SINGAPORE COHORT STUDY OF DIET AND CANCER

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This is a request for continued funding of a residential cohort of 60,000 Singapore Chinese men and women aged 45-74 years. The cohort was initiated in April 1993. At recruitment, each cohort subject is interviewed in-person by a trained interviewer using a structured questionnaire that focuses on current diet. The cohort has been passively followed for the occurrence of cancer and death through record linkage with the population-based Singapore Cancer Registry and the Singapore Vital Statistics Office. As shown in the grant application, this cost- efficient method of follow-up generates numbers of incident cancers and deaths that are as expected based on age-sex-specific general population rates applied to cumulative person-years of observation of the studied cohort. Beginning in April 1994, a 3 percent random sample of enrolled subjects were re-contacted and asked to provide a blood and spot urine sample. We propose to extend the blood and spot urine collection to 50 percent of all surviving members of the cohort under age 75 years. The expected size of this biospecimen subcohort is approximately 23,000. The availability of blood and urine specimens on cohort members will enable us to employ biochemical markers to assess exposures and to include genetic factors in exposure-disease association studies. A series of diet/cancer analyses will be conducted during the next five years. The aims are (1) to confirm Cantonese salted fish and related foods as major etiologic agents of nasopharyngeal carcinoma (NPC) and high-risk southern Chinese, and to evaluate the possibly beneficial effects of fresh fruit and vegetables and associated micronutrients on NPC development; (2) to determine the independent and interactive roles of dietary isothiocyanates, carotenoids, tocopherols, vitamin C and selenium in lung carcinogenesis, and to evaluate their effects on the smoking/lung cancer association; (3) to determine the roles of dietary soy and various types of dietary fat (total, saturated, monounsaturated, polyunsaturated, n-3 and n-6 fatty acids) in the development of female breast cancer; and (4) to determine the roles of dietary isothiocyanates and soy in the development of colorectal cancer.