Butler County is one of the healthiest counties in the state, according to a recent study.

The Robert Wood Johnson Foundation and the University of Wisconsin Population Health Institute has announced its annual County Health Rankings.

In that the county ranks the seventh best in health outcomes and eight in health factors. Last year it ranked 10th and seventh, respectively.

The county also is the only one in Western Pennsylvania to rank in the top 10. The best neighboring county is Clarion, which is ranked 24th in health outcomes.

For health outcomes, the study looked at potential life lost to premature death and average number of poor mental or physical health days reported per month. Butler County ranked better than the state average in all those categories.

For health factors, the study looked at health behaviors, clinical care, social and economic conditions and physical environment.

Areas of strength for the county include a 94 percent high school graduation rate, better than the 86 percent rate for the state.

Other strengths included a 9 percent uninsured rate for adults younger than 65 and a low teen birth rate.

However, in the physical environment category, the county only ranked 65 out of 67 counties in the state. One factor in that ranking was air pollution, where the county has a higher rate than the state average.