Health news of the month—statins, new vaccines, Mexican prescription drugs, and more.

News about health and medicine abounds; clear guidance often doesn't. We've picked a handful of important or intriguing health stories from the last month and asked Sydney Spiesel, a pediatrician who teaches atYale University's School of Medicine, to explain and venture an opinion about them. Below are his takes on statins, weight and mortality, Mexican prescription drugs, teens and oral sex, three new vaccines, and honey as a burn treatment.

Statins: They may lower the risk of cancer. But be careful which one you take.

State of the science: Statins, drugs that lower cholesterol by blocking its production, have demonstrated their value in decreasing coronary artery disease and heart attacks since they were introduced in the United States in 1987. They've also turned out to be surprisingly good at preventing medical problems that seem unrelated to cholesterol level—for example, strokes. And now it seems that taking a statin might lower the risk of some kinds of cancer. Though the results of previous research had been mixed, a recent study looking at colorectal cancer suggests an association between taking statins and a decreased risk for this illness. It's not yet clear whether the association is causal or coincidental, but it is nonetheless intriguing, especially because another recent large study of American veterans showed similar results for prostate, breast, lung, and other cancers.

Caveat: Statins have long been known to cause a major, if rare, side effect: the death of muscle cells, which leak materials that in turn clog and damage the kidneys and other organs. This risk depends on factors including dose and patient ethnicity and age, and some statins are more likely to lead to this problem than others. One (Baycol) was taken off the market for this reason. Now Crestor, which is heavily promoted and commonly prescribed, has been shown to pose a greater risk than other statins for muscle and kidney damage. 

Prognosis: Future research will clarify whether statins fulfill their promise for preventing strokes and some kinds of cancer. For now, it's clear that they help prevent heart disease, and the risks associated with them are pretty low when doctors are careful about dose and patient selection. Special care should be taken with Crestor for patients who need high doses or take other medications that increase the risk of muscle breakdown, and it's not clear that the drug has any additional benefit not found in the marginally safer statins. Oddly, Asian-Americans develop unusually high blood levels of Crestor, which might put them at higher risk for dangerous side effects.

Weight and Mortality: Is it really OK to be fat now?

State of the science: The old truism was that thinner is healthier. That conclusion was based on the 1943 Metropolitan Life Insurance tables (nicely illustrated and discussed here), which found that lower body weights were associated with lower mortality rates. But the tables were based on the company's insured population, which was probably relatively healthy and mostly white. In addition, the raw data were not collected in consistent, rigorous, or scientific ways and weren't broken down by age, which recent studies have shown influences risks related to weight. Now new studies, rigorously analyzed at the National Center for Health Statistics, are scrambling the old picture of the relationship between weight and mortality. Guidelines put out by the National Heart, Lung, and Blood Institute break people into groups according to their  scores: "underweight," "normal," "overweight," and "obese," which is further subdivided into three levels of severity. The new studies also look at how the relationship between weigh body mass index t and death rate is influenced by age, gender, smoking habits, and whether a patient's excess weight was maintained over a long period of time. The results that grabbed headlines:

• At any age, being "underweight" increases the risk of dying the most.

• People classified as "overweight" are less likely to die than those of "normal" weight, even if they carried the excess weight for a long time.

• For people under 70, being moderately or very obese increased the risk of death a lot, but for the more elderly, only a little.