Dr. H. Gilbert Welch makes some health care advocates nervous. Amid the frequent and vocal demands for early disease detection that have become the battle cry of preventative medicine, his opposition sounds like heresy, particularly his contention that universal screening for some conditions is more likely to make well people sick than it is to make sick people well.

Simply because we have the technological capability to screen for early signs of disease does not mean that we should, Dr. Welch said in his 2011 William J. Bicknell Lectureship in Public Health at the Boston University School of Public Health. In fact, screening for early signs of conditions ranging from elevated cholesterol to diabetes to cancer leads to overdiagnosis and, consequently, overtreatment, according to the general internist and professor of medicine at the Dartmouth Institute for Health Policy & Clinical Practice in Hanover, N.H.

The “better safe than sorry” mentality might hold more water as a justification for screening if, in fact, all subsequent treatments resulting from a positive screen could be considered safe. “The fact is, all of our treatments carry some harm,” he said, noting that drugs have side effects, surgery can have complications, and simply knowing one has or may be at risk for a given disease has emotional consequences. Further, all treatments have costs, and overtreatment is a huge drain on an already overburdened healthcare system, he said.

Pegged by some in the health care industry as a potentially dangerous renegade in the months since the January 2011 publication of his book, coauthored by colleagues Dr. Lisa M. Schwartz and Dr. Steven Woloshin, Overdiagnosed: Making People Sick in the Pursuit of Health (Boston: Beacon: 2011), Dr. Welch is unapologetic for his assertion that the chief benefactors of early screening protocols are device manufacturers, imaging centers, pharmaceutical companies and even local hospitals. Screening, he said, is a recruiting tool. It doesn’t necessarily lead to better patient care, but it does generate “new” patients, including those with no signs and symptoms of disease who would otherwise believe themselves to be healthy and those who turn into patients overnight by virtue of a threshold change, such as a reduction in fasting blood sugar values indicating prediabetes or an alteration in osteoporosis criteria, he said.

Case in point, according to Dr. Welch, is the prostate-specific antigen (PSA) test. “Many men with ‘abnormal’ PSAs don’t ever suffer from prostate cancer, yet are diagnosed and sometimes treated for it with radiation or radical surgery,” he said.

Similarly, the suggestion that screening mammography is responsible for saving the lives of screen-detected breast cancer patients is misleading. Dr. Welch, along with Dartmouth colleague Brittney Frankel recently concluded that screening mammography often leads to early diagnosis of breast cancer with no effect on mortality and to overdiagnosis of cancers that do not represent a health threat. In a study published online on Oct. 24 in the Archives of Internal Medicine, they determined that most women with screen-detected breast cancer have not had their lives saved by screening.