title: Role of IGF-I, IGF-II and IGFBP-3 in lung function of males: the Caerphilly Prospective Study.
abstract: Insulin-like growth factors are peptide hormones that have an endocrine role in the development, growth and repair of human tissues including the respiratory tract. To date, only one population study exists which found positive cross-sectional associations with IGF-I and higher lung volumes. We hypothesised that higher IGF-I, IGF-II, IGFBP-3 and IGF molar ratio would be associated with better cross-sectional and longitudinal lung function. We examined cross-sectional (n=843) and prospective associations (n=717) between IGF-I, IGF-II, IGFBP-3 and IGF molar ratio with lung function in the Caerphilly Prospective Study (CaPS) from blood samples obtained around 1986, with spirometry (forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)) performed in the same year and around 2003. Higher IGF molar ratio was associated with improved FEV1/FEV ratio cross-sectionally in both simple (0.007, 95% CI 0.001-0.013, P=0.02) and fully adjusted (0.001, 95% CI 0.001-0.012, P=0.03) models. With the exception of IGFBP-3 and FEV1/FVC in the simple model (0.009, 95% CI 0.001-0.018, P=0.04) all prospective associations between IGF and spirometric measures were consistent with chance. In this study of men, higher IGF molar ratio was associated with improved cross-sectional lung function, although these findings were not replicated prospectively. Further work is required with repeat IGF sampling during follow up to see if IGF levels play any role in predicting future lung function through the life course.
authors: School of Social and Community Medicine, University of Bristol UK.
authors: Christopher J
authors: CJ
authors: Green
authors: School of Clinical Sciences, University of Bristol UK.
authors: Jeffrey M
authors: JM
authors: Holly
authors: Nottingham Respiratory Research Unit, University of Nottingham UK.
authors: Charlotte E
authors: CE
authors: Bolton
authors: Institute of Primary Care and Public Health, School of Medicine, Cardiff University UK.
authors: Antony
authors: A
authors: Bayer
authors: London School of Hygiene and Tropical Medicine UK.
authors: Shah
authors: S
authors: Ebrahim
authors: Institute of Primary Care and Public Health, School of Medicine, Cardiff University UK.
authors: John
authors: J
authors: Gallacher
authors: School of Social and Community Medicine, University of Bristol UK.
authors: Yoav
authors: Y
authors: Ben-Shlomo
keywords: Insulin-like growth factors; cohort study; lung function; spirometry