title: [Study on the birth order of patients with esophagus cancer in Shanxi province].
abstract: OBJECTIVE
  To explore the relationship between esophagus cancer patients and both environmental and genetic factors, through analyzing the data on birth orders from esophagus cancer patients of Shanxi province.
  
  
  METHODS
  Both Greenwood and Haldane methods on birth order were used to study the 1101 cases with esophagus cancer from Shanxi province. All the patients had received surgery and were diagnosed, by pathological evidence. First certificates of the patients were confirmed through the standard genetic epidemiologic investigation. Birth order was investigated on probands of the 1101 cases with esophagus cancer and their 44 siblings.
  
  
  RESULTS
  
  
  
  RESULTS
  form the Greenwood method showed that there was a tendency for cases with esophagus cancer in birth orders First to Third. However, the Haldane method showed that the results were quite different between actual value and the average theory value of 6A (6A((actual value)) = 17 118, X ¯(6A(average theory value)) = 19 290, X = |6A-X ¯(6A)|/V(6A) = 7.63, X > 2) which suggested that the birth order had some effects on the occurrence of esophagus cancer. In addition, the actual value of 6A was lower than the theoretic average value, and the parents at younger productive age or baby at the first birth was easy to develop esophagus cancer.
  
  
  CONCLUSIONS
  Esophagus cancer was related with the birth order, especially at early order, which was not consistent with the national reports on esophagus cancer.
  
  
  RESULTS
  from this study suggested that there were certain effects of environmental risk factors on esophagus cancer patients.
authors.affiliation: Shanxi Provincial Tumor Hospital, Taiyuan, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Han
authors.forename: Ya-feng
authors.initials: YF
authors.lastname: Fan
authors.forename: Guo-ping
authors.initials: GP
authors.lastname: Wang
authors.forename: Ti
authors.initials: T
authors.lastname: Ding
authors.forename: Jian-min
authors.initials: JM
authors.lastname: Li
authors.forename: Wen
authors.initials: W
authors.lastname: Su
authors.forename: Ze-feng
authors.initials: ZF
authors.lastname: Gao
authors.forename: Xiao-you
authors.initials: XY
authors.lastname: Han
mesh_terms: D001722:Birth Order; D002681:China / Q000453:epidemiology; D004938:Esophageal Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010290:Parents; D012307:Risk Factors; D035781:Siblings