Native Americans in Alaska are more likely to be hospitalized with swine flu than whites in the state and the lack of running water in some areas may be a factor, researchers have found.

Health experts from the Centers for Disease Control and Prevention's four Anchorage hospitals and the state health department studied all known cases of H1N1 flu in the state to see if they could find any patterns.

One was striking -- Alaska's Native Americans were no more likely to die of swine flu, but were far more likely than whites to be sent to the hospital with severe symptoms, said the CDC's Dr. Thomas Hennessy.

From what we can tell from chart reviews, it appears the illness is the same in severity but much more frequent among Alaska natives, Hennessy said in a telephone interview.

Scientists and indigenous communities have been paying close attention to H1N1 rates among Inuit, American Indians and native Alaskans because of memories of the 1918 influenza pandemic, which wiped out entire villages.

Some early data from Canada also suggested that Inuit regions were harder hit by the first wave of H1N1 in May and June.

For the study, Hennessy's team tabulated all cases of H1N1 diagnosed at four Anchorage hospitals.

Of 59 cases, his team looked at carefully, only one died.

Twenty-nine percent had asthma, 44 percent were obese and 17 percent had heart disease.

But 24 cases were among whites and 15 among Alaska natives. That translated to 11 cases per 100,000 whites but 50 cases per 100,000 Alaska natives -- a rate almost five times as high.

LACK OF RUNNING WATER

Alaska natives also have high rates of some conditions known to make patients more likely to have severe symptoms, such as diabetes and heart disease, Hennessy said.

He noted that Alaska natives also had higher rates of respiratory disease in general, especially residents of rural areas, one-third of which do not have running water.

Without running water, people are hauling water in buckets to their homes, he said. They are unlikely to use this water to wash their hands -- one of the most basic ways to prevent disease spread.

We think that accounts for the higher burden of illness, Hennessy said.

Age may play a role as well, he said.

Alaska natives on the whole are a younger population than are other folks living in Alaska, he said. H1N1 has been hitting younger adults harder than seasonal flu usually does.

Hennessy said the state's comprehensive healthcare system for native Alaskans may have helped save lives. Each village has a clinic, he said, and the system pays to have the sickest patients transported to hospitals, usually by air.

The system also ensures that only patients who have been assessed by a medical professional go to the larger regional hospitals, so he doubts the high hospitalization rate among Alaska natives reflects anything but truly serious illness.

H1N1 is still spreading globally but global health officials say it may have peaked in the United States and Canada. U.S. officials said Friday that 70 million doses of vaccine were now available or had been administered.