In a cross-sectional study of older men, former tackle football players had a 61% higher likelihood of reporting a diagnosis of parkinsonism or PD, compared with men who played non-football sports.
solar22/Thinkstock
Longer duration of football participation and higher level of play (college and professional) were associated with higher risk.
Lead researcher Michael L. Alosco, PhD, director of the Boston University Alzheimer’s Disease Research Center, said it’s important to note that the findings are from a cohort of men “enriched” for having PD.
“These are people who are likely already concerned for or at risk for having this disease. We don’t yet know how our findings translate to the general population,” Dr. Alosco said in an interview.
The study was published online in JAMA Network Open.
Repetitive head impacts
Dating back to the 1920s, PD and parkinsonism an umbrella term that refers to motor symptoms associated with PD and other conditions have long been described in boxers who suffer repetitive head impacts.
Multiple studies have linked tackle football with progressive brain diseases such as chronic traumatic encephalopathy. Few studies, however, have investigated the association between participation in football and PD.
For their study, Dr. Alosco and colleagues leveraged data from Fox Insight, a longitudinal online study of some people with and some without PD that is sponsored by the Michael J. Fox Foundation for Parkinson’s Research.
They focused their analyses on 1,875 men (mean age, 67 years) who reported playing any organized sport. As noted, the cohort was enriched for parkinsonism or PD. A total of 1,602 (85%) had received a diagnosis of parkinsonism/PD, and 273 had not.
Altogether, 729 men had a history of playing tackle football, and 1,146 men played non-football sports (control group). Among the football players, 82% played at youth sports or at the high school level; 17% played at the college level; and fewer than 1% played at the pro or semi-pro level.
Among the football players, 648 (89%) reported a parkinsonism/PD diagnosis.
A history of playing football was associated with higher odds of reporting a parkinsonism/PD diagnosis (odds ratio, 1.61; 95% confidence interval, 1.19-2.17) after accounting for age, education level, history of diabetes and heart disease, body mass index (BMI), traumatic brain injury with loss of consciousness, and family history of PD.
Football players who had longer careers and who played at higher levels of competition were at increased risk of having parkinsonism or PD.
Playing one to four seasons yielded an OR of 1.39 (95% CI, 0.98-1.98). The OR was 2.18 (95% CI, 1.36-3.49) for playing five or more seasons.
Football players who competed at the college or professional level had nearly triple the odds of reporting a parkinsonism/PD diagnosis (OR, 2.93; 95% CI, 1.28-6.73), compared with athletes who played at the youth or high school level.
Age at first exposure to football was not associated with a parkinsonism/PD diagnosis.
The researchers cautioned that this was a convenience sample of mostly White people, and the sample was enriched for having PD – factors that limit the generalizability of the findings.
Also, diagnosis of PD was self-reported by participants through online assessments, and objective in-person evaluations were not conducted.