Risk for dementia higher among former professional footballers

Key takeaways:

• Former professional soccer players had a higher incidence of dementia.
• The rates of some modifiable dementia risk factors appeared lower among these professional athletes.

The risk for dementia was greater among former professional soccer players compared with the general population, according to results from a Scotland-based cohort study published in JAMA Network Open.

Researchers reported higher dementia risk for these athletes despite the rates of various modifiable risk factors for dementia among professional soccer players being comparable to — or even lower than — those of people who did not play the sport.

Several prior studies have suggested a higher risk for the development of cognitive disorders in former soccer players, possibly due to recurring incidences like traumatic brain injuries (TBIs), but “TBI represents just one of many potentially modifiable general health and lifestyle risk factors for dementia, with the contribution of these wider factors to dementia risk in contact sport athletes incompletely understood thus far,” Emma R. Russell, PhD, from the University of Glasgow in Scotland, and colleagues wrote.

In their analysis, the researchers used electronic health record data to examine modifiable dementia risk factors and dementia risk among former male professional soccer players (n = 11,984) aged 30 years or older on Dec. 31, 2020.

They then compared the modifiable risk factors and risk for dementia in these athletes with those of a matched control subjects representing the general population (n = 35,952).

Over a median 21 years of follow-up, researchers found 434 dementia cases among former soccer players and 453 among their matched controls (HR = 3.02; 95% CI, 2.54-3.58).

However, despite the higher percentage of dementia, former soccer players had lower rates of several dementia risk factors vs. the general population, which included:

• alcohol-related disorders (HR = 0.77; 95% CI, 0.69-0.87);
• smoking (HR = 0.55; 95% CI, 0.46-0.66);
• diabetes (HR = 0.75; 95% CI, 0.67-0.85); and
• obesity (HR = 0.72; 95% CI, 0.59-0.87).

Meanwhile, researchers observed similar risks for hypertension, depression and hearing loss in both study groups.

Russell and colleagues noted that the increased risk for dementia appeared tied to hypertension (HR = 4.62; 95% CI, 3.69-5.78) and depression (HR = 1.93; 95% CI, 1.23-3.02) among former soccer players.

These results and the findings of past analyses suggest “that a sport-associated factor (specifically, exposure to TBI or [repetitive head impacts]) may contribute to dementia risk” in these athletes, they wrote.

The researchers also acknowledged some study limitations. For example, the analysis did not consider some possible dementia risk factors — like educational attainment and pollution exposure — nor did it include information on people exclusively treated in primary care settings.

Further research “should seek to identify tests that detect earliest indices of evolving neurodegeneration prior to clinical disease presentation in contact sport athletes, allowing for timely interventions to reduce dementia risk or delay onset of the disease,” Russell and colleagues wrote. “In the interim, continued interventions directed toward risk mitigation addressing recognized, potentially modifiable risk factors should continue.”