WEDNESDAY, Dec. 31 (HealthDay News) -- Doubts over the safety of diabetes and heart treatments, disappointing results for vitamins as cancer fighters, and the withdrawal of over-the-counter cold medicines for kids were some of 2008's top health stories.

But there was good news, too, including a historic drop in deaths from both heart disease and cancer, and a breakthrough in the search for a malaria vaccine.

Here are some of the biggest health headlines for 2008:

Troubles Surface for Heart, Diabetes Treatments

Throughout 2008, data emerged supporting the notion that two blockbuster diabetes medications -- GlaxoSmithKline's Avandia and Takeda's Actos -- raised heart risks for users. The studies came on the heels of a "black box" label warning slapped on the drugs by the U.S. Food and Drug Administration late in 2007. In December, another study found that use of the drugs doubled the odds of bone fractures for women.

Earlier in the year, another major trial found that the widely used cholesterol medication Vytorin, which combines simvastatin with a second drug, ezetimibe, was no better at lowering LDL cholesterol than simvastatin alone.

And, at year's end, debate continued on whether very strict control of blood sugar actually helps diabetics cut their risk of heart attack and other cardiovascular troubles. Two major trials, called VADT and ACCORD, each found that the strategy was either ineffective in lowering heart risks (VADT) or actually boosted the death risk by 22 percent (ACCORD).

Standard Medical Tests Take a Hit

The value of a trip to the doctor got a little more dubious in 2008, as a few key diagnostic tests lost some of their luster. One study found that the EKG -- used for decades to assess heart risk -- may not predict cardiovascular troubles in patients struggling with angina. Another study suggested that mammograms often pick up breast cancers that, if left alone, would regress on their own. And a third report found that colonoscopy could miss as many as 40 percent of tumors, because it has a "blind spot" for growths on the right side of the colon.