Alzheimer’s Prevention – How to Prevent?

Prevention of Alzheimer’s Dementia and other Dementia Diseases

How to Prevent Neurodegenerative Diseases?

Prevention is important, necessary and, for the most part, doable. Looking at the 12 main risk factors, most people can do a lot themselves to prevent it. In “The Lancet”, one of the most renowned medical journals in the world, leading scientists worldwide have published a total of 12 modifiable risk factors and given recommendations for prevention in their most recent statement from 2020. In the following list, you will find those factors that the scientists in “The Lancet” currently rate as the most risky. The development of Alzheimer’s disease and other forms of dementia can in part be actively influenced.

Risk Factor 1 – Education

Being mentally active from childhood and having access to educational opportunities could reduce the risk of dementia by 60 per cent, according to a Lancet study. According to the Lancet Commission, educational attainment, or lack thereof, is the single most important factor in the risk of dementia in people under the age of 45 and is responsible for around 7% of dementia cases worldwide. However, it is not education per se that can protect against dementia. Rather, it is more likely that the respective level of education has an impact on the health behaviour of the population, as people with higher levels of education have more access to relevant information and can act accordingly. The authors therefore recommend that policy makers should invest in children’s education. However, adults and older people should also make sure to stay mentally active. This promotes neurogenesis – the brain’s lifelong ability to form new neurons.

Risk Factor 2 – Hearing Loss

Can hearing loss actually lead to dementia? Unfortunately, this factor is generally underestimated and largely unknown. Researchers estimate that about 8 percent of all dementia cases are due to hearing loss. However, on closer examination, the link becomes clear: untreated hearing loss (usually from not wearing a hearing aid) leads to social isolation and communication difficulties – a significant risk factor. In addition, hearing loss probably also causes changes in the brain: the intense focus on hearing puts a long-term strain on other brain functions and causes them to be neglected. In particular, the cerebral cortex and the hippocampus, the interface between short- and long-term memory, can be affected. If hearing loss is detected, one should not hesitate and consult an ENT doctor. Modern hearing aids are so small that they are barely visible, and the hearing loss can be effectively compensated.

Risk Factor 3 – Hypertension

High blood pressure is another risk factor for dementia. This is because too high blood pressure not only damages blood vessels and organs. Studies show that even slightly elevated blood pressure levels can increase the risk of dementia. A blood pressure of over 140 mmHg systolic (pressure during the heartbeat) in middle age can increase the risk of dementia by 60 percent, according to data. Prolonged high blood pressure accelerates the ageing of the brain, which can lead to increased loss of brain volume, damage to white matter (areas of the central nervous system) and increased accumulation of amyloids. These protein fragments are considered the main trigger of Alzheimer’s disease. In addition, studies have shown that people who suffered from high blood pressure in mid-life (between 40 and 64 years of age) were more likely to be diagnosed with vascular dementia later in life. Vascular dementia is the second most common form of dementia after Alzheimer’s disease. Decreased blood flow to the brain reduces the amount of oxygen and nutrients that brain cells need to function properly.

Risk Factor 4 – Obesity

Obesity is a trigger for many diseases, including dementia. According to studies, people with a body mass index (BMI) of over 30 have a 30 percent higher risk of developing dementia in old age. In particular, people who were heavily overweight in their middle years, i.e. between the ages of 40 and 64, are affected by this risk. The constant release of pro-inflammatory messenger substances promotes vascular diseases and circulatory disorders, also in the brain. In addition, excessive fat tissue appears to affect the metabolism in a way that favours the formation of amyloid deposits. In the USA, the number of obese people has more than doubled since 2010. About 42 per cent of the US adult population is currently considered obese. In Europe, too, the figures are alarming: around 59 per cent of adults live with overweight or obesity, according to the WHO Regional Office for Europe in its Obesity Report 2022. In Germany, almost one-fifth of adults (19%) are obese. The prevalence of overweight and obesity increases with age.

Risk Factor 5 – Smoking

According to the Lancet Commission, smoking is the most significant dementia risk factor for people over 65. In this age group, the risk of dementia increases by an impressive 60 percent. Worldwide, about 27 percent of people over 65 smoke, and it is estimated that 5.2 percent of all dementia cases are attributable to tobacco use. Smoking can cause atherosclerosis and damage brain metabolism, which impairs cognitive performance in old age. The brain is not spared the long-term effects of intensive tobacco use. This is probably due to the direct damaging effects of the substances contained in smoke. In addition, detoxification processes can lead to overtaxation and inflammation. Furthermore, a combination of smoke effects and deposits can occur. The consequences can trigger Alzheimer’s or other forms of dementia. After all, the number of adult smokers in Germany fell to 23 percent in 2018, and the trend continues to decline.

Risk Factor 6 – Depression and Stress

Persistent pressure, excessive demands, worries and fears, i.e. psychological stress, unfortunately also play a role in the risk of dementia. This also includes depression, which can have both psychological and physical effects. According to estimates by the AOK insurance company, about 8.2 percent or 5.2 million people in Germany suffer from depression every year. The COVID-19 pandemic, with its stresses, limitations and after-effects such as Long Covid and Post Covid Syndromes, has further increased these afflictions. Sadness, stress and depressive disorders impair brain function, and studies suggest that about 3.9 per cent of all dementia cases are due to this factor. Therefore, from a psychiatric point of view, it is extremely important to recognise depression at an early stage and to actively treat it in order to prevent possible dementia. Incidentally, many dementia patients are also affected by depression, as both diseases can cause each other.

Risk Factor 7 – Social Isolation

Loneliness and social isolation have an extremely negative effect on people, as humans are generally social creatures who thrive best in community and need social interaction as much as food and light. Yet millions of people, especially the elderly, are often lonely and have little or no social contact. This has a significant impact on brain function. According to this, lack of contact leads to a loss of grey brain matter over time. Researchers associate social isolation with an increased risk of dementia by about 60 percent and attribute 3.5 percent of the diseases to this alone. This is particularly significant for women, who often outlive their partners by many years. But what solutions could be considered? According to research, social engagement can provide mental stimulation, increase the sense of meaning in life and support interaction with other people. This could help improve brain health and reduce the risk of serious cognitive impairment.

Risk Factor 8 – Adult-onset Diabetes

Type 2 diabetes, often referred to as “adult-onset diabetes”, is the most common form of diabetes. In this metabolic disease, the body’s cells use the hormone insulin less and less effectively and can no longer optimally transport the sugar from the blood into the cell interior. Among other things, this leads to the fact that the disturbed insulin metabolism in the brain promotes the disease-promoting factors of dementia. According to the Lancet, adult-onset diabetes is associated with a 50 percent increased risk of dementia, and about 1.1 percent of all dementia cases worldwide can be traced back to it. In Germany, however, this factor must be set much higher, as about 10 percent of the population is affected by type 2 diabetes. Among the over-80s, even more than one third suffer from adult-onset diabetes. The most important preventive measure against both vascular and Alzheimer’s dementia is a well-controlled, carefully followed diabetes therapy and regular checks of mental performance, especially in older age. However, the most effective prevention is successful diabetes prevention.

Risk Factor 9 – Physical Inactivity

Regular physical activity and sport have positive effects on cognitive abilities, and even if dementia is already present, exercise can help to slow down the progression of the disease. The researchers found a 40 percent increased risk of dementia in predominantly inactive people who hardly move and do no sport. Lack of exercise does not directly lead to the risk; rather, permanent sitting and lack of exercise become noticeable over the years and increasingly in old age in the form of diabetes and cardiovascular diseases, which in turn promote dementia. Sporting activities or at least regular exercise – such as a daily walk, taking the stairs instead of the lift, running a few errands on foot or by bicycle instead of by car – have a positive long-term effect not only on the overall state of health, but also on the brain (keyword: oxygen supply).

In recent years, research has identified additional evidence-based risk factors for dementia that should be considered in addition to those already known. These three additional factors are:

Risk Factor 10 – Alcohol Consumption

Excessive alcohol consumption can increase the risk of dementia by impairing brain function, accelerating the breakdown of brain cells and promoting inflammation. Alcohol dependence and regular heavy drinking in particular can lead to an increased likelihood of dementia. Alcohol is a neurotoxin, and those who consume it in excessive amounts increase their risk of developing dementia in the medium to long term by 20 percent. Some renowned studies even estimate the risk at 39 percent. In addition, the risk of high blood pressure, diabetes, atrial fibrillation and heart failure increases. The World Health Organisation (WHO) defines excessive consumption for men as 60 grams of pure alcohol, which corresponds to about 1.5 litres of beer or a bottle of wine. Women should be even more careful: The recommended limit is 40 grams, which is reached with one litre of beer or half a bottle of wine. It used to be believed that regular alcohol consumption in small amounts – like the famous evening glass of red wine – was beneficial to health. However, this assumption is now controversial.

Risk Factor 11 – Craniocerebral Trauma

Craniocerebral injuries, especially those that occur repeatedly, can increase the risk of dementia. Craniocerebral injuries can cause swelling and inflammation in the brain, impairing cognitive function and increasing the risk of neurodegenerative diseases such as Alzheimer’s disease. Traumatic brain injuries are injuries to the skull bone that can lead to impaired brain function due to brain swelling and bleeding. Falls, traffic accidents and sports injuries are common causes. Symptoms vary depending on the severity of the trauma. The German Society for Neurointensive and Emergency Medicine (DGNI) states that about 270,000 people in Germany need medical treatment for head injuries every year. In recent years, researchers have increasingly identified traumatic brain injury as a risk factor for dementia. The authors of the Lancet study estimate that 3.4 percent of all dementia cases are due to traumatic brain injury. If such trauma is accompanied by unconsciousness, the risk may even quadruple.

Risk Factor 12 – Air Pollution

Particulate matter and other pollutants in the air can impair brain function and lead to inflammation, which is associated with an increased risk of dementia. Long-term exposure to poor air quality can lead to brain cell damage and impaired cognitive function. The Lancet study identifies environmental pollution as another risk factor for dementia. Particulate matter and nitrogen oxides in particular have harmful effects on the brain. It was previously believed that the blood-brain barrier protected the brain from harmful external attacks. However, particulate matter (tiny droplets and solid particles filled with toxins) can enter the brain directly through the olfactory bulb when inhaled through the nose, bypassing the blood-brain barrier. According to current data, the risk increase for dementia in polluted regions such as large cities and industrial areas is about ten percent. However, with about 75 percent of the world’s population living in such conditions, 2.3 percent of all dementia cases are attributed to air pollution. This underscores the importance of environmental protection and clean air for brain health and dementia prevention.

What about heavy metal pollution and resulting dementia diseases?

The role of heavy metal exposures and their influence on dementia risk is not yet fully understood and was not considered in the 12 risk factors study. Nevertheless, there is evidence of the neurotoxic effect of some heavy metals such as aluminium, which can lead to memory impairment and changes in nerve cells. The discussion about aluminium and its possible role in the development of dementia has been going on for decades and continues to be studied. Although aluminium has no essential function in the brain, it tends to accumulate there and trigger inflammatory reactions. Other metals such as iron, zinc or copper are necessary for the brain in certain amounts. However, excessive accumulation of these metals can be harmful. For example, excess iron can cause oxidative stress, which can lead to neurodegeneration. Further research is needed to better understand the link between heavy metal exposures and dementia risk and to develop possible preventive measures.