TULSA, Oklahoma - A new study finds the poor in Tulsa County will die about eight years before the rich.

And money isn't the only factor. Low-income residents in cities like San Francisco live longer than low-income residents in Tulsa.

The Tisdale Clinic brought specialty care to north Tulsa.

It does X-rays in house, and provides care to 300 people who don’t have insurance to pay for their heart trouble, diabetes or high blood pressure.

Its work has narrowed the life expectancy gap between richer and poorer zip codes in Tulsa from 14 years to 11 years.

"Our patients absolutely want to make the changes, but they need assistance. They need resources,” medical director Kara Beair-Butler said.

A new study shows the average life expectancy for a poor 40 year old in Tulsa County is 78 years.

But life expectancy for someone earning six figures in Tulsa County is 85 years.

That gap doesn't exist in some American cities.

This doctor would like to see Tulsa become a more walkable city.

"I ask my patients to go out and walk to get better health, but if they don't have a sidewalk to walk on, if they don't have a safe place to do that, it's really impractical to expect them to follow through on the things we're asking," Beair-Butler said.

Another concern is lack of access to healthy foods.

"Food insecurity is the biggest issue, and a lot of our patients are needing better resources to get fresh produce," she said. "It is very shocking to see those numbers, and it's something that we want to make sure that we're doing our best to getting those numbers higher out here."

Another factor that could play a role in this -- the percentage of people who smoke in Tulsa County is 29 percent, while the national average is 26 percent.

Tulsa County's median home value is $120,000, while the national average is $190,000.