title: Sex hormones and systemic inflammation are modulators of the obese-asthma phenotype.
abstract: Both systemic inflammation and sex hormones have been proposed as potential mediators of the obese-asthma phenotype. The aim of this study was to examine the associations between sex hormones, oral contraceptive pill (OCP) use, systemic inflammation and airway inflammation in adults with asthma.
  
  
  
  Obese (n = 39) and nonobese (n = 42) females and obese (n = 24) and nonobese (n = 25) males with asthma were recruited. Females were further categorized as reproductive-aged (<50 years old; n = 36) or older (>50 years old; n = 45). Thirteen (36.1%) reproductive-aged females were using the OCP. Participants had induced sputum cell counts measured and blood analysed for sex hormones and inflammatory markers.
  
  
  
  Obese reproductive-aged females had higher sputum %neutrophils than nonobese reproductive-aged females (45.4 ± 24.3% vs 27.5 ± 17.5%, P = 0.016); however, there was no difference in sputum neutrophils in obese compared with nonobese males (P = 0.620) or older females (P = 0.087). Multiple linear regression analysis found testosterone and OCP use to be negative predictors of sputum %neutrophils, while C-reactive protein and IL-6 were positive predictors of sputum %neutrophils. BMI and age were not significant predictors in the multivariate model. Reproductive-aged females using the OCP had significantly lower sputum %neutrophils than those not using the OCP (23.2 ± 12.6% vs 42.1 ± 23.8%, P = 0.015).
  
  
  
  This study suggests that sex hormones and systemic inflammation may be mediating the obese-asthma phenotype. The observation that OCP use was associated with lower sputum %neutrophils in reproductive-aged females warrants further investigation.
authors.affiliation: Centre for Asthma and Respiratory Diseases, Hunter Medical Research Institute, John Hunter Hospital, Newcastle, NSW, Australia.|School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia.|Lung and Allergy Research Centre, School of Medicine, The University of Queensland, Brisbane, Qld, Australia.
authors.forename: H A
authors.initials: HA
authors.lastname: Scott
authors.affiliation: Centre for Asthma and Respiratory Diseases, Hunter Medical Research Institute, John Hunter Hospital, Newcastle, NSW, Australia.|School of Medicine and Public Health, The University of Newcastle, Callaghan, NSW, Australia.
authors.forename: P G
authors.initials: PG
authors.lastname: Gibson
authors.affiliation: School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia.
authors.forename: M L
authors.initials: ML
authors.lastname: Garg
authors.affiliation: Lung and Allergy Research Centre, School of Medicine, The University of Queensland, Brisbane, Qld, Australia.
authors.forename: J W
authors.initials: JW
authors.lastname: Upham
authors.affiliation: Centre for Asthma and Respiratory Diseases, Hunter Medical Research Institute, John Hunter Hospital, Newcastle, NSW, Australia.|School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia.
authors.forename: L G
authors.initials: LG
authors.lastname: Wood
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism*; D015415:Biomarkers; D003276:Contraceptives, Oral / Q000009:adverse effects; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000150:complications* / Q000378:metabolism*; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism; D009765:Obesity / Q000150:complications* / Q000378:metabolism*; D010641:Phenotype; D012129:Respiratory Function Tests; D013183:Sputum / Q000166:cytology
chemical_list: D015415:Biomarkers; D003276:Contraceptives, Oral; D012739:Gonadal Steroid Hormones; D018836:Inflammation Mediators
keywords: asthma; neutrophil; obesity; sex hormone; systemic inflammation