Howraman Meteran1, Vibeke Backer2, Kirsten Ohm Kyvik3, Axel Skytthe4, Simon Francis Thomsen2. 1. Respiratory and Allergy Research Unit, Bispebjerg Hospital, Copenhagen, Denmark. Electronic address: hmeteran@gmail.com. 2. Respiratory and Allergy Research Unit, Bispebjerg Hospital, Copenhagen, Denmark. 3. Odense Patient Data Exploratory Network, Institute of Regional Health Services Research, University of Southern Denmark, Odense, Denmark; The Danish Twin Registry, University of Southern Denmark, Odense, Denmark. 4. The Danish Twin Registry, University of Southern Denmark, Odense, Denmark.
Abstract
BACKGROUND: Smoking is a major risk factor for lung diseases and lower respiratory symptoms, but since not all smokers develop chronic bronchitis and since chronic bronchitis is also diagnosed in never-smokers, it has been suggested that some individuals are more susceptible to develop chronic bronchitis due to genetics. OBJECTIVE: To study the relative influence of genetic and environmental factors on the variation in the susceptibility to chronic bronchitis. METHODS: In a population-based questionnaire study of 13,649 twins, 50-71 years of age, from the Danish Twin Registry, we calculated sex-specific concordance rates and heritability of chronic bronchitis. The response rate was 75%. RESULTS: The prevalence of chronic bronchitis was 9.3% among men and 8.5% among women. The concordance rate for chronic bronchitis was higher in monozygotic twins than in dizygotic twins among women; 0.30 vs. 0.17, but not among men; 0.15 vs. 0.18. The heritability of chronic bronchitis adjusted for smoking and age was 55% (36-71%) in women, whereas the susceptibility to chronic bronchitis in men for 25% (8-41%) was ascribable to familial environment but not to genetic factors. CONCLUSIONS: Chronic bronchitis shows a moderate familial aggregation, particularly in women. Increased susceptibility to respiratory disease among female smokers relative to male smokers may have a genetic origin.
BACKGROUND: Smoking is a major risk factor for lung diseases and lower respiratory symptoms, but since not all smokers develop chronic bronchitis and since chronic bronchitis is also diagnosed in never-smokers, it has been suggested that some individuals are more susceptible to develop chronic bronchitis due to genetics. OBJECTIVE: To study the relative influence of genetic and environmental factors on the variation in the susceptibility to chronic bronchitis. METHODS: In a population-based questionnaire study of 13,649 twins, 50-71 years of age, from the Danish Twin Registry, we calculated sex-specific concordance rates and heritability of chronic bronchitis. The response rate was 75%. RESULTS: The prevalence of chronic bronchitis was 9.3% among men and 8.5% among women. The concordance rate for chronic bronchitis was higher in monozygotic twins than in dizygotic twins among women; 0.30 vs. 0.17, but not among men; 0.15 vs. 0.18. The heritability of chronic bronchitis adjusted for smoking and age was 55% (36-71%) in women, whereas the susceptibility to chronic bronchitis in men for 25% (8-41%) was ascribable to familial environment but not to genetic factors. CONCLUSIONS:Chronic bronchitis shows a moderate familial aggregation, particularly in women. Increased susceptibility to respiratory disease among female smokers relative to male smokers may have a genetic origin.
Authors: Surya P Bhatt; Sandeep Bodduluri; Abhilash S Kizhakke Puliyakote; Elizabeth C Oelsner; Arie Nakhmani; David A Lynch; Carla G Wilson; Spyridon Fortis; Victor Kim Journal: Thorax Date: 2021-01-06 Impact factor: 9.139