When your doctor asks how often you exercise, do you give her an honest answer? How about when she asks what you’ve been eating lately? If you’ve ever stretched the truth, you’re not alone.

According to a new study, 60 to 80 percent of people surveyed have not been forthcoming with their doctors about information that could be relevant to their health. Besides fibbing about diet and exercise, more than one-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.

When respondents explained why they weren’t transparent, most said that they wanted to avoid being judged and didn’t want to be lectured about how bad certain behaviors were. More than half were simply too embarrassed to tell the truth.

“Most people want their doctor to think highly of them,” says the study’s senior author Angela Fagerlin, chair of population health sciences at University of Utah Health and a research scientist with the VA Salt Lake City Health System’s Informatics Decision-Enhancement and Analytic Sciences (IDEAS) Center for Innovation.

“They’re worried about being pigeonholed as someone who doesn’t make good decisions,” she adds.

Scientists at U of U Health and Middlesex Community College led the research study in collaboration with colleagues at University of Michigan and University of Iowa. The results were published online in JAMA Network Open on Nov. 30, 2018.

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 participants 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. The survey was developed with input from physicians, psychologists, researchers and patients and refined through pilot testing with the general public.

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

“I’m surprised that such a substantial number of people chose to withhold relatively benign information, and that they would admit to it,” says the study’s first author Andrea Gurmankin Levy, an associate professor in social sciences at Middlesex Community College in Middletown, Connecticut. “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,” says Levy.

Understanding the issue more in-depth could point toward ways to fix the problem. Levy and Fagerlin hope to repeat the study and talk with patients immediately after clinical appointments, while the experience is still fresh in their minds. Person-to-person interviews could help identify other factors that influence clinician-patient interactions. For instance, are patients more open with doctors they’ve known for years?

The possibility suggests that patients may not be the only ones to blame, says Fagerlin. “How providers are communicating in certain situations may cause patients to be hesitant to open up,” she says. “This raises the question, is there a way to train clinicians to help their patients feel more comfortable?” After all, a healthy conversation is a two-way street.