Mostly Young, Obese Adults Affected by This Year`s Flu

Feb. 09--A large percentage of American adults hospitalized with influenza so far this year were obese, a pattern seen in 2009, but is unusual when compared to other flu seasons, federal health officials said.

As of Jan. 25, at least 43 percent of all those hospitalized with influenza across the nation were considered obese, which is defined as having a body mass index of 30 or higher.

At one point in January, the percentage of those hospitalized who were obese had hit 46 percent, according to the federal Centers for Disease Control and Prevention.

Health researchers saw a similar trend during the H1N1 pandemic of 2009, in which an estimated 203,000 people died. This year's prominent strain also is H1N1. However, the current vaccine, though not perfect, protects against the strain.

But even though the CDC found that obesity was the top underlying medical condition among those who were hospitalized this season, researchers were careful not to call it a definitive risk factor. Diabetes and cardiovascular disease, also underlying medical conditions and also associated with those who are obese, may play a role.

"When we look at our indicators, a lot of what's going on has been among younger age groups, those 18 to 64," said Sandra Chaves, medical director of the Influenza Hospitalization Surveillance Network at the CDC. "If we think about it, where is the obesity epidemic? It's in that younger age group."

At least 36 percent of all Americans are considered obese or overweight, according to CDC data.

"It's not clear why obesity has been identified because we don't see this clearly in normal seasons," Chaves said. "Why obese people have higher complications and even death is unclear."

Meanwhile, the flu has appeared to peak including in some counties in California but remains at widespread levels in Los Angeles and San Bernardino counties, local and state officials said.

Fifteen flu-related deaths have been confirmed from San Bernardino County, while Los Angeles County has reported 26 so far.

The number of those who have died has garnered much attention this year, because many of the deaths and hospitalizations have been among those 18 to 64, or younger than usual. But in fact, the total number of deaths may never be known because influenza-related deaths among those 65 and older go unreported in California and in much of the nation.

A mixed virus

One reason why the young may be more affected this season is because H1N1 is a complex strain made up of a mixture of old and new, and the young may not have built up immunity, Chaves said.

"It's a funny virus, because it combines a little bit of avian, a little bit of swine and other strains," Chaves said.

Inside the emergency department at Los Angeles County -- USC Medical Center, the number of flu cases remains high, said Dr. Jessica Osterman, attending emergency medical physician with the Keck School of Medicine.

"We're still seeing a high activity here, and I wouldn't be surprised if it wasn't high throughout the rest of February," Osterman said.

She said she hasn't seen the correlation between obesity and influenza but has treated many younger people who are sick and also have diabetes.

"I've personally seen a lot of sicker patients than in years past," Osterman said. "Patients are coming in with significant respiratory illness. It's been astounding."

There have been 202 deaths already in California so far, surpassing last year's 106 of those 64 and younger. But last year's strain, H3, caused many deaths among the frail elderly in nursing homes, said Dr. Laurene Mascola, chief of the Acute Communicable Disease Control (ACD) unit for the Los Angeles County Department of Health's Public Health. But the premier of H1N1 in 2009 changed the familiar pattern.

"Everyone used to say that flu is a disease of the elderly, but actually flu is a disease for everyone," Mascola said. "The 2009 year served as a wake-up call."

Mascola and others said despite all the attention on influenza-related deaths among younger adults, flu is an inevitable part of life, like "taxes and death," she said. And like snowflakes, no two flu seasons are ever alike.

"If you've seen one flu season, you've seen one flu season," Mascola said.

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