Hormone replacement therapy, body mass index and asthma in perimenopausal women: a cross sectional survey

• Published in: Thorax
• Main Authors: Gómez Real, F, Svanes, C, Björnsson, E H, Franklin, K, Gislason, D, Gislason, T, Gulsvik, A, Janson, C, Jögi, R, Kiserud, T, Norbäck, D, Nyström, L, Torén, K, Wentzel-Larsen, T, Omenaas, E
• Format: Text
• Language: English
• Published: BMJ Publishing Group Ltd 2006
• Subjects: Asthma; Norway; Iceland
• Online Access: http://thorax.bmj.com/cgi/content/short/61/1/34; https://doi.org/10.1136/thx.2005.040881

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.