TY - JOUR

T1 - Seasonal fluctuation of lung function in cystic fibrosis

T2 - A national register-based study in two northern European populations

AU - Qvist, Tavs

AU - Schlüter, Daniela K

AU - Rajabzadeh, Vian

AU - Diggle, Peter John

AU - Pressler, Tania

AU - Carr, Siobhan B

AU - Taylor-Robinson, David

N1 - This is the author’s version of a work that was accepted for publication in Journal of Cystic Fibrosis. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Cystic Fibrosis, 18,3, 2018 DOI: 10.1016/j.jcf.2018.10.006

PY - 2019/5/1

Y1 - 2019/5/1

N2 - BackgroundMany risk factors for lung disease in cystic fibrosis (CF) display a seasonal pattern yet it is unclear whether this is reflected in seasonal fluctuations in lung function.MethodsWe conducted a longitudinal study using CF registries in Denmark and the UK. 485 individuals with a median of 103 FEV1 measurements per person and 7622 individuals with a median of nine FEV1 measures per person were included from Denmark and the UK respectively. We estimated the effect of seasonality on percent predicted FEV1 trajectories using mixed effects models whilst adjusting for clinically important covariates.ResultsWe found no significant cyclical seasonal variation in lung function in either country. The maximum variation in percent predicted FEV1 around the yearly average was estimated to be 0.1 percentage points (95%CI 0 to 0.21) and 0.14 percentage points (95%CI 0 to 0.29) in Denmark and the UK, respectively. When considering possible step-like changes between the four seasons, we found that lung function was higher in spring compared to winter in the UK (0.34 percentage points, 95%CI 0.1 to 0.59) though the difference was not of clinical significance. ConclusionIn both the UK and Denmark there may be small seasonal changes in lung function but this effect is not of clinical importance.

AB - BackgroundMany risk factors for lung disease in cystic fibrosis (CF) display a seasonal pattern yet it is unclear whether this is reflected in seasonal fluctuations in lung function.MethodsWe conducted a longitudinal study using CF registries in Denmark and the UK. 485 individuals with a median of 103 FEV1 measurements per person and 7622 individuals with a median of nine FEV1 measures per person were included from Denmark and the UK respectively. We estimated the effect of seasonality on percent predicted FEV1 trajectories using mixed effects models whilst adjusting for clinically important covariates.ResultsWe found no significant cyclical seasonal variation in lung function in either country. The maximum variation in percent predicted FEV1 around the yearly average was estimated to be 0.1 percentage points (95%CI 0 to 0.21) and 0.14 percentage points (95%CI 0 to 0.29) in Denmark and the UK, respectively. When considering possible step-like changes between the four seasons, we found that lung function was higher in spring compared to winter in the UK (0.34 percentage points, 95%CI 0.1 to 0.59) though the difference was not of clinical significance. ConclusionIn both the UK and Denmark there may be small seasonal changes in lung function but this effect is not of clinical importance.

KW - Seasonality

KW - Season

KW - Fluctuation

KW - Percent predicted FEV1

U2 - 10.1016/j.jcf.2018.10.006

DO - 10.1016/j.jcf.2018.10.006

M3 - Journal article

VL - 18

SP - 390

EP - 395

JO - Journal of Cystic Fibrosis

JF - Journal of Cystic Fibrosis

SN - 1569-1993

IS - 3

ER -