Compared to people with type O blood:
People with the AB blood type were 23% more likely to develop heart disease.
People with blood type A had a 5% increased risk.
People with blood type B had an 11% increased risk.
Earlier studies suggest that the A blood type is linked to higher levels of LDL ("bad") cholesterol, and that the AB blood type is tied to inflammation, which is also linked to heart disease.
Blood Type May Impact Heart Risk (WebMD)