Heart Risk

Common bacteria may cause heart attacks in younger men. Chlamydia pneumoniae causes a flu-like upper-respiratory infection that can turn into pneumonia. People infected with it produce antibodies called IgA and IgG.

New finding: Men ages 30 to 50 with high levels of the IgA antibody are more likely to have serious heart attacks. The more recent the bacterial infection, the more likely a heart attack.