Bisphenol A, Hypertension, and Cardiovascular Diseases: Epidemiological, Laboratory, and Clinical Trial Evidence

Bisphenol A (BPA) exposure has become one of the most common environmental chemical exposures in humans. There is growing evidence regarding an association between BPA exposure, hypertension, and cardiovascular diseases (CVD). If BPA exposure is indeed associated with raised blood pressure and CVD, it would be a major public health problem. Therefore, we reviewed the epidemiological, laboratory, and clinical trial evidence for an association between BPA exposure, CVD, and hypertension, and discussed the possible mechanisms in this article. Cross-sectional studies in various ethnicities suggested a possible association between BPA exposure and hypertension; this association was supported by a panel study and a randomized clinical trial. Despite the discordance among cross-sectional studies about an association between BPA exposure and CVD, a longitudinal study shows that BPA exposure is a risk factor for CVD. The effects of BPA exposure such as endocrinal disturbance, induction of oxidative stress and inflammation, epigenetic change, and links with other chronic diseases may highlight a possible mechanism between BPA exposure, CVD, and hypertension. To clarify the causal relationship, well-designed studies are needed in the future.

Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome

To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.

Maternal Stress and Depressive Symptoms and Infant Development at Six Months: the Mothers and Children's Environmental Health (MOCEH) Prospective Study

Our objective is to evaluate the relationships between prenatal maternal stress and depressive symptoms, respectively, and infant neurodevelopment at 6 months, adjusted for heavy metals and oxidative stress. This research is a part of a multi-center birth cohort study in South Korea. Information on stress and depressive symptoms was collected during the first trimester using Psychosocial Well-Being Index Short Form (PWI-SF) and Center for Epidemiological Studies Depression Scale (CES-D). The Korean Bayley Scales of Infant Development-II assessment (BSID-II), which includes the standardized mental development index (MDI) and psychomotor developmental index (PDI), and Korean Ages & Stages Questionnaires (K-ASQ) were applied to infants at six months of age. A higher index score indicates better development. Among 641 babies, 320 were female (50%). Maternal PWI ≥ 29 (vs. PWI ≤ 18) during early pregnancy was associated with a decrease in MDI scores of 5.37 points (P = 0.02) after adjusting for socioeconomic factors. Maternal CES-D ≥ 26 (vs. CES-D ≤ 10) during early pregnancy was associated with a decrease in MDI scores of 8.18 points (P = 0.01). The associations remained significant even after adjustment for lead, cadmium, and MDA levels (P < 0.05). However, no association was found between maternal PWI/CES-D and PDI score. No interaction was observed between stress and lead exposure. We found an inverse association between prenatal maternal stress and depressive symptoms, and MDI scores in 6-month-old infants after adjustment for prenatal lead exposure, which is known to affect cognitive function negatively.

Modification of the association of bisphenol A with abnormal liver function by polymorphisms of oxidative stress-related genes

Some studies suggested oxidative stress as a possible mechanism for the relation between exposure to bisphenol A (BPA) and liver damage. Therefore, we evaluated modification of genetic polymorphisms of cyclooxygenase 2 (COX2 or PTGS2), epoxide hydrolase 1 (EPHX1), catalase (CAT), and superoxide dismutase 2 (SOD2 or MnSOD), which are oxidative stress-related genes, on the relation between exposure to BPA and liver function in the elderly. We assessed the association of visit-to-visit variations in BPA exposure with abnormal liver function by each genotype or haplotype after controlling for age, sex, BMI, alcohol consumption, exercise, urinary cotinine levels, and low density lipoprotein cholesterol using a GLIMMIX model. A significant association of BPA with abnormal liver function was observed only in participants with COX2 GG genotype at rs5277 (odds ratio (OR)=3.04 and p=0.0231), CAT genotype at rs769218 (OR=4.16 and p=0.0356), CAT CT genotype at rs769217 (OR=4.19 and p=0.0348), SOD2 TT genotype at rs4880 (OR=2.59 and p=0.0438), or SOD2 GG genotype at rs2758331 (OR=2.57 and p=0.0457). Moreover, we also found higher OR values in participants with a pair of G-G haplotypes for COX2 (OR=2.81 and p=0.0384), G-C-A haplotype for EPHX1 (OR=4.63 and p=0.0654), A-T haplotype for CAT (OR=4.48 and p=0.0245), or T-G-A haplotype for SOD2 (OR=2.91 and p=0.0491) compared with those with the other pair of haplotypes for each gene. Furthermore, the risk score composed of 4 risky pair of haplotypes showed interactive effect with BPA on abnormal liver function (p=0.0057). Our study results suggest that genetic polymorphisms of COX2, EPHX1, CAT, and SOD2 modify the association of BPA with liver function.

Time to change from a simple linear model to a complex systems model

A simple linear model to test the hypothesis based on one-on-one relationship has been used to find the causative factors of diseases. However, we now know that not just one, but many factors from different systems such as chemical exposure, genes, epigenetic changes, and proteins are involved in the pathogenesis of chronic diseases such as diabetes mellitus. So, with availability of modern technologies to understand the intricate nature of relations among complex systems, we need to move forward to the future by taking complex systems model.

Effect of Breastfeeding Duration on Cognitive Development in Infants: 3-Year Follow-up Study

We investigated the association between breastfeeding and cognitive development in infants during their first 3 years. The present study was a part of the Mothers' and Children's Environmental Health (MOCEH) study, which was a multi-center birth cohort project in Korea that began in 2006. A total of 697 infants were tested at age 12, 24, and 36 months using the Korean version of the Bayley Scales of Infant Development II (K-BSID-II). The use and duration of breastfeeding and formula feeding were measured. The relationship between breastfeeding and the mental development index (MDI) score was analyzed by multiple linear regression analysis. The results indicated a positive correlation between breastfeeding duration and MDI score. After adjusting for covariates, infants who were breastfed for ≥ 9 months had significantly better cognitive development than those who had not been breastfed. These results suggest that the longer duration of breastfeeding improves cognitive development in infants.

Associations of air pollution exposure with blood pressure and heart rate variability are modified by oxidative stress genes: A repeated-measures panel among elderly urban residents

BACKGROUND

Oxidative stress has been suggested as a major cause of elevated blood pressure (BP) and reduced heart rate variability (HRV) due to air pollution. We hypothesized that the associations of air pollution exposure with BP and HRV are modified by oxidative stress gene polymorphisms.

METHODS

Between 2008 and 2010, we conducted up to 5 surveys of 547 elderly participants, measured their BP and HRV, and genotyped 47 single nucleotide polymorphisms (SNPs) in 18 oxidative stress genes. Linear mixed models were constructed to evaluate the associations of particulate matter ≤10 μm, nitrogen dioxide, and sulfur dioxide with BP and HRV, as well as the modifications of these associations by the genotyped SNPs.

RESULTS

Single-SNP analyses revealed interactions between air pollution and 15 SNPs (for BP) and 33 SNPs (for HRV) (all, P for interaction < 0.05). When we generated genetic risk scores for BP and HRV, using the SNPs with interactions in the single-SNP models, we found that associations of air pollution exposure with BP and HRV were modified by the genetic risk scores (P for interaction < 0.05).

CONCLUSIONS

These results strongly suggest that the associations of air pollution with BP and HRV are mediated by oxidative stress pathways.

Increased prevalence of some birth defects in Korea, 2009-2010

Background

Birth defects are a leading cause of neonatal and infant mortality, and several studies have indicated an increase in the prevalence of birth defects; more recent investigations have suggested that the trends of some defects are increasing in rapidly industrialized areas. This study estimates the prevalence rate and types of birth defects in Korea.

Methods

This study used medical insurance benefit data of 403,250 infants aged less than one year from the National Health Insurance Corporation from seven metropolitan areas in Korea for 2009 and 2010.

Results

The prevalence rate of birth defects was 548.3 per 10,000 births (95 % CI: 541.1–555.6), 306.8 among boys and 241.5 among girls. Anomalies of the circulatory system (particularly septal defects) were the most common (180.8 per 10,000), followed by defects of the genitourinary tract (130.1 per 10,000) (particularly obstructive genitourinary and undescended testis), musculoskeletal system (105.7 per 10,000), digestive system (24.7 per 10,000), and central nervous system (15.6 per 10,000).

Conclusions

Relatively higher rates of some birth defects were found in the metropolitan areas. The high differences of birth prevalences for septal heart defects and undescended testis are probably due in part to progress in clinical management and more frequent prenatal diagnosis. Environmental exposure might play a critical role in the development of some birth defects. In attempting to describe the prevalence and spatio-temporal variations of birth defects in Korea, establishment of a registry system of birth defects and environmental surveillance are needed.

Low-level lead exposure and autistic behaviors in school-age children

INTRODUCTION

The association between lead exposure and autism spectrum disorder is inconclusive. We hypothesized an association between higher blood lead concentrations and more autistic behaviors, including impaired social interactions and communication, stereotypical behaviors, and restricted interests, among school-age children.

METHODS

Data from 2473 Korean children aged 7-8years who had no prior history of developmental disorders were analyzed. Two follow-up surveys were conducted biennially until the children reached 11-12years of age. Blood lead concentrations were measured at every survey, and autistic behaviors were evaluated at 11-12years of age using the Autism Spectrum Screening Questionnaire (ASSQ) and Social Responsiveness Scale (SRS). The associations of blood lead concentration with ASSQ and SRS scores were analyzed using negative binomial, logistic, and linear regression models.

RESULTS

Blood lead concentrations at 7-8years of age (geometric mean: 1.64μg/dL), but not at 9-10 and 11-12years of age, were associated with more autistic behaviors at 11-12years of age, according to the ASSQ (β=0.151; 95% confidence interval [CI]: 0.061, 0.242) and SRS (β=2.489; 95% CI: 1.378, 3.600). SRS subscale analysis also revealed associations between blood lead concentrations and social awareness, cognition, communication, motivation, and mannerisms.

CONCLUSION

Even low blood lead concentrations at 7-8years of age are associated with more autistic behaviors at 11-12years of age, underscoring the need for continued efforts to reduce lead exposure.

Urinary phthalate metabolites and depression in an elderly population: National Health and Nutrition Examination Survey 2005-2012

Previous animal studies have demonstrated that phthalate exposure is associated with depression-like behaviors. However, no human study has explored this relationship. We explored the association between urinary phthalate metabolite concentrations and depression in a nationally representative sample of the U.S. elderly population. We analyzed 2030 participants aged 60 years or older with available data on phthalates and depression from the 2005 to 2012 National Health and Nutrition Examination Survey (NHANES). We selected 10 urinary phthalate metabolites with a weighted detection rate >60%. Depression was defined as a 9-item Patient Health Questionnaire score ≥10. The models were adjusted for age, sex, race/ethnicity, education level, income-to-poverty ratio, health insurance coverage, marital status, smoking status, alcohol consumption, moderate physical activity, body mass index, comorbidity status, NHANEs cycle, and urinary creatinine levels. One-unit increases in log-transformed mono-(3-carboxypropyl) phthalate (MCPP) (odds ratio [OR]=1.24, 95% confidence interval [CI]=1.02-1.52) and mono(carboxynonyl) phthalate (MCNP) (OR=1.42, 95% CI=1.15-1.75) were positively associated with depression. When we stratified the urinary phthalate metabolites into quartiles, the highest quartiles (Q4) of MCNP (OR=2.57, 95% CI=1.25-5.27) and mono-n-butyl phthalate (MBP) (OR=2.40, 95% CI=1.10-5.22) were associated with depression compared with the lowest quartiles (Q1). Concentrations of urinary phthalate metabolites MCPP, MCNP, and MBP were positively associated with the risk of depression in a representative sample of the U.S. elderly population. However, the present cross-sectional study is hypothesis generating and the associations need to be investigated through further longitudinal studies.

Meta-analysis of genome-wide association studies identifies multiple lung cancer susceptibility loci in never-smoking Asian women

Genome-wide association studies (GWAS) of lung cancer in Asian never-smoking women have previously identified six susceptibility loci associated with lung cancer risk. To further discover new susceptibility loci, we imputed data from four GWAS of Asian non-smoking female lung cancer (6877 cases and 6277 controls) using the 1000 Genomes Project (Phase 1 Release 3) data as the reference and genotyped additional samples (5878 cases and 7046 controls) for possible replication. In our meta-analysis, three new loci achieved genome-wide significance, marked by single nucleotide polymorphism (SNP) rs7741164 at 6p21.1 (per-allele odds ratio (OR) = 1.17; P = 5.8 × 10(-13)), rs72658409 at 9p21.3 (per-allele OR = 0.77; P = 1.41 × 10(-10)) and rs11610143 at 12q13.13 (per-allele OR = 0.89; P = 4.96 × 10(-9)). These findings identified new genetic susceptibility alleles for lung cancer in never-smoking women in Asia and merit follow-up to understand their biological underpinnings.

Association between urinary 3-phenoxybenzoic acid and body mass index in Korean adults: 1(st) Korean National Environmental Health Survey

BACKGROUND

According to US-EPA report, the use of pyrethrins and pyrethroids has increased during the past decade, and their area of use included not only in agricultural settings, but in commerce, and individual household. It is known that urinary 3-PBA, major metabolite of pyrethroid, have some associations with health effect in nervous and endocrine system, however, there's no known evidence that urinary 3-PBA have associations with obesity.

METHOD

We used data of 3671 participants aged above 19 from the Korean National Environmental Health Survey in 2009-2011. In our analysis, multivariate piece-wise regression and logistic regression analysis were used to investigate the association between urinary 3-PBA (3-Phenoxybenzoic Acid) and BMI.

RESULT

Log-transformed level of urinary 3-PBA had significantly positive association with BMI at the low-level range of exposure (p < 0.0001), and opposite associations were observed at the high level exposure (p = 0.04) after adjusting covariates. In piece-wise regression analysis, the flexion point that changes direction of the associations was at around 4 ug/g creatinine of urinary 3-PBA. As quintiles based on concentration of urinary 3-PBA increased to Q4, the ORs for prevalence of overweight (BMI ≥ 23 kg/m(2)) were increased, and the OR of Q5 was lower than that of Q4 (OR = 1.810 for Q4; OR = 1.483 for Q5). In the analysis using obesity (BMI ≥ 25 kg/m(2)) as outcome variable, significant associations were observed between obesity and quintiles of 3-PBA, however, there were no differences between the OR of Q5 and that of Q4 (OR = 1.659 for Q4; OR = 1.666 for Q5).

CONCLUSION

Our analysis suggested that low-level of pyrethroid exposure has positive association with BMI, however, there is an inverse relationship above the urinary 3-PBA level at 4 ug/g creatinine.

Neurodevelopment in Early Childhood Affected by Prenatal Lead Exposure and Iron Intake

No safe threshold level of lead exposure in children has been recognized. Also, the information on shielding effect of maternal dietary iron intake during pregnancy on the adverse effects of prenatal lead exposure on children's postnatal neurocognitive development is very limited. We examined the association of prenatal lead exposure and neurodevelopment in children at 6, 12, 24, and 36 months and the protective action of maternal dietary iron intake against the impact of lead exposure. The study participants comprise 965 pregnant women and their subsequent offspring of the total participants enrolled in the Mothers and Children's environmental health study: a prospective birth cohort study. Generalized linear model and linear mixed model analysis were performed to analyze the effect of prenatal lead exposure and mother's dietary iron intake on children's cognitive development at 6, 12, 24, and 36 months. Maternal late pregnancy lead was marginally associated with deficits in mental development index (MDI) of children at 6 months. Mothers having less than 75th percentile of dietary iron intake during pregnancy showed significant increase in the harmful effect of late pregnancy lead exposure on MDI at 6 months. Linear mixed model analyses showed the significant detrimental effect of prenatal lead exposure in late pregnancy on cognitive development up to 36 months in children of mothers having less dietary iron intake during pregnancy. Thus, our findings imply importance to reduce prenatal lead exposure and have adequate iron intake for better neurodevelopment in children.

Ten-year trends in urinary concentrations of triclosan and benzophenone-3 in the general U.S. population from 2003 to 2012

Despite their popular use and emerging evidences of adverse health effects, consequent trends in population level triclosan and benzophenone-3 exposure have been poorly evaluated. Therefore, we examined temporal trends of urinary triclosan and benzophenone-3 concentration in the general U.S. population by combining five cycles of National Health and Nutritional Examination Survey (NHANES, 2003-2012) data. We calculated percent changes and the least square geometric means (LSGMs) of urinary triclosan and benzophenone-3 concentration from 10,232 participants by using multivariable regression models. As a result, LSGM concentration of urinary triclosan and benzophenone-3 did not show statistically significant changes over the study period. [Percent change (95% CI): Triclosan, -7.35% (-20.86, 8.47); Benzophenone-3, 7.08% (-27.88, 58.99)] However, we found decreasing trend of urinary triclosan concentration and increasing trend of urinary benzophenone-3 concentration since 2005-2006. Socio-demographic factors which affected urinary concentration of triclosan and benzophenone-3 persisted throughout 10 year study period. Highest income group showed higher level of urinary triclosan and benzophenone-3 concentration. Overall concentration of benzophenone-3 was higher in female than in male, and higher in non-Hispanic Whites than any other races/ethnicities.

Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for Thirteen Cancer Types

BACKGROUND

Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites.

METHODS

Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers.

RESULTS

GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, hl (2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (ρ = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (ρ = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (ρ = 0.51, SE =0.18), and bladder and lung (ρ = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures.

CONCLUSION

Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.

Body mass index at age 18-20 and later risk of spontaneous abortion in the Health Examinees Study (HEXA)

Background

Spontaneous abortion (SA) affects 11.2% of recognized pregnancies in Korea. Many studies have focused on the increased risk of SA in obese populations, but there are few studies that have focused on underweight (Body mass index (BMI) <18.5 kg/m2) women, especially in relation to pre-pregnancy BMI. The aim of this study was to examine the role of pre-pregnancy BMI at age 18–20 in later SA.

Methods

Among the women who were ever pregnant in the Health Examinees Study (HEXA), which was one of the cohorts studied in the KoGES (Korean Genome and Epidemiology Study) from 2004 to 2012 (N = 80,447), the likelihood of SA based on pre-pregnancy BMI, classified by the criteria for Asians (Underweight: <18.5 kg/m2; Normal range: 18.5-22.9 kg/m2; Overweight at risk: 23–24.9 kg/m2; Obese I: 25–29.9 kg/m2; Obese II: ≥30 kg/m2), was presented as odds ratios (ORs) and 95% confidence intervals (95% CIs) using logistic regression models.

Results

Being underweight or obese relative to the normal weight range was associated with a higher likelihood of SA (OR = 1.10 [95% CI = 1.05–1.15] in underweight women and OR = 1.06 [95% CI = 0.96–1.16] in obese women), and this effect was much greater in women who experienced recurrent SAs (for three or more SAs: OR = 1.29 [95% CI 1.14–1.46] in underweight women and OR = 1.39 [95% CI 1.09–1.78] in obese women). Obesity was associated with an increased likelihood of SA at a younger age (≤25 years), whereas underweight was associated with an increased OR of SA at an older age (≥26 years).

Discussion

As this study was conducted with baseline data of original cohort which focused on other chronic diseases, recall for previous pregnancy-related information might be less accurate. However, this study shows strength in its large size and prospective potential.

Conclusions

Pre-pregnancy BMI at ages 18–20 years revealed a U-shaped association with SA, and underweight and obese women showed increased likelihood for SA during different age periods.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-015-0665-2) contains supplementary material, which is available to authorized users.

Interaction of Vitamin D and Smoking on Inflammatory Markers in the Urban Elderly

Objectives:

Epidemiological studies have reported that vitamin D deficiency is associated with inflammatory disease. Smoking is a well-known risk factor for inflammation. However, few studies have investigated the interactive effect of vitamin D deficiency and smoking on inflammation. This study aims to investigate the interaction of vitamin D and smoking with inflammatory markers in the urban elderly.

Methods:

We used data from the Korean Elderly Environmental Panel Study, which began in August 2008 and ended in August 2010, and included 560 Koreans ≥60 years old living in Seoul. Data was collected via questionnaires that included items about smoking status at the first visit. Vitamin D levels, high-sensitivity C-reactive protein (hs-CRP), and white blood cell (WBC) counts were repeatedly measured up to three times.

Results:

The association of vitamin D and hs-CRP was significant after adjusting for known confounders (β=-0.080, p=0.041). After separate analysis by smoking status, the association of vitamin D deficiency and hs-CRP in smokers was stronger than that in nonsmokers (smokers: β=-0.375, p=0.013; non-smokers: β=-0.060, p=0.150). Smoking status was an effect modifier that changed the association between vitamin D deficiency and hs-CRP (interaction estimate: β=-0.254, p=0.032). Vitamin D was not significantly associated with WBC count (β=0.003, p=0.805).

Conclusions:

Vitamin D deficiency was associated with hs-CRP in the urban elderly. Smoking status was an effect modifier of this association. Vitamin D deficiency was not significantly associated with WBC count.

Abatement of fluorinated compounds using a 2.45GHz microwave plasma torch with a reverse vortex plasma reactor

Abatement of fluorinated compounds (FCs) used in semiconductor and display industries has received an attention due to the increasingly stricter regulation on their emission. We have developed a 2.45GHz microwave plasma torch with reverse vortex reactor (RVR). In order to design a reverse vortex plasma reactor, we calculated a volume fraction and temperature distribution of discharge gas and waste gas in RVR by ANSYS CFX of computational fluid dynamics (CFD) simulation code. Abatement experiments have been performed with respect to SF6, NF3 by varying plasma power and N2 flow rates, and FCs concentration. Detailed experiments were conducted on the abatement of NF3 and SF6 in terms of destruction and removal efficiency (DRE) using Fourier transform infrared (FTIR). The DRE of 99.9% for NF3 was achieved without an additive gas at the N2 flow rate of 150 liter per minute (L/min) by applying a microwave power of 6kW with RVR. Also, a DRE of SF6 was 99.99% at the N2 flow rate of 60 L/min using an applied microwave power of 6kW. The performance of reverse vortex reactor increased about 43% of NF3 and 29% of SF6 abatements results definition by decomposition energy per liter more than conventional vortex reactor.

Utilizing Genetic Predisposition Score in Predicting Risk of Type 2 Diabetes Mellitus Incidence: A Community-based Cohort Study on Middle-aged Koreans

Contribution of genetic predisposition to risk prediction of type 2 diabetes mellitus (T2DM) was investigated using a prospective study in middle-aged adults in Korea. From a community cohort of 6,257 subjects with 8 yr' follow-up, genetic predisposition score with subsets of 3, 18, 36 selected single nucleotide polymorphisms (SNPs) (genetic predisposition score; GPS-3, GPS-18, GPS-36) in association with T2DM were determined, and their effect was evaluated using risk prediction models. Rs5215, rs10811661, and rs2237892 were in significant association with T2DM, and hazard ratios per risk allele score increase were 1.11 (95% confidence intervals: 1.06-1.17), 1.09 (1.01-1.05), 1.04 (1.02-1.07) with GPS-3, GPS-18, GPS-36, respectively. Changes in AUC upon addition of GPS were significant in simple and clinical models, but the significance disappeared in full clinical models with glycated hemoglobin (HbA1c). For net reclassification index (NRI), significant improvement observed in simple (range 5.1%-8.6%) and clinical (3.1%-4.4%) models were no longer significant in the full models. Influence of genetic predisposition in prediction ability of T2DM incidence was no longer significant when HbA1c was added in the models, confirming HbA1c as a strong predictor for T2DM risk. Also, the significant SNPs verified in our subjects warrant further research, e.g. gene-environmental interaction and epigenetic studies.