More than 13 million California adults — nearly half of the state’s adult population — are estimated to have prediabetes or undiagnosed diabetes, according to the 2013-14 California Health Interview Survey conducted by the UCLA Center for Health Policy Research. Another 2.5 million have been diagnosed with diabetes.

Prediabetes is a condition in which blood glucose levels are higher than normal but not high enough for a diagnosis of diabetes. People with prediabetes have a much higher risk of developing type 2 diabetes, as well as an increased risk for cardiovascular disease, though the concept of prediabetes as a medical condition is somewhat controversial.

Prediabetes disproportionately affects certain racial and ethnic groups. In California, at least half of Pacific Islanders, American Indians and African-Americans are estimated to have prediabetes, as shown in the graph above. According to the same data collected in the 2013-14 California Health Interview Survey, more than one-third of Latinos, Pacific Islanders, American Indians, African-Americans and those of multiple races aged 18-39 are estimated to have prediabetes.

Check out Barbara Feder Ostrov’s full story on UCLA’s report for an interactive version of the graphic above.

The UCLA study was funded by the California Health Care Foundation and The California Endowment (California Healthline is funded by the California Health Care Foundation).