While many risk factors can make you more likely to develop dementia, one in particular raises your dementia risk by roughly 50 percent, studies suggest. Read on to learn which one thing makes your chances of developing dementia soar according to recent studies, and what simple steps you can take to slash your risk. READ THIS NEXT: Taking These Medications for Even a Short Time Spikes Your Dementia Risk. Every year, roughly 1.7 million Americans experience a traumatic brain injury (TBI), and 275,000 of those individuals are hospitalized as a result. “An estimated 5.3 million Americans, almost two percent of the population, live with long-term disabilities due to a prior TBI,” explains a 2012 study published in the journal Archives of Neurology. In addition to causing other long-term effects, these injuries are of particular concern because they’ve been repeatedly linked with a significantly higher risk of dementia later in life. “Traumatic brain injury is perhaps the best established environmental risk factor for dementia. A meta-analysis of 15 case-control studies estimated that individuals who had had a head injury of sufficient severity to result in loss of consciousness were at approximately 50 percent increased risk of dementia compared with others,” the researchers wrote. READ THIS NEXT: This OTC Medication Can Increase Your Dementia Risk, Experts Warn. While a single severe injury resulting in unconsciousness does appear to result in heightened dementia risk, experts say that repeated mild injuries may pose a threat as well. That’s because these incidents can result in chronic traumatic encephalopathy (CTE), a progressive brain condition that can result in memory loss, impaired judgment, confusion, impulse control issues, aggression, mood changes, Parkinsonism—an umbrella term for a group of neurological problems that includes Parkinson’s—and ultimately, dementia. Symptoms can begin many years after the injuries themselves. Scientists are now working to determine the risk level associated with each injury type and frequency. “Researchers don’t yet know whether CTE is most likely to occur following a small number of severe traumatic brain injuries, a large number of mild or very mild traumatic brain injuries, or some other pattern of head trauma,” explains the Alzheimer’s Association. However, “repeated mild traumatic brain injuries that don’t cause unconsciousness may increase dementia risk.” People who play contact sports or serve in the military are at significantly increased risk of developing CTE, and later developing dementia as a result. In fact, a 2017 study published in the Journal of the American Medical Association, which analyzed the post-mortem brains of 202 deceased people who had played football at various levels, found that 87 percent of the players had developed CTE. Of the 111 athletes who played at the NFL level, 99 percent had CTE.ae0fcc31ae342fd3a1346ebb1f342fcb In addition to greatly increasing one’s chances of having dementia at all, these injuries are also believed to accelerate the age of onset dementia. People with a history of traumatic brain injury developed dementia two years sooner than those who did not, a 2016 study in the Journal of Neurology found. For more health news sent directly to your inbox, sign up for our daily newsletter. Though there is no way to guarantee that you won’t experience a traumatic brain injury or develop dementia, there are many ways to actively reduce your chances of a fall, motor vehicle accident, or sports-related injury—a few of the most common causes of TBI. To reduce your risk of everyday injuries, the Alzheimer’s Association recommends removing household hazards such as rugs, clutter, and poor lighting, having your vision checked regularly, using a walker if needed, and having your medications regularly reviewed by a doctor for side effects or drug interactions. You can also reduce your risk of TBI by taking precautions while driving: always wearing a seatbelt, keeping your car in good mechanical condition, and following the rules of the road are all essential to your safety. Finally, practice caution and wear the correct protective gear while playing sports or riding bikes. As doctors and researchers will tell you, protecting your head from injury now may slash your risk of developing dementia later. READ THIS NEXT: Doing This at Night Makes You 30 Percent More Likely to Develop Dementia.