Background: The aim of this study is to evaluate the magnitude of the aggregation of a stomach cancer history in parents and their offspring in comparison with that of a history at other sites.
Methods: We used the baseline data from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC Study), which was initiated during 1988-1990 in Japan. Association of the cancer history of the subjects' parents with that of the subjects themselves and any of the subjects' siblings was evaluated with odds ratios (OR) by the crude and generalized estimating equations (GEE) technique for four sites: stomach, colorectum, liver, and lung/bronchus.
Results: The aggregation of a history of stomach cancer between parents and their offspring was evident with significant OR >2.5. The magnitude of the parent-offspring association of a disease history of the colorectum and liver was found to be greater than that for stomach cancer. Conversely, lung and bronchus cancer failed to demonstrate a significant aggregation.
Conclusions: The hereditary and environmental influences shared by parents and offspring are likely to play a strong aetiological role in colorectal or liver cancer versus a weaker but still significant role in stomach cancer. In contrast, the aetiological role of familial predisposition to lung cancer was indeterminate, which suggests a predominant role of non-familial factors in the development of lung cancer.