Vermont leads the nation for all health determinants measured. The prevalence of smoking has declined to 17.6 percent of the population, there is a slower rise in obesity than the U.S. national average, and the number of people without health insurance remains low, the researchers' report said. Vermont has a low percentage of children in poverty, ready access to primary care for residents, a high rate of high school graduation and high immunization coverage.

A comparison of state rankings from 2007 to 2008 released Wednesday indicates 36 states had positive changes in their overall health scores and 14 experienced declines. The top healthiest states following Vermont are: Hawaii, New Hampshire, Minnesota and Utah.

States with the greatest overall health score improvement from 2007 are Arkansas, New Mexico, and Kentucky. Texas and Montana have shown the least improvement in health over the last year.

Louisiana's challenges include a high prevalence of obesity, a high percentage of children in poverty and a high rate of uninsured population. Mississippi, named least healthiest state last year, improved to 49th followed by South Carolina, Tennessee and Texas.

For 19 years, America's Health Ranking have been compiled by the American Public Health Association and the Partnership for Prevention.