Reproductive Factors Related to Serum Estrogen, Progesterone, and Sex Hormone Binding Globulin in Postmenopausal Women in Korea / 한국역학회지

The etiology of breast cancer is not yet clear. Several epidemiologic studies have supported the concepts that endogenous female sex hormones, i.e., estrogen and progesterone, may play a central role in the development of breast cancer. Female reproductive factors such as menstruation, pregnancy, and breast feeding are well-known risk factors of breast cancer. There have been many suggestions that all these factors are midiated by female sex hormeones. However, only a few studies have evaluated the relationship between the reproductive factors and endogenous female sex hormones. This study was designed to evaluate the relationship between the reproductive factors and endogenous female sex hormones in Korean women. We analyzed the relationship between reproductive factors and female sex hormones in 153 premenopausal women 153 postmenopausal women who participated in a community health promotion program in Haman County, Korea. The questionnaires about reproductive factors were completed by personal interview. Serum level of total estradiol(E2), progesterone(:g), and sex hormone binding globulin(SHBG) were measured by radioimmunoassay. There was no significant correlation between age at menarche and E2 in both premenopausal and postmenopausal groups. In postmenopausal subjects, E2 level increased significantly with the age at menopause increasing(r=0.25, p=0.009), adjusting for the potential confounding effect of both age and body mass index. There was a positive correlation between E2 and the intervals between age at menarche and age at menopause(r=0.25, p=0.009). Moreover, the serum level of SHBG was significantly correlated with total months of breast feeding(r=0.19, p=0.048), as well as with age at first fullterm pregnancy(r=-0.24, p=0.01). However, Pg was correlated with none of reproductive factors in both groups. This study observed that female reproductive factors, e.g., age at menopause, breast feeding, age at first fullterm pregnancy, were correlated with serum female hormones, particularly E2 and SHBG. The results provide an evidence that the relationship between the reproductive factors and breast cancer risk may be mediated, at least in part, through serum female hormones, especially estradiol in Korean women.

Current Status of Multicenter Cancer Cohort Study with Biological Materials Bank in Korea / 한국역학회지

This cohort study is a collaborative effort of 8 institutions. The goal is to establish a large scale cohort that can be followed for 10 or more years to assess the relationship between life-styles and cancer occurrence, and to evaluate the role of environmental exposures in the development of six major sites of cancers(stomach, liver, lung, colorectum, uterine cervix and female breast) in the rural population. Since 1993, 11,304 men and women aged over 35 living in four areas have been recruited. The number of target population is 30,000 persons, which is expected to be successfully recruited until 1999. Each subject has completed a detailed questionnaire on general life-styles, reproductive factors, and agricultural chemical exposures through the interview. Anthropometric measurements with body fat composition and the routine clinical laboratories were examined. For the cancer-free cohort, physical examination by the physicians and serologic tests for hepatitis markers, some tumor markers, and lipid profile have been done, but not all. In order to provide an opportunity to incorporate barious biomarkers of exposure and effect as well as genetic susceptibility, a biologic tissue bank has been established from blood and urine sample(plasma, WBC buffy-coat, RBC clots, and urine supernatant) stored at-70degrees C. Re-examination of changes in exposere to risk factors will be done periodically. Disease occurrence will be ascertained by the active(mainly through diagnosis by physicians) and the passive surveillance(through both death certificate and screening of medical utilization records).

Seroepidemiologic Study of Hepatitis B Virus(HBV) and Hepatitis C Virus(HCV) Infection among Koreans in Rural Area, Korea / 예방의학회지

To estimate the prevalence of hepatitis B virus(HBV) and hepatitis C virus(HCV) infection and to determine associated risk factors, a population-based seroepidemiologic study was carried out. In 1993, a health examination survey of the population was carried out in rural area known to have a high incidence of liver cancer. The study population were those who volunteered to participate in a health survey over 10 years of age. Examinees were interviewed by specially trained staffs. Sera from 1,033 study subjects were tested for hepatitis B surface antigen (HBsAg) by reverse passive hemagglutinin (RPHA) estimation and for hepatitis C virus antibody (anti-HCV) by 2nd generation passive hemagglutinin (PHA) estimation, The age and sex standardized prevalence of HBsAg was 6.3% which was similar to national average, but that of anti-HCV was 5.1% which was 4 to 5 times higher than that of blood or other health examinees in Korea. In a multivariate analysis, transfusion history, surgical operative history, and acupuncture history were not associated with HBsAg positivity. In contrast, acupuncture history (adjusted odds ratio[OR]=2.2 : 95% Confidence interval[CI] 1.0-4.7) and surgical operative history(adjusted OR=2.0 : 95% CI 1.0-4.1) were associated with anti-HCV positivity. The present study suggest that there is an highly endemic area of HCV infection in Korea and probably this endemicity is associated with a parenteral source of HCV infection other than blood transfusion.