LINDSEY TANNER, AP Medical Writer

CHICAGO (AP) — A new study suggests that Americans’ private medical information is under threat.

The research indicates that almost 30 million health records nationwide were involved in criminal theft, malicious hacking or other data breaches over four years. The incidents seem to be increasing.

Compromised information included patients’ names, home addresses, ages, illnesses, or Social Security numbers. Most involved electronic data and theft, including stolen laptops and computer thumb drives.

The study didn’t examine motives behind criminal breaches, or how stolen data might have been used. But cyber-security experts say thieves may try to use patients’ personal information to fraudulently obtain medical services.

Cases that didn’t involve malicious intent included private health information inadvertently mailed to the wrong patient.

The study appears in Tuesday’s Journal of the American Medical Association.