title: Prior TB, smoking, and airflow obstruction: a cross-sectional analysis of the Guangzhou Biobank Cohort Study.
abstract: BACKGROUND
  Prior pulmonary TB has been shown to be associated with a higher risk of airflow obstruction, which is the hallmark of COPD, but whether smoking modifies this relationship is unclear. We investigated the relationships between prior TB, smoking, and airflow obstruction in a Chinese population sample.
  
  
  METHODS
  Participants in the Guangzhou Biobank Cohort Study underwent spirometry, chest radiography, and a structured interview on lifestyle and exposures. Prior TB was defined as the presence of radiologic evidence suggestive of inactive TB. Airflow obstruction was based on spirometric criteria.
  
  
  RESULTS
  The prevalence of prior TB in this sample (N = 8,066, mean age: 61.9 years) was 24.2%. After controlling for sex, age, and smoking exposure, prior TB remained independently associated with an increased risk of airflow obstruction (odds ratio = 1.37; 95% CI, 1.13-1.67). Further adjustment for exposure to passive smoking, biomass fuel, and dust did not alter the relationship. Smoking did not modify the relationship between prior TB and airflow obstruction.
  
  
  CONCLUSIONS
  Prior TB is an independent risk factor for airflow obstruction, which may partly explain the higher prevalence of COPD in China. Clinicians should be aware of this long-term risk in individuals with prior TB, irrespective of smoking status, particularly in patients from countries with a high TB burden.
authors.affiliation: Institute of Occupational and Environmental Medicine, University of Birmingham, UK.
authors.forename: Kin-bong Hubert
authors.initials: KB
authors.lastname: Lam
authors.forename: Chao Qiang
authors.initials: CQ
authors.lastname: Jiang
authors.forename: Rachel E
authors.initials: RE
authors.lastname: Jordan
authors.forename: Martin R
authors.initials: MR
authors.lastname: Miller
authors.forename: Wei Sen
authors.initials: WS
authors.lastname: Zhang
authors.forename: Kar Keung
authors.initials: KK
authors.lastname: Cheng
authors.forename: Tai Hing
authors.initials: TH
authors.lastname: Lam
authors.forename: Peymané
authors.initials: P
authors.lastname: Adab
mesh_terms: D000402:Airway Obstruction / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D011379:Prognosis; D013902:Radiography, Thoracic; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D013147:Spirometry; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000150:complications* / Q000453:epidemiology