Sleepless in Seattle? Hardly. West Virginia is where people are really staying awake, according to the first government study to monitor state-by-state differences in sleeplessness.

West Virginians' lack of sleep was about double the national rate, perhaps a side effect of health problems such as obesity, experts said.

Nearly 1 in 5 West Virginians said they did not get a single good night's sleep in the previous month. The national average was about 1 in 10, according to a federal health survey conducted last year and released Thursday.

Tennessee, Kentucky and Oklahoma also were notably above average in their reported lack of sleep. In contrast, North Dakota had fewer problems sleeping, with only 1 in 13 reporting that degree of sleeplessness.

Health officials do not know the exact reasons for the differences.

"We didn't ask 'Why didn't you get enough rest or sleep?'" said Lela McKnight-Eily, an epidemiologist for the Centers for Disease Control and Prevention who led the study.

But experts noted several possible explanations: West Virginia ranks at or near the bottom of the nation in several important measurements of health, including obesity, smoking, heart disease and the proportion of adults with disabilities. Studies have increasingly found sleeping problems in people with certain health problems, including obesity.

"You would expect to see poorer sleep within a chronically diseased population," noted Darrel Drobnich of the National Sleep Foundation, a nonprofit advocacy and research organization.

Some experts believe sleep-deprived people are more inclined to eat fatty foods during the day.

"There's growing evidence sleep deprivation promotes obesity," said Dr. Ronald Chervin, a University of Michigan sleep disorders expert.

Financial stress and odd-hour work shifts can play roles in sleeplessness, too, Chervin added. He suggested those may be contributing factors in West Virginia, an economically depressed state with tens of thousands of people working in coal mining.

Thursday's report was based on results of an annual telephone survey of more than 400,000 Americans, including at least 3,900 in each state. The survey did not include people who use only cell phones.

(Read by Chantal Anderson. Chantal Anderson is a multimedia journalist at the China Daily Web site.)

(Agencies)