title: Childhood and adolescent passive smoking and the risk of female lung cancer.
abstract: BACKGROUND
  Few studies have reported the relationship between passive smoking (PS) in early life and the risk of lung cancer. This study was done to evaluate the risk of female lung cancer from PS, especially that during childhood and adolescence.
  
  
  METHODS
  Using household exposure to tobacco smoke as an estimate of PS, a 1:1 paired case-control study was conducted in Harbin, China. We interviewed 114 female primary lung cancer cases, aged 30-69 years, and their hospital-based controls. The controls were non-cancer patients, selected from the same hospital as the cases, and matched on age (+/- 5 years), residential area and smoking status over their lifetime. There were 59 pairs who ever smoked and 55 pairs who never smoked. Information on PS was collected by residence for each of the following periods: 0-6, 7-14, 15-22, 23-30 and 31-69 years.
  
  
  RESULTS
  Household PS significantly increases the risk of female lung cancer for those exposed at ages 22 or younger, who have ever smoked. The risk was also increased for those non-smoking pairs when exposed under the age of 15 years. Exposure to maternal smoking at ages 14 or younger increased the risk by about 170% (odds ratio, OR 2.7, 95% confidence interval [CI]: 1.49-4.88), but not to paternal smoking (OR 1.40, 95%CI: 0.92-2.50). The risk was highest for those exposed under the age of seven (OR 3.46, 95%CI: 1.80-6.65) and was also significant at ages 7-14 (OR 3.08, 95% CI: 1.62-5.57) and 15-22 (OR 3.10, 95%CI: 1.52-6.31) years. Under the age of 23 years, the OR increased with amount of PS (P < 0.001). Of note, the OR in all five exposure periods for non-smoking pairs were similar to those for all 114 pairs studied.
  
  
  CONCLUSIONS
  Household PS, particularly that during childhood, increases the risk of female lung cancer. The assessment of PS should be done by different periods of exposure.
authors.affiliation: Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Alberta, Canada.
authors.forename: F L
authors.initials: FL
authors.lastname: Wang
authors.forename: E J
authors.initials: EJ
authors.lastname: Love
authors.forename: N
authors.initials: N
authors.lastname: Liu
authors.forename: X D
authors.initials: XD
authors.lastname: Dai
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016902:Air Pollution, Indoor / Q000009:adverse effects; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000009:adverse effects*; D005220:Fathers / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007223:Infant; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009035:Mothers / Q000706:statistics & numerical data; D012307:Risk Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D014028:Tobacco Smoke Pollution