Blood Type May Impact Heart Risk

(WebMD) — A new analysis suggests that having blood type O conveys some protection against heart attack and stroke, while having the far less common AB blood type appears to increase risk.

Heart disease risk typically takes into account measurable factors, such as a person’s blood pressure, cholesterol, and weight.

But blood type may also prove important, says researcher Lu Qi, MD, PhD, of Harvard Medical School and Harvard School of Public Health.

“People can’t change their blood type,” Qi says. “But we may be able to use this information to help determine a patient’s risk for heart disease and how aggressively to treat them.”

Type O is the most common blood type in the United States.

About 45% of whites, 51% of African-Americans, 57% of Hispanics, and 40% of Asians in the U.S. have the blood type, according to the American Red Cross.

The AB blood type is much rarer. Only 4% of whites and African-Americans, 2% of Hispanics, and 7% of Asians in the U.S. have it.

In their new analysis, Qi and colleagues combined findings from two large studies that followed nearly 90,000 adults for at least two decades.

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.

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