Mount Sinai Hospital's Diabetes Center in East Harlem held free cooking demonstrations, exercise classes and blood screenings on Monday to mark World Diabetes Day.
Experts said many who have the disease don't even know it.
"Diabetes multiplies the risks for heart attack and stroke. It is the leading cause for blindness in adults. It is the leading cause of dialysis in this country. And so it's important to be aware of the risks and to get tested," said Dr. Ronald Tamler of the Mount Sinai Diabetes Center.
Doctors said healthier diets and an active lifestyle can help curb the effects of the disease.
The World Health Organization says 346 million people globally have diabetes.