CHICAGO, July 11 (Xinhua) -- Adults with obesity are more susceptible to influenza A/H1N1pdm, the swine flu virus, according to a study posted on the website of the University of Michigan (UM) on Thursday.
The researchers looked at data from more than 1,500 individuals in 330 households enrolled in the Nicaraguan Household Transmission Study, an ongoing community-based study tracking the health of a community in Managua, Nicaragua. Study participants were followed 10-15 days and given swab tests and blood tests to confirm infection.
They found that adults with obesity had twice the odds of symptomatic H1N1 infection compared to those without obesity. The association was not seen with the H3N2 seasonal influenza strain.
While the mechanism linking obesity to increased disease severity is not yet known, chronic inflammation increases with age and is associated with chronic diseases. Separate studies have shown that obesity increases proinflammatory and decreases anti-inflammatory cytokine levels, the researchers said. Obesity can also impair wound healing and lead to mechanical difficulties in breathing and increased oxygen requirements.
"This research is important because obesity around the whole world is increasing rapidly. It's approximately tripled since the 70s," said first author Hannah Maier, a postdoctoral fellow at UM School of Public Health. "If obesity is associated with increased risk and there's a lot more obesity, that could mean a lot more infections."
Just recently, a new study states that a new strain of H1N1 in swine in China has the potential to become a pandemic, highlighting the importance of continuing this type of research even while facing the COVID-19 pandemic, said senior author Aubree Gordon, an epidemiologist at UM's School of Public Health.
"This underscores that although we are in the middle of a pandemic, we cannot stop being vigilant for the emergence of other viruses, particularly influenza," she said. "In addition, this highlights that the U.S. needs to participate in the World Health Organization. The WHO influenza program provides a critical service to the world monitoring influenza circulation to make vaccine strain recommendations and surveilling for potential emergence of new influenza viruses."
The study has been published in the Journal Clinical Infectious Diseases.