The rising risk with age
While dementia is not an inevitable part of ageing, advanced age is the single most significant risk factor. The number of people living with dementia is projected to increase substantially over the coming years, largely due to the increasing longevity of the UK population. Research in Wales between 1999 and 2018 suggests that the average age of dementia diagnosis has been increasing, meaning people are developing the condition later in life.
Young-onset dementia: before age 65
About 7.5% of people in the UK with dementia are under 65, totaling over 70,800 individuals, a condition referred to as young-onset dementia. It can impact people as young as their 30s. Diagnosis can be difficult in this age group as symptoms are often initially mistaken for other conditions like stress or depression.
Common types of young-onset dementia include:
- Young-onset Alzheimer's disease: Roughly one-third of young-onset cases.
- Vascular dementia: The second most common, accounting for about 20%.
- Frontotemporal dementia (FTD): More frequent in younger individuals (45-65) than in the older population.
Late-onset dementia: 65 and over
Most dementia cases are late-onset, occurring at age 65 or older. The risk approximately doubles every five years after 65. NICE CKS prevalence estimates demonstrate this increase:
- Ages 65–69: 1.7%
- Ages 75–79: 6.0%
- Ages 85–89: 18.3%
- Ages 95+: 41.1%
Diagnosis age comparison: UK research
Data from Welsh medical records (1999-2018) provides insight into diagnosis trends for different dementia types.
| Feature | Overall Dementia | Alzheimer's Disease | Vascular Dementia | Frontotemporal Dementia |
|---|---|---|---|---|
| Late-Onset (>65) | Majority of cases | >90% of AD cases | >90% of VD cases | 24.4% of FTD cases |
| Early-Onset (<65) | ~7.5% of UK total | ~1 in 13 with AD | Uncommon | Majority of FTD cases |
| Prevalence Trend (over 70s) | Increased (1999-2018) | Increased (1999-2018) | Increased (1999-2018) | Increased (1999-2018) |
| Prevalence Trend (under 50s) | Decreased (1999-2018) | Decreased (1999-2018) | Decreased (1999-2018) | Fell in under 40s (1999-2018) |
| Incidence Trend (over 80s) | Increased (1999-2018) | Increased (1999-2018) | Increased (1999-2018) | Increased for late-onset FTD |
| Incidence Trend (under 60s) | Decreased (1999-2018) | Decreased (1999-2018) | Decreased (1999-2018) | Increased for early-onset FTD |
Conclusion
While dementia primarily affects older individuals, there is no single average age for diagnosis in the UK, as it can occur across a broad age range. Age is the most significant risk factor, but improved preventative measures and increased life expectancy have contributed to a later average diagnosis age. The risk dramatically rises with each decade after 65, and the growing number of people with dementia poses a considerable challenge for healthcare. Young-onset dementia, while less common, affects thousands of younger people and requires specific support.
Risk factors and prevention
Besides age, other factors influence dementia risk, some of which are modifiable. Focusing on cardiovascular health in midlife, by addressing issues like high blood pressure and diabetes, is a key preventative measure. Healthy lifestyle choices such as exercise, a balanced diet, maintaining a healthy weight, and not smoking can also reduce risk.
For more information on risk factors and prevention, please visit the Alzheimer's Society website.
Modifiable vs non-modifiable risk factors
It's important to distinguish between risk factors that can be changed and those that cannot. While non-modifiable factors like age, gender, and genetics exist, a substantial part of dementia risk is influenced by lifestyle and managing other health conditions.
Non-Modifiable Factors
- Age: The primary risk factor, increasing significantly after 65.
- Genetics: Specific gene mutations can cause familial types of dementia.
- Gender: Dementia is slightly more prevalent in women.
Modifiable Factors
- High blood pressure: A major risk for vascular dementia.
- Diabetes: Increases risk for both vascular dementia and Alzheimer's.
- Smoking: Harms blood vessels and brain health.
- Hearing loss: Linked to higher mid-life dementia risk.
- Poor diet and lack of exercise: Negatively impact cardiovascular and brain health.
