Studies show obesity may increase risk for swine flu

SALT LAKE CITY - Today, thousands of children, pregnant women and chronically sick adults, who have been granted priority by federal health officials, will receive H1N1 swine flu vaccine through government-sponsored mass vaccination clinics across the country.

Should the obese be able to join them?

Such patients may become sicker from the novel flu strain than patients with a healthy weight, even when they don't have other health problems, such as heart disease or diabetes, according to experts.

For now, federal and local health officials say no.

But doctors at Intermountain Healthcare and the University of Utah expect to publish a study in the next few weeks on Salt Lake County hospitalized H1N1 patients, trying to answer whether weight is its own risk factor that warrants inviting the obese to get in line.

The Salt Lake Valley Health Department has been tracking all hospitalized H1N1 patients in the county and found that 40 percent were obese. By comparison, 23 percent of the overall adult population in Utah is obese.

Russell Miller III, medical director of the respiratory intensive care unit at Intermountain Medical Center in Murray, Utah, said his study controlled for other factors that might explain the higher rate of obese patients in the hospital. Such factors include gender, race, age and some underlying health conditions.

He won't reveal his findings until the paper is published. But he noted that there are more obese patients who are critically ill in the ICU than he sees with seasonal influenza.

"These patients we've seen in the ICU are more (likely to be) obese than I would have expected, based upon the underlying population," he said. "You want to tease out whether that's just one race or one gender or these other factors that play into it."

The U.S. Centers for Disease Control and Prevention has prioritized who should receive the limited vaccine doses, selecting groups more likely to get infected or suffer complications like pneumonia. Over the summer, the CDC considered and rejected obesity as an independent risk factor, saying there wasn't enough evidence to support it.

Obesity is defined as having a body mass index of 30 or above. A 5'10" tall man or woman weighing 209 or more is considered obese.

Most of the obese Salt Lake County patients have underlying conditions that would qualify them for vaccine, according to health department data. But 22.5 percent don't.

A similar link between obesity and severe influenza has been found in California. A study published in the Journal of the American Medical Association earlier this month showed that among that state's hospitalized adults whose BMI was known, 58 percent were obese.

About one-third of them didn't have underlying conditions associated with influenza complications. The JAMA article noted that an association between obesity and severe and fatal cases also has been noted anecdotally in Chile, Manitoba and Mexico.

It also said obesity, along with diabetes, was the most frequently cited underlying condition among patients worldwide who died from the flu. "A link between obesity and severe influenza, while not proven, is plausible," the study said.

Nevertheless, local health officials aren't ready to warn obese patients they are at greater risk of complications. And they won't depart from the CDC guidelines for vaccine.

"It really has not been a proven link," said Dagmar Vitek, medical director of the Salt Lake Valley Health Department.

The U.S. Centers for Disease Control and Prevention has prioritized who qualifies for the limited H1N1 vaccine supply, specifying patients more likely to get infected or suffer complications. They are:

- Children ages 6 months to 24

- Caregivers of infants

- Adults up to age 64 with certain underlying chronic diseases, such as asthma

- Pregnant women

- Health care workers with direct patient contact.

Contact Heather May at hmay(at)sltrib.com.

(Distributed by Scripps Howard News Service, www.scrippsnews.com.)

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