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ABSTRACT: PURPOSE: To estimate the heritabilities of myopia and ocular biometrics among different family types in Korean population. METHODS: We studied 1508 adults in the Healthy Twin Study. Spherical equivalent, axial length, anterior chamber depth, and corneal astigmatism were measured by refraction, corneal topography, and A- scan ultrasonography. To see the degree of resemblance among different types of family relationships, intraclass correlation coefficients (ICC) were calculated. Variance-component methods were applied to estimate the genetic contributions to eye phenotypes as heritability based on the maximum likelihood estimation. Narrow sense heritability was calculated as the proportion of the total phenotypic variance explained by additive genetic effects, and linear and non-linear effects of age, sex, and interactions between age and sex were adjusted. RESULTS: Total 240 MZ twin pairs, and 45 DZ twin pairs, and 938 singleton adult family members who were first degree relatives of twins in 345 families were included in the study. ICCs for spherical equivalent from monozygotic twins, pooled first degree pairs, and spouse pairs were 0.83, 0.34 and 0.20, respectively. The ICCs of other ocular biometrics were also significantly higher in monozygotic twins compared to other relative pairs, with greater consistency and conformity. The estimated narrow sense heritability (95% CI) was 0.78 (0.71-0.84) for spherical equivalent, 0.86 (0.82-0.90) for axial length, 0.83 (0.76-0.91) for anterior chamber depth, and 0.70 (0.63-0.77) for corneal astigmatism. CONCLUSIONS: The estimated heritability of spherical equivalent and ocular biometrics in the Korean population suggests the compelling evidence that all traits are highly heritable.
Investigative ophthalmology & visual science 04/2013; · 3.43 Impact Factor
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ABSTRACT: Abstract Background: Metabolic syndrome has been suggested to have an association with C-reactive protein (CRP), a biomarker of cardiovascular disease risk. Given that genetic factors influence both metabolic syndrome and CRP, it seems necessary to examine the association with consideration of genetic influence. Methods: We conducted a cross-sectional study and a co-twin-control study in 2555 Korean adults composed of twins and their family members. For the co-twin-control study, 113 pairs of monozygotic twins who were discordant in regard to CRP level (>0.5 mg/L) were selected. Cross-trait additive genetic correlation between CRP and metabolic syndrome and the risk for having higher CRP level associated with components of metabolic syndrome were estimated. Results: With increasing CRP level, the prevalence of metabolic syndrome increased linearly. Among components of metabolic syndrome, high-density lipoprotein cholesterol (HDL-C) was inversely associated with CRP, whereas other components were positively associated. Most of the components of metabolic syndrome except for HDL-C had a significant genetic correlation with CRP, with the highest correlation for obesity indices. A co-twin-control study that allows full control of genetic influence showed that only obesity was significantly associated with higher CRP levels: Odds ratios (95% confidence intervals) were 1.23 (1.04,1.46) for 1 kg/m(2) increase in body mass index and 1.12 (1.03,1.22) for 1% increased in total body fat, respectively. Conclusions: Although genetic influence played a significant role in the associations between CRP and most metabolic syndrome components, environmental influence that may be modifiable also contributed to the association, especially to the associations between the obesity indices and CRP.
Metabolic syndrome and related disorders 01/2013;
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ABSTRACT: Meiotic recombination causes a shuffling of homologous chromosomes as they are passed from parents to children. Finding the genomic locations where these crossovers occur is important for genetic association studies, understanding population genetic variation, and predicting disease-causing structural rearrangements. There have been several reports that recombination hotspot usage differs between human populations. But while fine-scale genetic maps exist for European and African populations, none have been constructed for Asians.
Here we present the first Asian genetic map with resolution high enough to reveal hotspot usage. We constructed this map by applying a hidden Markov model to genotype data for over 500,000 single nucleotide polymorphism markers from Korean and Mongolian pedigrees which include 980 meioses. We identified 32,922 crossovers with a precision rate of 99%, 97% sensitivity, and a median resolution of 105,949 bp. For direct comparison of genetic maps between ethnic groups, we also constructed a map for CEPH families using identical methods. We found high levels of concordance with known hotspots, with approximately 72% of recombination occurring in these regions. We investigated the hypothesized contribution of recombination problems to age-related aneuploidy. Our large sample size allowed us to detect a weak but significant negative effect of maternal age on recombination rate.
We have constructed the first fine-scale Asian genetic map. This fills an important gap in the understanding of recombination pattern variation and will be a valuable resource for future research in population genetics. Our map will improve the accuracy of linkage studies and inform the design of genome-wide association studies in the Asian population.
BMC Genetics 01/2013; 14:19. · 2.47 Impact Factor
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ABSTRACT: The estimated glomerular filtration rate is a well-known measure of renal function and is widely used to follow the course of disease. Although there have been several investigations establishing the genetic background contributing to renal function, Asian populations have rarely been used in these genome-wide studies. Here, we aimed to find candidate genetic determinants of renal function in 1007 individuals from 73 extended families of Mongolian origin. Linkage analysis found two suggestive regions near 9q21 (logarithm of odds (LOD) 2.82) and 15q15 (LOD 2.70). The subsequent family-based association study found 2 and 10 significant single-nucleotide polymorphisms (SNPs) in each region, respectively. The strongest SNPs on chromosome 9 and 15 were rs17400257 and rs1153831 with P-values of 7.21 × 10(-9) and 2.47 × 10(-11), respectively. Genes located near these SNPs are considered candidates for determining renal function and include FRMD3, GATM, and SPATA5L1. Thus, we identified possible loci that determine renal function in an isolated Asian population. Consistent with previous reports, our study found genes linked and associated with renal function in other populations.Kidney International advance online publication, 19 December 2012; doi:10.1038/ki.2012.389.
Kidney International 12/2012; · 6.61 Impact Factor
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ABSTRACT: The Healthy Twin Study, Korea (HT) is an ongoing multi-center cohort study that was initiated in 2005, based on a nation-wide twin and family database. Since its inception, the HT has recruited 815 pairs of adult twins and a total of 3,690 individual twins and their families as of July 2012. Here we summarize updates since the previous report in 2006. Besides the increase in size, the HT has been enriched in several aspects: a biobank was constructed for ongoing and future omics studies; and genome-wide single nucleotide polymorphism markers (Affymetrix GeneChip version 6.0, 1 M probes) have been analyzed for 2,200 individuals, which enabled gene identification studies for measured phenotypes. In addition, longitudinal study protocols were established through the HT and a second wave survey was finished in 2010 with >70% follow-up rate. The parallel genome research projects were recently launched, which would expedite multi-omics studies maximizing the twin potentials such as metagenomics and epigenetics studies, and endow us with resources for recruiting more participants. We submit this report to share updates and research opportunities from the HT.
Twin Research and Human Genetics 12/2012; · 1.70 Impact Factor
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Hansoo Park,
Seungbok Lee,
Hyun-Jin Kim,
Young Seok Ju,
Jong-Yeon Shin,
Dongwan Hong,
Marcin von Grotthuss,
Dong-Sung Lee,
Changho Park,
Jennifer Hayeon Kim,
Boram Kim,
Yun Joo Yoo,
Sung-Il Cho, Joohon Sung,
Charles Lee,
Jong-Il Kim,
Jeong-Sun Seo
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ABSTRACT: BACKGROUND: Musical abilities such as recognising music and singing performance serve as means for communication and are instruments in sexual selection. Specific regions of the brain have been found to be activated by musical stimuli, but these have rarely been extended to the discovery of genes and molecules associated with musical ability. METHODS: A total of 1008 individuals from 73 families were enrolled and a pitch-production accuracy test was applied to determine musical ability. To identify genetic loci and variants that contribute to musical ability, we conducted family-based linkage and association analyses, and incorporated the results with data from exome sequencing and array comparative genomic hybridisation analyses. RESULTS: We found significant evidence of linkage at 4q23 with the nearest marker D4S2986 (LOD=3.1), whose supporting interval overlaps a previous study in Finnish families, and identified an intergenic single nucleotide polymorphism (SNP) (rs1251078, p=8.4×10(-17)) near UGT8, a gene highly expressed in the central nervous system and known to act in brain organisation. In addition, a non-synonymous SNP in UGT8 was revealed to be highly associated with musical ability (rs4148254, p=8.0×10(-17)), and a 6.2 kb copy number loss near UGT8 showed a plausible association with musical ability (p=2.9×10(-6)). CONCLUSIONS: This study provides new insight into the genetics of musical ability, exemplifying a methodology to assign functional significance to synonymous and non-coding alleles by integrating multiple experimental methods.
Journal of Medical Genetics 11/2012; · 6.36 Impact Factor
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ABSTRACT: OBJECTIVE: We examined the associations between eating behavior at baseline and changes in eating behaviors with weight change, and quantified the contribution of eating behavior and genetic effects on weight change. METHODS: A prospective study of male (n = 482) and female (n = 879) Korean twins and family members who were weighed and assessed twice (baseline visit from December 2005 to December 2008, follow-up visit 2.7 ± 0.9 y later) using eating behavior subscales (external, emotional, and restrained eating) as measured by the Dutch Eating Behavior Questionnaire. RESULTS: After adjusting for family variables, eating behavior subscales at baseline, changes in emotional and restrained eating, age, education, weight, and lifestyle at baseline, and menopausal status at baseline (for women), an increase in external eating was significantly associated with weight gain in men (1.08, 95% confidence interval 0.41-1.74) and in women (0.63, 95% confidence interval 0.13-1.12). None of the three eating behavior subscales at baseline or changes in emotional and restrained eating were associated with weight change. Eating behavior at baseline and changes in those eating behaviors accounted for 4% and 1% of the changes in weight in men and women, respectively. Additive genetic effects in women contributed to 18% of weight change, whereas in men there was no genetic contribution. CONCLUSIONS: These results suggest that an increase in external eating may predict adult weight gain in men and women. However, the relative contribution of eating behavior to weight change was very small, whereas the contribution of genetic effects on weight change was significant in women.
Nutrition 08/2012; · 3.03 Impact Factor
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Mi Kyeong Lee,
Sung-Il Cho,
Ho Kim,
Yun-Mi Song,
Kayoung Lee,
Jong-Il Kim,
Dong-Myung Kim,
Tae-Young Chung,
Youn Sic Kim,
Jeong-Sun Seo,
Don-Il Ham, Joohon Sung
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ABSTRACT: The purpose of this study was to demonstrate a negative association between intraocular pressure (IOP) and age in 2 Asian populations. In addition, we evaluated genetic and nongenetic factors associated with IOP.
Family-based cohort study.
Study subjects >10 years of age from one Korean (The Healthy Twin; n = 1431) and 2 Mongolian populations (The GENDISCAN; n = 859 and 806) with IOP values.
The IOP values were measured with a noncontact tonometer. Each participant received a standard health examination and received questionnaires, which include candidate risk factors on IOP. Mixed models were used to identify risk factors for IOP. Variance-component methods were applied to estimate the heritability of IOP.
The negative trend of IOP with aging and evaluation of impact of genetic and nongenetic components on IOP.
The mean ages were 43.6, 34.1, and 36.3 years for the Korean, Orhontuul, and Dashbalbar populations, respectively. The mean IOPs were 14.4 mmHg (95% confidence interval [CI], 14.3-14.6) in the Koreans and 14.1 mmHg (95% CI, 13.9-14.3) and 12.6 mmHg (95% CI, 12.4-12.9) in the Orhontuul and Dashbalbar populations, respectively. In the 3 populations, the IOP decreased as age increased. We replicated an association of systolic blood pressure (SBP) with IOP. In addition, components of the metabolic syndrome (MS), such as plasma glucose, lipid level, and body mass index, showed positive associations with IOP, after adjusting for age and SBP. The IOP also had strong genetic contributions in all populations (heritability, 0.47-0.51).
Negative associations between age and IOP were observed in all 3 populations, which cannot be explained by the increasing prevalence of myopia in the younger generation. The different age trend in IOP may in part be responsible for differences in the prevalence of glaucoma subtypes. Our findings suggest that associations between IOP and MS components were independent of established risk factors such as SBP or age. In addition, the importance of inherited risks requires further genetic dissection of IOP determinants for biological understandings of underlying pathophysiology.
Ophthalmology 03/2012; 119(3):450-7. · 5.45 Impact Factor
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ABSTRACT: The phenotypic and genetic relationships between carotid intima-media thickness (CIMT) and estimated glomerular filtration rate (eGFR) or urinary albumin-creatinine ratio (ACR) were evaluated in Korean twins and families.
We recruited 688 participants (296 individual twins and 392 singletons, age 30-74 years) who were without myocardial infarction and stroke among participants in the Healthy Twin Study. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. CIMT was measured using B-mode carotid ultrasound. Covariates were sex, Framingham risk scores, alcohol use, exercise, BMI, high-sensitivity C-reactive protein and triglycerides. Quantitative genetic and linear mixed analyses were performed.
In adjusted models there were associations between kidney function and CIMT with [beta] estimates ranging from -0.022 to -0.032 between eGFR and CIMT, and from 0.042-0.060 between ACR and CIMT. The covariate-adjusted heritabilities for eGFR, ACR and composite CIMT were 0.75, 0.32 and 0.45, respectively (p < 0.001). The adjusted genetic correlation between eGFR and CIMT was from -0.20 to -0.28 (p < 0.05), whereas there was no genetic correlation between ACR and CIMT.
Kidney function is a surrogate marker of carotid atherosclerosis and further studies of the pleiotropic relationships between CIMT and eGFR are warranted.
Kidney and Blood Pressure Research 02/2012; 35(4):259-64. · 1.46 Impact Factor
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ABSTRACT: The potential beneficial effects of increased body weight on bone mineral density (BMD) conflict with the adverse effects of obesity on various health outcomes, necessitating more specific evaluations of the association between each body component and BMD. In the present study, we evaluated associations of lean mass (LM) and fat mass (FM) with BMD in a Korean sample consisting of a total of 1782 men and women whose mean (standard deviation) age was 43.2 (12.6) years. They were selected from the Healthy Twin Study, a nationwide Korean twin and family study. BMD, FM and LM were measured using dual-energy X-ray absorptiometry. Quantitative genetic analysis and linear mixed analysis were performed with respect to familial relationships and a wide range of probable covariates. Linear mixed analysis revealed that BMD was positively associated with both FM and LM at each region of BMD measurement (whole body, spine, arms, and legs) in men, premenopausal women, and postmenopausal women. However, the association with BMD was stronger for LM than FM. Both LM and FM had positive genetic correlations with BMD at each region, although the correlation with BMD tended to be stronger for LM than FM. Together, these findings suggest that increased LM, rather than FM, is more beneficial for BMD in the Korean population and warrants further study of the common genetic determinants of BMD and body composition.
Bone 01/2012; 50(4):1006-11. · 4.02 Impact Factor
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ABSTRACT: The purpose of this study was to identify any influence of socioeconomic status on smoking and smoking cessation in a situation where genetic factors are controlled.
The sample for this study was 2502 members of the twins and families cohort who participated in the Korean Healthy Twins Study from 2005 to 2009. Groups of brothers or sisters, including twins and fraternal twins, were compared in terms of smoking and smoking cessation behaviors according to differences in socioeconomic status and gender.
In a situation with complete control of genetic factors, results showed that the daily smoking amount, cumulative smoking amount, and dependence on nicotine decreased with higher-status occupations, and the rate of smoking and amount of cumulative smoking decreased with higher levels of education. Regarding smoking cessation behavior, a higher level of education was associated with a lower smoking cessation rate, and no significant gender differences were found.
Environmental factors had a stronger influence on smoking behavior than did genetic factors. Genetic factors had greater influence on smoking cessation than did environmental factors; however, this requires verification in further studies.
Journal of preventive medicine and public health = Yebang Ŭihakhoe chi. 01/2012; 45(1):29-36.
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ABSTRACT: To estimate genetic influences accounting for macular thickness in the Korean population.
Study subjects were 830 healthy Korean adults (117 monozygotic twin pairs and 523 family members) from the Healthy Twin study. Macular thickness was measured with optical coherence tomography for nine subfields including the fovea, four inner quadrants (within 1 to 3 mm of the center), and four outer quadrants (within 3 to 6 mm of the center). Quantitative genetic analyses were performed to estimate the heritability of macular thickness with respect to familial correlations.
Macular thickness varied by subfield and was thinnest at the fovea and thickest at the inner superior area. Heritability of macular thickness at each subfield was 0.76, 0.73, 0.70, 0.56, 0.67, 0.70, 0.73, 0.29, and 0.36 at the fovea, inner superior area, inner inferior area, inner nasal area, inner temporal area, outer superior area, outer inferior area, outer nasal area, and outer temporal area, respectively.
Genetic factors play a significant role in determining macular thickness in the Korean population.
Investigative ophthalmology & visual science 11/2011; 52(13):9523-6. · 3.43 Impact Factor
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ABSTRACT: Background: Increased carotid intima-media thickness is associated with higher cardiovascular disease risk. This study aimed to evaluate the contributions of cardiovascular risk factors and inheritance to segment-specific carotid intima-media thickness. Design: Cross-sectional observational study. Methods: A total of 706 Korean adults was selected from the Healthy Twin Study. The intima-media thickness of common, carotid bifurcation, and internal carotid artery were measured using B-mode ultrasound. Behavioral and biological cardiovascular risk factors were measured. Quantitative genetic and linear mixed analyses were performed to examine inherited and environmental contributions to intima-media thickness variation. Results: Heritability of intima-media thickness was moderately high with estimates (95% confidence intervals) of 0.48 (0.37, 0.59), 0.38(0.27, 0.49), and 0.45(0.34, 0.55) for common, carotid bifurcation, and internal carotid artery, respectively. The additive genetic cross-trait correlations between the segments ranged between 0.43 and 0.75, suggesting a shared genetic influence on the three carotid segments. Additive inherited effects contributed 21% and 31% (common and internal carotid, respectively) to the total variance of the intima-media thickness, while measured cardiovascular risk factors accounted for 46% and 26% (common and internal carotid, respectively). The cardiovascular risk factors significantly associated with carotid intima-media thickness were as follows: in men, alcohol use (bifurcation); physical activity (common and internal); BMI (all segments); diabetes (bifurcation and internal); hypertension (internal); and HDL-cholesterol (common and bifurcation); and in women, smoking (bifurcation), hypertension (common), total and LDL cholesterol (bifurcation and internal), and hs-CRP (common and internal). Conclusions: Individual cardiovascular risk factors were differentially associated with carotid intima-media thickness by segments and sex. Inherited effects made a heterogeneous contribution to intima-media thickness by segment. These findings may explain the differences in cardiovascular disease occurrence between men and women.
European journal of preventive cardiology. 09/2011; 19(5):1161-72.
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ABSTRACT: We compared the composition of the fecal microbiotas of Korean and U.S. adult twins. Our data indicated that the gut microbiota shows some signature of biogeography, potentially mediated by differences in diet and/or other environmental factors; however, these regional differences may be masked by other phenotypic variations, such as obesity.
Applied and environmental microbiology 08/2011; 77(20):7433-7. · 3.69 Impact Factor
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ABSTRACT: It has been suggested that lifetime exposure to female hormones is related to cancer risk in women. The authors investigated the association between age at menarche and menopause and cancer risk in a prospective study of Korean women.
A total of 443 909 women, in the age group of 30-80 years in the 1993-94 time period were included in the analysis. During 12 years of follow-up, 17 959 incident cancer cases were identified by record linkage to the Central Cancer Registry database.
Early age at menarche was associated with an increased risk of breast cancer and a decreased risk of stomach and gallbladder cancer. Later age at menopause was associated with an increased risk of breast cancer. When the analysis was restricted to post-menopausal women, the associations of age at menarche and menopause with cancers of the breast, stomach and gallbladder persisted.
These findings suggest that female hormonal factors play a significant role in the development of cancer in Korean women.
International Journal of Epidemiology 08/2011; 40(5):1261-8. · 6.41 Impact Factor
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ABSTRACT: In 1995, an outbreak survey in Gozan-dong concluded that an association between fiberglass exposure in drinking water and cancer outbreak cannot be established. This study follows the subjects from a study in 1995 using a data linkage method to examine whether an association existed. The authors will address the potential benefits and methodological issues following outbreak surveys using data linkage, particularly when informed consent is absent.
This is a follow-up study of 697 (30 exposed) individuals out of the original 888 (31 exposed) participants (78.5%) from 1995 to 2007 assessing the cancer outcomes and deaths of these individuals. The National Cancer Registry (KNCR) and death certificate data were linked using the ID numbers of the participants. The standardized incidence ratio (SIR) and standardized mortality ratio (SMR) from cancers were calculated by the KNCR.
The SIR values for all cancer or gastrointestinal cancer (GI) occurrences were the lowest in the exposed group (SIR, 0.73; 95% CI, 0.10 to 5.21; 0.00 for GI), while the two control groups (control 1: external, control 2: internal) showed slight increases in their SIR values (SIR, 1.18 and 1.27 for all cancers; 1.62 and 1.46 for GI). All lacked statistical significance. All-cause mortality levels for the three groups showed the same pattern (SMR 0.37, 1.29, and 1.11).
This study did not refute a finding of non-association with a 13-year follow-up. Considering that many outbreak surveys are associated with a small sample size and a cross-sectional design, follow-up studies that utilize data linkage should become standard procedure.
Journal of preventive medicine and public health = Yebang Ŭihakhoe chi. 07/2011; 44(4):185-9.
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ABSTRACT: We performed a monozygotic (MZ) cotwin-control study using the MZ twin pair difference in bone mineral density (BMD) to assess the relationship between body composition and BMD at weight-bearing sites. This study controlled for common genetic factors and applied only to environmental factors, using 185 MZ twin pairs aged 30-50 years (140 male subjects, 230 female subjects). As expected, total lean mass (TLM) was greater in males and total fat mass (TFM) was greater in females. In male twins, TLM was associated with BMD at the legs, pelvis, and spine, with percent BMD increases of 0.41 (95% confidence interval [CI] 0.17-0.64), 0.62 (95% CI 0.35-0.89), and 0.27 (95% CI 0.01-0.54) for every 1 kg. In female twins, TFM was associated with BMD at the legs and pelvis, with percent BMD increases of 0.10 (95% CI 0.03-0.17) and 0.10 (95% CI 0.02-0.18) for every 1 kg. The results support the hypothesis that skeletal muscle and bone mass in middle-aged men are linked. In contrast, this association was not shown in women, and the impact of TFM on BMD was significant. Therefore, there were sex differences in the relationship of body composition on BMD.
Calcified Tissue International 06/2011; 88(6):495-502. · 2.38 Impact Factor
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ABSTRACT: Mammographic density is one of the strong risk factors for breast cancer. A potential mechanism for this association is that cumulative exposure to mammographic density may reflect cumulative exposure to hormones that stimulate cell division in breast stroma and epithelium, which may have corresponding effects on breast cancer development. Bone mineral density (BMD), a marker of lifetime estrogen exposure, has been found to be associated with breast cancer. We examined the association between BMD and mammographic density in a Korean population. Study subjects were 730 Korean women selected from the Healthy Twin study. BMD (g/cm(2)) was measured with dual-energy X-ray absorptiometry. Mammographic density was measured from digital mammograms using a computer-assisted thresholding method. Linear mixed model considering familial correlations and a wide range of covariates was used for analyses. Quantitative genetic analysis was completed using SOLAR. In premenopausal women, positive associations existed between absolute dense area and BMD at ribs, pelvis, and legs, and between percent dense area and BMD at pelvis and legs. However, in postmenopausal women, there was no association between BMD at any site and mammographic density measures. An evaluation of additive genetic cross-trait correlation showed that absolute dense area had a weak-positive additive genetic cross-trait correlation with BMD at ribs and spines after full adjustment of covariates. This finding suggests that the association between mammographic density and breast cancer could, at least in part, be attributable to an estrogen-related hormonal mechanism.
Breast Cancer Research and Treatment 04/2011; 129(2):583-91. · 4.43 Impact Factor
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ABSTRACT: To determine the mechanism by which menstrual and reproductive factors are associated with the risk of breast cancer, we examined the relationships between mammographic density and known menstrual and reproductive risk factors for breast cancer. A co-twin control study was conducted with 122 pairs of monozygotic Korean female twins selected from the Healthy Twin study. Mammographic density was measured from digital mammograms using a computer-assisted method. Information on selected menstrual and reproductive factors was collected through a self-administered questionnaire. Within-pair differences for each mammographic measure were regressed against within-pair differences for each menstrual and reproductive risk factor with an adjustment for body mass index and other menstrual and reproductive factors. The percent dense area was inversely associated with the age at the first full-term childbirth (FFTB) and the number of live births, although the associations were marginally significant with an adjustment for BMI and other reproductive factors. The non-dense area was positively associated with the age at the FFTB and the number of live births. The absolute dense area was positively associated with the duration of breast feeding. The age at menarche was not associated with any component of the mammographic measures. This finding suggests that mammographic density can mediate the protective effect of greater parity against breast cancer, at least in part while age at menarche, age at the FFTB, and breast feeding do not exert their effects through mammographic density.
Breast Cancer Research and Treatment 03/2011; 128(2):567-72. · 4.43 Impact Factor
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ABSTRACT: Microbial compositions of human and animal feces from South Korea were analyzed and characterized. In total, 38 fecal samples (14 healthy adult humans, 6 chickens, 6 cows, 6 pigs and 6 geese) were analyzed by 454 pyrosequencing of the V2 region of the 16S rRNA gene. Four major phyla, Actinobacteria, Proteobacteria, Firmicutes and Bacteroidetes, were identified in the samples. Principal coordinate analysis suggested that microbiota from the same host species generally clustered, with the exception of those from humans, which exhibited sample-specific compositions. A network-based analysis revealed that several operational taxonomic units (OTUs), such as Lactobacillus sp., Clostridium sp. and Prevotella sp., were commonly identified in all fecal sources. Other OTUs were present only in fecal samples from a single organism. For example, Yania sp. and Bifidobacterium sp. were identified specifically in chicken and human fecal samples, respectively. These specific OTUs or their respective biological markers could be useful for identifying the sources of fecal contamination in water by microbial source tracking.
The ISME Journal 02/2011; 5(2):362-5. · 7.38 Impact Factor
