Medical science is constantly bringing new evidence that often challenges what we think we know about risk for a disease or how a disease progresses.
Sometimes, the findings are revolutionary, while other research simply expands thinking on possible new paths to a cure.
Here are a few examples of unconventional wisdom in some recent work dealing with bone loss, tonsils and stress hormones.
It's long been thought that women are at increased risk for bone loss as they age, while men, particularly obese men, were generally safe from osteoporosis.
But a new study led by a Boston radiologist suggests that men with certain types of body fat -- deep belly fat -- are also at risk for bone loss and decreased bone strength.
Earlier research on bone fractures in men had indicated that obesity was a risk factor, but Dr. Miriam Bredella and her colleagues at Massachusetts General Hospital and Harvard Medical School focused on belly fat and its impact on bone strength.
Their scans of 35 obese men with a mean age of 34 included a stress analysis of a bone in the forearm to determine the force required for it to break.
According to results presented to the Radiological Society of North America in Chicago recently, the men with more fat behind muscle tissue in the abdomen and with more total abdominal fat had bones more prone to fail and with greater stiffness than men with less deep belly fat. Age and total body mass index did not make any difference to bone strength.
It's long been a given around children's wards: tonsils come out and the pounds pile on in the months that follow.
But a new analysis by head and neck specialists at Johns Hopkins University School of Medicine shows that the average weight gain after the surgery is only 2 to 5 pounds, and is almost entirely limited to children who have the surgery before age 6.
The researchers said parents of older children, even those who are overweight, don't need to worry about weight gain and even those with children under 6 can manage the change with some diet adjustments. Many younger children with chronic tonsillitis are actually underweight.
The study was presented at the annual meeting of the American Academy of Otolaryngology in September.
Everyone knows stress is bad for us. Chronic stress over weeks and months hammers the immune system, among other things.
But researchers at Stanford University recently showed that short-term stress -- basically a surge of fight-or-flight hormones lasting minutes to hours -- actually serves to stimulate immune system readiness.
The study, done in rats, was able to outline in detail how a massive redeployment of immune cells throughout the body was set in motion by the release of three hormones from the adrenal glands in response to a stress-induced event. The immune ramp-up took place over about two hours, involving several different types of cells.
Firdaus Dhabhar, an associate professor of psychiatry and behavioral science at Stanford, along with colleagues at several institutions, documented how the release of three stress hormones -- norephinephrine, epinephrine and corticosterone -- at different times each activated and directed the movement of different immune cells from reservoirs in the spleen and bone marrow into the bloodstream and then to various tissues.
The report was published online in June through the journal of Psychoneuroendocrinology. An earlier study of surgical patients by Dhabhar had suggested that some who had stronger short-term stress reactions to the operation healed more quickly than those with a muted response.