“At least you have your research world, where there are facts,” a journalist friend told me recently. He was referring, of course, to the sharp Orwellian turn that our public discourse has taken in the past year, when practically anyone who traffics in truth—scientists, reporters, intelligence experts, cyber-security specialists—has been dismissed by our President-elect as a liar or a shill. My friend was right: research has indeed provided a respite from the maddening media conversation, a chance to challenge the assumptions and biases of medical science and public health not with bluster and noise but with rigorous experimentation. It was with this in mind that I selected the notable findings of 2016. Welcome to the sanctuary.

Exculpating Patient Zero

The history of medicine, like the history of the justice system, is filled with cases of wrongful conviction. In the Middle Ages, for instance, Jews were accused of having orchestrated an outbreak of the Black Death by poisoning town wells; there were pogroms across Europe. In our era, the epidemic was AIDS and the scapegoat was Gaëtan Dugas, a gay flight attendant from Quebec. He featured prominently in “And the Band Played On,” Randy Shilts’s best-selling book from 1987, in which Dugas was identified as Patient Zero—that is, the person responsible for bringing the disease to the continental United States. Shilts’s characterization of Dugas as a “suave Quebecois” who travelled the world having high-risk sex was seized upon by homophobes as proof that the wages of sin is death. As a result, the Reagan Administration was shamefully passive in the face of an explosive epidemic, and some medical researchers, similarly colored by prejudice, initially dubbed the disease GRID, for “gay-related immune deficiency,” despite evidence of infection among straight immigrants from the Caribbean and hemophiliacs who had received transfusions of tainted blood.

Dugas succumbed to an AIDS-related cancer in 1984, but a sample of the H.I.V. strain that he carried was preserved. Earlier this year, in the journal Nature, the evolutionary biologist Michael Worobey and his colleagues reported that they had performed a genetic analysis of the sample, along with others from early on in the epidemic. Dugas, they concluded, was not Patient Zero, not the first carrier of H.I.V. to America; rather, their analysis revealed that the virus arrived in New York City from the Caribbean in the nineteen-seventies, a decade before Dugas entered our country. They trace the mistake to a simple typo: as investigators from the Centers for Disease Control and Prevention were attempting to track the AIDS outbreak, they labelled Dugas Patient O, where “O” indicated that he resided “outside of California.” Finally, science has corrected the record. This serves as a cautionary tale for medical professionals, journalists, and laypeople alike to resist clinical indictments based on hearsay, if not outright imagination.

Your Bubbe Is Not Always Right

Everyone loves a folk remedy. For more than a century, grandmothers and physicians have prescribed cranberry juice as a cure for urinary-tract infections, which are caused by bacteria in the bladder and urethra. Like many tenacious folk remedies, this one appears to have some basis in science. Quinic acid, which is present in cranberries, is metabolized by the body into hippuric acid, a substance that in very high concentrations is toxic to E. coli, the pathogen most commonly to blame for U.T.I.s. Researchers have also found that lectins, carbohydrate-rich molecules in cranberries, can (in a test tube, at least) prevent E. coli from attaching to the cells that line the urinary tract.

Alas, the wisdom of the bubbe often collapses under rigorous testing. Last month, researchers at the Yale School of Medicine published the results of an investigation into the cranberry remedy. They performed their study in nursing homes, where U.T.I.s are common, giving a hundred and eighty-five women aged sixty-five and older either cranberry capsules or a placebo. (Neither the participants nor the researchers knew what was given to whom.) The result was striking: the two groups showed no difference in either the number of symptomatic infections or the presence of bacteria in the urine. Furthermore, the group given cranberry capsules required as much antibiotic treatment as the placebo group to eradicate the bugs.

While other experiments have suggested the same results before, they were conducted with small numbers of patients. The Yale study is more definitive. Still, I am skeptical that the cranberry market will collapse. Folk wisdom has a way of overcoming science, as Gwyneth Paltrow and Michael Phelps have proved with their obsession over cupping, an ancient therapy lately given new life. On the other hand, maybe bubbes aren’t always wrong. As they say in Yiddish, “Es vet helfn vi a toytn bankes”—“It’s as helpful as cupping a corpse.”

Rethinking Prostate Cancer

For many years, American physicians have screened their older male patients for prostate cancer by looking at the level of a particular protein in the blood. The protein, called prostate-specific antigen (P.S.A.), can indicate the presence of a tumor long before any symptoms materialize. Recently, though, there has been a movement within the medical community against P.S.A. testing; since prostate cancers typically grow very slowly and rarely cause discomfort, the thinking goes, early screening may not be all that useful. The U.S. Preventive Services Task Force, based on data from two large clinical trials, currently recommends against routine screening, but other expert groups (using the same evidence) have countered that men should be allowed to choose for themselves.

Now the dispute has become even more fraught. In October, The New England Journal of Medicine published a study by a group of British researchers that examined three classes of prostate-cancer patients: those who had received surgery, those who had received radiation therapy, and those whose disease had been carefully monitored without intervention. After ten years, there was no difference in survival rates among the three groups. Active treatment does not change the over-all risk of death, and this was the headline in most news reports. But largely overlooked in the press was that metastases, meaning spread of the cancer beyond the prostate gland to tissues in the pelvis and to bone, occurred three times more frequently in those being monitored than in those who received surgery or radiation. Not surprisingly, the cancer also progressed more quickly in these men.

In an editorial that accompanied the study, Anthony D’Amico, a radiation oncologist at Boston’s Dana-Farber Cancer Institute, argued that men should be informed of the risk of metastasis and of its consequences, particularly pelvic tumors and bone pain and fracture. D’Amico advises that men who wish to avoid metastases should consider monitoring, rather than surgery or radiation, only if their life expectancy is less than a decade. Having cared for many men with prostate cancer that metastasized—an incurable situation often marked by severe suffering—I strongly concur.

A Knife in the Back, Again

As we age, the wear and tear on our joints can not only erode cartilage but also cause bone to overgrow. Bone spurs are familiar in the feet and knees, but they can occur in the spine as well, narrowing both the central canal through which nerves pass and the small openings, called foramina, where they exit. This narrowing is termed spinal stenosis, and has characteristic symptoms: walking exacerbates the condition, causing pain and muscle weakness, and rest makes it subside. Physical therapy and anti-inflammatory agents can afford some relief, but many patients ultimately require surgery, particularly if there is a chance that muscle strength will be permanently lost.

Spinal surgery is lucrative. A simple laminectomy, in which the back portions of a couple vertebrae are removed in order to widen the canal, might cost five or seven thousand dollars. But a popular addition to laminectomy is a so-called fusion, in which adjoining vertebrae are connected with titanium hardware, keeping them aligned and the spine stable. This raises the price to fifteen thousand or twenty thousand dollars, or more. Perhaps as a result, there has been a sharp rise in the number of fusion surgeries in the United States: between 2002 and 2007 alone, the increase was fifteen-fold.