People whose blood type is A, B or AB have an increased risk of heart disease and shorter life spans than people who have type O blood, according to a new study.
But that doesn't mean people with blood types other than O should be overly concerned, because heart disease risk and life span are influenced by multiple factors, including exercise and overall health
, experts said.
In the study, researchers followed about 50,000 middle-age and elderly people in northeastern Iran for an average of seven years. They found that people with non-O blood types were 9 percent more likely to die during the study for any health-related reason, and 15 percent more likely to die from cardiovascular disease, compared with people with blood type O.
"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," said the study's lead investigator, Dr. Arash Etemadi, an epidemiologist at the U.S. National Institutes of Health.
The researchers also examined whether people's blood type may be linked with their risk of gastric cancer, which has a relatively high incidence rate among the people living in northeastern Iran. They found that people with non-O blood types had a 55 percent increased risk of gastric cancer compared with people with type O blood, according to the study, published online today (Jan. 14) in the journal BMC Medicine.
The association between blood type
and people's disease risk and life span held even when the researchers accounted for other factors, including age, sex, smoking, socioeconomic status and ethnicity.
Previous studies have shown that people with non-O blood types may be at higher risk of certain cancers and cardiovascular disease
, but it was less clear whether blood type is linked with life span, Etemadi told Live Science.