Impact of Asthma on the Association between Childhood Obesity and Influenza.

Background: Despite long-standing recommendations for influenza vaccine in patients with asthma, whether asthma is a risk factor for medically-attended influenza is unclear. Obesity has more recently been found to be a risk factor for severe influenza in adults. Its role in children is less certain.

Materials and methods: We conducted a 1:1 matched case-control study of all 185 children 2 to 18 years old with PCR-confirmed influenza at our institution from 2010 to 2013.

Results: Having a prior history of asthma was 2 times more common (95% CI, 1.24-3.23) among the influenza cases than the controls. Obesity was not associated with influenza overall (OR 0.94, 95% CI 0.49-1.83). However, among patients with asthma, influenza cases were 4.4 times more likely to be obese compared with subjects without influenza (95% CI, 0.93-20.58).

Conclusion: In our population, a prior diagnosis of asthma was associated with a two-fold increased risk of medically-attended influenza. In addition, among patients with asthma there was a trend toward obesity increasing the risk of influenza.