Which Blood Group Has the Lowest Cancer Risk?

Large scientific reviews and cohort studies suggest that people with blood group O generally have a lower risk of developing certain cancers compared to non-O groups (A, B, and AB). One meta-analysis summarized the findings clearly: “Blood group A is associated with an increased risk of cancer, and blood group O is associated with a decreased risk.”

Patterns in Specific Cancers

The correlation appears most consistent with cancers affecting the digestive system:

Stomach Cancer: Studies show that people with blood group A or AB face a higher risk of gastric cancer than those with blood group O.
Pancreatic Cancer: The risk for pancreatic cancer tends to be greater among non-O blood types.

Findings can vary across different regions. For example, a study of Chinese men found that blood group B actually had a lower risk of gastrointestinal cancers than group A, highlighting how genetics and regional factors play a role.

The Statistical Breakdown

Overall, blood group O appears to offer the lowest relative cancer risk across many types, though the differences are often modest. One specific analysis estimated that individuals with blood group A had about a 19% higher risk of stomach cancer compared to those with group O.