Increased risk of thyroid cancer in female residents nearby nuclear power plants in Korea: was it due to detection bias?

BACKGROUND: The Korea Radiation Effect & Epidemiology Cohort METHODS: Using the KREEC-R raw data, we calculated age standardized rates (ASRs) of female thyroid cancer and re-analyzed the results of survey on the use of medical services. We also marked the administrative districts of residents who received the Radiation Health Research Institute (RHRI) health examinations and those in which thyroid cancer case occurred as per the Chonnam National University Research Institute of Medical Sciences (RIMS) final report on maps where the locations of NPPs and 5 km-radii around them were also indicated. And we compared the incidence rates of Radiation-induced cancer measured between the first period when RHRI health examinations were not yet implemented, and the second period when the RHRI health examinations were implemented. RESULTS: The ASR for the far-distance group, which comprised residents living in areas outside the 30 km radius of the NPPs, increased rapidly after 2000; however, that of the exposed group, which comprised residents living within a 5 km radius of the NPPs, started to increase rapidly even before 1995. The frequencies of the use of medical services were significantly higher in the intermediate proximate group, which comprised residents living within a 5–30 km radius of the NPPs, than in the exposed group in women. In case of female thyroid cancer, the second period ASR was higher than the first period ASR, but in case of female liver cancer and female stomach cancer no significant difference were observed between the periods. On map, many administrative districts of residents who received RHRI health examinations and most administrative districts in which thyroid cancer case occurred on RIMS final report were outside 5 km-radii around NPPs. CONCLUSIONS: We could not find any evidence supporting the assertion that detection bias influenced the increased risks of female thyroid cancer observed in the exposed group of the KREEC-R study, as opposed to the control group.

Quantitative analysis of acetylsalicylic acid in human blood using volumetric absorptive microsampling

Volumetric absorptive microsampling (VAMS) is a novel sampling technique that allows for the collection of an accurate volume of blood by dipping a microsampler tip. The purpose of this study is to compare the requirement of a stabilizing reagent for the conventional venous blood sampling method versus VAMS in the analytical measurement of the concentration of acetylsalicylic acid. A high-performance liquid chromatography with mass spectrometry (LC-MS/MS) method was developed and validated for the accurate determination of acetylsalicylic acid in human blood. The blood samples spiked with acetylsalicylic acid with and without stabilizing reagent were absorbed into VAMS tips. In the whole blood sample, the same concentration was shown regardless of the addition of the stabilizing reagent, but the concentration decreased when the stabilizing reagent was not added to the VAMS sample. To apply the VAMS technology as a new blood sampling method, stabilizing reagents should be added before the analysis of acetylsalicylic acid concentration.

Epigenetic modification of α-N-acetylgalactosaminidase enhances cisplatin resistance in ovarian cancer

Although cisplatin is one of the most effective antitumor drugs for ovarian cancer, the emergence of chemoresistance to cisplatin in over 80% of initially responsive patients is a major barrier to successful therapy. The precise mechanisms underlying the development of cisplatin resistance are not fully understood, but alteration of DNA methylation associated with aberrant gene silencing may play a role. To identify epigenetically regulated genes directly associated with ovarian cancer cisplatin resistance, we compared the expression and methylation profiles of cisplatin-sensitive and -resistant human ovarian cancer cell lines. We identified α-Nacetylgalactosaminidase (NAGA) as one of the key candidate genes for cisplatin drug response. Interestingly, in cisplatin-resistant cell lines, NAGA was significantly downregulated and hypermethylated at a promoter CpG site at position +251 relative to the transcriptional start site. Low NAGA expression in cisplatin-resistant cell lines was restored by treatment with a DNA demethylation agent, indicating transcriptional silencing by hyper-DNA methylation. Furthermore, overexpression of NAGA in cisplatin-resistant lines induced cytotoxicity in response to cisplatin, whereas depletion of NAGA expression increased cisplatin chemoresistance, suggesting an essential role of NAGA in sensitizing ovarian cells to cisplatin. These findings indicate that NAGA acts as a cisplatin sensitizer and its gene silencing by hypermethylation confers resistance to cisplatin in ovarian cancer. Therefore, we suggest NAGA may be a promising potential therapeutic target for improvement of sensitivity to cisplatin in ovarian cancer.

Evaluation of mercury exposure level, clinical diagnosis and treatment for mercury intoxication

Mercury occurs in various chemical forms, and it is different to health effects according to chemical forms. In consideration of the point, the evaluation of the mercury exposure to human distinguished from occupational and environmental exposure. With strict to manage occupational exposure in factory, it is declined mercury intoxication cases by metallic and inorganic mercury inhalation to occupational exposure. It is increasing to importance in environmental exposure and public health. The focus on the health impact of exposure to mercury is more on chronic, low or moderate grade exposure—albeit a topic of great controversy—, not high concentration exposure by methylmercury, which caused Minamata disease. Recently, the issue of mercury toxicity according to the mercury exposure level, health effects as well as the determination of what mercury levels affect health are in the spotlight and under active discussion. Evaluating the health effects and Biomarker of mercury exposure and establishing diagnosis and treatment standards are very difficult. It can implement that evaluating mercury exposure level for diagnosis by a provocation test uses chelating agent and conducting to appropriate therapy according to the result. but, indications for the therapy of chelating agents with mercury exposure have not yet been fully established. The therapy to symptomatic patients with mercury poisoning is chelating agents, combination therapy with chelating agents, plasma exchange, hemodialysis, plasmapheresis. But the further evaluations are necessary for the effects and side effects with each therapy.

Split hand/foot malformation with long-bone deficiency and BHLHA9 duplication: A prenatal diagnosis report

Distal limb deformities are congenital malformations with phenotypic variability and high genetic heterogeneity. Split hand/foot malformation, also known as ectrodactyly, is a congenital limb malformation characterized by a defect of the central rays of the hands and/or feet. Split hand/foot malformation with long-bone deficiency (SHFLD) is a rare condition related to a 17p13.3 duplication. Recently, genomic duplications encompassing BHLHA9 have been associated with SHFLD. We report a case of SHFLD presenting with campomelia of the right femur, bilateral agenesis of fibulae, bilateral club feet, and oligosyndactyly of the hands and feet, that was associated with a 17p13.3 duplication, as determined prenatally using array comparative genomic hybridization.

Evaluation and management of lead exposure

Lead, which is widely used in industry, is a common element found in low concentrations in the Earth's crust. Implementations to reduce environmental lead concentrations have resulted in a considerable reduction of lead levels in the environment (air) and a sustained reduction in the blood lead levels of the average citizen. However, people are still being exposed to lead through a variety of routes in everyday commodities. Lead causes health problems such as toxicity of the liver, kidneys, hematopoietic system, and nervous system. Having a carcinogenic risk as well, the IARC classifies inorganic lead compounds as probably carcinogenic to humans (Group 2A). Occupational lead poisonings have decreased due to the efforts to reduce the lead concentrations in the working environment. In contrast, health hazards associated with long-term environmental exposure to low concentrations of lead have been reported steadily. In particular, chronic exposure to low concentrations of lead has been reported to induce cognitive behavioral disturbances in children. It is almost impossible to remove lead completely from the human body, and it is not easy to treat health hazards due to lead exposure. Therefore, reduction and prevention of lead exposure are very important. We reviewed the toxicity and health hazards, monitoring and evaluation, and management of lead exposure.

Association Between Blood Lead Concentration and Computerized Neurobehavioral Performance in Korean Elementary School Students / 대한산업의학회지

OBJECTIVES: This study was conducted to evaluate association between computerized neurobehavioral performance and blood lead concentration in Korean elementary school students. METHODS: The subjects were 1,077 elementary school students of Seoul, Busan, Daegu and Gwangju. Blood lead concentration was measured and computerized neurobehavioral performance tests were performed. RESULTS: Blood lead concentration of the subjects was in the range of 0.20 and 7.39 microg/dl. The geometric mean of the subjects' blood lead concentration was 1.41 microg/dl. As blood lead concentration increased, reaction time to the symbol digit tended to increase significantly and linearly. As a result of LOWESS(locally weighted scatterplot smoothing), increasing reaction time to the symbol digit was observed. CONCLUSIONS: As blood lead concentration under the CDC (center for disease control and prevention) reference value increased, reaction time to the symbol digit tended to increase. But, as the number of subjects over 3 microg/dl is small, it is difficult to make a definite conclusion. If confounding variables are controlled properly in a follow-up study, we can obtain a more definite conclusion.

The Relationship Between Amalgam Tooth Fillings and Concentration of Blood Mercury in Elementary School Students in Korea / 대한산업의학회지

OBJECTIVES: The adverse health effects of mercury in dental amalgam have not yet been clarified. This study was conducted to examine the effects of dental amalgam on the concentration of blood mercury in Korean children. METHODS: A total of 1,275 students were enrolled in the elementary school in Seoul, Incheon, and Daegu. The number and location of dental amalgam filling of teeth were ascertained by oral examination. Dietary habits-including frequency of seafood intake-and other demographic factors were obtained from the children's parents. The concentration of blood mercury was measured by an atomic absorption spectrophotometer to which a hydride generator was installed. RESULTS: The geometric mean of blood mercury concentration was 1.91 microg/L. It was found that elementary school students in Seoul and the 4th grade elementary school students have the lowest concentration of blood mercury among the study groups. Both linear and secondary linear increase of the concentration of blood mercury, depending on the number of dental amalgam fillings, were statistically significant (p-trend < 0.01, p-quadratic < 0.01). As a result of multiple regression analysis on the blood mercury concentration of elementary school students, the regression coefficient (beta) of a dental amalgam filling was found to be 0.027 (standard error = 0.014, p = 0.048). CONCLUSIONS: In children, the dental amalgam fillings were significantly contribute to the concentration of blood mercury. To accurately assess the effect of dental amalgam on the concentration of body mercury, further studies using the concentration of urine mercury are needed.

A Study to Verify the Stability of Currently Stored Blood Donor Samples (A First Year Study) / 대한수혈학회지

BACKGROUND: The Korean Red Cross (KRC) has stored blood donor samples for 10 years under -20degrees C since 2004. These samples have been used for investigating transfusion related infections and for Look-back studies. We designed an experimental scheme to verify the stability of stored blood samples. METHODS: We collected and prepared samples such as blood donor samples (HBV, HCV, HIV nucleic acid positive; n=90), the HIV infected patient samples (n=20), the WHO nucleic acid international standards serologic positive samples (HBsAg, anti-HCV, anti-HIV; n=120) and the negative samples (n=20). The samples were aliquoted in cryo tubes with volumes of 0.5~5 mL and they were stored at -20~-30degrees C and -70~-80degrees C. We used enzyme immunoassay, chemiluminescence immunoassay and quantitative PCR for the base line and the follow up studies. The linear mixed statistical model using SAS 9.1 for windows was used for statistical analysis. RESULTS: The results of the baseline test of the stored samples showed a variable range of viral load (10(1)~10(7) IU/mL or copies/mL) and optical density (S/CO 3.0~500). The results of the stored samples after 6 month (n=82) did not show any significant differences compared to the baseline data for the viral loads (P>0.05) and the qualitative serologic tests. CONCLUSION: We established an experimental scheme to verify the stability of the stored blood donor samples. From now on, the stability of the stored samples is going to be monitored by every 6 month for 10 years.

Excel-based Design of Intermittent Intravenous Drip Dose Regimen of Antibiotics / 中国药房

OBJECTIVE:To design intermittent intravenous drip dose regimen of antibiotics. METHODS: The pharmacokinetic data were computed using the multidoses function method taking cefazolin,ceftriaxone and amikacin as examples. Then computation program was programmed using Excel software based on pharmacokinetic parameters combined with pharmacodynamic parameters to design rational dosage regimen. RESULTS: The bactericidal effect of time-dependent antibiotics was chiefly dependent on the time during which the drug blood concentration was higher than minimal inhibitory concentration(MIC).For those antibacterials with short elimination half life(t1/2)in plasma,the best regimen was to give patients the med-icine in a small average divided dose or continuous medication. For those with(t1/2) greater than 12～24 h,single dose admin-istration was advisable. For concentration-dependent antibiotics,the best PK/PD parameters for optimal clinical antibiotic effect were Cmax/ MIC,and which should be administered in single time (daily dose). CONCLUSION: PK/PD parameters -based intermittent intravenous drip dosage regimen of antibiotics designed by means of Excel function is simple,reliable and intuitionistic.

Effects of Ibuprofen on the Circadian Rhythm Variation of Body Temperature and Plasma Concentration in Rats / 中国药房

OBJECTIVE:To study the effect of different administration time of ibuprofen on the changing characteristics of circadian rhythm about body temperature and plasma concentration in rats.METHODS:60 rats were given single oral administration of ibuprofen at the dose of 50 mg per kilogram at different time(2∶00,6∶00,10∶00,14∶00,18∶00,22∶00) according to a randomized block design with another 10 rats serving as blank control.The effects of ibuprofen on circadian rhythm variations of body temperature and plasma concentration in rats were observed and analyzed using chronogram and cosine method.RESULTS:The body temperature of rats prior to and after administration both showed a significant circadian rhythm,with mean declined only,yet acrophase and amplitude showed no significant differences.The best cosinor curve equation were Yt i=38.7+0.52 Cos(15??ti—86.80?) and Yt i=37.8+0.55 Cos(15??ti—117?) respectively.The plasma concentration also showed a significant circadian change in rats at the different time points of administration.The plasma concentration in light phase was higher than that in dark phase,and the best cosinor curve equation was Yt i=41.95+5.30 Cos(15??ti—272.83?).CONCLUSION:The differences of circadian rhythm were both shown about body temperature and plasma concentration in rats when ibuprofen was orally administered at the different time points.

Cost-Effectiveness Analysis on3Chinese and Western Medicines in the Treatment of Senile Functional Constipation / 中国药房

OBJECTIVE:To evaluate the cost-effectiveness of3Chinese and western medicines in treating senile func?tional constipation.METHODS:186patients with senile functional constipation were randomly assigned to receive Forlax powder preparation for infusion,Liuweianxiao capsule and Buzhongyiqitang respectively,the therapeutic efficacies of the3groups were observed and the cost-effectiveness analysis were conducted12weeks after treatment.RESULTS:The cure rates for the3groups were77.6%,83.3%and85.5%,respectively;the costs for the3groups were963.52yuan,877.00yuan and850.12yuan,respectively;the ratio of cost to effectiveness were1241,1052and975,respectively;the incremental cost-effectiveness ratio of Group A and B were1435and1221as compared with Group C.CONCLUSION:Liuweianxiao capsule(Group B)was the preferred option for the treatment of senile functional constipation.

Pharmacoeconomic Evaluation of 2 Therapeutic Schemes for Chronic Hepatitis C / 中国药房

0.05), and the treatment costs of the two groups were 30 235.20 yuan and 36 950.40 yuan, respectively (P

Shiftwork Duration and Metabolic Risk Factors of Cardiovascular Disease / 대한산업의학회지

AIMS: To explore the relationship between shiftwork duration and metabolic risk factors on cardiovascular disease in shiftworkers. METHODS: The study subjects comprised of 226 nurses, from a hospital, and 130 male workers, from a diaper and feminine hygienic material manufacturing firm. The mean ages of the male workers and nurses were 29 and 28.5 years, respectively. The fasting blood sugar, serum cholesterol, blood pressure, height and weight, waist and hip circumferences (only in nurses), and number of step for a shift as indices of physical activity were measured. Using the Korean version of Karasek's job contents questionnaire, the job stress was assessed. Information about the number of years worked, duration of shiftwork, and past medical and behavioral histories, including smoking, were obtained by self-administrated questionnaires. Linear regression analyses were performed, to show the relationships between shiftwork duration and metabolic risk factors, using simple and multivariate models, adjusted for age, smoking, job strain and physical activity. The following criteria were defined: hypertension as a SBP>or160 or a DBP>or=90 mmHg at least once, hypercholesterolemia, as a serum total cholesterol >or=240 mg/dl, obesity as BMI (Body Mass Index) >or=25kg/m2 and central obesity as a WHR (Waist to Hip Ratio) >or=0.85; and the logistic regression analyses, according to years of shiftwork, were performed using simple and adjusted models. RESULTS: The cholesterol and fasting blood sugar showed increasing trends, but without statistical significances, according to the increase in shiftwork duration of the male workers, although, the increases in the blood pressure and BMI were statistically significant. In the nurses, only the WHR showed a significant increase in relation to the shiftwork duration. In the logistic regression analyses, hypercholesterolemia and obesity showed significant increasing risks according to the number of years of shiftwork (OR=3.32 95%CI 1.27-8.72 and OR=3.21 95%CI 1.24-8.32 respectively) in the male workers, but hypertension showed no significance. In the nurses, only an increased central obesity was significant as a risk factor (OR=1.30 95%CI 1.05-1.62). CONCLUSIONS: These results provide evidence of the associations between shiftwork and metabolic risk factors for cardiovascular disease, although healthy shiftworker effects might exist in our cross sectional study design.

Clinical Significance of Conventional Papanicolaou Cervical Cytology Test: A Cytohistologic Comparison / 대한산부인과학회잡지

OBJECTIVE: The purpose of this study was to obtain an important basic data which would be useful not only in clinical practice but also in clinical trial of ThinPrep Pap Test and Computerized Screening Test as the new trends of cervical cancer detection, by analyzing the conventional Papanicolaou cervical cytologic test according to The Bethesda System (TBS) and investigating the correlation between abnormal cytologic diagnoses and histologic diagnoses. METHODS: This study was performed in Obstetrics and Gynecology outpatient clinic (OG group: high risk and screening population) and in Health Check-up Center/Industrial Medicine clinic (HC group: screening population) at Dankook University Medical Center from January 1, 1999 to December 31, 2000. Ten thousand and seven hundred eighty seven cases (5,019 cases in OG group and 5,768 cases in HC group) who underwent conventional Papanicolaou cervical cytologic test were analyzed. Abnormal cytologic diagnoses ([Atypical Squamous Cells of Undetermined Significance (ASCUS) or worse]) were compared with histologic diagnoses as a reference standard. RESULTS: Followings are the results summarized. 1. Of the 10,807 patients, 20 (0.19%) were diagnosed as unsatisfactory for evaluation. Of 10,787 cases, there were 5,501 (51.00%) cytologic diagnoses of Within Normal Limit (WNL), 4,911 (45.53%) of Benign Cellular Change (BCC), 168 (1.56%) of ASCUS, 67 (0.62%) of Low-grade Squamous Intraepithelial Lesion (LSIL), 89 (0.83%) of High-grade Squamous Intraepithelial Lesion (HSIL), 34 (0.32%) of Squamous Cell Carcinoma (SCC), 16 (0.15%) of Atypical Glandular Cells of Undetermined Significance (AGUS) and 1 (0.01%) of Adenocarcinoma (ACC), respectively in conventional Papanicolaou smear series. The ASCUS/SIL ratio was 1.08. Statistically, there were more cytologic diagnoses of WNL, ASCUS, LSIL, HSIL, and SCC in OG group but BCC in HC group. 2. The age distribution of patients were as follows: 9 cases under 19 years, 1,011 in the 20's, 3,244 in the 30's, 3,110 in the 40's, 2,218 in the 50's, 1,035 in the 60's, 148 in the 70's, and 12 over 80 years. The mean age was 44.03 years. The mean age of HC group was significantly higher than that of OG group. The mean ages of BCC and ASCUS in HC group were significantly higher than those in OG group. 3. Of 10,787 cases, there were 375 abnoraml cytologic diagnoses (ASCUS/AGUS or worse): 245 in OG group and 130 in HC group. Statistically, there were more high-grade cytologic diagnoses (HSIL, SCC, and ACC) both in older age and in OG group. 4. Of 375 cases with abnormal cytologic diagnoses, 176 patients had histologic diagnoses. Of the 56 ASCUS, 21 (37.5%) showed positive histologic LSIL or worse diagnoses. Of the 112 cytologic LSIL or worse cases, 91 (81.25%) showed positive histologic LSIL or worse diagnoses. Of 176 cases, 105 (59.66%) showed high-grade histologic diagnoses (HSIL or worse). Of the 7 AGUS, 5 (71.43%) showed HSIL or worse diagnoses. There was a statistically significant relation between cytologic diagnoses and high-grade histologic diagnoses in squamous abnormalities. CONCLUSION: This study showed that our data according to TBS criteria were similar to other reports in the literatures. There were statistically significant difference between OG group and HC group in age and some diagnoses. And there was a statistically significant relation between cytologic diagnoses and high-grade histologic diagnoses in squamous cell abnormalities. This study will play a relevant role in clinical trial of ThinPrep Pap Test and Computerized Screening Test as well as in clinical practice.

The Effects of Job Stress on the Autonomic Nerve Activity of Workers in Manufacturing Industry / 대한산업의학회지

OBJECTIVE: A cross-sectional study was conducted to evaluate the relationships between autonomic nerve activity (i.e., heart rate variability and urinary catecholamines) and job stress. METHODS: The study was conducted on 134 workers from a company producing consumer goods (i.e., diaper, paper towel) located in Cheonan, Korea. Job stress was assessed by Karasek's Job Content Questionnaire (JCQ). Autonomic function was assessed by heart rate variability (HRV) and urinary catecholamines (epinephrine, norepinephrine, and dopamine). Urine samplings, and measurings of HRV, were repeated three times for each shift. Information on demographic characteristics, previous job histories, past medical history, smoking and drinking were also collected. RESULTS: No statistically significant differences were observed in any HRV and urinary catecholamines among the four groups, which were categorized by the Job Strain Model. When data were stratified by work duration, low field HRV was borderline significantly higher in the high strain group in individuals with a shorter work duration (<48.5 months, N=28, p-value of 0.92 by analysis of variance). CONCLUSIONS: Neither HRV nor urinary catecholamines are significantly associated with job stress, as assessed by the Karasek's JCQ. However, HRV seems to be a potential physiological indicator of job stress only in the workers with a shorter work duration.

The Present Status and Perspective of Nationwide Occupational Diseases Surveillance System / 대한산업의학회지

No abstract available.

Influence of Shiftwork Duration on Blood Pressure and Heart Rate Variability in Short Rotating 8-hour Shiftworkers / 대한산업의학회지

OBJECTIVES: This study was performed to investigate the chronic health effect of shiftwork on cardiovascular system. METHODS: We checked blood pressure(BP) and heart rate variability(HRV) at every shift on 134 male workers whose shift type was 8-hour and short rotating of 3 days shift interval. As confoundings, job stress was measured by Karasek's JCQ 49 items questionnaire and circardian type was assessed by morningness-eveningness questionnaire. Smoking and alcohol drinking habit, marital status and past medical history were also acquired. We used the method of repeated measured data analysis with mixed model to show the association between shiftwork duration and BP or HRV. RESULTS: Average age of workers was 29 years olds(range 25~44). Among them, 77.9 % were current smokers, 50 % were the passive type of job strain in Karasek's model. Mean shiftwork duration was 5.21 years(range 5.4 months~10 years). In circadian type, no one was definitely morning type or definitely evening type. In multivariate analyses adjusted by age, job strain, shift, circadian rhythm and smoking, blood pressure were showed significantly increasing trends according to shiftwork duration in both systolic and diastolic(p<0.05). Heart rate variability were also showed significantly decreasing trends according to shiftwork duration in both parasympathetic and sympathetic functions(p<0.05). CONCLUSIONS: The results of this studs suggests the chronic negative health effect of shiftwork on cardiovascular system.

Cancer Incidence in the Vicinity of Korean AM Radio Broadcast Towers / 대한산업의학회지

OBJECTIVES: Several studies have raised the possibility that exposure to electrical and/or magnetic fields may be particularly harmful in the promotion or initiation of cancer. The purpose of this study which was based on a geographical correlation design was to investigate any association that may exist between residing near radio broadcast towers and carcinogenic activity in Korea. METHODS: In this study, the health effects of EMF of 10 AM radio broadcast towers in Korea were investigated. The electric powers of the towers were above 100kW. We chose exposed areas that were located within 2 km from the towers as well as four control regions which had similar populations in the same province(Do) but had no towers nearby. The incidence of leukemia, malignant lymphoma, brain tumor and breast cancer between the exposed areas and the control areas was compared. The standardized incidence ratios(SIRs) were calculated. Korean Medical Insurance data(between Nov,1,1993 and Oct,31,1996) was used for the cancer incidence estimation. The Nationwide Population Census data(in 1995) and the Resident Register data(in 1995) were used for information about population and locations. RESULTS: Among the 10 exposed areas, one area for leukemia and one area for brain tumor showed a significantly high incidence compared to the control areas. There were no significant increased areas for malignant lymphoma and breast cancer. CONCLUSIONS: This study design must be considered to be exploratory and not used for determining causality. However, the results suggest the necessity for further analytical epidemiological studies that have a more precise exposure measurement scale and information on confounding factors.

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.