More than 40 percent of California adults have a chronic health condition, and rates are higher in some regions, according to a new report.

High blood pressure is the most common chronic condition, affecting about one in four adults in California, or 7.6 million people, says the April 28 report by the UCLA Center for Health Policy Research.

Adults living in the Inland Empire, San Joaquin Valley, and Northern and Sierra counties had higher rates of health conditions, with about 45 percent with a chronic illness or disease, researchers found. Meanwhile, the rate for adults in the more affluent Orange County was only 36 percent.

Household income is linked to health issues. Adults living under the federal poverty level were nearly twice as likely as wealthy adults to have two or more chronic conditions, according to the report.

Researchers used data from the 2011-12 California Health Interview Survey and looked at five major conditions: asthma, diabetes, heart disease, high blood pressure and serious psychological distress.

“Chronic conditions are the leading cause of death and disability in the U.S., as well as the biggest contributor to health care costs,” the report states. “But there is a wide variation in their incidence, with major differences depending on age, income, race and ethnicity, and insurance status. In addition, many Californians with chronic conditions are delaying needed care because of cost.”

Many of the adults in the report said they delayed getting care for their condition, often because of the bills it would incur or because they lacked insurance.

About 34 percent of those who reported serious psychological distress — saying they were extremely nervous, hopeless or depressed, or had other similar symptoms — waited to get needed medical care. Of that same group, 27 percent delayed filling prescriptions.