Newswise — As it does every December, the Harvard Health Letter has chosen the top 10 health stories of the year. Here are this year's winners:

1. Lowdown on cholesterol, high-dose statins. Revised government guidelines carved out a new "very-high-risk" category and set a super-low standard of 70 mg/dL or less of "bad" LDL cholesterol for people in this new category.

2. Cloning for stem cells. Two controversial research paths crossed this year when South Korean scientists announced that they had created 30 cloned human embryos and harvested embryonic stem cells from one of them. If this "therapeutic" cloning becomes acceptable and practical, this breakthrough would make a steady supply of stem cells available. Not only that, but the stem cells could contain the patient's own genes, reducing the risk that they would be rejected by the immune system.

3. The rise and fall of Vioxx. In September, Merck yanked its blockbuster "super aspirin" off the market after a study showed that it doubled heart attack and stroke risk in people who took it longer than 18 months.

4. Making smart drugs even smarter. The latest generation of cancer drugs zeroes in on abnormalities particular to tumor cells, as opposed to traditional cancer drugs, which attack all dividing cells.

5. Bad news about drugs should see the light of day. A new solution has been proposed to make sure that the findings of drug trials get reported. Researchers would have to post information about trials in a public database before they embarked on them to make sure the media and the public know what trials are taking place, and when they should look for results.

6. Take your brain for a walk. Taking regular walks may also be good for your mind according to recent studies. Results from Harvard's Nurses' Health Study suggest that regular physical activity, including plain old walking, lowers the risk for cognitive impairment by 20% for women in their 70s. Results from another study also found that walking seemed to afford some protection against dementia.

7. PSA: Speed may matter. Judging by the declining mortality statistics for prostate cancer, most experts agree that PSA screening for the disease does more good than harm. But there are other important factors to consider besides the PSA number, including how fast PSA levels have increased — often called "PSA velocity." One study found that patients whose PSA levels had increased by more than 2.0 in the year before a diagnosis of prostate cancer had a much higher mortality rate than those with slower rates of increase.

8. Cost shifting to pay-tients. For the third year in a row, private health insurers have tried to rein in double-digit premium increases by shifting costs to their customers. One way they do it is by increasing copayments for doctor and hospital visits. Many insurers have tiered their drug coverage: low copayments for generic drugs, more for brand-name medications on a "preferred" list (a formulary), and much more for brand-name drugs that aren't on the formulary. Some companies are applying the same approach to hospital care.

9. Controversy over coronary calcium scanning. Scanning coronary arteries for signs of calcium is a high-tech way to uncover atherosclerosis early. However skeptics believe that this test adds more cost than benefit. Even people with minimal atherosclerosis (and almost all Americans have some) may have a "positive" scan that leads to unnecessary further tests and even treatment. After a press report said the American Heart Association was getting ready to endorse the scans, the organization decided against publishing a new statement and reemphasized the position it took in 2000: The scans are best used as tie-breakers when some criteria indicate increased risk and others do not.

10. The flu vaccine shortage. The flu vaccine shortage this winter shows that the American system for immunizing people may be a disaster waiting to happen. Part of the problem is economic—because vaccines aren't big money-makers, American companies shy away from them. Proposals to realign economic incentives to lure American companies back into vaccine manufacturing may help, as would new advances in the flu vaccine itself.

The Harvard Health Letter is available from Harvard Health Publications, the publishing division of Harvard Medical School. You can subscribe for $28 per year at http://www.health.harvard.edu/health or by calling 1-877-649-9457 toll-free.