Non-Modifiable Risk Factors  

Age  

Older Adults (65+ Years)  

Age is the most significant non-modifiable risk factor for Alzheimer disease (AD). The risk increases significantly after the age of 65, with the incidence doubling approximately every five years. Older adults are more likely to develop AD, although it can also occur in younger individuals (early-onset Alzheimer’s), but this is much rarer.  

Children and Adolescents 

 Alzheimer's disease is primarily a disease of older adults. Children and adolescents are not at risk for developing Alzheimer's, though early-onset forms can occur in rare cases due to genetic mutations.  

Gender  

Women are at a higher risk of developing Alzheimer’s than men, especially as they age. Studies suggest that women may be more vulnerable to AD due to hormonal differences (such as oestrogen levels), although the reasons behind this disparity are not fully understood. Women also tend to live longer than men, which increases the likelihood of developing Alzheimer as age is a significant risk factor.  

Genetics  

Family History

A family history of Alzheimer increases the risk, as certain genetic factors can be inherited. The most well-known gene associated with AD is the APOE-e4 allele, which increases the risk of developing the disease. However, not everyone with the APOE-e4 gene develops Alzheimer’s, and not everyone with Alzheimer’s has this gene. 

Early-Onset Alzheimer

Rare genetic mutations in genes such as PSEN1, PSEN2, and APP can cause early-onset Alzheimer’s disease, typically before the age of 65. 

Pre-existing Medical Conditions  

Neurological Conditions  

Conditions such as Parkinson's disease, multiple sclerosis, and previous brain injuries (e.g., traumatic brain injury) can increase the risk of developing Alzheimer’s. Damage to the brain’s structures and cells can promote the development of neurodegenerative diseases like AD. 

Chronic Medical Conditions

Other conditions, like hypertension, diabetes, high cholesterol, and cardiovascular diseases, may not directly cause Alzheimer’s, but they increase the risk of developing it over time.  

Modifiable Risk Factors  

Socioeconomic Status  

Lower Socioeconomic Status (SES)  

People from lower socioeconomic backgrounds tend to have a higher risk of developing Alzheimer’s. Factors like limited access to healthcare, lower education levels, and increased stress contribute to higher risks for AD. A lower SES can also correlate with lifestyle factors that may increase the likelihood of developing Alzheimer’s, such as poor diet and limited physical activity.  

Participation in High-Risk Activities  

Contact Sports 

Participation in contact sports, such as football, increases the risk of developing Alzheimer’s, particularly due to repeated head injuries (concussions). Chronic traumatic encephalopathy (CTE), a brain disorder associated with repeated trauma, is a concern for athletes in contact sports, leading to cognitive decline and dementia-like symptoms.  

Extreme Sports  

While less studied than contact sports, certain extreme sports that involve head injuries (e.g., boxing, mixed martial arts) may increase the risk of developing neurodegenerative diseases, including Alzheimer’s, later in life. However, evidence is still emerging on this topic.  

Risky Behaviours  

Substance Abuse  

Chronic alcohol abuse, drug use, and smoking have been linked to an increased risk of Alzheimer’s. These substances can negatively affect brain function, exacerbate inflammation, and damage neurons, increasing the likelihood of cognitive decline.  

Mental Health 

Untreated Mental Illness 

Mental health conditions such as depression and chronic anxiety can increase the risk of developing Alzheimer’s. Untreated depression, in particular, has been linked to brain changes that may accelerate the development of Alzheimer’s, possibly due to factors like increased inflammation, oxidative stress, and hormone dysregulation.  

Environmental Hazards 

Unsafe Living or Working Conditions 

Exposure to environmental toxins, chemicals, and pollutants can increase the risk of Alzheimer’s. For example, prolonged exposure to air pollution or heavy metals (such as lead or mercury) may contribute to neurodegeneration and Alzheimer’s disease.  

Lack of Safety Measures 

Failing to implement safety measures in the home or workplace can lead to physical injuries or accidents that may increase the risk of developing Alzheimer’s in the long term, particularly if repeated head trauma occurs.