Nearly 27 percent of American adults are obese, a condition that significantly increases their risk of cardiovascular disease, some types of cancer and diabetes.
As if that weren’t enough of a health burden, an international study published this month in the open-access journal PLoS Medicine, obesity increased the risk of death or admission to an intensive care unit among patients hospitalized for the 2009 pandemic strain of H1N1 influenza – swine flu.
The researchers, including one from the Epidemiology and Prevention Branch of the U.S. Centers for Disease Control and Prevention in Atlanta, analyzed the records of more than 82,000 patients from 19 countries hospitalized with confirmed cases of the H1N1 virus. They then identified the characteristics of those patients who died or were admitted to an ICU during their hospitalization for the illness.
Among the risk factors for those who contracted the most severe cases of H1N1 flu or died were older age, other health problems (one or more chronic health conditions) and obesity, the researchers found.
“The proportion of patients with obesity (body mass index (BMI) ≥30 or clinically judged as obese) increased with increasing disease severity and represented a median of 6%, 11.3%, and 12.0% of all hospitalized, ICU-admitted, and fatal H1N1pdm cases, respectively,” the researchers reported.
“Our results provide supportive evidence that obesity may be a risk factor for severe disease, as seen in the increasing proportion of morbidly obese patients with severity level,” the researchers concluded, while noting that the pattern did not hold across all the countries included in the study.
“The association between obesity (or morbid obesity) and severe outcomes may reflect direct causation (e.g. due to greater respiratory strain of infection on obese individuals), causation through other known risk factors (e.g. obesity causes diabetes and heart disease, which pose an increased risk for severe outcome), or a non-causal association, if some other factor (e.g. genetic or dietary) caused both morbid obesity and increased risk of severe outcome.”