Introduction: Gastric cancer is one of the major causes of cancer related death in the world. A number of risk factors are now known to be related to the development of the disease. Previous reports indicated that a family history is a serious risk, but there is a little information about this in Iran. The aim of this study was to explore the relation between family history of cancer in first and second degree relatives and the risk of GC in Iran. Methods: The present study was designed as unmatched case control study. Cases were 746 patients with histologically confirmed GC and the 746 controls were randomly selected among the healthy participants in a health survey. Family history was extracted from a standard history form completed by the patient or from records created by a health care provider. Mantel-Heanszel odds ratios were computed for removing the confounding effect of age and sex. Results: Overall, 9.7% of cases versus 5.6% of controls reported a family history of GC. Risk increased over twofold for this group. There was no significant association among family history of other cancers and GC (P>0.05). Conclusion: In conclusion, this study showed that family history of GC, especially in first-degree relatives, increases the risk of development of the disease. Further studies are needed to better understand the roles of genetic and environmental factors and their interaction in gastric cancer development in the Iranian community.
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