Obesity as a risk factor for severe influenza-like illness

• Type of Material: Article
• Authors: Noelle M Cocoros, Massachusetts Department of Public Health; Timothy L Lash, Emory University; Alfred DeMaria, Massachusetts Department of Public Health; Michael Klompas, Harvard University
• Language: English
• Date: 2014-01-01
• Publisher: Wiley Open Access
• Publication Version: Final Published Version
• Copyright Statement: © 2013 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1111/irv.12156
• Title of Journal or Parent Work: Influenza and Other Respiratory Viruses
• ISSN: 1750-2640
• Volume: 8
• Issue: 1
• Start Page: 25
• End Page: 32
• Keywords: HOSPITALIZATION; A H1N1; Virology; Life Sciences & Biomedicine; CARE; BMI; DEATH; CALIFORNIA; CANADA; influenza; Infectious Diseases; A(H1N1) INFECTION; obesity; Science & Technology
• Research Categories: Health Sciences, Public Health; Health Sciences, Epidemiology

Abstract

Background: Obesity was recognized as in independent risk factor for influenza during the 2009 H1N1 influenza pandemic. Objectives: We evaluated the association between body mass index (BMI) and influenza-like illness (ILI) during two non-pandemic influenza seasons (2003-2004 and 2004-2005) and during the spring and fall waves of the 2009 H1N1 pandemic. Methods: Adults with severe (inpatient) and mild (outpatient) ILI were compared to those without ILI using a case-cohort design. The study was nested among those insured by a single health insurance company, receiving care from a large multispecialty practice. Data were collected from insurance claims and the electronic health record. The primary exposure was obesity (BMI ≥ 30·0 kg/m 2 ). Results: Across three seasons, the crude and adjusted ORs for obesity and severe ILI were 1·65 (95% CI 1·31, 2·08) and 1·23 (95% CI 0·97, 1·57), respectively. An association was observed for those aged 20-59 years (adjusted OR 1·92, 95% CI 1·26, 2·90), but not for those 60 and older (adjusted OR 1·08, 95% CI 0·80, 1·46). The adjusted ORs for obesity and severe ILI in 2003-2004, 2004-2005, and during H1N1 were 1·14 (95% CI 0·80, 1·64), 1·24 (95% CI 0·86, 1·79), and 1·76 (95% CI 0·91, 3·42), respectively. Among those with a Charlson Comorbidity Index score of zero, the adjusted ORs for 2003-2004, 2004-2005, and H1N1 were 1·60 (95% CI 0·93, 2·76), 1·43 (95% CI 0·80, 2·56), and 1·90 (95% CI 0·68, 5·27), respectively. Conclusions: Our results suggest a small to moderate association between obesity and hospitalized ILI among adults.