Breast cancer has recently become the most common cancer in Korea. Although traditional epidemiological approaches, which are defined as "the study of the distribution and determinants of disease frequency in human population" have increased the understanding of breast cancer development in the human population, it cannot address the importance of the genetic susceptibility of humans to this disease. Therefore, a molecular epidemiological study which uses biological or genetic markers to identify and characterize the disease with the help of advances in molecular biology and human genetics might provide a better understanding of the multi-factorial or multi-step occurrence of human breast cancer. The susceptibility genes involved in the pathogenesis of breast cancer have been categorized into two groups: high penetrance genes (i.e., BRAC1, RB, etc.) and low penetrance genes (i.e., GSTs, XRCC1, etc.). This paper addresses the usefulness of biomarkers in epidemiological research of breast cancer and provides examples of the use of selected low penetrance genes involved in breast carcinogenesis in Korean women. Molecular epidemiological studies of breast cancer have enormous potential in helping researchers understand the gene-environmental interactions involved breast carcinogenesis and provide valuable insights into disease progression and survival.
Biomarkers ; Breast Neoplasms* ; Breast* ; Carcinogenesis ; Disease Progression ; Epidemiologic Studies ; Female ; Genetic Markers ; Genetic Predisposition to Disease ; Genetics, Medical ; Humans ; Korea ; Molecular Biology ; Molecular Epidemiology* ; Penetrance

A cross-sectional study was conducted to evaluate the relationship between sick building syndrome (SBS) and the factors affecting SBS among 90 office workers. The study consisted of 1) a review of previous environmental investigations, 2) measurements of COy temperature, and relative humidity (RH), 3) a questionnaire survey of symptom prevalence and perception of environmental conditions using the National Institute for Occupational Safety and Health Indoor Air Quality (NIOSH IAQ) questionnaire, and 4) confidential interview and a review of medical records of employees having respiratory symptoms. COy temperature, and RH measured on the day of questionnaire survey were within the recommended range by American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). Sixty-six percent of respondents were women and 60% considered their job description either "managerial (28%) "or "professional (32%)". Respondents had worked in the building for an average of 5.8 years. Forty-four percent reported having SBS defined as "having one or more symptoms that had occurred at work one or more days a week and tended to get better when away from work". Sex(p=0.001), duration of computer use(p=0.02), use of laser printer (p=0.02), use of cleanser or other office chemicals (p=0.004), feeling too little air movement (p=0.001), feeling air too dry(p=0.001), and unsatisfied with the current job(p=0.02) were related to an increased prevalence of SBS. Use of cleanser or other office chemicals (pO. 01), feeling too little air movement (p=0.01), and feeling air too dry (p=0.02) remained significant predictors of SBS when adjusting other variables by logistic regression analysis. The results of medical record review revealed a discrepancy in the number of diagnosed asthma cases by personal physician and an independent physician. Although this study contains several .limitations (e. g., cross-sectional study, small numbers of study, subjects, etc.), these results indicated that SBS is related to personal, environmental, and psychosocial factors and the precision of diagnosis is critical when evaluating environment-relatedness during disease cluster investigation.
Air Movements ; Air Pollution, Indoor ; Asthma ; Cross-Sectional Studies ; Data Collection ; Diagnosis ; Female ; Heating ; Hot Temperature ; Humans ; Humidity ; Job Description ; Logistic Models ; Medical Records ; National Institute for Occupational Safety and Health (U.S.) ; Prevalence ; Psychology ; Questionnaires ; Sick Building Syndrome*

Genomic epidemiology is defined as "an evolving field of inquiring that uses the systematic application of epidemiologic methods and approaches in population-based studies of the impact of human genetic variation on health and disease (Khoury, 1998) ". Most human diseases are caused by the intricate interaction among environmental exposures and genetic susceptibility factors. Susceptibility genes involved in disease pathogenesis are categorized into two groups: high penetrance genes (i.e., BRAC1, RB, etc.) and low penetrance genes (i.e., GSTs, Cyps, XRCC1, ets.), and low penetrance susceptibility genes has the higher priority for epidemiological research due to high population attributable risk. In this paper, the summarized results of the association study between single nucleotide polymorphisms (SNPs) and breast cancer in Korea were introduced and the international trends of genomic epidemiology research were reviewed with an emphasis on internet-based case-control and cohort consortium.
Breast Neoplasms ; Case-Control Studies ; Cohort Studies ; Environmental Exposure ; Epidemiologic Methods ; Epidemiology* ; Genetic Predisposition to Disease ; Genetic Variation ; Genome ; Humans ; Korea ; Penetrance ; Polymorphism, Single Nucleotide

The age-standardized incidence and mortality rates of gastric cancer have been decreasing worldwide. However, due to the rapid increase in the aging population, the absolute number of cases is actually increasing, and some countries, including Korea, show a divergent trend in the incidence of gastric cancer in younger generations. Gastric cancer is the second most common cancer in Korea. In the present review, several epidemiologic factors associated with the risk of gastric cancer are evaluated, including family history of gastric cancer, Helicobacter pylori infection, cigarette smoking, and adverse dietary factors. The practice of and participation in gastric cancer screening are reviewed. Prevention strategies based on evidence from Korean epidemiologic studies and early detection by regular screening are important for the reduction of the burden from gastric cancer.
Aging ; Diagnosis ; Epidemiologic Factors ; Epidemiologic Studies ; Epidemiology* ; Family Characteristics ; Helicobacter pylori ; Humans ; Incidence ; Korea ; Mass Screening* ; Mortality ; Risk Factors ; Smoking ; Stomach Neoplasms*

The age-standardized incidence and mortality rates of gastric cancer have been decreasing worldwide. However, due to the rapid increase in the aging population, the absolute number of cases is actually increasing, and some countries, including Korea, show a divergent trend in the incidence of gastric cancer in younger generations. Gastric cancer is the second most common cancer in Korea. In the present review, several epidemiologic factors associated with the risk of gastric cancer are evaluated, including family history of gastric cancer, Helicobacter pylori infection, cigarette smoking, and adverse dietary factors. The practice of and participation in gastric cancer screening are reviewed. Prevention strategies based on evidence from Korean epidemiologic studies and early detection by regular screening are important for the reduction of the burden from gastric cancer.
Aging ; Diagnosis ; Epidemiologic Factors ; Epidemiologic Studies ; Epidemiology* ; Family Characteristics ; Helicobacter pylori ; Humans ; Incidence ; Korea ; Mass Screening* ; Mortality ; Risk Factors ; Smoking ; Stomach Neoplasms*

Biomarkers are characteristic biological properties that can be detected and measured in a variety of biological matrices in the human body, including the blood and tissue, to give an indication of whether there is a threat of disease, if a disease already exists, or how such a disease may develop in an individual case. Along the continuum from exposure to clinical disease and progression, exposure, internal dose, biologically effective dose, early biological effect, altered structure and/or function, clinical disease, and disease progression can potentially be observed and quantified using biomarkers. While the traditional discovery of biomarkers has been a slow process, the advent of molecular and genomic medicine has resulted in explosive growth in the discovery of new biomarkers. In this review, issues in evaluating biomarkers will be discussed and the biomarkers of environmental exposure, early biologic effect, and susceptibility identified and validated in epidemiological studies will be summarized. The spectrum of genomic approaches currently used to identify and apply biomarkers and strategies to validate genomic biomarkers will also be discussed.
Disease Progression ; Environmental Exposure ; *Epidemiologic Studies ; *Genetic Markers ; Humans ; Molecular Epidemiology/*methods ; Neoplasms/epidemiology ; Republic of Korea/epidemiology

PURPOSE: A hospital-based case-control study was designed to assess whether obesity may differ in breast cancer risk according to the estrogen receptor (ER) or progesterone receptor (PR) status. MATERIALS AND METHODS: Information on life-styles was obtained in a hospital-based cancer registry at the Aichi Cancer Center Hospital, Japan, 1988~1992. Newly diagnosed cases with breast cancer (n=1,154) and controls with no history of cancer (n=21,714) were selected. Body mass index with known and suspected risk factors for breast cancer was included simultaneously in the logistic regression model. Hypothesis tests for differences in odds ratios were done by Wald test based on the polytomous logistic regression models. RESULTS: Both current weight and body mass index were significantly related to the risk of breast cancer; OR for body weight per 5 kg=1.11 (1.05~1.73), OR for body mass index per 10 kg/m2=1.54 (1.25~1.90). The risks of both body weight and body mass index, however, was not modified by ER, nor by PR. CONCLUSION: This study strongly suggests that obesity may be associated with breast cancer risk. The possibility that obesity differs according to hormonal receptor status should be pursued in further studies.
Body Mass Index ; Body Weight ; Breast Neoplasms* ; Breast* ; Case-Control Studies ; Estrogens ; Japan ; Logistic Models ; Obesity* ; Odds Ratio ; Receptors, Progesterone ; Risk Factors

BACKGROUND: Polycyclic aromatic hydrocarbons (PAH) are well known environmental pollutants. The measurement of PAH in ambient air is not commonly used, because it is quite difficult to perform and is unreliable. Using biomarkers of PAH can be an alternative approach to this problem. The PAH in ambient air is absorbed in particulate matter. Total suspended particulate(TSP) or particulate matter of less than 10 micrometer in diameter (PM10) can be easily measured. Therefore, TSP or PM10 can be used as a surrogate measurements of ambient air PAH. CONCLUSIONS: We investigated whether the urinary concentration of two biomarkers of PAH, 1-hydroxypyrene (1-OHP) and 2-naphthol, could reflect the total suspended particulate in the general population. METHODS: In order to exclude the effects of occupational exposure and smoking, first grade middle school students were included in this study. Four middle schools within a one kilometer boundary of ambient air monitoring stations were selected. Total suspended particulate was regarded as the marker of airborne PAH. Diet and smoking data were collected by self administered questionnaires, and spot urine samples were collected. Urinary 1-OHP and 2-naphthol were analyzed by high performance liquid chromatography. RESULTS: The correlation between urinary 1-OHP, 2-naphthol and passive smoking was not statistically significant. The correlation between urinary 1-OHP and TSP indices was not statistically significant. The correlations between urinary 2-naphthol and TSP of two lag days, one lag day, and zero lag days were statistically significant. The statistical significance of two lag days was the strongest (p=0.001), one lag day was the next (p=0.0275), and zero lag days was the weakest (p=0.0349). CONCLUSION: Our results imply that the urinary concentration of 2-naphthol can be applied as a PAH exposure marker for the general population with low PAH exposure.
Air Pollution ; Biomarkers ; Chromatography, Liquid ; Diet ; Environmental Pollutants ; Humans ; Occupational Exposure ; Particulate Matter ; Polycyclic Hydrocarbons, Aromatic ; Surveys and Questionnaires ; Smoke ; Smoking ; Tobacco Smoke Pollution

PURPOSE: Helicobacter pylori (H. pylori) is now generally accepted to be strongly associated with the development of gastric cancer, as well as intakes of some salted foods, charred foods, etc. To evaluate the association among dietary habits, H. pylori infection, and early gastric cancer in Koreans, a hospital based case-control study was conducted. Material and Method: A total of 268 persons participated in this case-control study. Sixty nine patients were newly diagnosed as an early gastric cancer (EGC) at the Division of Gastroenterology, Department of Internal Medicine, Asan Medical Center, Seoul, Korea. One hundred ninety-nine subjects with no symptoms who visited the Health Promotion Center for their general checkups were selected as the controls. All subjects were examined for H. pylori infection, biochemical blood test the life style, and dietary habit were interviewed by a trained dietition with semi-quantitative food frequency question naire (FFQ) and adaptive salt concentration were taste evaluated. RESULTS: H. pylori seropositivity was observed in 88.4% in cases, as compared with 74.9% in controls (OR=2.5, 95% CI: 1.1-5.7). The adaptive salt concentration was associated with early gastric cancer risk (chi-squir=50.8, p<0.001). The analysis of food intake frequency demonstrated that early gastric cancer risk was reduced by the intake of clear soups, raw vegetables, fruits and juices, beef with vegetables and soybean curds. On the other hand, high intake of salt-fermented fish and kimchi elevated the risk of early gastric cancer. CONCLUSION: These results suggest that some dietary factors and H. pylori infection have a significant association with the development of early gastric cancer.
Case-Control Studies ; Chungcheongnam-do ; Eating ; Food Habits* ; Fruit ; Gastroenterology ; Hand ; Health Promotion ; Helicobacter pylori* ; Helicobacter* ; Hematologic Tests ; Humans ; Internal Medicine ; Korea ; Life Style ; Seoul ; Soybeans ; Stomach Neoplasms* ; Trout ; Vegetables

OBJECTIVES: Malondialdehyde (MDA), a lipid peroxidation by-product, has been widely used as an indicator of oxidative stress. Urinary 2-naphthol, a urinary PAH metabolite, is used as a marker of ambient particulate exposure and is associated with lung cancer and chronic obstructive pulmonary disease. However, the stability and intra-individual variation associated with urinary MDA and 2-naphthol have not been thoroughly addressed. The objective of this study was to assess the stability and intraindividual variation associated with urinary MDA and 2-naphthol. METHODS: Urine samples were collected from 10 healthy volunteers (mean age 34, range 27~42 years old). Each sample was divided into three aliquots and stored under three different conditions. The levels of urinary MDA and 2-naphthol were analyzed 1) just after sampling, 2) after storage at room temperature (21degrees C) for 16 hours, and 3) after storage in a -20degrees C freezer for 16 hours. In addition, an epidemiological study was conducted in 44 Chinese subjects over a period of 3 weeks. The urinary MDA and 2-naphthol were measured by HPLC three times. RESULTS: There was no difference in the levels of urinary MDA and 2-naphthol between the triplicate measurements (n=10, p=0.84 and p=0.83, respectively). The intra-class correlation coefficients (ICC) for urinary MDA and 2-naphthol were 0.74 and 0.42, respectively. However, the levels of PM2.5 in the air were well correlated with the levels of both MDA and 2-naphthol in the epidemiological study. CONCLUSIONS: These results suggest that urinary MDA and 2-naphthol remain stable under variable storage conditions, even at room temperature for 16 hours, and indicate that these markers can be used in epidemiological studies involving various sample storage conditions. The intra-CC of urinary 2-naphthol and MDA were acceptable for application to epidemiological studies.
Adult ; Biological Markers ; Female ; Humans ; Male ; Malondialdehyde/*metabolism/*urine ; Middle Aged ; Naphthols/*metabolism/*urine ; Oxidative Stress/physiology ; Reproducibility of Results