During this weekend’s Super Bowl, New England Patriots offensive lineman Jared Wilson will wear a Guardian Cap, a helmet cover designed to blunt head impacts. But conflicting claims by the NFL and Guardian Sports bring the benefit of the caps into question, according to a recent article by Ken Belson for The New York Times.

A study found that former college football players are at “increased risk for degenerative brain diseases,” and reported cognitive impairment diagnoses, recurrent headaches, and cardiovascular disease at higher rates than an age-matched control group.

A study investigated the prevalence of Mild Cognitive Impairment (MCI) and dementia in former NFL players ages 50+. The authors found significant disparities in the rate of self-reported MCI and dementia diagnoses between the study participants (who had spent at least one year in the NFL) and national incidence estimates. Alarmingly, almost 23% of participants aged 50-60 reported MCI.

Part of Harvard’s Football Players Health Study found an association between concussions suffered while playing in the NFL and low testosterone and erectile dysfunction later in life. Head trauma injuries to the pituitary gland likely cause low testosterone levels, and the authors believe that the results have implications for everyone who has experienced a head injury.