OBJECTIVES: Recently, low systolic blood pressure (SBP) was found to be associated with an increased risk of death from vascular diseases in a rural elderly population in Korea. However, evidence on the association between low SBP and vascular diseases is scarce. The aim of this study was to prospectively examine the association between low SBP and mortality from all causes and vascular diseases in older middle-aged Korean men. METHODS: From 2004 to 2010, 94 085 Korean Vietnam War veterans were followed-up for deaths. The adjusted hazard ratios (aHR) were calculated using the Cox proportional hazard model. A stratified analysis was conducted by age at enrollment. SBP was self-reported by a postal survey in 2004. RESULTS: Among the participants aged 60 and older, the lowest SBP (<90 mmHg) category had an elevated aHR for mortality from all causes (aHR, 1.9; 95% confidence interval [CI], 1.2 to 3.1) and vascular diseases (International Classification of Disease, 10th revision, I00-I99; aHR, 3.2; 95% CI, 1.2 to 8.4) compared to those with an SBP of 100 to 119 mmHg. Those with an SBP below 80 mmHg (aHR, 4.5; 95% CI, 1.1 to 18.8) and those with an SBP of 80 to 89 mmHg (aHR, 3.1; 95% CI, 0.9 to 10.2) also had an increased risk of vascular mortality, compared to those with an SBP of 90 to 119 mmHg. This association was sustained when excluding the first two years of follow-up or preexisting vascular diseases. In men younger than 60 years, the association of low SBP was weaker than that in those aged 60 years or older. CONCLUSIONS: Our findings suggest that low SBP (<90 mmHg) may increase vascular mortality in Korean men aged 60 years or older.
Aged ; Asian Continental Ancestry Group ; *Blood Pressure ; Cause of Death ; Cohort Studies ; Follow-Up Studies ; Humans ; Hypertension/mortality/physiopathology ; Male ; Middle Aged ; Proportional Hazards Models ; Prospective Studies ; Republic of Korea ; Surveys and Questionnaires ; Vascular Diseases/mortality/*physiopathology ; Veterans Health

OBJECTIVES: The aim of this study was to examine the levels of serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and evaluate their association with age, body mass index, smoking, military record-based variables, and estimated exposure to Agent Orange in Korean Vietnam veterans. METHODS: Serum levels of TCDD were analyzed in 102 Vietnam veterans. Information on age, body mass index, and smoking status were obtained from a self-reported questionnaire. The perceived exposure was assessed by a 6-item questionnaire. Two proximity-based exposures were constructed by division/brigade level and battalion/company level unit information using the Stellman exposure opportunity index model. RESULTS: The mean and median of serum TCDD levels was 1.2 parts per trillion (ppt) and 0.9 ppt, respectively. Only 2 Vietnam veterans had elevated levels of TCDD (>10 ppt). The levels of TCDD did not tend to increase with the likelihood of exposure to Agent Orange, as estimated from either proximity-based exposure or perceived self-reported exposure. The serum TCDD levels were not significantly different according to military unit, year of first deployment, duration of deployment, military rank, age, body mass index, and smoking status. CONCLUSIONS: The average serum TCDD levels in the Korean Vietnam veterans were lower than those reported for other occupationally or environmentally exposed groups and US Vietnam veterans, and their use as an objective marker of Agent Orange exposure may have some limitations. The unit of deployment, duration of deployment, year of first deployment, military rank, perceived self-reported exposure, and proximity-based exposure to Agent Orange were not associated with TCDD levels in Korean Vietnam veterans. Age, body mass index and smoking also were not associated with TCDD levels.
2,4,5-Trichlorophenoxyacetic Acid/*poisoning ; 2,4-Dichlorophenoxyacetic Acid/*poisoning ; Adult ; Age Factors ; *Body Mass Index ; Defoliants, Chemical/*poisoning ; Humans ; Male ; Middle Aged ; Questionnaires ; Regression Analysis ; Republic of Korea/epidemiology ; Self Report ; Smoking/*blood ; Tetrachlorodibenzodioxin/*blood/poisoning ; Time Factors ; Veterans/*statistics & numerical data ; Vietnam Conflict ; Young Adult

OBJECTIVES: The aim of this study was to evaluate the association between Agent Orange exposure and self-reported diseases in Korean Vietnam veterans. METHODS: A postal survey of 114 562 Vietnam veterans was conducted. The perceived exposure to Agent Orange was assessed by a 6-item questionnaire. Two proximity-based Agent Orange exposure indices were constructed using division/brigade-level and battalion/company-level unit information. Adjusted odds ratios (ORs) for age and other confounders were calculated using a logistic regression model. RESULTS: The prevalence of all self-reported diseases showed monotonically increasing trends as the levels of perceived self-reported exposure increased. The ORs for colon cancer (OR, 1.13), leukemia (OR, 1.56), hypertension (OR, 1.03), peripheral vasculopathy (OR, 1.07), enterocolitis (OR, 1.07), peripheral neuropathy (OR, 1.07), multiple nerve palsy (OR, 1.14), multiple sclerosis (OR, 1.24), skin diseases (OR, 1.05), psychotic diseases (OR, 1.07) and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the division/brigade-level proximity-based exposure analysis, compared to the low exposure group. The ORs for cerebral infarction (OR, 1.08), chronic bronchitis (OR, 1.05), multiple nerve palsy (OR, 1.07), multiple sclerosis (OR, 1.16), skin diseases (OR, 1.05), and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the battalion/company-level analysis. CONCLUSIONS: Korean Vietnam veterans with high exposure to Agent Orange experienced a higher prevalence of several self-reported chronic diseases compared to those with low exposure by proximity-based exposure assessment. The strong positive associations between perceived self-reported exposure and all self-reported diseases should be evaluated with discretion because the likelihood of reporting diseases was directly related to the perceived intensity of Agent Orange exposure.
2,4,5-Trichlorophenoxyacetic Acid/*poisoning ; 2,4-Dichlorophenoxyacetic Acid/*poisoning ; Cardiovascular Diseases/epidemiology/etiology ; Defoliants, Chemical/*poisoning ; Endocrine System Diseases/epidemiology/etiology ; Gastrointestinal Diseases/epidemiology/etiology ; Humans ; Logistic Models ; Male ; Middle Aged ; Neoplasms/epidemiology/etiology ; Neuromuscular Diseases/epidemiology/etiology ; Odds Ratio ; Prevalence ; Republic of Korea/epidemiology ; Respiratory Tract Diseases/epidemiology/etiology ; *Self Report ; Tetrachlorodibenzodioxin/*poisoning ; *Veterans ; Vietnam Conflict

Elevated heart rate has been proposed as an independent risk factor for cardiovascular diseases, but their interrelationships are not well understood. In this study, we performed a genome-wide linkage scan in 1,026 individuals (mean age 30.6 years, 54.5% women) from 73 extended families of Mongolia and determined quantitative trait loci that influence heart rate. The DNA samples were genotyped using deCODE 1,039 microsatellite markers for 3 cM density genome-wide linkage scan. Correlation analysis was carried out to evaluate the correlation of the covariates and the heart rate. T-tests of the heart rate were also performed on sex, smoking and alcohol intake. Consequently, this model was used in a nonparametric genome-wide linkage analysis using variance component model to create a multipoint logarithm of odds (LOD) score and a corresponding P value. In the adjusted model, the heritability of heart rate was estimated as 0.32 (P<.0001) and a maximum multipoint LOD score of 2.03 was observed in 77 cM region at chromosome 18. The second largest LOD score of 1.52 was seen on chromosome 5 at 216 cM. Genes located on the specified locations in chromosomes 5 and 18 may be involved in the regulation of heart rate.
Adolescent ; Adult ; Chromosome Mapping/*methods ; Female ; Genetics, Population ; Genome, Human/*genetics ; Genome-Wide Association Study/methods ; *Heart Rate ; Humans ; Linkage (Genetics) ; Male ; Middle Aged ; Mongolia ; Quantitative Trait Loci/*genetics ; Young Adult

Family-based designs are commonly used in genetic association studies to identify and to locate genes that underlie complex diseases. In this paper, we review two examples of genome-wide association studies using family-based cohort studies, including the Framingham Heart Study and International Multi-Center ADHD Genetics Project. We also review statistical methods of family-based designs, including the transmission disequilibrium test (TDT), linkage analysis, and imprinting effect analysis. In addition, we evaluate the strengths and limitations of the family-based cohort design. Despite the costs and difficulties in carrying out this type of study, a family-based cohort study can play avery important role in genome wide studies. First, the design will be free from biases due to population heterogeneity or stratification. Moreover, family-based designs provide the opportunity to conduct joint tests of linkage and association. Finally, family-based designs also allow access to epigenetic phenomena like imprinting. The family-based cohort design should be given careful consideration in planning new studies for genome-wide strategies.
Bias (Epidemiology) ; Cohort Studies ; Epigenomics ; Genetic Association Studies ; Genome ; Genome-Wide Association Study ; Heart ; Joints ; Lifting ; Population Characteristics

It is not yet clear whether Glutathione S-transferase M1 (GSTM1) polymorphisms affect the risk of breast cancer. The aim of this study is to provide a comprehensive meta-analysis of all the available, published case-control studies on the extent of the possible association between GSTM1 polymorphisms and susceptibility to breast cancer. Twenty case-control studies on GSTM1 and breast cancer were identified using both PUBMED and a manual search. Meta-analysis was conducted by the Peto method. Subgroup analyses were undertaken, in order to explore the relationship between effect sizes and the study characteristics. The overall odds ratio (OR) was found to be 1.06 (95% CI, 0.99-1.14). The OR for post-menopausal women with GSTM1 deficiency was determined to be 1.19 (95% CI, 1.05-1.34). In populations with a low frequency of GSTM1 deficiency, a greater increase was observed (OR, 1.20; 95% CI, 1.08-1.34). Furthermore, the highest associations were found in post-menopausal women with a low frequency of GSTM1 deficiency (OR, 1.44; 95% CI, 1.20-1.73). The fact that GSTM1 deficiency is not rare in the general population implies that the attributable risk for breast cancer could be sizable. Further studies focusing on the structure of haplotype blocks of GSTM1 are required in order to find a specific haplotype with a predisposing breast cancer susceptibility allele.
Breast Neoplasms/*epidemiology/*genetics ; Female ; Glutathione Transferase/*genetics ; Humans ; *Polymorphism, Genetic ; Research Support, Non-U.S. Gov't ; Risk Factors

OBJECTIVES: This study was to investigate the mental health status and quality of life of Korean-Chinese workers, who are residing illegally in Korea. METHODS: Total 147 illegal status Korean-Chinese workers completed to the questionnaire for demographic data, Korean version of Symptom Check List-90-Revision (SCL-90-R) and Korean version of World Health Organization Quality of Life Scale (WHOQOL-BREF). RESULTS: The results of this study showed that general mental health was relatively poor and the quality of life was relatively poorer among Korean-Chinese. Mental health and quality of life were worse among those who accompanied spouses, had no religion, had less income, and those who experienced unjust treatments such as delayed payment, violence and industrial accidents. There were significant correlations between scores of all categories of SCL-90-R and scores of domains of physical health, social relationship and environment in WHOQOL-BREF. CONCLUSION: These results suggest that Korean-Chinese laborers in illegal status in Korea need improved treatment neleved from delayed payment, social violence and industrial accidents and with extended medical service and better residential environment.
Accidents, Occupational ; Humans ; Korea* ; Mental Health* ; Quality of Life* ; Surveys and Questionnaires ; Spouses ; Violence ; World Health Organization

OBJECTIVE: The aim of this study was to identify the validity of recruiting medical checkup participants of Vietnam veterans using a mail survey, and to identify the 'Vietnam service related characteristics' and `general characteristics' of Vietnam veterans groups. METHOD: In this study, a total 900 veterans were randomly selected from the list of Vietnam veterans from 1964 to 1973. The veterans were classified into 5 groups, taking into consideration their registered status in the Ministry of Patriots and Veterans Affairs; the VRD (veterans who have agent orange-related diseases), VSD (veterans who have agent orange-suspected disease), VM (veterans who performed meritorious deeds during the war), VR (veterans who were registered with the Ministry of Patriots and Veterans Affair) and OV (other veterans) groups. By means of postal surveys, the veterans' intention to participate in the medical checkup for our research, and their socioeconomic and general characteristics were investigated. 52 surveys were returned due to the subjects not residing at the listed address, and were excluded from the analysis. RESULT: 699 of the 848 veterans (82.4%) responded to the survey, of which 619 (88.6%) intended to participate in the medical checkup for our research. The 5 veterans groups all had similar ages, Vietnam service period, Agent Orange exposure, troop characteristic and wartime class, with the exception of VM, who were older, and with a greater number of officers than the other 4 groups. There was a big difference in the health statius among the Vietnam veterans group. The VM and OV were much healthier than VRD, VSD and VR groups. The socioeconomic stati of the VRD, VSD and VR groups were lower than those of the VM and OV groups. CONCLUSION: Although there were some limitations, the recruitment, by mail, of medical checkup participants from Vietnam veterans is a valid and feasible method. The VM and OV groups were much healthier, and with higher socioeconomic stati, than the VRD, VSD, and VR groups.
Citrus sinensis ; Humans ; Intention ; Methods ; Pilot Projects* ; Postal Service* ; Veterans* ; Vietnam*

OBJECTIVES: There are many concerns about ginseng as a cancer chemopreventive substance, but there have been few epidemiological studies on ginseng. This study sought to examine the relationships between ginseng intake and cancer incidence in the Kangwha cohort. METHODS: Between March 1985 and December 1999, 2697 males, aged 55 or over, as of 1985, were followed up for their cancer incidence. The cancer incidence rate, standardized incidence ratio and risk ratios were calculated according to ginseng intake. A Cox proportional hazard model was used to adjust for age at entry, smoking, alcohol intake, hypertension, and body mass index. RESULTS & CONCLUSIONS: The ginseng intake group had the same cancer (C00-C97) incidences (Standardized Incidence Ratio: SIR=1.11, 95% Confidence Interval = 0.97-1.27) and the same risk ratio (RR=1.09, 95% Confidence Interval = 0.85-1.41) as the no-intake group. Analyzing the subjects that had followed up from 1990, however, the ginseng intake group had lower cancer incidences at all sites (RR = 0.79, 95% Confidence Interval = 0.58-1.09). This was a cohort study to try and evaluate the association between ginseng intake and the incidences of cancer. The results of this study provide no clear conclusions on the cancer preventive effects of ginseng. Therefore, further study is needed in the future.
Body Mass Index ; Cohort Studies* ; Epidemiologic Studies ; Humans ; Hypertension ; Incidence* ; Male ; Odds Ratio ; Panax* ; Proportional Hazards Models ; Smoke ; Smoking

OBJECTIVE: To investigate the relationship between medical expenses and the burden of families caring for the elderly in the last 6 months of life, and to evaluate the factors relating to the burden of family caregivers. METHODS: The families of 301 persons older than 65 years, who died between 1 July and 31 December 2001, and were registered in Resident-based- Health Insurance Programs in Seoul, were interviewed. The medical expenses and length of stay among the elderly were collected from Korean Health Insurance Corporations. RESULTS: 31 percents of the elderly had no medical expenses in the last 6 months of life. On average, the objective burden (4.92) was higher than the subjective burden (3.35). Families caring for male elderly had a higher burden. With increasing age at death, the objective burden was significantly increased. The burden on a family seemed to be influenced more by the family income than the property of the elderly. With increasing total health care costs, the objective burden on the family caregivers was significantly increased, but with increasing medical expenses, the subjective burden was significantly decreased. CONCLUSION: An association between healthcare utilization and burden on families was observed. The reason for the decreasing subjective burden when medical expenses were decreased was unclear. Further research will be needed.
Aged* ; Caregivers ; Delivery of Health Care* ; Health Care Costs ; Humans ; Insurance, Health ; Length of Stay ; Male ; Seoul