Although obesity has been considered a risk factor for severe acute respiratory illness, including more severe cases of the flu, a recently-published study found that weight may not be associated with increased illness severity.1

Study data from the 2009 pandemic flu season had shown obesity as an independent risk factor for hospitalized adults, but few studies have investigated the association between weight and severity of respiratory illnesses seeking care in the emergency department during other winter respiratory seasons.

"We undertook this study thinking that obesity would put patients at greater risk for other respiratory illnesses," Elizabeth Halvorson, MD, assistant professor of pediatrics at Wake Forest Baptist and study author, said in a press release.2 Unexpectedly, the study found no evidence of obesity as a risk factor for more severe acute respiratory illnesses, including the flu, in children or adults.

In the study, published in the International Journal of Obesity, the researchers examined 3,560 children and adults who came to the emergency department with acute respiratory illness over consecutive winter respiratory seasons from 2010 to 2014. The researchers defined acute respiratory illness as any illness that included symptoms such as fever, cough, runny nose, sore throat, and difficulty breathing.

The researchers looked at data based on division of weight category, such as normal-weight, overweight, and obese. Severity was determined based on several different measures, such as admission to hospital, treatment with antibiotics, length of stay after being admitted, and the need for extra oxygen during hospitalization. Study limitations included a relatively small sample size for children and the exclusion of patients who received care at outpatient clinics and urgent care centers.

The study was supported by the National Institutes of Health. Overall, the researchers found no increased risk of hospitalization based on weight in either children or adults, but noted that further study is needed with more participants in different regions of the country.

  1. Halvorson E, Peters TR, Skelton JA, et al. Is weight associated with severity of acute respiratory illness? International Journal of Obesity. 2018. Doi: 10.1038/s41366-018-0044-y.
  2. Obesity Not a Risk Factor for Acute Respiratory [news release]. North Carolina. Wake Forest's website.