Nancy Shute

Head injuries have long been considered a risk factor for Alzheimer's, but the evidence on that is mixed. A study finds that people who have memory problems decades after a concussion are more likely to have the brain plaques associated with Alzheimer's.

Surgery to repair a damaged knee meniscus is very common, but it may not help a lot of people, a study finds. That may be because some people benefit more than others, and doctors still don't know who is going to get the most out of surgery.

Many people over 60 won't have to work so hard to lower their blood pressure, if doctors adhere to guidelines for treatment. That's because there's a lack of proof that people with moderately high blood pressure can reduce their risk of heart attacks and strokes by trying to lower it substantially with drugs.

The Victorian proverb touting the health benefits of daily apple consumption has data to support it, British researchers say. And cholesterol-lowering statin drugs do, too. People who eat plenty of fruits and vegetables and take statins when directed would be healthier still.

Vitamin deficiencies can cause deadly diseases like scurvy, and other major health problems like spina bifida. But for most people, adding a multivitamin to their daily routine doesn't affect their health at all, studies say. Still, 40 percent of Americans continue to take multivitamins.

Many soaps and other consumer products have chemicals that are advertised as antibacterial. But there's no evidence that they actually keep people from getting sick, the FDA says. And they may increase the threat of bacteria that are resistant to antibiotics.

Parents of newborns say they're often surprised to see how much bigger their older children suddenly look. Psychologists say that may be because mothers seriously underestimate the height of their youngest children, an error that could lead to more care and attention for them.

Who wouldn't want something better than mammograms for breast cancer screening? But machines that extract breast fluid to look for abnormal cells aren't it, according to the Food and Drug Administration. Still, some doctors have been offering the test to patients.

Student athletes know they need to avoid concussions. But hits that don't cause concussion symptoms can affect the brain, too. Researchers are now trying to figure out who is most at risk from those smaller hits, and if they can be warned in advance.

People who have surgery or are hospitalized for serious illnesses sometimes develop dangerous staph infections. The culprits can be bacteria that were living on people all along. Scientists say the germs thrive in remote parts of the nose that aren't typically tested. Other benign microbes might help keep the bad ones at bay.

All medications come with risks, and one of the risks with popular heartburn medicines seems to be that they interfere with the absorption of vitamin B-12. That can cause troubling symptoms, from anemia and depression to dementia.

Watching violent movies makes teenagers more aggressive, and that violence is almost always associated with sex, drinking and smoking. Violent characters in PG-13 movies are as likely to indulge in violent activities as those in R-rated flicks.