New data suggests people with Type O blood are at a significantly lower risk of developing heart disease.
A researcher at the Harvard School of Public Health looked nearly 90-thousand people in two multi-decade health studies.
After adjusting for diet, gender, and other factors, the analysis shows study participants with type A-B blood had a 20-percent highest risk of developing heart disease than people with Type O blood.
People with Type B blood had an 11-percent greater risk and people with Type A had an 8-percent greater risk than those with Type O.
As for having "negative" or "positive" blood, the R-H factor didn't seem to have any affect on heart disease risk.