Here’s a rare bit of optimism from the headlines: Americans, on average, are living longer these days.

According to the National Center for Health Statistics’ latest Mortality Report, life expectancy increased slightly for Americans in 2010. It’s now at 78.7 years, instead of 78.6. True, that’s not much of a change … just over a month of additional time … but who’s complaining?

There also were fewer deaths in 2010 from the top five causes: heart disease, cancer, lung disease, stroke and accidental injuries. However, the top culprits still kill astonishing numbers of Americans. Forty-seven percent of deaths in the U.S. in 2010 were due to heart disease or cancer. That’s nearly half.

For Americans between the ages of 1 and 44, accidental injury was the most prevalent cause of death. Infants were most likely to die from birth defects and abnormalities.

Now, back to the good news. The homicide rate in our country also was down in 2010. In fact, homicide moved out of the top 15 causes of death for the first time since 1965. It’s currently at No. 16. The report doesn’t speculate on why the murder rate is down.

A condition called “pneumonitis (noo-moe-NIE-tis) due to solids and liquids” now occupies spot number 15. That’s lung inflammation that occurs when a person sucks food or drinks into their lungs while trying to swallow. It’s common among the elderly and those confined to a bed.

Medical conditions such as Alzheimer’s disease, diabetes, kidney disease, influenza, chronic liver disease, hypertension and Parkinson’s disease remain leading causes of death.

That’s an intimidating list, and researchers are hard at work looking for cures and better treatments to tackle these problems. Let’s hope 2012 brings solutions for some of these tough medical challenges.