Carroll County was ranked the fifth healthiest county in Maryland for the fourth year in a row, according to a ranking of counties across the U.S. released this week.

The rankings were released by the Robert Wood Johnson Foundation and the University of Wisconsin Population Health Institute, which examined factors such as premature death, adult smoking, high school graduation rates and insurance coverage rates to determine the overall health of counties.

Researchers found that Carroll ranked better than the state average in physical inactivity, sexually transmitted infections and teen birth rate. 

"The County Health Rankings and Roadmaps makes us aware of Carroll's excellent numbers and rankings in some areas including education, social and economic factors," said Dorothy Fox, executive director of the Partnership for a Healthier Carroll County.

Carroll County ranked third overall in social and economic factors, showing levels equal to or better than the state average in high school graduate rate, unemployment rate, violent crime rate and the number of children in poverty. 

Researchers found that Carroll County ranks worse than the state average in the areas of adult smoking, where Carroll is at 19 percent compared to the state average of 16 percent. The county also ranked worse excessive drinking, where Carroll is at 19 percent compared to the state average of 15 percent. 

"We still have areas that need continued efforts to effect change," Fox said. "Like most of our country, we have work to do better in the area of obesity and lack of physical activity, changes in these areas can have a positive effect on our overall health."

Howard County ranked best in the state and Montgomery, Frederick and Queen Anne’s rounded out the top five healthiest counties in the state. Baltimore City was found to be the least healthy.

The Robert Wood Johnson Foundation began ranking counties on health factors in 2010.