Dementia is a progressive decline in cognitive function, affecting memory, thinking, and social skills, leading to a loss of independence in daily living.

Alzheimer’s disease is the most common form of dementia, accounting for up to 70% of cases in older adults. Age is the biggest risk factor, with the prevalence of dementia doubling every 5 years after the age of 65. However, not all people who reach old age develop dementia, and not all cases of dementia are due to Alzheimer’s disease.

The connection between ageing and dementia is complex, involving multiple factors that interact over time.

Neurodegeneration and Brain Changes

Dementia is associated with neurodegeneration, the progressive death of nerve cells, and brain changes, including the accumulation of abnormal proteins, such as beta-amyloid and tau, and the formation of plaques and tangles in the brain.

These changes can start many years before clinical symptoms appear, and their extent and distribution can vary between individuals. Genetics plays a role in the susceptibility to dementia, with several genes associated with an increased risk of Alzheimer’s disease, such as the APOE4 gene.

However, genetic factors alone are not sufficient to explain the development of dementia, and environmental and lifestyle factors can modulate their expression.

Environmental and Lifestyle Factors

Environmental and lifestyle factors can influence the risk of dementia and interact with genetic and brain changes.

Some of these factors are modifiable, meaning that they can be targeted by interventions to reduce the risk or delay the onset of dementia. Examples of modifiable risk factors include:.

Physical inactivity and sedentary behaviour
Smoking and exposure to second-hand smoke
Unhealthy diet, high in saturated and trans fats and low in fruits, vegetables, and whole grains
Excessive alcohol consumption
Uncontrolled hypertension, high cholesterol, and diabetes
Untreated depression and social isolation
Head injury and traumatic brain injury

Addressing these factors can have a positive impact on brain health and reduce the likelihood of developing dementia.

For example, regular physical activity can improve blood flow to the brain, increase the production of growth factors and neurotrophins, and reduce inflammation and oxidative stress. A healthy diet can provide essential nutrients for brain function, such as omega-3 fatty acids, B-vitamins, and antioxidants.

Social engagement and cognitive stimulation can also promote brain resilience and reserve, enabling better coping with brain changes and reducing the risk of dementia.

The connection between ageing and dementia is not only biological but also psychological and social. Mental health and wellbeing, as well as social networks and support, can influence the risk and outcome of dementia.

Psychological factors, such as stress, anxiety, and depression, can affect cognitive function and brain plasticity, and increase the risk of dementia. Social factors, such as living alone, having a low income, and being socially isolated, can also exacerbate the negative effects of ageing on brain health and cognitive function.

Conversely, positive psychological and social factors can promote brain health and reduce the risk of dementia.

For example, having a sense of purpose and meaning in life, engaging in creative and challenging activities, and maintaining social connections and social support have been associated with better cognitive outcomes and lower risk of dementia. These factors can enhance cognitive reserve and resilience, enabling the brain to cope with age-related changes and recover from cognitive impairment.

Dementia Prevention and Management

Due to the complex and multifactorial nature of dementia, prevention and management require a comprehensive and interdisciplinary approach, involving healthcare professionals, researchers, policymakers, and the public.

Several initiatives and guidelines have been developed to promote brain health and reduce the risk of dementia, such as:.

The World Health Organization’s Global Action Plan on the Public Health Response to Dementia
The Alzheimer’s Association’s 10 Ways to Love Your Brain
The European Brain Council’s Value of Treatment for Brain Disorders
The National Institute on Aging’s Go4Life Exercise and Physical Activity Campaign
The UK Dementia Research Institute’s Brain Health Clinics

These initiatives focus on raising awareness of modifiable risk factors, promoting healthy lifestyle behaviours, and improving early detection, diagnosis, and treatment of cognitive impairment and dementia.

In addition to prevention, managing dementia involves providing care and support for people with dementia and their families, ensuring access to evidence-based interventions and services, and addressing the social, economic, and ethical dimensions of dementia.

Conclusion

The connection between ageing and dementia is a complex, multifactorial, and ongoing process, involving biological, psychological, and social factors that interact over time.

While age is the biggest risk factor for dementia, modifiable environmental and lifestyle factors, as well as psychological and social factors, can influence the risk and outcome of dementia. Prevention and management of dementia require a comprehensive, interdisciplinary, and person-centred approach, guided by evidence and best practices.

By promoting brain health and reducing the impact of dementia, we can improve the quality of life and well-being of people affected by this devastating condition.