Maybe you've seen a relative or neighbor suddenly change his medical habits after encountering some popular health news. That shift can be disconcerting. Dad, what do you mean the TV made you stop taking your pills? But at least you—and he—are not alone: Two recent studies demonstrate just how common this response is, and how influential TV news can be.

The studies link declines in people's use of two classes of prescription drugs to media reports about the drugs' side effects. They underscore the ability of health shows to alter people's behavior, particularly older folks. It's no coincidence that the median TV watcher in the United States is 54 years old, and that the drugs in question are generally prescribed to senior citizens. News companies cover the stuff they know audiences will care about. The consequences can be good or ill, depending on how accurate and convincing the shows are.

One of the new studies, conducted by a team of researchers at the National Institutes of Health, tracks the fate of bisphosphonates, a popular class of osteoporosis drugs. In 2010, New York-based ABC World News reported that, for a small number of women, using bisphosphonates such as Fosamax for more than five years can lead to femur fractures. The show triggered a spike in Google searches for "Fosamax," the NIH researchers found. By 2012, fewer than half as many American white women were taking bisphosphonates as they were in 2008. Admittedly, other factors could have played a role, too. For example, the World Health Organization published new recommendations in 2008 that called for only higher-risk women to take bisphosphonates.

The studies underscore the ability of health shows to alter people's behavior, particularly older folks.

The other study, conducted by researchers from the University of Sydney and Australian National University, found that Australian pharmacies dispensed about three percent fewer cholesterol-lowering statins every week following two episodes on the show Catalyst. That corresponds to about 61,000 Australians not taking statins who otherwise would have.

The Catalyst episodes "questioned the link between high cholesterol levels and cardiovascular disease," as the researchers put it. Soon after airing, health experts criticized the episodes as misleading and irresponsible. The Australian Broadcasting Corporation eventually removed the episodes from the Web.

So it's clear these shows affected the choices people made. Did they affect their health, too? The Catalyst study didn't examine this crucial question, but other studies of bisphosphonate use have. In 2010, a different team of Australian researchers found that a drop in bisphosphonate use in their home country was associated with an increase in hip fractures in women. The NIH study found the opposite: Less bisphosphonate use in American women was associated with fewer hospitalizations for a particular type of hip fracture called subtrochanteric fractures. The NIH scientists wrote they aren't sure why there's this discrepancy between their study and the 2010 bisphosphonates one.

Journalism organizations do have standards for reporting on health news fairly and accurately, but not all programs always hit the mark. Research shows just how important it is that they do.