title: Prospective Study on the Relationship of Obesity to Asthma Impairment and Risk.
abstract: BACKGROUND
  Although studies consistently show an association between obesity and increased asthma incidence, the role of obesity in asthma control is less clear.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the association between baseline body mass index (BMI) and measures of subsequent asthma control in a large real-world cohort of adults with persistent asthma.
  
  
  METHODS
  In Kaiser Permanente Southern California (KPSC), a large managed care organization, we identified adults with persistent asthma in 2006, continuous health plan enrollment in 2007 and 2008, and a BMI measurement in 2006 or 2007. Each patient's last BMI measure in 2006 or 2007 was categorized into a BMI group: normal (<25 kg/m(2)), overweight (25-29.9 kg/m(2)), or obese (≥30 kg/m(2)). Asthma control outcomes in 2008 included asthma hospitalizations or emergency department visits (EDHO), oral corticosteroid dispensings linked to an asthma encounter (OCS), and dispensing of ≥7 short-acting beta-agonist canisters (SABA7). Multivariable analyses were conducted to assess the relationships of BMI categories with the risk of the asthma control outcomes after controlling for potential confounders.
  
  
  RESULTS
  In the 10,233 eligible adults-after adjusting for potential demographic, comorbidity, and prior utilization confounders-we found an increased relative risk (RR) of EDHO in overweight and obese (RR 1.40, 95% CI 1.10-1.78) individuals. Only obesity was associated in adjusted analyses with a significant increased relative risk of SABA7 (RR 1.27, 95% CI 1.15-1.40).
  
  
  CONCLUSIONS
  Elevated BMI, particularly obesity, is associated with subsequent poor asthma control, especially in the risk domain (exacerbations). These findings further support the importance of facilitating weight loss in overweight and obese adults with asthma.
authors.affiliation: Department of Allergy, Kaiser Permanente Medical Center, San Diego and Los Angeles, Calif. Electronic address: michael.x.schatz@kp.org.
authors.forename: Michael
authors.initials: M
authors.lastname: Schatz
authors.affiliation: Department of Allergy, Kaiser Permanente Medical Center, San Diego and Los Angeles, Calif.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Zeiger
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Medical Center, San Diego and Los Angeles, Calif.
authors.forename: Su-Jau
authors.initials: SJ
authors.lastname: Yang
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Medical Center, San Diego and Los Angeles, Calif.
authors.forename: Wansu
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Global Health Outcomes, Merck & Co., Inc., West Point, Pa.
authors.forename: Shiva
authors.initials: S
authors.lastname: Sajjan
authors.affiliation: Department of Global Health Outcomes, Merck & Co., Inc., West Point, Pa.
authors.forename: Felicia
authors.initials: F
authors.lastname: Allen-Ramey
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Mass.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use; D000328:Adult; D001249:Asthma / Q000188:drug therapy / Q000453:epidemiology*; D015992:Body Mass Index; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000453:epidemiology*; D011446:Prospective Studies; D012306:Risk; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D000318:Adrenergic beta-Agonists
keywords: Asthma; Asthma control; Asthma exacerbations; Asthma impairment; Asthma risk; BMI; Obesity; Overweight; Short-acting beta-agonists