A new study on Tuesday found that the U.S. blood centers were depending more on teenage donors to maintain an adequate blood supply, but these teenage donors were more likely than older ones to faint or have other complications. Yes, according to a study published in the Journal of the American Medical Association, the teenage donors aging between 16-17 are at greater risk for reactions such as fainting and bruising.

The study found that blood donating was uneventful for most donors of all ages, but complications such as lightheadedness, loss of consciousness or bruising occurred after 10.7 percent of donations by 16 and 17 year olds, 8.3 percent of donations by 18 and 19 year olds and 2.8 percent of donations by people age 20 and up.

Led by Dr. Anne Eder of the American Red Cross in Washington, the researchers examined 2006 data on 1.8 million donations from people of all ages from nine U.S. regions. They found that most complications were mild to moderately severe. In a small number of cases, fainting led to a concussion, a cut requiring stitches, dental injury or a broken jaw. Fainting-related injuries were 2.5 times more common among donors ages 16 and 17 than those aged 18 and 19 -- and 14 times more common compared with donors ages 20 and older.

The researchers also found that donations by teens ages 16 and 17 account for a surprising amount of whole blood collected by the American Red Cross -- about 8 percent of it.

In an interview, Dr. Eder said, "Our study did not explore the underlying reasons for the increased tendency for reactions in young donors. But others have shown that teens respond to stress differently, related to age-related physiological and psychological differences.”