Soccer and dementia: defenders had five times the brain disease risk, goalkeepers no clear rise

In 2019 a study of former professional soccer players in Scotland reported that they were dying with dementia and related brain diseases at about three and a half times the rate of other men their age. The obvious suspect was the one thing soccer players do that almost nobody else does, which is to strike a ball with the head, again and again, over many years.

A suspect still has to be tested. Professional athletes differ from the general public in fitness, in body weight, in how they live after they retire and in a good many other ways, any of which could matter. So in 2021 the same team at the University of Glasgow went back to the records with a sharper question. If head impacts are responsible, the risk should not be spread evenly across a team. It should fall hardest on the players who head the ball most, and it should grow the longer they play.

What the first study of soccer and dementia found

The original analysis, led by Daniel Mackay and published in the New England Journal of Medicine, set out to compare mortality from neurodegenerative disease among 7,676 former professional players with that among 23,028 controls from the general population who were matched to the players on the basis of sex, age, and degree of social deprivation. Neurodegenerative disease is the term for conditions in which brain and nerve cells are progressively lost. It covers dementia, including Alzheimer’s disease, along with motor neuron disease and Parkinson’s disease.

In most respects the former players were the healthier group. Mortality from all causes was lower among former players than among controls up to the age of 70 years and was higher thereafter. Mortality from ischemic heart disease was lower among former players than among controls, as was mortality from lung cancer.

Brain disease was the exception. Mortality with neurodegenerative disease listed as the primary cause was 1.7% among former soccer players and 0.5% among controls. The excess varied by diagnosis, largest for Alzheimer’s disease at about five times the rate in controls and smallest for Parkinson’s disease at about twice the rate, and dementia-related medications were prescribed more frequently to former players than to controls.

Why field position is a test of heading in soccer

Death certificates miss a good deal of dementia, and a death rate says nothing about which players were affected. The second analysis, led by Emma Russell and published in JAMA Neurology, dealt with both problems.

Russell and colleagues counted diagnoses in the living as well as the dead. They drew on hospital admissions, dispensed prescriptions for dementia drugs and death certification, with hospital and death records available from January 1, 1981, to December 31, 2016. They then sorted the players by where they played and for how long.

The logic rests on the goalkeeper. In the words of the paper, evidence suggests risk of head injury in goalkeepers around one-third that of players in other positions and heading by goalkeepers being exceptionally rare. A goalkeeper trains with the same squad, travels on the same bus, lives the same professional life and retires into the same world as the defender standing a few yards ahead. What differs is how often the ball meets the head. If the excess of brain disease among former players came from fitness, diet, fame or anything else that players share, goalkeepers should carry it too.

What the soccer positions and career lengths showed

Over a median follow-up of 18 years, 386 of the 7,676 former players, or 5.0%, were identified with neurodegenerative disease diagnoses, against 366 of the 23,028 controls, or 1.6%. The overall risk was roughly three and a half times higher, matching the earlier death-certificate figure.

The authors found that risk of neurodegenerative disease varied by field position, in the direction the heading hypothesis predicts.

Group of former players	Risk compared with matched men from the general population
Goalkeepers	About 1.8 times, too uncertain to distinguish from no increase
Forwards	About 2.8 times
All outfield players	About 3.8 times
Defenders	About 5 times
Careers under 5 years	About 2.3 times
Careers over 15 years	About 5.2 times

Goalkeepers showed a slightly higher rate than the public, but the difference was small enough to be chance, and it shrank further once deaths from other causes were taken into account. Risk was high across all outfield positions and highest in defenders. Outfield players as a group had more than twice the risk of goalkeepers. In a later survey of retired professionals, defenders were the players who reported heading the ball most.

Time in the game mattered as well. The authors report that risk of neurodegenerative disease increased with increasing career length, from a little over double for those who played professionally for less than five years to about five times for those with the longest careers. A risk that climbs with exposure is what epidemiologists look for when they suspect a cause.

One thing did not change. The risk of neurodegenerative disease diagnosis remained similar across all birth cohorts for former professional outfield soccer players born from 1910 to 1969. For much of the last century the ball had a leather shell, which was later replaced by a synthetic one, with the benefit that the synthetic covering does not absorb water. Players from the years of that transition fared no better than those before them. The current data set does not permit analysis of outcomes in players participating in an era when the soccer ball was solely synthetic.

William Stewart, the consultant neuropathologist who leads the research, said in the university’s release: “These latest data from FIELD take that observation further and suggest this risk reflects cumulative exposure to factors associated with outfield positions.”

Could something other than heading explain the dementia risk?

The position analysis rules out explanations shared by a whole squad. It does not rule out everything, so in 2024 the Glasgow group examined the usual suspects for dementia directly, in a larger cohort of 11,984 former players and 35,952 matched controls.

Once more the players had more dementia: 434 former soccer players and 453 matched population controls were identified with a dementia diagnosis, which is 3.62% against 1.26%. The known risk factors ran the other way. Rates of diabetes, obesity, smoking, and alcohol-related disorders were lower among soccer players, while rates of hypertension, hearing loss, and depression were similar in both groups. The authors concluded that they had found no evidence that high dementia risk among former professional soccer players was associated with potentially modifiable general health and lifestyle dementia risk factors.

That leaves a group of men who smoked less, were less often obese and died less often of heart disease than comparable men, and who nonetheless developed dementia about three times as often.

What other countries and direct counts of heading in soccer show

A single country’s records could carry a local quirk, which makes the Swedish study led by Peter Ueda of Karolinska Institutet a useful check. It followed 6,007 men who had played at least one game in the Swedish top division since 1924, 510 of them goalkeepers, alongside 56,168 matched controls.

The risk of neurodegenerative disease was higher among football players than controls, by about half as much again, a far smaller excess than in Scotland. The shape was the same. The increase was seen in outfield players and not in goalkeepers, and outfield players had a higher risk of neurodegenerative disease than did goalkeepers. It was confined to Alzheimer’s disease and other dementias. Motor neuron disease showed no clear difference, and Parkinson’s disease was less common among football players than in the comparison group.

Neither set of national records contains a count of headers. Shima Espahbodi and colleagues at the University of Nottingham tried to supply one by asking. In a survey of 459 retired male professional soccer players older than 45 years, those who recalled heading the ball more than 15 times a match were about three and a half times as likely to show cognitive impairment on a telephone test as those who recalled five or fewer, after adjustment for other factors. Concussion involving memory loss was also associated with a greater risk of cognitive impairment. The estimates are imprecise, because of the 326 players who completed cognitive testing, only 44 had cognitive impairment, and the authors note that retrospective self-reported questionnaires may be subject to recall bias. A man of 65 is being asked how often he headed a ball at 25.

What autopsies of former soccer players add

Much of the public discussion of head impacts in sport concerns chronic traumatic encephalopathy, or CTE, a specific pattern of damage seen under the microscope in the brains of people with a history of head injury or repeated blows to the head. It is identified at autopsy.

An autopsy series led by Edward Lee of the University of Pennsylvania, with Stewart as senior author, examined the brains of eleven former soccer and rugby players who had died with dementia. Changes consistent with CTE were confirmed in five of seven former soccer and three of four former rugby players’ brains, always alongside other kinds of damage. When the pathology was set against each man’s clinical history, though, in just three cases was the integrated dementia diagnosis consistent with CTE. The most frequent diagnosis was Alzheimer’s disease.

The authors’ conclusion is that CTE may be common in former athletes with dementia while in many cases its clinical significance remains uncertain. That fits the population data, in which the excess among players was mostly ordinary Alzheimer’s disease and other dementias.

Heading in amateur soccer and the response of the game

Almost everything above concerns elite men. Russell and colleagues acknowledge that some of the population control individuals are likely to have participated in soccer below the professional level, and they call for further studies including risks in amateur and youth soccer.

What exists for amateurs so far is brain imaging in the living. A 2025 study led by Joan Song at Albert Einstein College of Medicine scanned 352 amateur soccer players aged 18 to 53 from the New York area, each with at least five years in the game. Those who reported more heading over the previous year showed subtle differences in the boundary between gray and white matter at the front of the brain, and those differences accounted for part of an association of more heading with poorer verbal learning task performance. The study took one measurement at one point in time, in adults with an average age of about 26. It shows a measurable trace of heading and cannot say whether that trace leads to disease decades later.

Governing bodies have acted without waiting for that answer. In 2022 the Football Association announced a trial to remove deliberate heading in football matches across U12 level and below in England, meaning children under 12, following guidance on heading in training introduced a year earlier. Its statement described the policy this way: “it represents a cautious approach to playing and enjoying football while ongoing research continues in this area”.

What the soccer and dementia evidence cannot yet say

The Scottish researchers had no access to direct information on head impact exposure or on head injuries in their records. Field position and career length stand in for both. The inference that heading is responsible is reasonable, and it is still an inference. Head injuries, like headers, are less common in goalkeepers than in other positions, and these records cannot separate years of routine heading from a handful of serious knocks.

Every study of dementia described here was made up of men, most of whom played decades ago. None included women, and the data do not reach players whose whole careers were spent with modern balls. The numbers also need to be kept in scale. Over about 18 years, 95 in every 100 former professionals in the Scottish study had no neurodegenerative diagnosis on record.

Among former professionals, the men who headed the ball most and played longest were the ones most often diagnosed with brain disease, and whether the same holds for amateurs, for women and for the modern game has not been measured.