Key points from article :
PPIs reduce the amount of acid in the stomach.
Used to treat heartburn and people at risk of stomach ulcers (e.g. if taking low-dose aspirin).
Cohort study of over 300,000 US veterans shows an association - not cause.
Not seen in people taking H2 blockers like ranitidine (Zantac).
The study was published in the BMJ Open journal.