By Mike StobbeNEW YORK -- The nation's diabetes problem is getting worse, and the biggest jump over 15 years was in Oklahoma, according to a new federal report issued Thursday.The diabetes rate in Oklahoma more than tripled, and Kentucky, Georgia and Alabama also saw dramatic increases since 1995, the study showed.The South's growing weight problem is the main explanation, said Linda Geiss, lead author of the report by the Centers for Disease Control and Prevention study."The rise in diabetes has really gone hand in hand with the rise in obesity,'' she said.Bolstering the numbers is the fact that more people with diabetes are living longer because better treatments are available.The disease exploded in the United States in the last 50 years, with the vast majority from obesity-related Type 2 diabetes. In 1958, fewer than 1 in 100 Americans had been diagnosed with diabetes. In 2010, it was about 1 in 14. Most of the increase has happened since 1990. Diabetes is a disease in which the body has trouble processing sugar; it's the nation's seventh leading cause of death. Complications include poor circulation, heart and kidney problems and nerve damage.The new study is the CDC's first in more than a decade to look at how the nationwide boom has played out in different states.It's based on telephone surveys of at least 1,000 adults in each state in 1995 and 2010. Participants were asked if a doctor had ever told them they have diabetes.Not surprisingly, Mississippi -- the state with the largest proportion of residents who are obese -- has the highest diabetes rate. Nearly 12 percent of Mississippians say they have diabetes, compared to the national average of 7 percent.But the most dramatic increases in diabetes occurred largely elsewhere in the South and in the Southwest, where rates tripled or more than doubled. Oklahoma's rate rose to about 10 percent, Kentucky went to more than 9 percent, Georgia to 10 percent and Alabama surpassed 11 percent.Several Northern states saw rates more than double, too, including Washington, Idaho, Montana, Wyoming, South Dakota, Minnesota, Missouri, Ohio and Maine.The study was published in CDC's Morbidity and Mortality Weekly Report.