An overview of the Guangzhou biobank cohort study-cardiovascular disease subcohort (GBCS-CVD): a platform for multidisciplinary collaboration

Association of Measures of Glucose Metabolism with Colorectal Cancer Risk in Older Chinese: A 13-Year Follow-up of the Guangzhou Biobank Cohort Study-Cardiovascular Disease Substudy and Meta-Analysis

BACKGRUOUND

Abnormal glucose metabolism is a risk factor for colorectal cancer (CRC). However, association of glycosylated hemoglobin (HbA1c) with CRC risk remains under-reported. We examined the association between glycemic indicators (HbA1c, fasting plasma glucose, fasting insulin, 2-hour glucose, 2-hour insulin, and homeostasis model of risk assessment-insulin resistance index) and CRC risk using prospective analysis and meta-analysis.

METHODS

Participants (n=1,915) from the Guangzhou Biobank Cohort Study-Cardiovascular Disease Substudy were included. CRC events were identified through record linkage. Cox regression was used to assess the associations of glycemic indicators with CRC risk. A meta-analysis was performed to investigate the association between HbA1c and CRC risk.

RESULTS

During an average of 12.9 years follow-up (standard deviation, 2.8), 42 incident CRC cases occurred. After adjusting for potential confounders, the hazard ratio (95% confidence interval [CI]) of CRC for per % increment in HbA1c was 1.28 (95% CI, 1.01 to 1.63) in overall population, 1.51 (95% CI, 1.13 to 2.02) in women and 1.06 (95% CI, 0.68 to 1.68) in men. No significant association of other measures of glycemic indicators and baseline diabetes with CRC risk was found. Meta-analyses of 523,857 participants including our results showed that per % increment of HbA1c was associated with 13% higher risk of CRC, with the pooled risk ratio being 1.13 (95% CI, 1.01 to 1.27). Subgroupanalyses found stronger associations in women, colon cancer, Asians, and case-control studies.

CONCLUSION

Higher HbA1c was a significant predictor of CRC in the general population. Our findings shed light on the pathology of glucose metabolism and CRC, which warrants more in-depth investigation.

Changes in physical activity and all-cause mortality in the oldest old population: Findings from the Chinese Longitudinal Healthy Longevity Survey (CLHLS)

BACKGROUND

Insufficient or decreasing physical activity is common in older adults. Most studies on physical activity changes and mortality were conducted in adults younger than 80 years old in developed countries. We aimed to investigate the relationship between changes in physical activity and longevity in the oldest old (80 years or older) population using the Chinese Longitudinal Healthy Longevity Survey.

METHODS

Participants aged 80 or older at baseline were categorized into four groups: 1) remaining physically inactive (n = 14,287), 2) remaining physically active (n = 5411), 3) shifting from being inactive to active (n = 1364), and 4) shifting from being active to inactive (n = 1401). We fitted accelerated failure time Weibull survival regression models, adjusting for baseline sociodemographics, lifestyle factors and disease status. We further examined whether the associations differed by subgroups.

RESULTS

A total of 15,707 participants died during follow-up (median duration of follow-up = 3.0 years). Compared with participants who remained physically inactive, those who remained active (fully adjusted event time ratio (ETR): 1.14, 95%CI: 1.11-1.17) or shifted from being inactive to active (fully adjusted ETR: 1.14, 95%CI: 1.08-1.20) had statistically significant longer survival time. No significant association was observed between remaining physically inactive and shifting from being active to inactive. Subgroup analyses showed consistent associations in nearly all strata.

CONCLUSION

Maintaining frequent physical activity or shifting from being physically inactive to active was consistently associated with longer survival time in the oldest old population. Our findings provide evidence for encouraging older adults to regularly engage in physical activity to gain longevity benefits.

Integrating research infrastructures into infectious diseases surveillance operations: Focus on biobanks

Technological advances in the first two decades of the 21st century have profoundly impacted medical research in many ways, with large population cohorts, biological sample collections and datasets through biobanks becoming valued global resources to guide biomedical research, drug development, and medical practice. However, in order for biobanks to maximize their impact and scientific reach of their resources, they would need to act within a complex network of infrastructures and activities. Therefore, different ways have emerged in which biobanks, including those for infectious diseases, can emerge as (part of) infrastructures, integrate within existing ones, or become an independent, yet an interoperable component of the existing infrastructural landscape. However, there has been a limited understanding and study of such mechanisms to date. This perspective aims to address this knowledge gap and illustrates these three high-level ways in which such infrastructures could integrate their activities and identifies the necessary key pre-conditions for doing so, while drawing from specific examples.

Bridging gaps between images and data: a systematic update on imaging biobanks

BACKGROUND AND OBJECTIVE

The systematic collection of medical images combined with imaging biomarkers and patient non-imaging data is the core concept of imaging biobanks, a key element for fuelling the development of modern precision medicine. Our purpose is to review the existing image repositories fulfilling the criteria for imaging biobanks.

METHODS

Pubmed, Scopus and Web of Science were searched for articles published in English from January 2010 to July 2021 using a combination of the terms: "imaging" AND "biobanks" and "imaging" AND "repository". Moreover, the Community Research and Development Information Service (CORDIS) database ( https://cordis.europa.eu/projects ) was searched using the terms: "imaging" AND "biobanks", also including collections, projects, project deliverables, project publications and programmes.

RESULTS

Of 9272 articles retrieved, only 54 related to biobanks containing imaging data were finally selected, of which 33 were disease-oriented (61.1%) and 21 population-based (38.9%). Most imaging biobanks were European (26/54, 48.1%), followed by American biobanks (20/54, 37.0%). Among disease-oriented biobanks, the majority were focused on neurodegenerative (9/33, 27.3%) and oncological diseases (9/33, 27.3%). The number of patients enrolled ranged from 240 to 3,370,929, and the imaging modality most frequently involved was MRI (40/54, 74.1%), followed by CT (20/54, 37.0%), PET (13/54, 24.1%), and ultrasound (12/54, 22.2%). Most biobanks (38/54, 70.4%) were accessible under request.

CONCLUSIONS

Imaging biobanks can serve as a platform for collecting, sharing and analysing medical images integrated with imaging biomarkers, biological and clinical data. A relatively small proportion of current biobanks also contain images and can thus be classified as imaging biobanks.

KEY POINTS

• Imaging biobanks are a powerful tool for large-scale collection and processing of medical images integrated with imaging biomarkers and patient non-imaging data. • Most imaging biobanks retrieved were European, disease-oriented and accessible under user request. • While many biobanks have been developed so far, only a relatively small proportion of them are imaging biobanks.

Prediabetes Is Independently Associated with Subclinical Carotid Atherosclerosis: An Observational Study in a Non-Urban Mediterranean Population

This was a prospective, observational study to compare the burden of subclinical atherosclerosis as measured by carotid ultrasonography in a cohort of subjects with prediabetes vs. subjects with normal glucose tolerance (NGT) from a non-urban Mediterranean population. Atherosclerosis was assessed through carotid intima-media thickness (c-IMT), the presence/absence of carotid plaques, and plaque number. Among 550 subjects included, 224 (40.7%) had prediabetes. The mean c-IMT and the prevalence of carotid plaque were significantly higher in the prediabetes group compared to the NGT group (0.72 vs. 0.67 mm, p < 0.001; and 37.9% vs. 19.6%; p < 0.001, respectively). Older age, male gender, and increased systolic blood pressure were positively correlated with c-IMT and were independent predictors of the presence of plaques. In contrast, prediabetes and low-density lipoprotein (LDL)-c were predictors of the presence of plaque (odds ratio [OR] = 1.64; 95% confidence interval [CI] = 1.05-2.57; p = 0.03 and OR = 1.01; 95% CI = 1.00-1.02; p = 0.006, respectively) together with tobacco exposure and the leukocyte count (OR = 1.77; 95% CI = 1.08-2.89; p = 0.023 and OR = 1.20; 95% CI = 1.05-1.38; p = 0.008, respectively). In a non-urban Mediterranean population, prediabetes was associated with established subclinical carotid atherosclerosis. These findings could have implications for the prevention and treatment of CV risk in these subjects before the first symptoms of cardiovascular disease appear.

The mediating role of inflammation in the association between cigarette smoking and intima-media thickness: The Guangzhou biobank cohort study

Cigarette smoking is associated with thicker carotid intima-media thickness (IMT), probably partly through inflammatory pathways. However, to what extent does inflammation mediate the smoking-carotid atherosclerosis association is unclear. We investigated the mediating effect of inflammation on the association between cigarette smoking and carotid IMT, and quantified the respective contributions of inflammatory markers to this association.A total of 1752 participants from Guangzhou Biobank Cohort Study-Cardiovascular Disease Sub-cohort (GBCS-CVD) were included. Using causal mediation analysis under the counterfactual framework, we decomposed total effects of cigarette smoking on IMT into indirect effects (through inflammatory response) and direct effects (not through inflammatory response).After adjusting for traditional risk factors, the indirect effects of per 10/L increment in leukocyte and granulocyte, per mg/L increment in high-sensitivity C-reactive protein (hs-CRP), and per mg/dL increment in fibrinogen on carotid IMT was 0.0028 mm (95% confidence interval [CI], 0.0011-0.0047), 0.0019 mm (95% CI, 0.0006-0.0034), 0.0017 mm (95% CI, 0.0006-0.003), and 0.001 mm (95% CI, 0.0001-0.0021), respectively. No evidence for a mediating role of lymphocyte was found. The proportion of the smoking-IMT association mediated by leukocyte, granulocyte, hs-CRP, and fibrinogen was 12.57% (95% CI, 8.50%-22.11%), 8.50% (95% CI, 5.76%-15.09%), 7.64% (95% CI, 5.20%-13.79%), and 4.48% (95% CI, 3.04%-8.03%), respectively. Restricting data analysis to men showed similar results.The effects of cigarette smoking on IMT were partly mediated by leukocyte, hs-CRP, and fibrinogen. The mediating role of leukocyte was likely mainly driven by higher granulocyte.

Axes of a revolution: challenges and promises of big data in healthcare

Health data are increasingly being generated at a massive scale, at various levels of phenotyping and from different types of resources. Concurrent with recent technological advances in both data-generation infrastructure and data-analysis methodologies, there have been many claims that these events will revolutionize healthcare, but such claims are still a matter of debate. Addressing the potential and challenges of big data in healthcare requires an understanding of the characteristics of the data. Here we characterize various properties of medical data, which we refer to as 'axes' of data, describe the considerations and tradeoffs taken when such data are generated, and the types of analyses that may achieve the tasks at hand. We then broadly describe the potential and challenges of using big data in healthcare resources, aiming to contribute to the ongoing discussion of the potential of big data resources to advance the understanding of health and disease.

Discriminatory performance of adiponectin and leptin in the identification of impaired glucose tolerance: The Guangzhou Biobank Cohort Study - Cardiovascular Disease Subcohort

Background

To evaluate the additional discriminatory performance of adiponectin, leptin, and their ratio in the identification of impaired glucose tolerance (IGT) in men and women without diabetes on top of conventional risk factors.

Methods & results

A total of 698 subjects underwent an oral glucose tolerance test (oGTT) and adipocytokine measurements. A comprehensive stepwise selection procedure was performed, followed by c-statistics and integrated discrimination improvement (IDI) analysis. In males, adiponectin levels were significantly lower in the IGT group compared to the non-IGT group (Whitney U test, p < 10–4), whereas leptin levels were significantly higher (p = 0.009) in IGT group. In females, adiponectin and leptin levels were not significantly different between groups (Mann-Whitney U test, p = 0.073 and p = 0.08, respectively). Adjusting for the most informative, sex-specific, clinical and biochemical factors, adiponectin, leptin and their ratio were not found to be significant predictors of the response to the glucose load, when modelled as continuous terms or tertiles. In males, the area-under-the-curve (AUC) for adiponectin was estimated at 0.620 (95% CI: 0.558–0.682) and the addition of adiponectin into the basic model provided a ΔAUC benefit of 0.004, showing no additional discriminatory benefit on top of conventional risk factors (IDI p-value: 0.27), nor did the addition of leptin or their ratio. The results were similar in females.

Conclusions

In Chinese individuals without diabetes, no significant evidence for the potential discriminatory value of adiponectin, leptin or their ratio in the identification of IGT on top of conventional risk factors was observed.

Glycated Hemoglobin, Albuminuria and Surrogate Markers of Macrovascular Disease in Adults Without Diabetes: The Guangzhou Biobank Cohort Study, Cardiovascular Disease Subcohort

OBJECTIVES

To explore the clinical utility of glycated hemoglobin (A1C) levels as an early marker of albuminuria, macrovascular disease and subclinical cardiovascular disease in comparison to fasting and postprandial glucose levels in a well-characterized Chinese population with no history of diabetes.

METHODS

The study population consisted of 1223 individuals who were enrolled in the Guangzhou Biobank Cohort Study, Cardiovascular Disease Subcohort, and who had undergone oral glucose tolerance tests. The associations between each glycemic measure and albuminuria, carotid intima-media thickness (CIMT) and CIMT-based presence of carotid plaques and aortic arch calcification were assessed by chest radiographs.

RESULTS

The overall prevalence of albuminuria, carotid plaque and any aortic arch calcification was 20.6%, 22.8% and 25.8%, respectively. All 3 glycemia indices were significantly associated with albuminuria, but only 1 (fasting glucose) was associated with carotid plaques. No significant difference was detected among them in the area under the curve for albuminuria (chi-square test; p=0.84), carotid plaques (p=0.28) or calcifications (p=0.29). In sensitivity analysis, adjusted for age and sex, the above findings remained unchanged.

CONCLUSIONS

Although there was evidence suggesting differential associations, the performance of the glycemic indices was similar, and their association with macrovascular disease and albuminuria was modest.

The Global in Global Health is Not a Given

AbstractThe process of globalization is commonly espoused as a means for promoting global health. Efforts to "go global" can, however, easily go awry as a result of lack of attention to local social, economic, and political contexts and/or as a result of commercial and political imperatives that allow local populations to be exploited. Critical analysis of the processes of globalization is necessary to better understand the local particularities of global projects and confront challenges more transparently. We illustrate the potential adverse impacts of globalization in the global health setting, through examination of international tuberculosis control, global mental health, and the establishment of transnational biobank networks.

Exome-chip association analysis reveals an Asian-specific missense variant in PAX4 associated with type 2 diabetes in Chinese individuals

AIMS/HYPOTHESIS

Genome-wide association studies (GWASs) have identified many common type 2 diabetes-associated variants, mostly at the intronic or intergenic regions. Recent advancements of exome-array genotyping platforms have opened up a novel means for detecting the associations of low-frequency or rare coding variants with type 2 diabetes. We conducted an exomechip association analysis to identify additional type 2 diabetes susceptibility variants in the Chinese population.

METHODS

An exome-chip association study was conducted by genotyping 5640 Chinese individuals from Hong Kong, using a custom designed exome array, the Asian Exomechip. Single variant association analysis was conducted on 77,468 single nucleotide polymorphisms (SNPs). Fifteen SNPs were subsequently genotyped for replication analysis in an independent Chinese cohort comprising 12,362 individuals from Guangzhou. A combined analysis involving 7189 cases and 10,813 controls was performed.

RESULTS

In the discovery stage, an Asian-specific coding variant rs2233580 (p.Arg192His) in PAX4, and two variants at the known loci, CDKN2B-AS1 and KCNQ1, were significantly associated with type 2 diabetes with exome-wide significance (p _discovery < 6.45 × 10^-7). The risk allele (T) of PAX4 rs2233580 was associated with a younger age at diabetes diagnosis. This variant was replicated in an independent cohort and demonstrated a stronger association that reached genome-wide significance (p _{meta-analysis} [p _meta] = 3.74 × 10^-15) in the combined analysis.

CONCLUSIONS/INTERPRETATION

We identified the association of a PAX4 Asian-specific missense variant rs2233580 with type 2 diabetes in an exome-chip association analysis, supporting the involvement of PAX4 in the pathogenesis of type 2 diabetes. Our findings suggest PAX4 is a possible effector gene of the 7q32 locus, previously identified from GWAS in Asians.

Exposure to secondhand smoke and risk of peripheral arterial disease in southern Chinese non-smokers: The Guangzhou Biobank Cohort Study-Cardiovascular Disease Sub-cohort

Objectives

We studied the association between secondhand smoke (SHS) exposure and peripheral arterial disease (PAD) in Chinese non-smokers.

Methods

We conducted a cross-sectional study using baseline data from the Guangzhou Biobank Cohort Study: Cardiovascular Disease Sub-cohort Study (GBCS-CVD). Guangzhou residents aged ≥ 50 years were recruited between 2003 and 2008. Baseline data included measurement of ankle brachial pressure index (ABPI) and self-reported smoking status and SHS exposure. Univariate and multivariate logistic regression analyses were used to analyze the association between SHS and PAD (defined as ABPI < 0.9).

Results

Of the 1507 non-smokers, 24 (1.6%) had PAD. Of these, 12 were men and 12 were women. Exposure to SHS at home of ≥25 h per week was reported by 16.7% of PAD cases compared with 3.8% of those without PAD (χ2 test, p = 0.003). After adjustment for potential confounders, exposure to ≥25 h per week at home was still associated with PAD (adjusted OR 7.86, 95% CI 2.00–30.95, p = 0.003), with suggestion of a dose-response relationship.

Conclusions

Our results extend the US Surgeon General’s 2006 report that SHS exposure is an independent risk factor for PAD. National smoke-free legislation is needed to protect all people from exposure.

DogMATIC--A Remote Biospecimen Collection Kit for Biobanking

Canine tumors are valuable comparative oncology models. This research was designed to create a sustainable biobank of canine mammary tumors for breast cancer research. The aim was to provide a well-characterized sample cohort for specimen sharing, data mining, and long-term research aims. Canine mammary tumors are most frequently managed at a local veterinary clinic or hospital. We adopted a biobank framework based on a large number of participating veterinary hospitals and clinics acting as collection centers that were serviced by a centralized storage facility. Recruitment was targeted at rural veterinary clinics. A tailored, stable collection kit (DogMATIC) was designed that was used by veterinarians in remote or rural locations to collect both fresh and fixed tissue for submission to the biobank. To validate this methodology the kit design, collection rate, and sample quality were analyzed. The Australian Veterinary Cancer Biobank was established as a network of 47 veterinary clinics and three veterinary pathology laboratories spanning over 200,000 km(2). In the first 12 months, 30 canine mammary tumor cases were submitted via the DogMATIC kit. Pure intact RNA was isolated in over 80% of samples with an average yield of 14.49 μg. A large network biobank, utilizing off-site collection with the DogMATIC kit, was successfully coordinated. The creation of the Australian Veterinary Cancer Biobank has established a long-term, sustainable, comparative oncology research resource in Australia. There are broader implications for biobanking with this very different form of collection and banking.

Liver enzymes and incident diabetes in China: a prospective analysis of 10 764 participants in the Guangzhou Biobank Cohort Study

BACKGROUND

Impaired liver function has been shown to be associated with incident diabetes. The independent role of the different liver enzymes, including γ-glutamyltransferase (GGT), alanine transaminase (ALT) and aspartate transaminase (AST), has not been addressed properly, taking into account their high collinearity. We used partial least squares (PLS) regression to identify the contribution of ALT, AST and GGT, which appears causally associated with diabetes as a validation factor, to incident diabetes in a South China population where liver impairment and diabetes are common.

METHODS

Participants were from the Guangzhou Biobank Cohort Study recruited in 2003-2008, with follow-up re-examination up to the end of 2012. Multivariable generalised linear models and PLS were used to examine the adjusted associations of ALT, AST and GGT with diabetes. Incident diabetes was defined as self-reported diabetes, and/or initiation of hypoglycaemia medication or insulin during follow-up, or fasting glucose ≥7.0 mmol/L, or 2 h oral glucose tolerance test, glucose ≥11.1 mmol/L at follow-up examination.

RESULTS

In 10 764 Chinese participants aged ≥50 years with no diabetes at baseline, 1228 (11.4%) developed diabetes during the median 4 years of follow-up. Using PLS, the risk for incident diabetes was higher by 18% (95% CI 8% to 27%) per 1 SD increment in log-ALT, and expectedly higher by 36% (95% CI 26% to 52%) for log-GGT, adjusted for age, sex, education, smoking, alcohol, physical activity, waist circumference and body mass index. Similarly adjusted, no association for log-AST (relative risk 0.92, 95% CI 0.85 to 1.01) was found.

CONCLUSIONS

ALT but not AST was associated with incident diabetes. Further experimental studies are needed to confirm the causal association and clarify the underlying mechanisms.

Genetically predicted testosterone and systemic inflammation in men: a separate-sample Mendelian randomization analysis in older Chinese men

Objectives

Observationally, testosterone is negatively associated with systemic inflammation, but this association is open to both residual confounding and reverse causality. Large-scale randomized controlled trials (RCTs), assessing exogenous effects, are presently unavailable. We examined the association of endogenous testosterone with well-established systemic inflammatory markers (white blood cell, granulocyte, lymphocyte and high-sensitivity C-reactive protein (hsCRP)) using a separate-sample Mendelian randomization analysis to minimize reverse causality.

Methods

A genetic prediction rule for serum testosterone was developed in 289 young Chinese men with mean age of 21.0, using selected testosterone-related SNPs (rs10046, rs1008805 and rs1256031). Multivariable linear regression was used to examine the association of genetically predicted serum testosterone with inflammatory markers among 4,212 older Chinese men from the Guangzhou Biobank Cohort Study.

Results

Genetically predicted testosterone was unrelated to white blood cell count (-0.01 109/L per nmol/L testosterone, 95% confidence interval (CI) -0.05 to 0.04), granulocyte count (-0.02 109/L, 95% CI -0.06 to 0.02), lymphocyte count (0.005 109/L, 95% CI -0.01 to 0.02) and hsCRP (-0.05 mg/L, 95% CI -0.15 to 0.06).

Conclusion

Our findings did not corroborate any anti-inflammatory effects of testosterone or corresponding potentially protective effects of testosterone on chronic diseases resulting from reduced low-grade systemic inflammation.

Effects of tea consumption on renal function in a metropolitan Chinese population: the Guangzhou biobank cohort study

OBJECTIVE

Green tea consumption has been associated with many prophylactic health benefits. This study examined for the first time associations between tea consumption and renal function in a Chinese population.

DESIGN AND METHODS

Cross-sectional baseline data including demographics, and lifestyle and weekly consumption of green, black, and oolong tea were analyzed from 12,428 ambulatory subjects aged 50 to 85 years (67.3% female) that were randomly selected from the membership list of a community social and welfare association in Guangzhou, China.

INTERVENTION

Associations between tea consumption and renal function were assessed using regression analyses to adjust for potential confounding factors.

MAIN OUTCOME MEASURE

Renal function was assessed using the estimated glomerular filtration rate (eGFR) and in a subcohort of 1,910 participants using a spot urinary albumin-to-creatinine ratio.

RESULTS

Six thousand eight hundred and seventy-two participants drank at least 1 type of tea. Oolong tea consumption was negatively associated with eGFR (β-coefficient -0.019, P = .025), but in a gender-stratified analysis this was not the case. In men, black tea was positively associated with eGFR (β-coefficient 0.037, P = .013), but not in women (β-coefficient -0.002, P = .856). Otherwise, no statistically significant consistent associations between the measures of renal function and consumption of green tea, black tea, or oolong tea individually or total tea consumption were identified.

CONCLUSION

Overall there was no clear evidence to suggest any consistent association between renal function and tea consumption in this large population-based study of older Chinese individuals.

Usefulness of physical fitness and the metabolic syndrome to predict vascular disease risk in older Chinese (from the Guangzhou Biobank Cohort Study-Cardiovascular Disease Subcohort [GBCS-CVD])

Physical fitness can independently lower the risk of cardiovascular disease (CVD). We explored the independent and combined associations of physical fitness, measured using the seated at rest heart rate (RHR), and the metabolic syndrome (MS), with CVD risk, as described by an elevated pulse wave velocity (PWV) in older Chinese. Data from 1,996 participants were drawn from the Guangzhou Biobank Cohort Study-Cardiovascular Disease Subcohort. Analysis of variance and logistic regression analysis were used to establish the independent and combined associations of the RHR and the MS with PWV. The RHR was independently associated with an elevated PWV (odds ratio [OR] 1.63, 95% confidence interval [CI] 1.22 to 2.18), as was the MS (OR 2.36, 95% CI 1.76 to 3.17). The participants with a high RHR, but without the MS, had an adjusted OR of 1.63 (95% CI 1.15 to 2.30) for the presence of the CVD proxy. Those with a low RHR and the MS had an adjusted OR of 2.35 (95% CI 1.66 to 3.33). The risk of an elevated PWV increased almost fourfold with both a high RHR and a diagnosis of the MS (OR 3.87, 95% CI 2.39 to 6.28, p = 0.52 for interaction). In conclusion, physical fitness, measured using the RHR, and the MS are independently associated with an elevated PWV, a surrogate marker for CVD. The strength of this association was further increased in the presence of both. These findings confirm the beneficial effects of physical fitness on attenuating the risk of CVD among older Chinese.

The utility of collaborative biobanks for cardiovascular research

Differences between animal and human atherosclerosis have led to the requirement for clinical data, imaging information and biological material from large numbers of patients and healthy persons. Where such "biobanks" exist, they have been fruitful sources for genomewide association, diagnostic accuracy, ethnicity, and risk stratification cohort studies. In addition once established, they attract funding for future projects. Biobanks require a network of medical contributors, secure storage facilities, bioinformatics expertise, database managers, and ethical working practices to function optimally. There is the opportunity for collaboration between individual biobanks to further amplify the advantages afforded.

White blood cell subsets are associated with carotid intima-media thickness and pulse wave velocity in an older Chinese population: the Guangzhou Biobank Cohort Study

Cross-sectional associations between white blood cell (WBC) count, lymphocyte and granulocyte numbers, and carotid intima-media thickness (IMT) and brachial-ankle pulse wave velocity (PWV) were examined in a novel older Chinese community sample. A total of 817 men and 760 women from a sub-study of the Guangzhou Biobank Cohort Study had a full blood count measured by an automated hematology analyzer, carotid IMT by B-mode ultrasonography and brachial-ankle PWV by a non-invasive automatic waveform analyzer. Following adjustment for confounders, WBC count (β=0.07, P<0.001) and granulocyte (β=0.07, P<0.001) number were significantly positively related to PWV, but not lymphocyte number. Similarly, WBC count (β=0.08, P=0.03), lymphocyte (β=0.08, P=0.002) and granulocyte (β=0.03, P=0.04) number were significantly positively associated with carotid IMT, but only the association with lymphocyte count survived correction for other cardiovascular risk factors. In conclusion, higher WBC, particularly lymphocyte and granulocyte, count could be used, respectively, as markers of cardiovascular disease risk, measured through indicators of atherosclerosis and arterial stiffness. The associations for WBC count previously observed by others were likely driven by higher granulocytes; an index of systemic inflammation.

Plasminogen activator inhibitor-1 and HbA1c defined prediabetes: the Guangzhou Biobank Cohort Study-CVD

OBJECTIVE

To examine the association between plasminogen activator inhibitor-1 (PAI-1) and diabetes status.

RESEARCH DESIGN AND METHODS

One thousand three hundred and ninety-three older Chinese were randomly selected from the Guangzhou Biobank Cohort Study. Diabetes status was classified as impaired HbA1c (IA1c) level of 5·7-6·4%, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes using the American Diabetes Association diagnosis criteria in 2010.

RESULTS

Compared to the normoglycemic (NG) group, 421 subjects with IA1c, but without diabetes, IFG or IGT, had adverse levels of vascular risk factors, including PAI-1, lipid profile, blood pressure and anthropometry. After adjusting for multiple potential confounders, compared to the NG group, the level of plasma PAI-1 was independently and significantly increased in the IA1c and the IFG/IGT group (mean difference: 32·0 (95% confidence interval: 5·5-58·6) ng/ml and 33·3 (6·3-60·3) ng/ml, respectively; P<0·01).

CONCLUSIONS

Plasma PAI-1 level was increased in people with haemoglobin A1c (HbA1c) of 5·7-6·4% but without IFG or IGT, and in people with IFG/IGT, suggesting an increased risk for future diabetes and cardiovascular diseases in these groups.

Association of a genetic variant in the apolipoprotein A5 gene with the metabolic syndrome in Chinese

OBJECTIVE

Single nucleotide polymorphisms (SNPs) in the apolipoprotein A5 gene (APOA5) are associated with hypertriglyceridaemia in our population. We studied the associations of SNPs in APOA5 with the metabolic syndrome (MetS) in the Hong Kong and Guangzhou Chinese.

METHODS

We genotyped five tagging SNPs in 1330 unrelated subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study cohort with follow-up after a median interval of 6·4 years; 1952 subjects from the Guangzhou Biobank Cohort Study-Cardiovascular Disease Subcohort were used to replicate the findings. The MetS was defined according to the consensus criteria proposed jointly by several organizations in 2009.

RESULTS

The SNP rs662799 (-1131T>C) was associated with the MetS (odds ratio = 1·47, P = 0·00082) and the number of its components present (regression coefficient = 0·204, P = 4·6 × 10(-5) ) after adjusting for age, sex, smoking, drinking and education in Hong Kong subjects at baseline. Similar association of this SNP was found in Hong Kong subjects at follow-up (P = 0·010 and 0·00021, respectively) and in Guangzhou subjects (P = 0·0041 and 0·017, respectively). The association of rs662799 with the number of the MetS components was significant regardless of age, sex, obesity and alcohol drinking, but almost disappeared after further adjusting for plasma triglycerides.

CONCLUSION

Our results showed that the -1131T>C polymorphism in APOA5 was associated with the MetS because of its strong effect on plasma triglycerides. This may partly explain the higher cardiovascular risk in people with this polymorphism.

A polymorphism in transforming growth factor-β1 is associated with carotid plaques and increased carotid intima-media thickness in older Chinese men: the Guangzhou Biobank Cohort Study-Cardiovascular Disease Subcohort

OBJECTIVE

Polymorphisms of the transforming growth factor-β1 (TGFB1) gene have not been associated with asymptomatic atherosclerosis previously. We investigated the relationship between a single nucleotide polymorphism (SNP) rs4803455 in TGFB1 and atherosclerosis identified by the presence of carotid plaque and increased intima-media thickness (IMT) in an older Chinese population.

METHODS

1996 subjects (992 (49.7%) men aged 50-85 years) from the Guangzhou Biobank Cohort Study-Cardiovascular Subcohort (GBCS-CVD) were genotyped. Carotid plaque and IMT were assessed by B-mode ultrasonography.

RESULTS

In male subjects, the C allele of TGFB1 rs4803455 was significantly associated with prevalence of carotid plaque (adjusted OR: 2.49, 95% CI: 1.16-5.36, P = 0.03). The C allele was related to increased number of common carotid artery (CCA) plaques (P=0.03) and larger carotid plaque area (P = 0.02) in men. The homozygous carriers of allele C in male subjects also had a higher risk of having carotid IMT ≥ 1 mm (adjusted OR: 1.75, 95% CI: 1.05-2.93, P = 0.03). These associations were independent of age, smoking, physical activity, body mass index, blood pressure, lipid profile, fasting glucose and high sensitivity C-reactive protein.

CONCLUSION

This is the first study to show that the C allele in TGFB1 was associated with increased risk of atherosclerosis in older Chinese men. Further investigations on the linkage between the TGFB1 gene and progression of atherosclerosis in asymptomatic populations are warranted.

Hip circumference and incident metabolic risk factors in Chinese men and women: the People's Republic of China study

BACKGROUND

The associations between adiposity and metabolic risk factors have been suggested to vary across ethnicities. Studies in Caucasians have shown that after adjusting for waist circumference and body mass index (BMI), a larger hip circumference may be protective for metabolic risk factors. To our knowledge, these associations have never been examined in a Chinese population.

METHODS

Baseline (1987-1988) and follow-up (1993-1994) data were from the People's Republic of China Study (n = 1,144 men, n = 1,776 women). Logistic models were stratified by sex and adjusted for age, smoking, center, and education. Incidence differences (ID) comparing the sex specific 85(th) percentile to the 15(th) percentile of hip circumference were computed for elevated blood pressure, blood glucose and triglycerides, low high-density lipoprotein cholesterol (HDL-C), and multiple metabolic abnormalities (three or more of the aforementioned).

RESULTS

In models adjusted for waist circumference and BMI, the ID [95% confidence interval (CI)] per 1,000 persons associated with a 12-cm larger hip were -132 (-237, -26) for low HDL-C; -85 (-138, -31) for elevated triglycerides; and -49 (-83, -4) for multiple metabolic abnormalities. In males, a larger hip circumference was not associated with a reduction of incident risk factors, although the ID tended to be negative.

CONCLUSIONS

In Chinese women, greater mass in the lower trunk region was inversely associated with incident high triglycerides, low HDL-C, and multiple metabolic abnormalities when adjusted for general and central adiposity. This association was not detected in men. Additional research is needed to better understand the mechanisms by which fat at different depots results in differential risk.

Interleukin-6 receptor gene polymorphism modulates interleukin-6 levels and the metabolic syndrome: GBCS-CVD

Interleukin-6 (IL-6) is a key pleiotropic cytokine that modulates the inflammatory response. Single-nucleotide polymorphisms (SNPs) within associated genes may contribute to the metabolic syndrome (MES). We examined the role of the IL-6 (rs1524107-C/T) and IL-6 receptor (IL-6R, rs8192284-A/C, Asp358Ala) SNPs in modulating IL-6 levels and the syndrome. A total of 1,979 older Chinese subjects aged 50-92 years from Guangzhou Biobank Cohort Study (GBCS) were recruited. SNPs were detected using Taqman SNP genotyping kits. IL-6 was measured using enzyme-linked immunosorbent assay. The genotype frequencies were 4.9, 33.9, and 61.3% for the IL-6 CC, CT, and TT, and 12.0, 44.9, and 43.1% for the IL-6R CC, AC, and AA, respectively. Both SNPs were in Hardy-Weinberg equilibrium. The IL-6 SNP was not associated with IL-6 levels or the MES, but was dose-dependently associated with fibrinogen levels, P = 0.049. IL-6 levels significantly decreased with increasing proportions of the IL-6R A-allele 9.8 ± 4.9, 9.3 ± 4.8, and 8.4 ± 4.3, respectively, P = 0.001. Conversely, the A-allele was associated with elevated triglyceride, P = 0.009, C-reactive protein, P = 0.047, and potentially with fasting glucose levels, P = 0.077. There was an increasing prevalence of the MES in those carrying the IL-6R CC, AC, and AA genotypes at 18.1, 21.5, 25.2%, respectively, P = 0.010. The SNP was a significant independent predictor of the MES after adjusting for general obesity, age, gender and lifestyle, and socioeconomic parameters, P = 0.023. These data, which are in accord with studies from white populations suggest the IL-6R SNP may play a role in the pathogenesis of the MES possibly through modulating IL-6 levels.

A single nucleotide polymorphism in APOA5 determines triglyceride levels in Hong Kong and Guangzhou Chinese

Single nucleotide polymorphisms (SNPs) in the apolipoprotein A5 (APOA5) gene have been associated with hypertriglyceridaemia. We investigated which SNPs in the APOA5 gene were associated with triglyceride levels in two independent Chinese populations. In all, 1375 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study were genotyped for five tagging SNPs chosen from HapMap. Replication was sought in 1996 subjects from the Guangzhou Biobank Cohort Study. Among the five SNPs, rs662799 (-1131T>C) was strongly related to log-transformed triglyceride levels among Hong Kong subjects (β=0.192, P=2.6 × 10(-13)). Plasma triglyceride level was 36.1% higher in CC compared to TT genotype. This association was confirmed in Guangzhou subjects (β=0.159, P=1.3 × 10(-12)), and was significantly irrespective of sex, age group, obesity, metabolic syndrome, hypertension, diabetes, smoking and alcohol drinking. The odds ratios and 95% confidence interval for plasma triglycerides ≥1.7 mmol/l associated with TC and CC genotypes were, respectively, 1.81 (1.37-2.39) and 2.22 (1.44-3.43) in Hong Kong and 1.27 (1.05-1.54) and 1.97 (1.42-2.73) in Guangzhou. Haplotype analysis suggested the association was due to rs662799 only. The corroborative findings in two independent populations indicate that the APOA5-1131T>C polymorphism is an important and clinically relevant determinant of plasma triglyceride levels in the Chinese population.

Arterial stiffness and left-ventricular diastolic dysfunction: Guangzhou Biobank Cohort Study-CVD

Brachial-ankle pulse wave velocity (baPWV), a marker of arterial stiffness, is an established cardiovascular risk factor of ventricular stiffening. We studied the association of baPWV with left-ventricular (LV) diastolic function in a sub-study of the Guangzhou Biobank Cohort Study. In all, 378 Chinese subjects with a normal ejection fraction (>50%) had baPWV measurement by a noninvasive automatic waveform analyser, carotid intima-medial thickness (IMT) measurement by B-mode ultrasonography and cardiac diastolic function assessment by echocardiography. After adjusting for age, both baPWV and IMT were associated with LV mass index, posterior wall end-diastolic thickness and inter-ventricular end-diastolic thickness, but only baPWV was associated with deceleration time, atrial flow velocity and E/A ratio. Multivariable linear regression model showed that baPWV and mean arterial pressure, but not IMT, were significantly associated with E/A ratio (β=-0.02, P=0.03 and β=-0.36, P=0.02, respectively). The receiver operator characteristic curve showed that baPWV was better than pulse pressure or mean arterial pressure to detect LV diastolic dysfunction (E/A<1.0). Our study suggested that increased baPWV might be an independent risk factor or marker for diastolic dysfunction. Early detection of an intervention on increased baPWV may be important for prevention of cardiac diastolic dysfunction.