For the third consecutive year -- and the fifth time in the past seven years -- a national study has ranked Delaware County residents as the healthiest in Ohio.

The Robert Wood Johnson Foundation and the University of Wisconsin's Population Health Institute last week released the annual County Health Rankings and Roadmaps report. Delaware County earned the No. 1 overall ranking.

The county also topped the report's two categories: health factors and health outcomes. Health factors measure the behavioral and environmental conditions that predict county residents' future health, while health outcomes measures how long county residents live and how healthy they feel, according to the report.

Shelia Hiddleson, commissioner of the Delaware General Health District, said the county's No. 1 ranking reflects a collaboration among multiple groups throughout the county.

"We are thrilled with that, because we know it is the partnerships we have with many community partners that has allowed us to achieve this ranking," she said.

Traci Whittaker, spokeswoman for the health district, said the achievement also reflects the commitment residents throughout the county have made toward living healthier lifestyles.

Of Delaware County's contiguous neighbors, only Union County cracked the top five overall healthiest counties in the report. Franklin County ranked 49th healthiest among the state's 88 counties.

Hiddleson said in the coming weeks, the health district staff will review the report's data and analyze whether district initiatives have had positive effects over the past year.

Despite the top ranking, Hiddleson said, the report highlights areas where the county can improve.

For instance, the county ranks in the bottom 12 for air quality. It also ranks among the 15 counties with the highest percentage of people who drive alone for more than 30 minutes during their daily commutes.

Hiddleson said health district officials hope to take a more active role in tackling air-quality issues in the future.

"We're just beginning to look at what we can do as a community to help that," she said.

Hiddleson said although Delaware County's proximity to Columbus and the number of commuters in the county make air-quality problems difficult to solve, some mitigation at the local level is possible.