Does heading in football increase your risk of dementia?
Research in professional footballers shows a link between years of frequent heading and an increased risk of dementia. That link has not yet been found in recreational players.
Of the 925 professional footballers covered in a large summary of nine studies, six studies found a link between heading and reduced cognitive ability. Three studies found nothing. The researchers' own conclusion: a link is likely, but not yet proven. This is partly because the studies differed greatly from one another and almost all of them capture only a single point in time rather than following people for years.
Among former professional athletes who repeatedly took blows to the head, a higher risk of dementia as a cause of death has been found. However, this applies only to professionals, not to amateurs. In addition, most studies had methodological weaknesses and did not account for other explanations, such as genetic predisposition or lifestyle. The relationship could therefore also run in the opposite direction, or have other causes.
The brain damage sometimes detected in blood after heading is less alarming than it sounds. A summary of eleven experiments with controlled heading movements found no measurable rise in blood proteins that signal brain damage, including in the 24 hours afterwards. In contact sports as a whole, rises are detected, but those studies almost never accounted for the effect of physical exertion on its own, which seriously muddies that measurement. The researchers rated this body of evidence at the lowest possible quality.
In one individual case of a former professional footballer who played for more than twelve years and developed dementia at an early age, examination after death revealed brain abnormalities consistent with chronic traumatic encephalopathy. Across the entire scientific literature, only fourteen footballers have so far been described in whom that diagnosis was confirmed after death. That is too few to draw firm conclusions from, but it does point to a biologically plausible mechanism.
Depression and suicidal thoughts are, contrary to what is sometimes assumed, not more common in former athletes with high exposure to head impacts. No elevated risk was found for either amateurs or professionals.
This answer draws on five summary studies and additional case descriptions. The evidence is limited: most studies measure associations at only a single point in time, do not adequately account for other explanations, and involve almost exclusively professional athletes. The researchers behind the blood-marker analyses rated their own findings at the lowest possible quality. For amateur footballers, the evidence is thinner still.
Is there a link between depression and a higher risk of dementia?
Depression is strongly associated with a higher risk of dementia, though it remains uncertain whether depression causes dementia or is sometimes an early sign of it. Treating depression appears to lower the risk, so if you or someone close to you is experiencing depressive symptoms, it is worth taking them seriously and discussing them with a doctor.
Does hearing loss increase your risk of dementia, and does a hearing aid help?
Hearing loss demonstrably increases the risk of dementia, and a hearing aid appears to help, but proven protection for everyone has not yet been established. Have your hearing assessed regardless, if only because of the other health risks associated with hearing loss.
Can high blood pressure in your 40s cause dementia later in life?
High blood pressure in your forties demonstrably increases your risk of dementia later in life, and early treatment appears to reduce that risk. Get your blood pressure checked and discuss with your GP whether treatment is worthwhile.
Does type 2 diabetes increase your risk of dementia?
Type 2 diabetes substantially increases the risk of dementia, and the younger you are at diagnosis, the greater that risk. Good blood sugar management and the choice of medication appear to be relevant; discuss this with your doctor if you have diabetes.
Is there a link between hormones and the risk of dementia?
Does poor sleep cause dementia sooner?
Poor sleep probably increases your risk of dementia, but ordinary insomnia does not make dementia inevitable. One exception: if you physically act out your dreams while sleeping, discuss that with a doctor.