While it has long been recognized that dietary factors play an important role in the etiology of cancer, information regarding the preventive potential of specific dietary compounds is scarce. The Shanghai Men's Health Study (SMHS) is a population-based cohort study of 61,582 Chinese men between 40 and 74 who lived in urban Shanghai at enrollment. Because intake levels of many suspected cancer-inhibitory dietary factors are high and diverse in Shanghai, the SMHS offers unique opportunities to fill such knowledge gaps. Detailed information on dietary and other lifestyle factors was collected at baseline and is being updated in a follow-up survey. Biological samples were collected from 89% of cohort members. The cohort has been followed for cancer occurrence and deaths via linkage with the population-based Shanghai Cancer Registry and the Shanghai Vital Statistics Unit, as well as through visits to all living cohort members every 2 years. We propose in this renewal application to extend the follow-up of this cohort for 5 more years and to evaluate dietary hypotheses for the lung, stomach, and colorectal (CRC). The primary focus of the study is to determine whether regular tea consumption and high intake of folate, soy foods, allium vegetables, and crucifers are associated with a reduced risk of cancer. We also propose to conduct a nested case-control study to evaluate whether the levels of blood folate, urinary phytoestrogens (CRC only) and isothiocyanate are inversely associated with the risk of cancers of colorectum, lung, and stomach. These biomarkers are aggregate measures of level of intake, absorption, and metabolism and will provide added insight in elucidating the relationship of dietary factors with cancer risk. Blood level C-reactive protein and H.pylori antibodies will also be evaluated in the nested case-control study for CRC and stomach cancer. Finally, we propose to re-survey all living cohort-members to update information on usual dietary intake and other lifestyle factors to refine exposure assessments and to characterize and evaluate how temporal changes in exposures may influence cancer risk. Because of its size, setting, and unique exposure patterns and biological specimens, the SMHS provides an exceptional opportunity to address dietary hypotheses for cancer that cannot be adequately investigated in any other existing cohort study. The results from this study may guide new strategies in the primary prevention of common cancers in both Western and Asian men.
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