One out of three Rose Park adults is obese, compared to fewer than one in 10 in the Avenues neighborhood, according to a new study released Thursday by the Utah Department of Health.

While they are in close proximity to each other, those communities rank as the state's most and least obese.

It doesn't end there. Seven of the state's 10 most obese areas are suburban west-side neighborhoods, while east-side neighborhoods rank among Utah's leanest.

"We wanted to look at various factors in the communities against the obesity rates for those communities and ask: 'What is contributing to people being lighter or heavier?' '' said LaDene Larsen, director of the Utah Department of Health's Health Promotion Bureau.

Researchers first divided the state into 61 geographic areas of 20,000 to 60,000 residents, based on population size, economic factors and political boundaries of cities and counties. Then they looked at census data on age, race, ethnicity, income, education and household size in each area. Those factors were compared to the weight estimates offered by more than 16,000 Utahns in annual telephone surveys between 2001 and 2004.

Age and women's education were the only factors statistically linked to areas' obesity rates. Those two factors accounted for about half of the difference between the most and least obese areas, Larsen said.

"It's very interesting because you would think income would have something to do with it," she said. "My intuitive sense is that a higher proportion of college-educated women means they're more likely to be physically active and perhaps take care of their spouse differently, but we really aren't sure why that was a factor."

Health officials speculate the geographic differences may have something to do with the "walkability" of each community, that is, whether people have reasons and safe ways to walk from place to place.

Rose Park resident Cliff Higbee questions that reasoning.

"I've never had a problem walking in my neighborhood," he said. "We've got ladies that walk in the mornings and evenings."

In West Valley City, where the western part of the city ranked as the state's fifth most obese, officials are planning a city center that gets people out of their cars.

"It's health related, but it's also the idea that we don't need everybody to get in a car to get a gallon of milk, go to a restaurant or see some entertainment," said planner John Janson. "We'd like to have enough things in a concentrated area that walking is an incredibly viable action."

Health officials hope to do additional studies to nail down specifically what factors influence each community's obesity rate.

In the meantime, community leaders can evaluate whether they encourage physical activity. Do they have sidewalks on both sides of the street? Do they have well-lit sidewalks? Is there a variety of food choices? Are residential areas within walking distance to parks, shops and other attractions?

"Communities that are heavier could take a look around and see if zoning makes a difference," Larsen said. "They could also look at whether there's access to healthy foods or maybe too much access to unhealthy foods."