Head injury
A single head injury raises dementia risk by about 24 percent. Five or more raise it nearly threefold.
A large group of people followed for years or decades. Shows a real-world link, though not proof of cause by itself.
Why it matters
Head injuries cause inflammation and protein buildup in the brain. Preventing falls and using helmets reduces future risk.
What to ask at the checkup
Ask whether a neurological evaluation is warranted given the head injury history
Screening: History of head injury with loss of consciousness or confusion
Sources
Long-term risk of dementia among people with traumatic brain injury in Denmark: a population-based observational cohort study
Fann JR, Ribe AR, Pedersen HS et al.. The Lancet Psychiatry, 2018.
Even one head injury raised dementia risk by about a quarter, and the risk grew with each additional injury.
Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission
Livingston G, Huntley J, Liu KY et al.. The Lancet, 2024.
Fourteen things people can change account for nearly half of dementia cases at the population level.
Routines for this factor
Check the house for fall hazards
Walk through the main rooms and note any loose rugs, dark hallways, or cluttered walkways.
10 min, difficulty 1/3
Put a night light in the hallway
Plug in a night light between the bedroom and the bathroom.
2 min, difficulty 1/3
This is research information, not medical advice. Nothing here replaces your parent's doctor.