Concussion Causes and Risk Factors

In emergency departments, the leading causes of concussions are falls, motor vehicle trauma, assaults, and sports.

Sport, position, and style of play. In sports-related concussions, contact sports have the highest rate of concussions. Below is a list of National Collegiate Athletic Association (NCAA) sports and the number of concussions reported per every 1,000 athletes.¹NCAA. SSI task force explores issues, challenges around concussions. http://www.ncaa.org/health-and-safety/medical-conditions/ssi-task-force-explores-issues-challenges-around-concussions Published July 11, 2013. Accessed September 21, 2014.

• Football 2.9
• Lacrosse 2.5
• Women’s Ice Hockey 2.1
• Men’s Ice Hockey 2.1
• Women’s Soccer 2.0
• Men’s Wrestling 1.6
• Men’s Soccer 1.3
• Women’s Lacrosse 1.2
• Women’s Field Hockey 1.1
• Women’s Basketball 1.0
• Men’s Basketball 0.6
• Women’s Softball 0.4
• Women’s Volleyball 0.2
• Men’s Baseball 0.2

An athlete’s position and style of play also affect his or her risk of concussion. For example, a study of National Football League (NFL) data²Pellman EJ, Powell JW, Viano DC, Casson IR, Tucker AM, Feuer H, Lovell M, Waeckerle JF, Robertson DW. Concussion in professional football: epidemiological features of game injuries and review of the literature--part 3. Neurosurgery. 2004 Jan;54(1):81-94; discussion 94-6. Review. PubMed PMID: 14683544. found that quarterbacks are the most likely players to suffer concussions, and that the overall risk of concussion was highest during kickoff plays. High school football play differs, and evidence shows that the defensive players who are at greatest risk of concussion are linebackers, while the offensive players who are at greatest risk are running backs.³Harmon KG, Drezner JA, Gammons M, Guskiewicz KM, Halstead M, Herring SA, Kutcher JS, Pana A, Putukian M, Roberts WO. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. 2013 Jan;47(1):15-26. doi: 10.1136/bjsports-2012-091941. Review. Erratum in: Br J Sports Med. 2013 Feb;47(3):184. PubMed PMID: 23243113.

Individual sports with high incidences of concussions are boxing, karate, and tae kwon do.⁴Buse GJ. No holds barred sport fighting: a 10 year review of mixed martial arts competition. Br J Sports Med. 2006 Feb;40(2):169-72. Review. PubMed PMID: 16432006; PubMed Central PMCID: PMC2492032.^,5Hutchison MG, Lawrence DW, Cusimano MD, Schweizer TA. Head Trauma in Mixed Martial Arts. Am J Sports Med. 2014 Mar 21;42(6):1352-1358. [Epub ahead of print] PubMed PMID: 24658345.

Previous concussion. People who have suffered a concussion(s) in the past are more likely to sustain another concussion in the future.

Age. People younger than 24 and people older than 75 are at the greatest risk for concussion.⁶Heads Up: Facts for Physicians about Mild Traumatic Brain Injury (MTBI). US Department of Health and Human Services, Centers for Disease Control and Prevention. http://www.cdc.gov/concussion/headsup/pdf/Facts_for_Physicians_booklet-a.pdf Accessed September 14, 2014. In fact, children ages 0 to 14 account for nearly half a million emergency room visits for concussion.⁷Faul M, Xu L, Wald MM, Coronado VG. Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations and Deaths 2002–2006. Atlanta (GA): Centers for Disease Control and Prevention, National Center for Injury Prevention and Control; 2010.

See Helping Kids Return to Physical Activity After Concussion

Gender. Female athletes report more concussions and more severe symptoms than their male counterparts playing the same sport.⁸Dick RW. Is there a gender difference in concussion incidence and outcomes? Br J Sports Med. 2009 May;43 Suppl 1:i46-50. doi: 10.1136/bjsm.2009.058172. Review. PubMed PMID: 19433425.^,9Covassin T, Elbin RJ 3rd, Larson E, Kontos AP. Sex and age differences in depression and baseline sport-related concussion neurocognitive performance and symptoms. Clin J Sport Med. 2012 Mar;22(2):98-104. doi: 10.1097/JSM.0b013e31823403d2. PubMed PMID: 22246342. For example, female soccer players are more likely to report concussions than male soccer players. It is not yet clear if this is a difference in reporting or an actual difference in injury risk.

Learning and mood disorders. Concussions in people with learning disorder or mood disorders may have a more complicated recovery.¹⁰Harmon KG, Drezner JA, Gammons M, et al. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med 2013, 47 15-26.

Migraines. Some experts suspect that people who suffer migraines are more likely suffer a concussion and/or may have a longer concussion recovery.¹¹Harmon KG, Drezner JA, Gammons M, Guskiewicz KM, Halstead M, Herring SA, Kutcher JS, Pana A, Putukian M, Roberts WO. American Medical Society for Sports Medicine position statement: concussion in sport. Br J Sports Med. 2013 Jan;47(1):15-26. doi: 10.1136/bjsports-2012-091941. Review. Erratum in: Br J Sports Med. 2013 Feb;47(3):184. PubMed PMID: 23243113.

Risky behavior. People engaging in risky behavior, such as drinking and driving, have an increased risk for concussion.

Precautions such as wearing helmets (e.g. bike and football helmets) or car safety belts can reduce the risk of concussion but will not eliminate it.