Cohort study of tofu intake and prostate cancer: no apparent associationNomura AM, Hankin JH, Lee J, Stemmermann GN
Three case-control studies and one cohort study have suggested that soy products reduce the risk of prostate cancer (1-4), but overall evidence from these epidemiologic studies is still limited. To investigate this issue further, we conducted a cohort study on the association of tofu (soybean curd) intake with prostate cancer among Japanese Americans in Hawaii. The annual mortality rate of prostate cancer among Japanese American men is 11.7 per 100,000, which is lower than the mortality rate of 24.1 per 100,000 among U.S. Whites (5). However, unlike clinical prostate cancer, occult prostate cancer, as determined by step sections of the prostate at autopsy, is as common among the Japanese Americans in Hawaii as among the U.S. Whites (6). This suggests the operation of factors that inhibits the progression of this tumor after induction among Japanese American men.
Cancer Epidemiol Biomarkers Prev. 2004 Dec;13(12):2277-9. PMID: 15598793
Body size and prostate cancer, anthropometry and body fat distributionNomura AM
A number of studies have been done to assess the relation of body size to prostate cancer. These investigations have usually used anthropometric measurements in describing their findings. Table 1 summarizes the results from 12 case control studies which were conducted from 1986 to 1999 (21-32). The investigations were done in Greece, the United States, Sweden, Canada, South Africa, and Italy; 10 of them reported no significant association between prostate cancer and various measurements, including weight, height, BMI, waist/hip ratio, waist circumference, and triceps skinfold thickness. The number of cases in these studies ranged from 120 to 1,655. The sources of controls was variable as there were seven studies with population controls, two with hospital or clinic controls, and one with neighborhood controls. Six of the 10 studies collected interview data, three examined the study participants, and one obtained questionnaire data.
Epidemiologic Reviews. 2001 Feb;23(1)126-31 PMID: None
Serum selenium and subsequent risk of prostate cancerNomura AM, Lee J, Stemmermann GN, Combs GF Jr
It is suspected that selenium is protective against prostate cancer. To test this hypothesis, we conducted a nested case-control study in a cohort of 9345 Japanese-American men examined between 1971 and 1977. At the time of examination, a blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 249 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 249 matched controls were measured for selenium levels. Odds ratios for prostate cancer, based on quartiles of serum selenium levels, were determined using the General Estimating Equations approach. The multivariate odds ratio for the highest quartile was 0.5 (95% confidence interval, 0.3-0.9) with a two-sided P for trend of 0.02. The inverse association was more notable for cases with advanced disease and for cases diagnosed 5-15 years after phlebotomy. However, the association was mainly present in current or past cigarette smokers rather than nonsmokers, which leads to caution in the interpretation of the results.
Cancer Epidemiol Biomarkers Prev. 2000 Sep;9(9):883-7. PMID: 11008904
Serum vitamin D metabolite levels and the subsequent development of prostate cancer (Hawaii, United States)Nomura AM, Stemmermann GN, Lee J, Kolonel LN, Chen TC, Turner A, Holick MF
OBJECTIVES: Because several serum studies of vitamin D metabolites have produced equivocal results on their relation to prostate cancer risk, the purpose of this study is to evaluate this association further. METHODS: A nested case-control study in a cohort of 3,737 Japanese-American men examined from 1967 to 1970 was conducted in Hawaii (United States). At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of over 23 years, 136 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 136 matched controls were measured for the following: 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, calcium, phosphorus, and parathyroid hormone. RESULTS: There were no notable differences between cases and controls in their median serum levels of the five laboratory measurements. Odds ratios (OR) for prostate cancer, based on the quartiles of serum levels in controls, were also determined. The ORs for the highest quartiles relative to the lowest were 0.8 (95 percent confidence interval [CI] = 0.4-1.8) for 25-hydroxyvitamin D and 1.0 (CI = 0.5-2.1) for 1,25-dihydroxyvitamin D. CONCLUSION: It is possible that the lack of sufficient numbers of study subjects with low vitamin D levels affected the results. Nonetheless, the findings suggest that there is a lack of a strong association between vitamin D and prostate cancer.
Cancer Causes Control. 1998 Aug;9(4):425-32. PMID: 9794175
Serum micronutrients and prostate cancer in Japanese Americans in HawaiiNomura AM, Stemmermann GN, Lee J, Craft NE
Numerous dietary studies and several serum micronutrient studies have produced equivocal results on the relation of vitamins A and E to prostate cancer risk. To evaluate this association further, we conducted a nested case-control study in a cohort of 6860 Japanese-American men examined from 1971 to 1975. At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 142 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 142 matched controls were measured by high-performance liquid chromatography for the following: total carotenoids, lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, total retinoids, retinol, total tocopherols, alpha-tocopherol, delta-tocopherol, and gamma-tocopherol. Odds ratios for prostate cancer, based on quartiles of serum micronutrient levels, were determined using conditional logistic regression analysis. The odds ratio for the highest quartiles were 1.8 (95% confidence interval, 0.9-3.9) for beta-cryptoxanthin, 1.6 (0.8-3.5) for beta-carotene, 0.8 (0.4-1.5) for retinol, and 0.7 (0.3-1.5) for gamma-tocopherol, but none of the differences was statistically significant. For the other micronutrients, the results were also unremarkable. The findings of this study indicate that none of the micronutrients is strongly associated with prostate cancer risk.
Cancer Epidemiol Biomarkers Prev. 1997 Jul;6(7):487-91. PMID: 9232334
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