By Jacque Wilson
(CNN) -- NASCAR driver Trevor Bayne has been diagnosed with multiple sclerosis, according to his racing team.
Multiple sclerosis is a chronic disease that affects the central nervous system, often causing pain, numbness in the limbs and a loss of vision. Symptoms vary by patient and can disappear for months at a time, making it difficult to diagnose early on.
Doctors have cleared Bayne, 22, to compete, said a statement by Roush Fenway Racing.
"I am in the best shape I've ever been in, and I feel good," Bayne said. "There are currently no symptoms and I'm committed to continuing to take the best care of my body as possible."
Bayne was the youngest driver in NASCAR history to win the Daytona 500 in 2011. He said he plans to race in the NASCAR Nationwide Series Championship in 2014.
Scientists do not know what causes multiple sclerosis, according to the Mayo Clinic, although a person's risk increases if a family member has the disease.
Women are more likely than men to develop the disease, and it affects Caucasians more than other ethnic groups. More than 2.3 million people worldwide have been diagnosed, according to the National MS Society.
With MS, the body's immune system destroys a fatty substance called myelin that protects nerve fibers in the brain and spinal cord. This causes communication problems between the brain and body, according to the Mayo Clinic, and may damage the nerves permanently.
There is currently no cure for MS. Doctors focus treatment on managing the patient's symptoms and slowing the progression of the disease with medication, physical therapy and an overall healthy lifestyle, such as getting plenty of sleep and eating right. Stress can trigger MS symptoms, so patients often do yoga or meditate to relieve anxiety.
As the disease progresses, patients may experience extreme fatigue, balance problems and muscle weakness. Occasionally MS will lead to partial or full paralysis. It is not normally fatal; most patients with MS have "a normal or near-normal life expectancy," the National MS Society says.
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