Iowans are losing ground when it comes to leading more healthful lifestyles and improving their individual health, according to a report released today by United Health Foundation.

Iowa’s rank slipped to 20^th-healthiest among the states, down from 16^th-healthiest in 2011, according to the foundation’s 2012 America’s Health Rankings survey, which has been conducted annually since 1990.

The ranking is unwelcome news for Iowa, which two years ago embarked on a public-private initiative to become the healthiest state in the nation within five years. According to the Gallup-Healthways Index, a separate nationwide survey being used to measure that effort, Iowa most recently ranked 16^th- healthiest, up from 19^th in 2010. The next Gallup-Healthways Index results are due out in February.

Dr. Mariannette Miller-Meeks, director of the Iowa Department of Public Health, said because the methodology of the data collection used for the report changed this year, her department does not consider the data comparable with the previous year. For instance, the data included cell-phone-only households and renters for the first time.

“I don’t think that (Iowans are) less healthy than they were a year ago,” she said. “In other aspects, we see a lot more enthusiasm among people in adopting healthier lifestyles.”

Miller-Meeks also said she believes the survey results may not fully reflect the initiatives that have been put in place within the past two years to encourage healthier behaviors.

“All of the efforts going on I think put out a consistent message that’s easy for people to remember,” she said. “And it’s easier when other people in your community are engaged in healthier behaviors.”

According to the just-released America’s Health Rankings, some 680,000 Iowa adults – 29 percent  – are obese and 600,000 Iowans got no exercise beyond going to work in a 30-day period, the survey found. Nationwide, 27.8 percent of the adult population is considered obese.

Obesity was one of 16 health “determinants” ranked by the survey, which also looked at eight “outcome” factors such as the prevalence of diabetes and cardiovascular deaths, to determine states’ overall rankings.

The high prevalence of sedentary behavior, obesity, diabetes and hypertension “means that a freight train of preventable chronic illnesses is going to crash into our health care system unless we take action now,” said Dr. Reed Tuckson, the foundation’s medical adviser and chief of medical affairs of UnitedHealth Group, in a release. “This trend is already affecting individuals’ lives and the system as a whole, but it will be devastating if left unchecked.”

Iowa ranked No. 27 among the states in the determinant factors, meaning that its overall health ranking is likely to slip further in the future, the report said.

Iowa fared among the best in the nation for least number of work days lost due to poor physical and mental health, No. 2 and No. 3 respectively, but was among the worst states – 48^th — for binge drinking. The state also had one of the highest rates of prevalence of infectious disease, 17 cases per 100,000 people. That rate was up from 11.3 cases per 100,000 a year ago.

For the sixth year in a row, Vermont was the nation’s healthiest state. Hawaii ranked second, followed by New Hampshire, Massachusetts and Minnesota. The five least healthy states were South Carolina (46), West Virginia (47), Arkansas (48), and Mississippi and Louisiana, which tied for the 49^th slot. States that showed the most substantial improvement in rankings include: New Jersey (nine slots), Maryland (five slots), and Alabama, Colorado, Massachusetts, Nebraska, Oklahoma and Rhode Island (three slots).