title: Hormone replacement therapy, body mass index and asthma in perimenopausal women: a cross sectional survey.
abstract: BACKGROUND
  Hormone replacement therapy (HRT) and obesity both appear to increase the risk of asthma. A study was undertaken to investigate the association of HRT with asthma and hay fever in a population of perimenopausal women, focusing on a possible interaction with body mass index (BMI).
  
  
  METHODS
  A postal questionnaire was sent to population based samples in Denmark, Estonia, Iceland, Norway, and Sweden in 1999-2001, and 8588 women aged 25-54 years responded (77%). Pregnant women, women using oral contraceptives, and women <46 years were excluded. Analyses included 2206 women aged 46-54 years of which 884 were menopausal and 540 used HRT. Stratified analyses by BMI in tertiles were performed.
  
  
  RESULTS
  HRT was associated with an increased risk for asthma (OR 1.57 (95% CI 1.07 to 2.30)), wheeze (OR 1.60 (95% CI 1.22 to 2.10)), and hay fever (OR 1.48 (95% CI 1.15 to 1.90)). The associations with asthma and wheeze were significantly stronger among women with BMI in the lower tertile (asthma OR 2.41 (95% CI 1.21 to 4.77); wheeze OR 2.04 (95% CI 1.23 to 3.36)) than in heavier women (asthma: p(interaction) = 0.030; wheeze: p(interaction) = 0.042). Increasing BMI was associated with more asthma (OR 1.08 (95% CI 1.05 to 1.12) per kg/m2). This effect was only found in women not taking HRT (OR 1.10 (95% CI 1.05 to 1.14) per kg/m2); no such association was detected in HRT users (OR 1.00 (95% CI 0.92 to 1.08) per kg/m2) (p(interaction) = 0.046). Menopause was not significantly associated with asthma, wheeze, or hay fever.
  
  
  CONCLUSIONS
  In perimenopausal women there is an interaction between HRT and BMI in the effects on asthma. Lean women who were HRT users had as high a risk for asthma as overweight women not taking HRT. It is suggested that HRT and overweight increase the risk of asthma through partly common pathways.
authors.affiliation: Department of Gynecology and Obstetrics, Haukeland University Hospital, 5021 Bergen, Norway. francisco.real@med.uib.no
authors.forename: F
authors.initials: F
authors.lastname: Gómez Real
authors.forename: C
authors.initials: C
authors.lastname: Svanes
authors.forename: E H
authors.initials: EH
authors.lastname: Björnsson
authors.forename: K A
authors.initials: KA
authors.lastname: Franklin
authors.forename: K
authors.initials: K
authors.lastname: Franklin
authors.forename: D
authors.initials: D
authors.lastname: Gislason
authors.forename: T
authors.initials: T
authors.lastname: Gislason
authors.forename: A
authors.initials: A
authors.lastname: Gulsvik
authors.forename: C
authors.initials: C
authors.lastname: Janson
authors.forename: R
authors.initials: R
authors.lastname: Jögi
authors.forename: T
authors.initials: T
authors.lastname: Kiserud
authors.forename: D
authors.initials: D
authors.lastname: Norbäck
authors.forename: L
authors.initials: L
authors.lastname: Nyström
authors.forename: K
authors.initials: K
authors.lastname: Torén
authors.forename: T
authors.initials: T
authors.lastname: Wentzel-Larsen
authors.forename: E
authors.initials: E
authors.lastname: Omenaas
mesh_terms: D000328:Adult; D001249:Asthma / Q000139:chemically induced / Q000209:etiology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D047648:Perimenopause; D006255:Rhinitis, Allergic, Seasonal / Q000209:etiology; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires