to increase inflammation which raises Aβ burden, leading to Alzheimer's disease and further sleep disturbance.
Occurs when your blood sugar is too high. High blood sugar levels can raise your blood pressure, a risk factor for atherosclerosis and other forms of cardiovascular disease, and cerebrovascular disease, which can lead to dementia. A study conducted by Kaiser Permanente researchers found that people with type 1 diabetes were 83 percent more likely to develop dementia than seniors without diabetes. And type 2 diabetes also raises the risk because the vascular problems associated with type 2 diabetes are similar to those of dementia.
A common mental health problem characterized by persistent feelings of sadness and lack of interest in activities. Depression also has some of the same symptoms as dementia such as forgetfulness, confusion and lack of concentration. Research indicates that depression in later-life may be a sign of early-stage dementia.
A genetic disorder caused by an additional (or third) copy of chromosome 21. People with down syndrome usually have developmental delays, distinct facial characteristics, mild to moderate intellectual disability and a higher risk for thyroid disease, heart conditions and developing dementia in their thirties. By middle age, most people with Down syndrome have the plaques and tangles of Alzheimer’s disease.
Low levels of formal education:
People who actively use their brains throughout their life may be building a ‘cognitive reserve’ that can provide more protection against brain cell damage caused by dementia. Higher childhood education levels and lifelong higher educational attainment reduce dementia risk. New work suggests overall cognitive ability increases, with education, before reaching a plateau in late adolescence, when brain reaches greatest plasticity; with relatively few further gains with education after age 20 years.
Experiencing severe or repeated head injuries increases a person’s risk of developing dementia.
It is still unclear how exactly hearing loss increases the risk of dementia, but it can lead to social isolation, loss of independence and problems with everyday activities.
Social contact, now an accepted protective factor, enhances cognitive reserve or encourages beneficial behaviours.
Air pollution and particulate pollutants are associated with poor health outcomes, including those related to non-communicable diseases. Attention has turned to their potential effect on the brain. Animal models suggest airborne particulate pollutants accelerate neurodegenerative processes through cerebrovascular and cardiovascular disease, Aβ deposition, and amyloid precursor protein processing. Although the higher levels of dementia from air pollutants are still subject to the potential for residual confounding, the effects on animal models are evidence of physiological effects over and above those driven by life-course deprivation.
New evidence supports adding three modifiable risk factors—excessive alcohol consumption, head injury, and air pollution—to the 2017 Lancet Commission on dementia prevention, intervention, and care life-course model of nine factors (less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and infrequent social contact).
The 2017 report identified nine modifiable risk factors that were estimated to account for a third of all dementia cases. The Lancet Commission included those same nine risk factors in this year's report, as well, but the Commission updated the weighted population attributable fraction attributed to the risk factors. They are:
- Midlife hearing loss, accounting for 8.2% of dementia cases;
- Not completing secondary education, accounting for 7.1% of cases;
- Later-life smoking, accounting for 5.2% of cases;
- Later-life depression, accounting for 3.9% of cases;
- Later-life physical inactivity, accounting for 1.6% of cases;
- Later-life social isolation, accounting for 3.5% of cases;
- Midlife hypertension, accounting for 1.9% of cases;
- Later-life diabetes, accounting for 1.1% of cases; and
- Midlife obesity, accounting for 0.7% of cases.
The Commission also included three new modifiable factors in the updated report:
- Excessive alcohol intake in midlife, accounting for 0.8% of cases;
- Traumatic brain injury (TBI) in midlife, accounting for 3.4% of cases; and
- Air pollution in later life, accounting for 2.3% of cases.
Of key importance is that modifying 12 risk factors might prevent or delay up to 40% of dementias.