The high cost of housing has created a public health crisis in Oakland, Dr. Muntu Davis, head of the Alameda County Public Health Department, said during a news conference at Oakland City Hall on Tuesday.

Hypertension and asthma rates are increasing as residents grapple with increased rents and lack of stability. The associated stress can cause depression, anxiety and even schizophrenia, according to studies by the Health Department and the Oakland research firm PolicyLink Center for Infrastructure Equity.

Health Department officials began analyzing the link between housing insecurity and health after watching hundreds of their clients get displaced from Oakland and surrounding cities. To understand the depth and magnitude of the housing crisis, officials conducted interviews with 188 Health Department workers and 167 Behavioral Services staff and contractors. Ninety-four percent of respondents said the stress of inadequate or unstable housing was affecting their clients’ health, in many cases nullifying the services that county health programs provide for needy communities.

More than 10 staff members who filled out the survey said that they, too, had been priced out of the metropolitan areas of Alameda County, where rents are steadily escalating — the median rent for a two-bedroom is now $2,850 a month, according to the real estate site Trulia. Many of them now have long commutes from places like Tracy, Modesto or Antioch, which cause them to lose sleep and have led to car accidents, the study said.

“The more you can’t afford things, the more stresses you have, and those stresses increase your blood pressure,” Davis said. As a result, he added, Oakland is seeing an uptick in emergency-room visits for many of these health conditions.

Data published in the study showed that between 2012 and 2014, Alameda County residents who spent 35 percent of their income on rent were twice as likely to be hospitalized for hypertension or mental illness as residents who spent less than 25 percent of their income on rent.

Children living in homes packed with 10 to 12 extra people were six times more likely to go to the emergency room for asthma than children living in homes that were not overcrowded.

Health Department workers who participated in the study said families living in overcrowded homes are often afraid to ask their landlords to clean up mold, mildew or other pests that can trigger asthma, for fear of eviction.

Housing pressures have tremendous impacts on individuals, some of whom cannot afford to buy healthy food or medicine because they have to save the bulk of their income for housing, Davis said. But the housing crisis has also reshaped cities, said Kalima Rose, senior director of PolicyLink.

Oakland, which lost a quarter of its African American residents between 2000 and 2010, is on track to become wealthier and less diverse, Rose said. Right now, 63 percent of African American households in Oakland are “cost-burdened,” she said, meaning they spend more than 30 percent 2of their income on rent.

“Oakland and the surrounding region are experiencing extraordinary economic growth,” she said, “but the accompanying housing crisis is tearing apart the social fabric of one of the most diverse cities in America.”

“In many instances we’re having to pay ‘home visits’ to families on the street, because they don’t have a stable place to call home,” Davis said.

City and county officials are taking steps to quell the problem, most notably with a $580 million affordable housing bond that will go before Alameda County voters in November. That, coupled with a city ballot measure that will require property owners to petition for certain rent increases, could help some residents keep their homes.

But the city and county will have to act fast, Rose warned.

“There has practically been free range of the market for the last decade, and very little intervention on behalf of tenants,” she said.

To Davis, the housing crisis has become a matter of life or death.

“As we look at the leading causes of death over past decades, it’s chronic diseases that don’t go away with a vaccination,” he said.

One of the best ways to stem such health conditions, he said, is to improve people’s housing quality.

Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan