Does heading the ball frequently in football, or sustaining a concussion, increase my risk of dementia later in life?

Multiple studies point in the same direction: heading the ball frequently during a professional football career likely increases the risk of dementia later in life. The strongest evidence comes from a large Swedish cohort study involving more than 6,000 elite footballers and over 56,000 comparison individuals from the general population¹. Outfield players had a 50% higher chance of developing a neurodegenerative disease and nearly 62% higher chance of Alzheimer's disease or another form of dementia than people without an elite sporting background. Goalkeepers, who head the ball only rarely, showed no significantly elevated risk. That difference between goalkeepers and outfield players suggests that heading itself is the connecting factor, although this type of research does not prove a causal relationship.

The frequency of heading appears to matter. A study of 459 retired male professional footballers found that those who headed the ball more than 15 times per match had more than three times the risk of cognitive decline compared with players who headed it only rarely (0-5 times per match, adjusted odds ratio 3.53). The same association applied to heading in training². A smaller study of 60 English ex-professionals confirmed this: a higher estimated total number of career headers predicted worse performance on a memory test, whereas ordinary head injuries did not. Heading therefore appears to be a specific risk factor, independent of other collisions³. Both studies rely on self-reported heading counts, however, which may be inaccurate.

Concussions accompanied by memory loss are also associated with an increased risk of dementia in later life. In the same study of 459 retired professional footballers, such a concussion was associated with more than three times the risk of cognitive decline (adjusted odds ratio 3.16,². A broader review of contact sports emphasises that repeated concussions may raise the long-term risk of cognitive decline for some athletes, and that repeated mild head impacts without a diagnosed concussion are also regarded as a possible risk factor, although a definitive causal relationship has not yet been fully established scientifically⁴.

At the brain level, post-mortem examination of six deceased professional footballers who had dementia found Chronic Traumatic Encephalopathy (CTE) in four cases -- a brain disease linked to repeated blows to the head. All six also had other brain pathologies, such as Alzheimer's disease and TDP-43 protein accumulation⁵. This concerns a very small and highly selected group, however: only individuals who already had dementia were examined. It is therefore not possible to conclude from this how commonly CTE occurs among footballers in general.

Not all studies are in agreement. An early small study of 92 retired professional footballers found no significant association between playing position or career length and cognitive decline, and the prevalence of cognitive impairment did not differ significantly from that of the general population⁶. The researchers suggest that the risk may drop back to population level after a player stops competing. The study was too small to draw firm conclusions, however, and dates from a period when methods were less refined. Its findings therefore stand in contrast to the larger and more recent studies, which consistently show an elevated risk.

In practical terms, the following applies. These findings concern exclusively professional male footballers with years of intensive exposure to heading. Whether recreational players or women face the same risk cannot be determined on the basis of these studies. Anyone who is or was professionally active has good reason to be cautious about unnecessary heading drills in training, particularly at high frequency or following a concussion that involved memory loss. If you experience problems with memory or concentration, it is advisable to consult a doctor.