The top 10 health stories of 2008, chosen by the editorial board of the Harvard Health Letter.

1. Blood sugar: How low should it go?

The single-minded pursuit of low blood sugar levels is probably not the best approach to type 2 diabetes, particularly in people ages 60 and older. People with diabetes should not give up blood sugar control, but three clinical trials show it’s unwise to be overzealous about lowering high blood sugar, and certainly not without also attending to high BP and cholesterol.

2. 80 ain’t old.

Results from the Hypertension in the Very Elderly Trial (HYVET) showed that reining in high BP pays off even in an age group that was once viewed as being extremely old—those 80 and older. After two years, the treated group in the study had lower rates of heart failure, strokes, and deaths overall. HYVET is more evidence that the age for effective medical intervention—through pills, surgery, or devices—is getting older and older.

3. Nice name, nice numbers, but let’s see what you can do.

Results from two clinical trials reported this year dinged the reputation of cholesterol drug Vytorin (ezetimibe plus simvastatin). One showed that in people with a rare inherited condition, Vytorin did a great job lowering cholesterol but didn’t reduce atherosclerosis. In a second trial, among people with aortic valve stenosis, Vytorin again lowered cholesterol, but it didn’t slow progression of the valve disease or reduce serious cardiovascular events. Vytorin seems to be another example of a new medication that ought to be prescribed sparingly until we have better evidence that it really improves health.

4. What “adult” stem cells might do for you.

Last year, several research groups discovered ways to genetically tinker with adult cells so they look and behave like stem cells from embryos. These reprogrammed cells are called induced pluripotent stem (iPS) cells. This year, researchers showed how iPS cells might be used. Skin cells from two older patients with Lou Gehrig’s disease were transformed into iPS cells and then coaxed into becoming neurons and other cells that might be used to treat the disease. Insulin-producing pancreatic cells were made from iPS cells that came from human skin. And two research teams reported that they had found new ways to make iPS cells, another step toward the day stem cell therapy will leave the lab and enter the clinic.

5. Gene tests: Progress and Pandora’s Box
Personalized medicine based on an individual’s genes inched closer to routine use this year. Doctors have started to order gene tests to assess how sensitive people are to the blood thinner warfarin (Coumadin), although there are some doubts about how useful such tests will be. Meanwhile, many direct-to-the-consumer genetic tests hit the market. The tests have raised some concerns. Will they be done correctly? And even if they are, the predictive powers of this early generation of gene tests might be oversold, so some people could be unduly scared while others are falsely assured.

6. Seeing right through you.

A new generation of imaging machines, called multidetector CT scanners, is making pictures of the inside of the body faster and with incredible detail. Speedy CT scanners are proving to be especially valuable in hospital emergency departments, where time is of the essence. But are we going to pay a price for all of these pictures? The cancer-inducing radiation from CT scans is much higher than that of the traditional x-ray. Radiologists are taking steps to reduce the amount of radiation per scan and to eliminate unnecessary scans.

7. War wounds that don’t show.

Psychiatrists at the Walter Reed Army Institute of Research reported the results of a study this year that counted the number of mild traumatic brain injuries—concussions—among returning troops. Almost half of the soldiers whose concussions had caused a loss of consciousness met the criteria for post-traumatic stress disorder, and about a quarter of them were suffering from major depression.

8. Generic Rx: Shopping for health care in the global village.

Once the exception, generic drugs are now the norm. This year, about two thirds of the prescriptions written by doctors were for generic drugs. Generic drugs have taken off for many reasons. Brand-name blockbusters (Fosamax, Zocor, and Zoloft) have lost their patent protection in recent years. The Medicare Part D prescription plans have loaded up their formularies with generics. But a crucial and underappreciated factor has been the role of low-cost suppliers, many of them in India. Given the potential problems with contaminated imports, the FDA has promised to step up its overseas inspections.

9. Awareness test doesn’t make the grade.

Being awake during surgery after being given general anesthesia is one of those bad dreams that sometimes comes true. The bispectral index (BIS) is a formula that uses the values of measurements of the brain’s electrical activity to come up with a single number that is supposed to measure “anesthetic depth.” More than half of the operating rooms in the United States have BIS technology. But it’s been controversial, partly because the company that sells it has kept the formula secret. This year, researchers reported the results of a study that tested the BIS monitoring in a 2,000-person randomized trial. BIS-guided anesthesia was no better at identifying anesthesia awareness than another kind of monitoring. This is another case when the results of an independent clinical trial have called into question the value of a widely adopted medical practice.

10. Health-care reform: If not soon, when?

Some argue that the Obama administration will be hard pressed to take on something so organizationally and politically complicated as health-care reform during such a sharp economic downturn. The counterpoint: health-care reform is essential for any kind of durable economic recovery. So far, the signs are that health-care reform will stay near top of the new administration’s agenda. Regardless, the effects of the downturn were beginning to show in late 2008 and are likely to increase in 2009. The health-care building boom of the past few years will almost certainly slow down, and the number of Americans without health insurance may increase if the economy continues to she