Dementia is a progressive and irreversible decline in cognitive function that affects millions of people worldwide. It can impair memory, language, reasoning, and other mental abilities. While some risk factors for dementia are beyond our control, such as age and genetics, others are modifiable, such as lifestyle and environmental factors. A new study has identified 15 factors that significantly increase the risk of developing early-onset dementia, a form of dementia that occurs before the age of 65. Among these factors are alcohol misuse and loneliness, which can have detrimental effects on brain health and social well-being.
The study, published in the journal Lancet Neurology, was conducted by an international team of researchers from the UK, France, Canada, and Australia. They analysed data from more than 1.3 million people who were part of the UK Biobank, a large-scale biomedical database that collects genetic and health information from volunteers. The researchers identified 15 factors that were associated with an increased risk of early-onset dementia, and calculated the population attributable fraction (PAF) for each factor, which is the proportion of cases that could be prevented if the factor was eliminated. The factors and their PAFs were:
- Alcohol misuse (39.2%)
- Low educational attainment (23.8%)
- Hearing loss (22.8%)
- Smoking (14.9%)
- Hypertension (12.1%)
- Obesity (9.9%)
- Diabetes (9.4%)
- Depression (8.7%)
- Physical inactivity (7.5%)
- Air pollution (6.9%)
- Head injury (6.8%)
- Loneliness (6.6%)
- Anxiety (4.6%)
- Sleep problems (3.9%)
- Low social support (3.4%)
The researchers found that alcohol misuse was the most important risk factor for early-onset dementia, accounting for nearly 40% of the cases. Alcohol misuse can damage brain cells, cause vitamin deficiencies, and increase the risk of other conditions that affect brain health, such as liver disease, stroke, and infections. The researchers defined alcohol misuse as consuming more than 14 units of alcohol per week, which is equivalent to six pints of beer or seven glasses of wine.
Loneliness was another significant risk factor for early-onset dementia, contributing to 6.6% of the cases. Loneliness can affect mental health, emotional regulation, and cognitive function. It can also reduce social interaction and stimulation, which are essential for brain health. The researchers measured loneliness using a validated scale that asked participants how often they felt left out, isolated, or lacking companionship.
The Implications and Recommendations
The study is the first to provide a comprehensive and quantified assessment of the risk factors for early-onset dementia. It highlights the importance of prevention and intervention strategies that target modifiable factors, especially alcohol misuse and loneliness. The researchers estimated that if these two factors were eliminated, more than 45% of the cases of early-onset dementia could be prevented.
The researchers also emphasised the need for more awareness and support for people with early-onset dementia, who often face challenges in diagnosis, treatment, and care. They called for more research to understand the causes and mechanisms of early-onset dementia, and to develop effective therapies and services for this population.
The study also has implications for the general public, who can take steps to reduce their risk of dementia by adopting a healthy lifestyle and maintaining social connections. The researchers suggested that people should limit their alcohol intake, engage in regular physical and mental activity, protect their hearing, avoid smoking, control their blood pressure and blood sugar, seek help for mental health problems, and avoid exposure to air pollution. They also recommended that people should stay socially active and connected, and seek support if they feel lonely.
The Limitations and Future Directions
The study has some limitations that should be considered when interpreting the results. First, the study was observational, which means that it can only show associations, not causation, between the risk factors and early-onset dementia. Second, the study relied on self-reported data, which may be subject to recall bias, measurement error, and social desirability bias. Third, the study used a single measure of alcohol misuse, which may not capture the complexity and variability of alcohol consumption patterns. Fourth, the study did not include some potential risk factors for early-onset dementia, such as genetic mutations, infections, and autoimmune diseases. Fifth, the study was based on a UK population, which may not be representative of other populations and regions.
The researchers acknowledged these limitations and suggested some directions for future research. They proposed that more studies should be conducted to confirm and refine the findings, using different methods, measures, and populations. They also suggested that more studies should explore the interactions and synergies between the risk factors, and the underlying biological and psychological mechanisms that link them to early-onset dementia. They also advocated for more studies that evaluate the effectiveness and cost-effectiveness of prevention and intervention programs that target the modifiable risk factors, especially alcohol misuse and loneliness.