EPIDEMIOLOGY AND BIOSTATISTICS DIVISION

23.EPIDEMIOLOGY AND BIOSTATISTICS DIVISION

    The Epidemiology and Biostatistics Division has planned and conducted independent and collaborative studies on cancer etiology and prevention, with a special focus on dietary, environmental and genetic factors. Several epidemiological projects are currently in progress.
Population-based Prospective Study (JPHC Study)

    Diet has been implicated in the etiology of cancer occurrence and in the unique patterns of cancer incidence in Japan. However, epidemiological evidence regarding this issue has been limited. The division has therefore initiated a population-based prospective study on diet and cancer (JPHC Study) in collaboration with the Cancer Information and Epidemiology Division and the National Cardiovascular Center, in which approximately 140,000 individuals from 11 public health center areas will be followed-up for 20 years. As of November 2002, 8,079 deaths, 6,998 cancers, 3,047 strokes and 753 myocardial infarctions had been documented. Several basic investigations have been conducted to validate the quality of the JPHC study. Mortality among subjects who responded to a baseline questionnaire was lower than nonresponders, especially in the first 2 years of follow-up ⁽²⁷⁸⁾. Recall-based self-reports on senile cataracts were reasonably valid as a means of its case definition ⁽²⁷⁹⁾. Dietary heterocyclic amines were estimated based on food frequency questionnaire ^(280,²⁸¹⁾. Lifestyle factors that assessed in the baseline questionnaire were examined with relation to subsequent risk of mortality and cancer incidence by histological type. Cigarette smoking has been confirmed to be closely associated with risk of premature death ⁽²⁸²⁾, and stomach ⁽²⁸³⁾ cancer. Alcohol consumption was dose-dependently associated with cancer mortality on the whole among smokers, and not nonsmokers ⁽²⁸⁴⁾. Being both under- and overweight was an important determinant of premature death and the impact of being underweight was larger especially in men ⁽²⁸⁵⁾. Intake of fruit and vegetables were associated with decreased risk of gastric cancer, especially the differentiated type ⁽²⁸⁶⁾.
Gastric Cancer Prevention Trials (Hiraka Study)

    The available evidence suggests that the risk of gastric cancer is increased in individuals with chronic atrophic gastritis and is decreased in those with a high consumption of fruit and vegetables and a low consumption of salted foods. A randomized controlled trial to assess the effectiveness of vitamin C supplementation on gastric cancer has progressed to the eighth year for individuals with chronic atrophic gastritis. A five-year supplementation of vitamin C did not affect on blood pressure levels ⁽²⁸⁷⁾. Another randomized controlled trial to assess the effectiveness of dietary modification (less salt and more vitamin C and carotene) completed its intervention program for 550 residents in a high risk area for gastric cancer with reasonable compliance and its analysis has been underway. Oxidative stress as measured by urinary level of 1, N6-ethenodeoxyadenosine was measured using sub-sample of this trial and the intake of salt and n-6 polyunsaturated fatty acid were associated with its level ⁽²⁸⁸⁾.
Epidemiological Study on Japanese Brazilians (Sao Paulo - Japan Cancer Study)

    The ethnic differences in cancer occurrence suggest an interaction between environmental and genetic factors. The division has been conducting several epidemiological studies in Brazil, a multi-ethnic nation with 1.2 million people of Japanese ancestry. Two case-control studies of gastric cancer in Japanese Brazilians and Brazilians not of Japanese ancestry in Sao Paulo has been conducted to clarify the role of genetic susceptibility and environmental carcinogenesis. The first case-control study of gastric cancer conducted in Brazil confirmed that low socio-economic status, cigarette smoking and low consumption of fruit and vegetable were risk factors of gastric cancer ⁽²⁸⁹⁾. The introduction of the habit of daily beef consumption among Japanese immigrants and their descendants may be associated with the risk ⁽²⁹⁰⁾. Two case-control studies of breast cancer, using a similar design as the gastric cancer study, have been conducting in Sao Paulo.
Epidemiological Study on Endocrine Disrupting Chemicals

    To examine the health effects of endocrine disrupting chemicals, some preliminary studies were conducted. Worldwide DDT contamination in fish and meat was suggested in an international collaborative study ⁽²⁹¹⁾. Some of the organochlorines were detected in the serum of the general population in Japanese rural areas and an association with specific food intakes was suggested ⁽²⁹²⁾. The health condition of epoxy resin workers was surveyed and they showed higher urinary bisphenol A and lower serum follicle stimulating hormone levels ^(293,²⁹⁴⁾. Cytochrome P450 1B1 mRNA levels in peripheral blood cells were suggested to be a biomarker of exposure to AhR ligands in a study of coke oven workers ⁽²⁹⁵⁾.
Epidemiological and Biostatistical Support for Basic and Clinical Research Programs

    Epidemiological and biostatistical supports have been provided for the prognostic and clinical analysis of breast cancer and for psychological studies on HIV infection ^(296,²⁹⁷⁾.




23.EPIDEMIOLOGY AND BIOSTATISTICS DIVISION



	The Epidemiology and Biostatistics Division has planned and conducted independent and collaborative studies on cancer etiology and prevention, with a special focus on dietary, environmental and genetic factors. Several epidemiological projects are currently in progress. Population-based Prospective Study (JPHC Study) Diet has been implicated in the etiology of cancer occurrence and in the unique patterns of cancer incidence in Japan. However, epidemiological evidence regarding this issue has been limited. The division has therefore initiated a population-based prospective study on diet and cancer (JPHC Study) in collaboration with the Cancer Information and Epidemiology Division and the National Cardiovascular Center, in which approximately 140,000 individuals from 11 public health center areas will be followed-up for 20 years. As of November 2002, 8,079 deaths, 6,998 cancers, 3,047 strokes and 753 myocardial infarctions had been documented. Several basic investigations have been conducted to validate the quality of the JPHC study. Mortality among subjects who responded to a baseline questionnaire was lower than nonresponders, especially in the first 2 years of follow-up ⁽²⁷⁸⁾. Recall-based self-reports on senile cataracts were reasonably valid as a means of its case definition ⁽²⁷⁹⁾. Dietary heterocyclic amines were estimated based on food frequency questionnaire ^(280,²⁸¹⁾. Lifestyle factors that assessed in the baseline questionnaire were examined with relation to subsequent risk of mortality and cancer incidence by histological type. Cigarette smoking has been confirmed to be closely associated with risk of premature death ⁽²⁸²⁾, and stomach ⁽²⁸³⁾ cancer. Alcohol consumption was dose-dependently associated with cancer mortality on the whole among smokers, and not nonsmokers ⁽²⁸⁴⁾. Being both under- and overweight was an important determinant of premature death and the impact of being underweight was larger especially in men ⁽²⁸⁵⁾. Intake of fruit and vegetables were associated with decreased risk of gastric cancer, especially the differentiated type ⁽²⁸⁶⁾. Gastric Cancer Prevention Trials (Hiraka Study) The available evidence suggests that the risk of gastric cancer is increased in individuals with chronic atrophic gastritis and is decreased in those with a high consumption of fruit and vegetables and a low consumption of salted foods. A randomized controlled trial to assess the effectiveness of vitamin C supplementation on gastric cancer has progressed to the eighth year for individuals with chronic atrophic gastritis. A five-year supplementation of vitamin C did not affect on blood pressure levels ⁽²⁸⁷⁾. Another randomized controlled trial to assess the effectiveness of dietary modification (less salt and more vitamin C and carotene) completed its intervention program for 550 residents in a high risk area for gastric cancer with reasonable compliance and its analysis has been underway. Oxidative stress as measured by urinary level of 1, N6-ethenodeoxyadenosine was measured using sub-sample of this trial and the intake of salt and n-6 polyunsaturated fatty acid were associated with its level ⁽²⁸⁸⁾. Epidemiological Study on Japanese Brazilians (Sao Paulo - Japan Cancer Study) The ethnic differences in cancer occurrence suggest an interaction between environmental and genetic factors. The division has been conducting several epidemiological studies in Brazil, a multi-ethnic nation with 1.2 million people of Japanese ancestry. Two case-control studies of gastric cancer in Japanese Brazilians and Brazilians not of Japanese ancestry in Sao Paulo has been conducted to clarify the role of genetic susceptibility and environmental carcinogenesis. The first case-control study of gastric cancer conducted in Brazil confirmed that low socio-economic status, cigarette smoking and low consumption of fruit and vegetable were risk factors of gastric cancer ⁽²⁸⁹⁾. The introduction of the habit of daily beef consumption among Japanese immigrants and their descendants may be associated with the risk ⁽²⁹⁰⁾. Two case-control studies of breast cancer, using a similar design as the gastric cancer study, have been conducting in Sao Paulo. Epidemiological Study on Endocrine Disrupting Chemicals To examine the health effects of endocrine disrupting chemicals, some preliminary studies were conducted. Worldwide DDT contamination in fish and meat was suggested in an international collaborative study ⁽²⁹¹⁾. Some of the organochlorines were detected in the serum of the general population in Japanese rural areas and an association with specific food intakes was suggested ⁽²⁹²⁾. The health condition of epoxy resin workers was surveyed and they showed higher urinary bisphenol A and lower serum follicle stimulating hormone levels ^(293,²⁹⁴⁾. Cytochrome P450 1B1 mRNA levels in peripheral blood cells were suggested to be a biomarker of exposure to AhR ligands in a study of coke oven workers ⁽²⁹⁵⁾. Epidemiological and Biostatistical Support for Basic and Clinical Research Programs Epidemiological and biostatistical supports have been provided for the prognostic and clinical analysis of breast cancer and for psychological studies on HIV infection ^(296,²⁹⁷⁾.