Kuai Yu

Genome-Wide Analysis of DNA Methylation and Cigarette Smoking in a Chinese Population.

Background: Smoking is a risk factor for many human diseases. DNA methylation has been related to smoking, but genome-wide methylation data for smoking in Chinese populations is limited. Objectives: We aimed to investigate epigenome-wide methylation in relation to smoking in a Chinese population. Methods: We measured the methylation levels at > 485,000 CpG sites (CpGs) in DNA from leukocytes using a methylation array and conducted a genome-wide meta-analysis of DNA methylation and smoking in a total of 596 Chinese participants. We further evaluated the associations of smoking-related CpGs with internal polycyclic aromatic hydrocarbon (PAH) biomarkers and their correlations with the expression of corresponding genes. Results: We identified 318 CpGs whose methylation levels were associated with smoking at a genome-wide significance level (false discovery rate < 0.05), among which 161 CpGs annotated to 123 genes were not associated with smoking in recent studies of Europeans and African Americans. Of these smoking-related CpGs, methylation levels at 80 CpGs showed significant correlations with the expression of corresponding genes (including RUNX3, IL6R, PTAFR, ANKRD11, CEP135 and CDH23), and methylation at 15 CpGs was significantly associated with urinary 2-hydroxynaphthalene, the most representative internal monohydroxy-PAH biomarker for smoking. Conclusion: We identified DNA methylation markers associated with smoking in a Chinese population, including some markers that were also correlated with gene expression. Exposure to naphthalene, a byproduct of tobacco smoke, may contribute to smoking-related methylation. Citation: Zhu X, Li J, Deng S, Yu K, Liu X, Deng Q, Sun H, Zhang X, He M, Guo H, Chen W, Yuan J, Zhang B, Kuang D, He X, Bai Y, Han X, Liu B, Li X, Yang L, Jiang H, Zhang Y, Hu J, Cheng L, Luo X, Mei W, Zhou Z, Sun S, Zhang L, Liu C, Guo Y, Zhang Z, Hu FB, Liang L, Wu T. 2016. Genome-wide analysis of DNA methylation and cigarette smoking in Chinese. Environ Health Perspect 124:966–973; http://dx.doi.org/10.1289/ehp.1509834

Genome-Wide Analysis of DNA Methylation and Acute Coronary Syndrome.

Rationale: Acute coronary syndrome (ACS) is a leading cause of death worldwide. Immune functions play a vital role in ACS development; however, whether epigenetic modulation contributes to the regulation of blood immune cells in this disease has not been investigated. Objective: We conducted an epigenome-wide analysis with circulating immune cells to identify differentially methylated genes in ACS. Methods and Results: We examined genome-wide methylation of whole blood in 102 ACS patients and 101 controls using HumanMethylation450 array, and externally replicated significant discoveries in 100 patients and 102 controls. For the replicated loci, we further analyzed their association with ACS in 6 purified leukocyte subsets, their correlation with the expressions of annotated genes, and their association with cardiovascular traits/risk factors. We found novel and reproducible association of ACS with blood methylation at 47 cytosine-phosphoguanine sites (discovery: false discovery rate <0.005; replication: Bonferroni corrected P<0.05). The association of methylation levels at these cytosine-phosphoguanine sites with ACS was further validated in at least 1 of the 6 leukocyte subsets, with predominant contributions from CD8+ T cells, CD4+ T cells, and B cells. Blood methylation of 26 replicated cytosine-phosphoguanine sites showed significant correlation with expressions of annotated genes (including IL6R, FASLG, and CCL18; P<5.9×10−4), and differential gene expression in case versus controls corroborated the observed differential methylation. The replicated loci suggested a role in ACS-relevant functions including chemotaxis, coronary thrombosis, and T-cell–mediated cytotoxicity. Functional analysis using the top ACS-associated methylation loci in purified T and B cells revealed vital pathways related to atherogenic signaling and adaptive immune response. Furthermore, we observed a significant enrichment of the replicated cytosine-phosphoguanine sites associated with smoking and low-density lipoprotein cholesterol (Penrichment⩽1×10−5). Conclusions: Our study identified novel blood methylation alterations associated with ACS and provided potential clinical biomarkers and therapeutic targets. Our results may suggest that immune signaling and cellular functions might be regulated at an epigenetic level in ACS.

Coding-sequence variants are associated with blood lipid levels in 14,473 Chinese

Previously identified common variants explain only a small fraction of the trait heritability and at most loci the identities of the underlying causal genes and their functional variants still remain unknown. To identify the low-frequency and rare coding variants that influence lipid levels, we conducted a meta-analysis of exome-wide association studies in 14,473 Chinese subjects, followed by a joint analysis with 1000 genomes imputed data from 6,534 samples. We replicated 24 previously reported lipid loci with exome-wide significance (P < 3.3 × 10 -  7), including fourteen coding variants at ten confirmed lipid loci (P range from 1.44 × 10 -  7 to 1.64 × 10 -  45). Of these, six coding variants showed population-specific associations and were independent of previously identified associations in European populations, including four low-frequency (PCSK9 p.Arg93Cys, HMGCR p.Tyr311Ser, APOA5 p.Gly185Cys and CETP p.Asp399Gly) and two common (APOB p.Arg532Trp and APOA4 p.Ser147Asn) variants. Furthermore, we detected three new lead non-coding variants at LPA, LIPC and LDLR in Chinese. The independent variants at PCSK9, HMGCR, LPA, APOA5 and LDLR were also associated with increased risk of coronary artery disease in the expected direction. In gene-based tests, the burden of rare or low frequency variants in PCSK9, HMGCR and CEPT exhibited strong associations with blood lipid levels (P < 2.8 × 10 -  6). Our findings identify additional population-specific possible causal variants. Our data demonstrate that the inter-ethnic differences in allele frequencies of coding variants may lead to different association signals across ethnic groups, highlighting the importance of including diverse populations to uncover genetic variation associated with lipid levels.

Association of Solid Fuel Use With Risk of Cardiovascular and All-Cause Mortality in Rural China.

Importance When combusted indoors, solid fuels generate a large amount of pollutants such as fine particulate matter. Objective To assess the associations of solid fuel use for cooking and heating with cardiovascular and all-cause mortality. Design, Setting, and Participants This nationwide prospective cohort study recruited participants from 5 rural areas across China between June 2004 and July 2008; mortality follow-up was until January 1, 2014. A total of 271 217 adults without a self-reported history of physician-diagnosed cardiovascular disease at baseline were included, with a random subset (n = 10 892) participating in a resurvey after a mean interval of 2.7 years. Exposures Self-reported primary cooking and heating fuels (solid: coal, wood, or charcoal; clean: gas, electricity, or central heating), switching of fuel type before baseline, and use of ventilated cookstoves. Main Outcomes and Measures Death from cardiovascular and all causes, collected through established death registries. Results Among the 271 217 participants, the mean (SD) age was 51.0 (10.2) years, and 59% (n = 158 914) were women. A total of 66% (n = 179 952) of the participants reported regular cooking (at least weekly) and 60% (n = 163 882) reported winter heating, of whom 84% (n = 150 992) and 90% (n = 147 272) used solid fuels, respectively. There were 15 468 deaths, including 5519 from cardiovascular causes, documented during a mean (SD) of 7.2 (1.4) years of follow-up. Use of solid fuels for cooking was associated with greater risk of cardiovascular mortality (absolute rate difference [ARD] per 100 000 person-years, 135 [95% CI, 77-193]; hazard ratio [HR], 1.20 [95% CI, 1.02-1.41]) and all-cause mortality (ARD, 338 [95% CI, 249-427]; HR, 1.11 [95% CI, 1.03-1.20]). Use of solid fuels for heating was also associated with greater risk of cardiovascular mortality (ARD, 175 [95% CI, 118-231]; HR, 1.29 [95% CI, 1.06-1.55]) and all-cause mortality (ARD, 392 [95% CI, 297-487]; HR, 1.14 [95% CI, 1.03-1.26]). Compared with persistent solid fuel users, participants who reported having previously switched from solid to clean fuels for cooking had a lower risk of cardiovascular mortality (ARD, 138 [95% CI, 71-205]; HR, 0.83 [95% CI, 0.69-0.99]) and all-cause mortality (ARD, 407 [95% CI, 317-497]; HR, 0.87 [95% CI, 0.79-0.95]), while for heating, the ARDs were 193 (95% CI, 128-258) and 492 (95% CI, 383-601), and the HRs were 0.57 (95% CI, 0.42-0.77) and 0.67 (95% CI, 0.57-0.79), respectively. Among solid fuel users, use of ventilated cookstoves was also associated with lower risk of cardiovascular mortality (ARD, 33 [95% CI, −9 to 75]; HR, 0.89 [95% CI, 0.80-0.99]) and all-cause mortality (ARD, 87 [95% CI, 20-153]; HR, 0.91 [95% CI, 0.85-0.96]). Conclusions and Relevance In rural China, solid fuel use for cooking and heating was associated with higher risks of cardiovascular and all-cause mortality. These risks may be lower among those who had previously switched to clean fuels and those who used ventilation.

Serum creatinine levels and risk of metabolic syndrome in a middle-aged and older Chinese population

BACKGROUND The prevalence of metabolic syndrome (MetS) persistently increased. Several studies have found serum creatinine (SCr) concentrations related to cardiovascular disease and type 2 diabetes. The relationship between SCr concentrations and MetS is unknown. METHODS We measured SCr concentrations and MetS in 22363 individuals (10,151 males, 12,212 females) from the Dongfeng-Tongji Cohort in Shiyan, China from 2008 to 2009. RESULTS The prevalence of MetS was 30.6% in the study population. In the multivariable-adjusted logistic regression analyses, higher SCr concentrations were associated with a higher risk of MetS (P trend<0.0001). Compared with the lowest extreme quintiles, subjects with the highest quintiles had 1.34 fold risk of MetS (95% confidence interval (CI): 1.22-1.47). The SCr concentrations were also associated with the individual component of MetS. In addition, higher SCr concentrations were associated with higher risk of MetS with more components. CONCLUSIONS There is a graded positive association between the SCr concentrations and MetS risk in a middle aged and older Chinese population. Higher SCr concentrations, even within normal ranges, were associated with higher risk of MetS. The SCr might be a useful indicator of MetS and its related diseases.

Association of drinking pattern with risk of coronary heart disease incidence in the middle-aged and older Chinese men: Results from the Dongfeng-Tongji cohort

Background Epidemiologic studies have found that moderate alcohol consumption was associated with a decreased risk of coronary heart disease (CHD) incidence. Nevertheless, whether the drinking pattern is associated with CHD incidence still remains inconclusive. Methods We included 8,469 Chinese men aged 45–81 years, who were free of CHD, stroke, or cancer at baseline from Dongfeng-Tongji cohort. A semi-structured questionnaire was used to collect information on alcohol consumption and other covariates. Cox proportional hazard regression model was applied to estimate the multivariable-adjusted hazard rations (HRs) and 95% confidence intervals (95% CIs). Results During an average of 4.36 years of follow-up, we identified 959 incident CHD events. Compared with non-drinkers, the multivariable-adjusted HR (95% CI) of CHD incidence was 0.84 (0.71–0.98) in current drinkers. With respect to drinking pattern, men who consumed 20.01–40 grams ethanol once a time had a 24% lower risk of incident CHD (HR = 0.76, 95% CI = 0.62, 0.94) compared with non-drinkers. The adjusted HRs (95% CI) of CHD incidence were 0.80 (0.65, 0.99), 1.02 (0.84, 1.22), and 0.75 (0.59–0.96) in subjects who consumed 0.01–10, 10.01–30, and > 30 grams ethanol per day, respectively. Participants who consumed 20.01–40 grams ethanol per time with less than 5 times per week had the lowest risk of CHD incidence (HR = 0.73, 95% CI = 0.52, 0.96). No significant associations were observed between type or frequency of alcohol consumption and CHD incidence. Conclusions Drinking was associated with a lower risk of CHD incidence in middle-aged and older Chinese men and moderate quantity of ethanol amounts once a time with lower frequency could been considered as a healthy drinking pattern, which might modify the relationship between alcohol consumption and incident CHD.

Exposure to polycyclic aromatic hydrocarbons and accelerated DNA methylation ageing: an observational study

Abstract Background Ageing is related to the risk of many diseases and is affected by genetic, epigenetic, and environmental factors. Exposure to the ubiquitous pollutant polycyclic aromatic hydrocarbons (PAHs) is known to cause health damage, but the relation between such exposure with methylation ageing has not been studied. We undertook an association analysis of exposure to PAHs and DNA methylation ageing, a novel and promising ageing marker. Methods We built a model of methylation age and defined two ageing indicators (ageing rate, calculated as ratio of methylation to chronological age; and Δage, calculated as methylation minus chronological age) on the basis of genome-wide methylation data of blood in five panels of Chinese individuals (N=596). Participants included 137 coke oven workers (aged 26–60 years) who were chronically and occupationally exposed to high levels of PAHs; 101 patients with acute coronary syndrome (aged 40–86 years) from Wuhan, China; 97 patients with this syndrome (aged 38–83 years) from Guangdong, China; 162 healthy individuals (aged 26–79 years) from Wuhan; and 99 healthy individuals (aged 37–80 years) from Zhuhai, China. Exposure to individual PAHs was assessed by ten urinary PAH metabolites. We examined the relations between PAH exposure and the two ageing indicators, and investigated the potential CpGs mediating the association. Written informed consent was obtained from all participants. Our study was approved by the ethics committee of Tongji Medical College, Wuhan, China. No study subjects were from clinical trials. Findings Coke oven workers, who were exposed to high levels of PAHs at work (mean nature-log-transformed total urinary PAHs −1·909 [SD 0·461]), had significant age acceleration (2·7% increase in ageing rate [p=0·002] and 1·218-year increase in Δage [p=0·01] compared with all other panels). Urinary 3-OH-phenanthrene and 9-OH-phenanthrene were independently and significantly associated with the two ageing indicators in our non-disease panels. One unit increase of nature-log-transformed 9-OH-phenanthrene was associated with a 1·8% increase (p=0·0029) in ageing rate and a 1·1-year increase (p=0·0002) in Δage, whereas for 3-OH-phenanthrene the increase was 1·3% (p=0·0050) for ageing rate and 0·57 year (p=0·0109) for Δage. Methylation at several ageing-related and PAH-related CpGs (annotated on ELOVL2 , KLHL35 , FHL2 , BOK , PDP1 , and OTUD7A ) was reported to mediate the effect of PAH exposure on methylation ageing. Interpretation Our study revealed a significant association between PAH exposure and accelerated methylation ageing. The importance of exposure-related ageing needs to be further investigated. Funding National Key Basic Research and Development Program, Natural National Scientific Foundation, the 111 Project, the Program for Changjiang Scholars, and Innovative Research Team Scholars.

Relation of Platelet Parameters with Incident Cardiovascular Disease (The Dongfeng-Tongji Cohort Study)

Prospective studies on the relations between platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and incident cardiovascular disease (CVD) were still limited. This study aimed to investigate the above-mentioned prospective relations in the middle-aged and older Chinese populations based on the Dongfeng-Tongji cohort. We included 31,751 participants who were free of coronary heart disease (CHD), stroke, cancer, or severely abnormal electrocardiogram at baseline. During a median follow-up of 5.9 years, we identified 5,683 incident CVD cases, including 4,423 CHD and 1,260 stroke cases. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confident intervals (CIs) for the relation analyses. Compared with participants with 146 ≤ PLT ≤ 233 10E9/L, the adjusted HR (95% CI) of those with PLT < 146 10E9/L was 0.80 (0.68 to 0.95) for incident stroke. Compared with participants with 7.3 ≤ MPV ≤ 10.3 fl, the adjusted HRs (95% CIs) of those with MPV < 7.3 fl were 0.81 (0.75 to 0.88), 0.80 (0.73 to 0.88) and 0.84 (0.71 to 1.00) for incident CVD, CHD and stroke, respectively. Compared with participants with 13.2 ≤ PDW ≤ 18.1 %, the adjusted HRs (95% CIs) of those with PDW < 13.2 % were 0.80 (0.73 to 0.87) and 0.78 (0.70 to 0.86) for incident CVD and CHD, respectively. In conclusion, lower levels of PLT and MPV were significantly related to lower risk of stroke, while lower levels of MPV and PDW were significantly related to lower risks of CVD and CHD.

Associations of estimated glomerular filtration rate and blood urea nitrogen with incident coronary heart disease: the Dongfeng-Tongji Cohort Study

Estimated glomerular filtration rate (eGFR) has been reported to be associated with risk of incident coronary heart disease (CHD), and blood urea nitrogen (BUN) has been shown to be a strong predictor of mortality in patients with heart failure (HF). However, such epidemiological evidence from Chinese population was still limited. We used Cox proportional-hazards regression models to investigate the associations of eGFR and BUN with risk of incident CHD in the prospective Dongfeng-Tongji (DFTJ) cohort. After fully adjusted for potential confounders, a 10-unit decline in eGFR was associated with higher risk for CHD (hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.01–1.09); compared with individuals with normal eGFR levels (eGFR ≥ 90 ml/min per 1.73 m2), individuals with a mild-to-severe eGFR decline (15 to 60 ml/min per 1.73 m2) were at significantly greater risk for CHD (HR 1.25, 95% CI 1.05–1.48; P = 0.011). Compared with individuals in the lowest tertile of BUN, those in the highest tertile were at significantly greater risk for CHD (HR 1.17, 95% CI 1.03–1.33; P = 0.014). In conclusion, a mild-to-severe decline in eGFR or a raised level of BUN might be associated with increased risk of incident CHD in middle-aged and elderly Chinese populations.