HONOLULU — What, me worry? I live in Hawaii.

The islands' laid-back charm and no-rush attitude are known around the world, but a new study may confirm what residents have known all along — Hawaii is the least-stressed state in the nation.

The Aloha State had the nation's lowest rate of frequent mental distress, or FMD, for adults. Hawaii's rate of 6.6 percent was lower than the national average of 9.4 percent, according to a study to be published in the June issue of the American Journal of Preventive Medicine.

South Dakota and Nebraska were among the lowest, while Kentucky was the most stressed state at 14.4 percent, the report said.

The study concluded that where people live could affect their state of mind. And some areas consistently have high or low incidences of FMD, defined as a person suffering from stress, depression or emotional problems for 14 or more days in the previous month.

The study was based upon data from annual surveys conducted by phone between 1993-2001 and 2003-06 by the Centers for Disease Control and Prevention. More than 1.2 million people were randomly surveyed in each of the two periods.

Kentucky and Alabama were the only states whose FMD prevalence was in the top five in both periods.

The Appalachian and the Mississippi Valley regions had high and increasing FMD prevalence, and the upper Midwest had low and decreasing FMD prevalence.

The report said mental distress is a major source of suffering in the U.S. and worldwide. Several factors can contribute to FMD, including everything from physical conditions to the loss of a job.

"Both biologically based mental illnesses and mental health problems with a social or situational cause sometimes lead to prolonged, yet avoidable, periods of mental distress that can disable an individual and result in substantial social and economic costs," the study said.

Dr. Matthew M. Zack, the study's lead investigator, said the next step is to figure out why Hawaii is less stressed than other states. The state's ethnic makeup or consistently sunny weather could be factors.

"Hawaiian residents may have something that could be very helpful for the rest of the U.S.," he said in an interview with Hawaii Public Radio.

In the study, Zack said since FMD often indicates potentially unmet health and social service needs, programs in high rate areas should collaborate to identify and eliminate the specific preventable sources of distress.

"With the growing scientific literature linking FMD to treatable mental illnesses and preventable mental health problems, the increased use of these surveillance data in community mental health decision making is especially warranted," Zack wrote. "The continued surveillance of mental distress may help these programs to identify unmet needs and disparities, to focus their policies and interventions and to evaluate their performance over time."