Football Increases Future Risk of Symptomatic Radiographic Knee Osteoarthritis

Male youth in the United States commonly participate in gridiron (American) football. There are little data substantiating current popular opinion that it is associated with knee pain or osteoarthritis (OA) later in life. We aimed to evaluate the relationship of football with these outcomes in the Osteoarthritis Initiative (OAI).

This is a study of male OAI participants with knee x-ray readings, symptom assessments, and completed surveys on lifetime physical activity. The OAI is a multicenter, observational cohort recruited from the community not based on football participation status. A history of exposure to American football was ascertained via self-report. Knee radiographs were scored for Kellgren-Lawrence grade (0-4). Radiographic OA (ROA) was defined as Kellgren-Lawrence ≥ 2 in at least one knee. Frequent knee pain meant at least one knee with frequent knee pain. Symptomatic ROA required at least one knee with both ROA and frequent knee pain.

A total of 1166 men had a mean age of 63.7 (SD, 9.2) yr and body mass index of 28.6 (SD, 4.2) kg·m. Thirty-one percent (365/1166) played football at some point in their lives, 95% of whom participated from ages 12 to 18 yr. The ORs for symptomatic ROA from the lowest to highest football participation were 1.2, 1.5, and 2.2, respectively (P for trend = 0.004). Findings were similar for football from ages 12 to 18 yr and for outcomes of knee pain and ROA.

This is the first large epidemiologic study to suggest that football participation, including in the teen years, may be detrimental toward knee health. Prospective studies evaluating football players are warranted.