Hundreds of motorcyclists fastened their helmets and left Boston for Onset on Sunday, participating in the 15th annual Rick Graham Diabetes Awareness Memorial Ride, a meaningful cause to many riders.

LaCarl Russell, part of the planning committee for the ride and a diabetic, estimated 350 people made the ride of more than 50 miles this year, starting at the Boston Firefighters Union Hall and ending at the Dudley L. Brown VFW in Onset.

The ride is held in honor of Rick Graham, a Boston firefighter who had a diabetes-related heart attack in 2001 while riding his motorcycle. The money raised on Sunday goes to the American Diabetes Association and to families of bikers who have passed away from diabetes. Typically, up to $9,000 is raised during the day of the event, held annually on the third Sunday of September.

After Graham died, bikers raised money to pay for his son to finish school, Russell said, something the bikers have tried to repeat for other families each year.

“Just to see all these people out here having a great time for a good cause, it means a lot to me,” Russell said.

The ride brings people together from New York, New Jersey and Washington, D.C. Senior citizens and young children were all at the VFW in Onset enjoying music, a barbecue and raffles.

“It’s like a reunion,” said Bobby Adams, a founding organizer of the ride.

Adams said many people who have diabetes don’t realize it, so he hopes the ride will be a reminder of how prevalent the disease is. An estimated 7.2 percent of the United States population has diagnosed diabetes, according to the Centers for Disease Control and Prevention, and diabetes is the seventh leading cause of death in the country.