The effects of growing up on a farm on adult lung function and allergic phenotypes: an international population-based study.

RATIONALE: Evidence has suggested that exposure to environmental or microbial biodiversity in early life may impact subsequent lung function and allergic disease risk. OBJECTIVES: To investigate the influence of childhood living environment and biodiversity indicators on atopy, asthma and lung function in adulthood. METHODS AND MEASUREMENTS: The European Community Respiratory Health Survey II investigated ∼10 201 participants aged 26-54 years from 14 countries, including participants' place of upbringing (farm, rural environment or inner city) before age 5 years. A 'biodiversity score' was created based on childhood exposure to cats, dogs, day care, bedroom sharing and older siblings. Associations with lung function, bronchial hyper-responsiveness (BHR), allergic sensitisation, asthma and rhinitis were analysed. MAIN RESULTS: As compared with a city upbringing, those with early-life farm exposure had less atopic sensitisation (adjusted OR 0.46, 95% CI 0.37 to 0.58), atopic BHR (0.54 (0.35 to 0.83)), atopic asthma (0.47 (0.28 to 0.81)) and atopic rhinitis (0.43 (0.32 to 0.57)), but not non-atopic outcomes. Less pronounced protective effects were observed for rural environment exposures. Women with a farm upbringing had higher FEV1 (adjusted difference 110 mL (64 to 157)), independent of sensitisation and asthma. In an inner city environment, a higher biodiversity score was related to less allergic sensitisation. CONCLUSIONS: This is the first study to report beneficial effects of growing up on a farm on adult FEV1. Our study confirmed the beneficial effects of early farm life on sensitisation, asthma and rhinitis, and found a similar association for BHR. In persons with an urban upbringing, a higher biodiversity score predicted less allergic sensitisation, but to a lesser magnitude than a childhood farm environment.

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

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.