People with an A, B, or AB blood type have an increased risk of heart disease and shorter life spans than those with type O blood, a new study reveals. Researchers followed about 50,000 middle-aged and elderly people in northeastern Iran for an average of seven years for the study, Live Science reported.

"People with non-O blood types were nine percent more likely to die over the duration of the study for any health-related reason, and 15 percent more likely to die from cardiovascular disease, compared with people with blood type O," the website said.

Arash Etemadi, the study's lead investigator said, "It was very interesting to me to find out that people with certain blood groups - non-O blood groups - have a higher risk of dying of certain diseases." Cancer risk is influenced by multiple factors such as overall health and exercise, this is why blood types other than O should be more concerned, experts said.