one characteristic occurs more frequently among people with a particular health outcome, that establishes an association. It does not necessarily establish that the characteristic caused the outcome.
Other factors may partly or completely explain the relationship.
Researchers therefore look at whether findings are replicated in other populations, whether there is a plausible biological mechanism, how large the association is, and whether other variables could have influenced the results.
Can Your Blood Type Affect Your Health at All?
Yes. Rejecting the claim that blood type determines aging does not mean blood
