CHICAGO, Dec. 1 -- Between 60 and 80 percent of people surveyed have not been forthcoming with their doctors about information that could be relevant to their health, according to a study.

Insights into the doctor-patient relationship came from a national online survey of two populations. One survey captured responses from 2,011 participants who averaged 36 years old. The second was administered to 2,499 participants who were 61 on average.

Survey-takers were presented with seven common scenarios where a patient might feel inclined to conceal health behaviors from their clinician, and asked to select all that had ever happened to them. Participants were then asked to recall why they made that choice.

In both surveys, people who identified themselves as female and were younger and who self-reported as being in poor health were more likely to report having failed to disclose medically relevant information to their clinician.

Besides fibbing about diet and exercise, more than a third of respondents didn't speak up when they disagreed with their doctor's recommendation. Another common scenario was failing to admit they didn't understand their clinician's instructions.

"I'm surprised that such a substantial number of people chose to withhold relatively benign information, and that they would admit to it," said the study's first author Andrea Gurmankin Levy, associate professor in social sciences at Middlesex Community College in Massachusetts. "We also have to consider the interesting limitation that survey participants might have withheld information about what they withheld, which would mean that our study has underestimated how prevalent this phenomenon is."

The trouble with a patient's dishonesty is that doctors can't offer accurate medical advice when they don't have all the facts.

"If patients are withholding information about what they're eating, or whether they are taking their medication, it can have significant implications for their health-especially if they have a chronic illness," Levy said.

Understanding the issue more in-depth could point toward ways to fix the problem. The possibility suggests that patients may not be the only ones to blame.

The study has been published online in JAMA Network Open.