Researchers from the University of Exeter in England and Maastricht University in the Netherlands have identified 15 key risk factors that could lead to dementia before the age of 65.

Dementia “is a general term for conditions that cause loss of memory severe enough that they may impact a person’s ability to carry out daily activities,” says the Centers for Disease Control and Prevention (CDC). Alzheimer’s disease is the most common form of dementia, affecting 5.6 million people in the U.S., ages 65 and older. About 200,000 people younger than 65 suffer from early-onset, or young-onset, dementia, says USA Today.

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For the new study, published in JAMA Neurology, the researchers examined data from more than 356,052 participants in the U.K. Biobank to establish potential modifiable and non-modifiable risk factors for early-onset dementia.

Some of the data analyzed involved socioeconomic status, biological samples, education, alcohol and drug use, psychiatric data, environmental exposure to toxins, and general health information. The researchers found that out of 39 possible risk factors, 15 were “significantly associated” with a higher risk of early-onset dementia. They are:

• Lower formal education.

 •Lower socioeconomic status.

• The presence of 2 apolipoprotein 4 allele, or APOE, a major genetic risk factor for Alzheimer’s disease.

• Complete abstinence from alcohol.

• Alcohol use disorder.

• Social isolation.

• Vitamin D deficiency.

• High levels of C-reactive protein.

• Reduced handgrip strength.

• Hearing impairment.

• Orthostatic hypotension.

• Stroke.

• Diabetes.

• Heart disease.

• Depression.

“All of these factors increase dementia risk as they all lead to the same fundamental mechanisms that ultimately threaten the brain,” said Dr. David Perlmutter, a board-certified neurologist and co-author of Power Up Your Brain. “These mechanisms include inflammation and increased activity of damaging chemicals called free radicals.”

To reduce your risk of dementia, the CDC suggests staying physically active and maintaining a healthy weight, managing blood sugar, and preventing or managing high blood pressure. The agency also suggests preventing or managing hearing loss and getting support for depression, according to USA Today. Avoid binge drinking and smoking to reduce your risk of early dementia.