title: Serum bilirubin is associated with lung function in a Swiss general population sample.
abstract: Bilirubin is a strong antioxidant. Increased serum levels have been associated with lower respiratory disease and mortality risk. We studied the association of bilirubin with lung function in the Swiss study on Air Pollution and Lung Disease in adults (SAPALDIA) cohort. Associations between natural logarithmised bilirubin and forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC and mean forced expiratory flow between 25%-75% of FVC (FEF25-75%) were tested using multiple linear regression in the whole study population (n=4195) and strata of ever-smoking and high body mass index (BMI, defined by the highest distribution quartile). Associations were retested with single nucleotide polymorphism rs6742078, a genetic determinant of bilirubin. High bilirubin levels were significantly associated with higher FEV1/FVC and FEF25-75% overall. Upon stratification, significant associations persisted in ever-smokers, amounting to 1.1% (95% CI 0.1-2.2%) increase in FEV1/FVC, and 116.2 mL·s(-1) (95% CI -15.9-248.4 mL·s(-1)) in FEF25-75% per interquartile range of bilirubin exposure in smokers with high BMI. Associations were positive but nonsignificant in never-smokers with high BMI. Similarly, rs6742078 genotype TT was associated with increased FEV1/FVC and FEF25-75%. Our results suggest a possible protective role of bilirubin on lung tissue, which could be important for prevention and therapy.
authors.affiliation: Swiss Tropical and Public Health Institute, SwissTPH, Basel.
authors.forename: Ivan
authors.initials: I
authors.lastname: Curjuric
authors.forename: Medea
authors.initials: M
authors.lastname: Imboden
authors.forename: Martin
authors.initials: M
authors.lastname: Adam
authors.forename: Robert W
authors.initials: RW
authors.lastname: Bettschart
authors.forename: Margaret W
authors.initials: MW
authors.lastname: Gerbase
authors.forename: Nino
authors.initials: N
authors.lastname: Künzli
authors.forename: Thierry
authors.initials: T
authors.lastname: Rochat
authors.forename: Lucia
authors.initials: L
authors.lastname: Rohrer
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Rothe
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Daiana
authors.initials: D
authors.lastname: Stolz
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Tschopp
authors.forename: Arnold
authors.initials: A
authors.lastname: von Eckardstein
authors.forename: Florian
authors.initials: F
authors.lastname: Kronenberg
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Probst-Hensch
mesh_terms: D000293:Adolescent; D000328:Adult; D001663:Bilirubin / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005541:Forced Expiratory Volume; D005838:Genotype; D006801:Humans; D016014:Linear Models; D008168:Lung / Q000502:physiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012120:Respiration Disorders / Q000097:blood / Q000235:genetics* / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012907:Smoking / Q000009:adverse effects; D013147:Spirometry; D013557:Switzerland; D014797:Vital Capacity; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001663:Bilirubin