Women doctors were twice as likely than their male counterparts to be called by their first names, a new study shows.

Researchers at the Mayo Clinic analyzed about 90,000 messages between 1,092 doctors and nearly 15,000 of their patients.

Altogether, about a third of people call use either a first or last names when communicating with their doctors, according to the research.

Additionally, osteopathic doctors were twice as likely to be called by their first names than doctors with M.D. degrees. Additionally, primary care physicians were 50% more likely to be referred to by their first names than specialty doctors.

Women patients were 40% less likely to use their doctors' first names.

Researchers analyzed patient and doctor demographics, such as age and gender, but did not account for "potential cultural, racial, or ethnic nuances in greeting structure," they said.

They also did not measure whether a physician prefers to be called by their first name or not. Messages were evaluated by a natural language processing algorithm.