O'ahu is the healthiest place to live in Hawai'i, according to a new report that ranks the overall health of counties throughout the nation.

The study released by the University of Wisconsin Population Health Institute and the Robert Wood Johnson Foundation found that the City and County of Honolulu is tops in overall health, followed by Kaua'i, Maui and the Big Island.

"The report shows us that there are big differences in overall health across Hawai'i's counties due to many factors, ranging from individual behavior to quality of health care, to education and jobs, to access to healthy foods, and to quality of the air," said Patric Remington, associate dean for public health at the University of Wisconsin.

Researchers looked at health outcomes such as the rate of people dying before age 75 and the percent of residents who reported being in fair or poor health. They also considered factors affecting health, including the availability of primary care providers, the number of uninsured adults, high school graduation rates and number of children in poverty.

Honolulu ranks first in several subcategories, including length of life, health behaviors, clinical care, and social and economic factors.

Kaua'i is best in health-related quality of life, while Maui is best in physical environment, including measures of environmental quality and the built environment , the study said.