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OBJECTIVE To investigate the role of family aggregation and genetic factors of esophageal cancer (EC), including carcinoma of gastric cardia (CGC), in Cixian county, and to calculate the segregation ratio and heritability of fi rst-degree relatives (FDR) in EC cases. METHODS A case control study was conducted, and each of 285 esophageal cancer cases and FDRs case history and family medical history of EC in 1415 controls was carried by home visits to compare the incidence of EC in the crowds. The family aggregation of EC was found by χ2 test for goodness of fit test according to binomial distribution. Li-Mantel-Gart method was used to calculate the segregation ratio and Falconer method was employed to compute the heritability (h2). RESULTS The incidence rate of the FDR in the index case of EC (12.80%) was higher than that in the controls (7.52%). There were significant differences between the 2 groups (χ2= 44.34, P = 0.000). The distribution of EC in the family did not agree with the binomial distribution, which presented a conspicuous familial aggregation (χ2= 288.19, P < 0.0001). The heritability of EC was (29.67 ± 4.32)%, and segregation ratio was 0.1814 (95%CI =0.1574-0.2054), which is lower than 0.25, and can be regarded as a disease of multi-factorial inheritance. CONCLUSION The occurrence of EC in the Cixian County is the outcome of the mutual effect of genetic and environmental factors. The family history of upper gastrointestinal cancers increases the risk of EC in late generations.