In a new book, “Overdiagnosed: Making People Sick in the Pursuit of Health,” Dartmouth researchers and physicians H. Gilbert Welch, Lisa Schwartz and Steven Woloshin argue that the medical establishment’s embrace of early diagnosis and treatment as the key to keeping people healthy actually does the opposite.

When doctors order screenings or tests for people who have no symptoms, then diagnose them with illnesses, that’s often overdiagnosis, these authors maintain. Since many of the patients will never develop symptoms, much less get sick or die from these ailments, it leads to costly, unnecessary medical interventions and promotes a culture of sickness rather than health. I spoke with Welch, a professor at Dartmouth’s Institute for Health Policy and Clinical Practice, about what health care might look like if more people adopted their approach.

Q. Prevention is at the heart of the health reform law. New health plans are now required to cover for free all measures recommended by the U.S. Preventive Services Task Force, a group of medical experts that evaluates the effectiveness of preventive services. Their recommendations include screenings for osteoporosis, breast and colon cancer. Is this the right way to prevent disease and save the system money?

A. I’m a supporter of health care reform. The country needs it. Do I have trouble with the emphasis on screening and annual check-ups? Sure. I don’t think people fully understand the ramifications of early detection and that’s why I’m raising questions about it in this book.

There’s the idea that this kind of prevention – identifying medical problems in healthy people – will save money and improve people’s health. It certainly won’t save money. The reason is that early detection identifies so many new patients. Any savings from avoiding the cost of a few patients with advanced disease quickly evaporate in the face of the new cost of intervening early on millions of additional patients.

Q. But will it improve health? 

A. It may improve health for some, but it also harms the health of others. The reason is overdiagnosis: the detection of abnormalities in people who are never destined to develop symptoms – or die – from their condition. We don’t know who these patients are, so we treat everybody. That means we are treating some people who can’t benefit from treatment – because there’s nothing to fix. But they can be harmed. The truth is it’s hard to make a well person better, but it’s not hard to make them worse.

Q. Let’s talk about a specific example. You discuss breast cancer screening in your book.

A. Whether a woman should get a mammogram is a personal decision because it’s an incredibly close call. I believe mammography does help some women avoid a breast cancer death, but it’s rare. Our best guess is that you have to screen 2,500 50-year-old women for 10 years in order to help one avoid a breast cancer death.

To be fair to patients, I believe we need to be clear about what happens to the other 2,499. Nearly half will have an abnormal mammogram over that period and have to worry about cancer needlessly. Half of them will have to go on to have a biopsy. And somewhere between 5 and 15 will be overdiagnosed and receive surgery, radiation and/or chemotherapy for a cancer that was never going to bother them.

No one can say what is the “right” thing to do. It’s a personal choice.

Q. Many health care experts today say it’s important that everyone have a “medical home”: a primary care physician who’s their regular go-to person for routine and preventive care, and who coordinates their care with specialists and other health care providers when necessary. If you’re healthy, do you need a medical home?

A. The patients that most need a medical home are those with multiple chronic conditions and who are on many medications.

For people who are well, the virtue of having a regular primary care physician is to establish a relationship and to establish the set of values that will guide your care. You can talk about where you are on the spectrum between aggressively looking for early signs of disease and waiting until you have symptoms to seek out treatment. The first may have the potential benefit of early diagnosis, but the potential harm of being diagnosed and treated for problems that will never become relevant.

Q. Wellness programs for employees used to be pretty limited, offering discounted gym memberships perhaps, but not much else. Now they’re moving into a new realm, with financial incentives for not smoking, and keeping blood pressure, cholesterol and BMI within recommended levels, for example. Is this a good move?

A. It depends. I have no problem with promoting general principles of good health: Eat right, exercise, don’t smoke. Encouraging someone to watch their weight, without being too rigorous or obsessive about it, is reasonable. And people ought to know their blood pressure and cholesterol levels, and get treated if they’re truly at high risk for problems.

But I do worry about two things. First, I believe the recommended thresholds for treating blood pressure, cholesterol and blood sugar have fallen too low. At those levels, the risk that treatment will cause an adverse event – like fainting, in the case of blood pressure medication – is too high. Wellness programs have to be careful not to become part of the problem.

Second, I get a little nervous about tying financial incentives to wellness goals. I don’t want to punish sick people – particularly since they tend to be the most economically vulnerable.

Q. What’s on your wellness wish list?

A. Let’s help people learn how to ask good questions of their doctors. How to understand risk and health statistics so they can make better decisions. Wellness programs could educate and inform people about how to be a critical consumer of health care. Wouldn’t that be something?

Q. You haven’t had a routine physical since you were a child, and it’s not recommended by the U.S. Preventive Services Task Force. Yet many health plans cover an annual physical and health care providers encourage it. Is it a waste of time?

A. If the annual physical is really what it says it is – a comprehensive physical exam to look for something that’s wrong with you – it’s a total waste of time. If it’s an effort to connect with a physician and talk about the way things are going, without looking for lumps and bumps, then having that annual visit may be a good thing.