More than Half of California's Adults Have Diabetes, Prediabetes, UCLA Study Finds

The study revealed large disparities in prediabetes levels among young adults by race and ethnicity, underscoring the challenge for public officials in finding solutions to poor access to healthy food and safe places for children to play.

If there’s such a thing as a healthcare earthquake, in California, diabetes is the Big One.

A study published today by UCLA’s Center for Health Policy Research estimates that 13 million adults in California, or 46%, have prediabetes or undiagnosed diabetes. Another 2.5 million adults, or 9%, have already been diagnosed with the disease. This means 15.5 million people—or 55% of the state’s population—either has diabetes or is on the way to developing it.

“This is the clearest indication to date that the diabetes epidemic is out of control and getting worse,” said Harold Goldstein, DrPH, executive director of the California Center for Public Health Advocacy, which commissioned the study. “With limited availability of healthy food in low-income communities, a preponderance of soda and junk food marketing, and urban neighborhoods lacking safe places to play, we have created a world where diabetes the natural consequence.”

The study analyzed glycated hemoglobin (A1C) and fasting plasma glucose findings form the National Health and Nutrition Examination Survey (NHANES), along with California Health Interview Survey data from 40,000 respondents. Researchers were able to breakdown prediabetes estimates by county and reveal large disparities across the state, especially among those ages 18 to 39.

Among young adults, prediabetes rates ranged from a low of 26% in Lake County—in the northern part of the state—and 28% in San Francisco County, to highs of 40% in rural Kings County, an agricultural area in the San Joaquin Valley, and Imperial County, a vast area on the border of Mexico. Racial and ethnic disparities were enormous: among young adults, Pacific Islanders had prediabetes rates of 43%, African Americans and Native Americans had rates of 38%, multiracial Californians had rates of 37%, and Latinos had 36%. Asia Americans had rates of 31% and whites had rates of 29%.

The news comes on the heels of a December 2015 CDC report that found overall rates of new diagnoses of diabetes had dropped for the first time in a generation. However, that report also revealed stark disparities by race and ethnicity and suggested that most of the decline was coming among whites or more educated Americans.

With its diverse population, California presents a different healthcare picture—and a different challenge for public health officials. (The researchers noted that California’s rate of diagnoses had climbed 35% since 2001, putting it at the midpoint among states, based on a 2012 study by CDC.)

For starters, many people do not get tested for prediabetes because the test is often not covered by insurance, especially for people under age 45, according to the researchers. The same goes with many lifestyle interventions, even though poor diet and lack of exercise are what drive the disease.

“There are significant barriers not only to people knowing their status, but getting effective help,” said lead author Susan Babey, PhD.

In the past year, the CDC and the American Medical Association have made identify persons with prediabetes a priority, with the hope of averting full-blown disease and saving healthcare dollars in the long run. Up to 30% of people with prediabetes will develop type 2 diabetes within 5 years, and 70% will develop the disease in their lifetime.


Babey SH, Wolstein J, Diamant AL, Goldstein H. Prediabetes in California: Nearly half of California adults on path to diabetes. Los Angeles, CA: UCLA Center for Health Policy Research and California Center for Public Health Advocacy, 2016. Published and accessed March 10, 2016.