For the second year in a row, Kern County is ranked among the worst of California counties in health outcomes, according to data released this week.

Kern ranked better than Siskiyou, Del Norte and Lake counties. Marin County placed first.

The County Health Rankings & Roadmaps program is a collaborative project of the Robert Wood Johnson Foundation and the University of Wisconsin Population Health Institute.

They’ve been tracking overall health across the United States for five years, ranking counties within each state according to health outcomes, behaviors, clinical care, social and economic factors, and physical environment.

“We not only looked at demographics, but also things that were modifiable,” said Kate Konkle, a community coach at the institute. “The hope is that the rankings will be a starting point for conversations about local solutions.”

Kern’s rank of 54 out of 57 California counties was unchanged from last year but down from 2012, when the county was No. 49. California has 58 counties, but data for Alpine County was unreliable or insufficient, so it was excluded from the 2013 and 2014 rankings.

The study “does indicate that we have a lot of room to improve on a lot of different indicators,” said Kimberly Hernandez, an epidemiologist with the Kern County Department of Public Health.

Still, comparing overall rankings year-to-year isn’t as helpful as examining the individual elements that go into the ranking formula, Hernandez said.

If the county and the state both improve or both decline in overall health, a ranking will not change, but checking out the county’s performance on key indicators “helps us to prioritize,” she said.

Nearly a quarter of deaths in Kern County so far this year were “premature,” according to the study, compared with about 18 percent of deaths statewide.

The county also exceeded state rates of smoking, obesity, violent crime and excessive drinking, among other factors.

One of the most glaring contrasts was in drinking water violations. The percentage of the population potentially exposed to water exceeding a violation limit during the past year was 14 percent in Kern, compared with 2 percent in California.

Stephanie Hearn, water quality program manager at California Water Service Co., said she wasn’t sure what those numbers were based on, but speculated the county’s poor assessment may be related to the heavy presence of agriculture and the many small water systems in Kern.

“At Cal Water, we have a lot of experts who make sure our water does meet drinking water standards and complies with regulations, but there are also tiny water systems here that may only serve an RV park or a development of just 25 homes.

“They don’t have the resources to hire someone to oversee all that full time.”

Kern also is hurt by a relatively low number of health care providers. There is one primary care doctor for every 1,999 residents in Kern, compared with one for every 1,326 residents statewide.

The local ratio of dentists and mental health providers was high, too.

That could be why the county lags behind the state on preventive care such as mammography and diabetes screenings.

Both the county and the state did poorly on air quality — specifically, the average daily measure of fine particulate matter in micrograms per cubic meter, which was 9.2 in Kern and 9.3 in California.

Kern’s air quality, although bad, has gotten better in recent years, said Jaime Holt, a spokeswoman for the San Joaquin Valley Air Pollution Control District.

“It’s really just one component of a very complex issue,” she said. “It just goes to show how many things we have to confront to improve health in the valley.”

If Kern’s consistently poor showing in national health rankings is a bit exhausting, there is one upside to this latest one, Hernandez said.

The “roadmap” portion of the report shares best practices that have been used successfully to improve health in other communities.

“That is what’s helpful about these national rankings, looking at things that have worked in other areas,” Hernandez said. “We can pull ideas from other places to see what might work here.”