Lin Xu

The University of Hong Kong, Hong Kong, Hong Kong

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Publications (22)73.11 Total impact

  • Article: Smoking and Hemorrhagic Stroke Mortality in a Prospective Cohort Study of Older Chinese.
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    ABSTRACT: BACKGROUND AND PURPOSE: Hemorrhagic stroke is more common in non-Western settings and does not always share risk factors with other cardiovascular diseases. The association of smoking with hemorrhagic stroke subtypes has not been established. We examined the association of cigarette smoking with hemorrhagic stroke, by subtype (intracerebral hemorrhage and subarachnoid hemorrhage), in a large cohort of older Chinese from Hong Kong. METHODS: Multivariable Cox regression analysis was used to assess the adjusted associations of smoking at baseline with death from hemorrhagic stroke and its subtypes, using a population-based prospective cohort of 66 820 Chinese aged >65 years enrolled from July 1998 to December 2001 at all the 18 Elderly Health Centers of the Hong Kong Government Department of Health and followed until May 31, 2012. RESULTS: After follow-up for an average of 10.9 years (SD=3.1), 648 deaths from hemorrhagic stroke had occurred, of which 530 (82%) were intracerebral hemorrhage. Current smoking was associated with a higher risk of hemorrhagic stroke (hazard ratio, 2.19; 95% confidence interval, 1.49-3.22), intracerebral hemorrhage (1.94; 1.25-3.01), and subarachnoid hemorrhage (3.58; 1.62-7.94), adjusted for age, sex, education, public assistance, housing type, monthly expenditure, alcohol use, and exercise. Further adjustment for hypertension and body mass index slightly changed the estimates. CONCLUSIONS: Smoking is strongly associated with hemorrhagic stroke mortality, particularly for subarachnoid hemorrhage.
    Stroke 05/2013; · 5.73 Impact Factor
  • Article: Effect of alcohol and aldehyde dehydrogenase gene polymorphisms on alcohol-associated hypertension: the Guangzhou Biobank Cohort Study.
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    ABSTRACT: The effects of alcohol dehydrogenase (ADH) 2 and aldehyde dehydrogenase (ALDH) 2 genotypes on the alcohol-blood pressure association are unclear. We examined the association of ADH2 or ALDH2 genotypes with blood pressure in older Chinese men. Based on the Guangzhou Biobank Cohort Study (GBCS), 4792 men with valid ADH2, ALDH2 genotypes were included, and genotyping of rs1229984 ADH2 and rs671 ALDH2 (AA, AG/GA or GG) was performed using a Sequenom Mass-Array platform. Information on socio-demographics and lifestyle factors, including alcohol use, was obtained from a questionnaire, and blood pressure was measured. Among alcohol drinkers, systolic and diastolic blood pressure (SBP and DBP) and mean arterial pressure (MAP) were highest for men with the GG ADH2 genotype (136.6, 77.9 and 97.5 mm Hg, respectively), followed by those with the (AA/AG ADH2+GG ALDH2) genotype (133.4, 77.6 and 96.2 mm Hg, respectively) and then the (AA/AG ADH2+AA/AG ALDH2) genotype (SBP=132.6, DBP=76.6 and MAP=95.2 mm Hg) (P for trend ranged 0.025-0.035). After adjustment for potential confounders, as well as frequency or amount of alcohol use, men with the GG ADH2 genotype were more likely to have hypertension (odds ratio (OR)=1.62, 95% confidence interval 1.15-2.28) as were men with the (AA/AG ADH2+AA/AG ALDH2) genotype (OR=1.40, 95% confidence interval 1.01-1.96) compared with men with the (AA/AG ADH2+GG ALDH2) genotype). ADH2 or ALDH2 genotypes were unrelated to hypertension among those who never drink alcohol. ADH2 genotype influences blood pressure and risk of hypertension among male alcohol drinkers, suggesting that the hypertensive effect of alcohol is due to ethanol rather than acetaldehyde.Hypertension Research advance online publication, 25 April 2013; doi:10.1038/hr.2013.23.
    Hypertension Research 04/2013; · 2.58 Impact Factor
  • Article: Testosterone therapy and cardiovascular events among men: a systematic review and meta-analysis of placebo-controlled randomized trials.
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    ABSTRACT: BACKGROUND: Testosterone therapy is increasingly promoted. No randomized placebo-controlled trial has been implemented to assess the effect of testosterone therapy on cardiovascular events, although very high levels of androgens are thought to promote cardiovascular disease. METHODS: A systematic review and meta-analysis was conducted of placebo-controlled randomized trials of testosterone therapy among men lasting 12+ weeks reporting cardiovascular-related events. We searched PubMed through the end of 2012 using "("testosterone" or "androgen") and trial and ("random*")" with the selection limited to studies of men in English, supplemented by a bibliographic search of the World Health Organization trial registry. Two reviewers independently searched, selected and assessed study quality with differences resolved by consensus. Two statisticians independently abstracted and analyzed data, using random or fixed effects models, as appropriate, with inverse variance weighting. RESULTS: Of 1,882 studies identified 27 trials were eligible including 2,994, mainly older, men who experienced 180 cardiovascular-related events. Testosterone therapy increased the risk of a cardiovascular-related event (odds ratio (OR) 1.54, 95% confidence interval (CI) 1.09 to 2.18). The effect of testosterone therapy varied with source of funding (P-value for interaction 0.03), but not with baseline testosterone level (P-value for interaction 0.70). In trials not funded by the pharmaceutical industry the risk of a cardiovascular-related event on testosterone therapy was greater (OR 2.06, 95% CI 1.34 to 3.17) than in pharmaceutical industry funded trials (OR 0.89, 95% CI 0.50 to 1.60). CONCLUSIONS: The effects of testosterone on cardiovascular-related events varied with source of funding. Nevertheless, overall and particularly in trials not funded by the pharmaceutical industry, exogenous testosterone increased the risk of cardiovascular-related events, with corresponding implications for the use of testosterone therapy.
    BMC Medicine 04/2013; 11(1):108. · 6.03 Impact Factor
  • Article: Uric acid levels, even in the normal range, are associated with increased cardiovascular risk: The Guangzhou Biobank Cohort Study.
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    ABSTRACT: OBJECTIVE: To examine the association between serum uric acid (UA) levels and cardiovascular risk factors in subjects without diabetes or hyperuricemia. METHODS: 6172 women and 2662 men aged 50+ years without diabetes from Phase 1 of the Guangzhou Biobank Cohort Study were included. Data on personal history, physical examination and biochemical parameters were collected. Subjects were categorized by serum UA concentration, and the association between UA levels and cardiovascular risk factors was examined using generalized linear models. RESULTS: In both men and women with normouricemia (UA<420μmol/l in men and <360μmol/l in women), tertiles of UA levels were adversely associated with body mass index, waist circumference, waist-to-hip ratio, total- and HDL-cholesterol, apolipoprotein A1, systolic and diastolic blood pressures, pulse pressure, fasting plasma glucose and white blood cell count (P value for trend ranged from 0.04 to <0.001), and also consistently associated with metabolic disorders including obesity, hypertension, hypertension treatment, dyslipidemia, waist circumference increased since the age of 18years and the metabolic syndrome (P value for trend ranged from 0.02 to <0.001). CONCLUSION: Increasing UA levels, even in subjects with normouricemia and without diabetes, were associated with increasing prevalence of cardiovascular risk factors, suggesting that clinically dichotomous definition of hyperuricemia may be inadequate and high-normal value of UA may warn of metabolic disorders.
    International journal of cardiology 02/2013; · 7.08 Impact Factor
  • Article: Are Depressive Symptoms Associated With Cardiovascular Mortality Among Older Chinese: A Cohort Study of 64,000 People in Hong Kong?
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    ABSTRACT: BACKGROUND:: Depression was positively associated with cardiovascular disease (CVD) or mortality in previous studies. However, whether the observed association can be explained by health status is not clear. OBJECTIVES:: To study the association of depressive symptoms with CVD, stroke, and coronary heart disease (CHD) mortality in older Chinese in Hong Kong, and whether the associations varied by gender or health status. DESIGN:: Prospective population-based study. SETTING:: Elderly Health Centers. PARTICIPANTS:: A total of 62,839 people age 65 or older (21,473 men and 41,366 women) enrolled during July 1998 to December 2001 at all 18 Elderly Health Centers of the Department of Health of Hong Kong. MEASUREMENTS:: Fifteen-item Geriatric Depression Scale (GDS) was used and presence of depressive symptoms was defined by GDS score 8 or more. The cohort was followed up for mortality till March 31, 2009. RESULTS:: Depressive symptoms were only associated with CHD mortality in men (hazard ratio [HR] 1.41, 95% confidence interval [CI]: 1.08-1.84; p for gender interaction = 0.02) adjusted for age, education, monthly expenditure, smoking, alcohol use, physical activity, body mass index, health status, and self-rated health. GDS score was associated with stroke mortality (similarly adjusted HR 1.02 per score, 95% CI: 1.00-1.04) in all subjects (adjusted also for gender), and CHD mortality (1.04 [1.01-1.07]) in men. Health status attenuated but did not modify any associations. CONCLUSION:: Depressive symptoms were independently associated with higher CHD mortality in older Chinese men, and with higher stroke mortality in both genders. However, attenuation by health status, and lack of consistency by gender indicate that these associations could be noncausal and further studies by treatment trials and Mendelian randomization are needed.
    The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry 08/2012; · 3.35 Impact Factor
  • Article: Alcohol consumption and aortic arch calcification in an older Chinese sample: The Guangzhou Biobank Cohort Study
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    ABSTRACT: Objective To examine the association between alcohol consumption and aortic arch calcification (AAC) in an older Chinese sample.Methods In 27,844 older people aged 50–85, socioeconomic position and lifestyle factors were assessed by a questionnaire. The presence and severity of AAC were diagnosed from chest X-ray by two experienced radiologists.ResultsIn men, the risk for AAC increased significantly in frequent or excessive drinkers [adjusted odds ratio (OR) = 1.36 (95% confidence interval (CI) 1.16–1.59) and 1.49 (1.21–1.83) for those who drank >5 times/week and those who drank excessively, respectively] (P for trend from 0.002 to 0.001). When AAC was analyzed as an outcome variable with 3 categories of severity, significant dose–response relations between the severity of AAC and alcohol consumption were observed, with those who drank frequently (> 5/week) or excessively having more serious AAC (P for trend = 0.03 and 0.02, respectively). No significant association was found in women as few drank excessively.Conclusion The presence and severity of AAC were associated with quantity or frequency of alcohol consumption in a dose–response pattern, suggesting that alcohol drinking, even when moderate, has no benefit for AAC. Excessive drinking increased the risk of AAC by 50% compared to never drinkers.
    International journal of cardiology 08/2011; · 7.08 Impact Factor
  • Article: Dose-response relation between physical activity and cognitive function: guangzhou biobank cohort study.
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    ABSTRACT: To examine, via cross-sectional analysis, the dose-response association between physical activity and cognitive function in Chinese subjects. A total of 27,651 participants aged 50 to 85 years were recruited from 2003 to 2008. Information on potential confounders, including demographic and anthropometric characteristics, socioeconomic position, lifestyle, and disease history, was collected by standardized interview and procedures. Cognitive function was assessed by the delayed 10-word recall test (DWRT). When the International Physical Activity Questionnaire was used, we found that most of the participants were classified as physically active (53.1%), with 42.4% moderately active and 4.5% physically inactive. Significant dose-response relations across quintiles of metabolic equivalent value (METs) with DWRT score in participants with or without good self-rated health were found (all p for trend <.001). In participants with poor self-rated heath, compared with the first quintile of METs, those in the fifth quintile (highest METs) had a significantly reduced risk for mild cognitive impairment by 28% (adjusted odds ratio, 0.72; 95% confidence interval, 0.58-0.89, p < .01; p for trend = .006). After additional adjustment for depression, we found that the association between physical activity and DWRT score remained significant. A significant dose-response relationship between physical activity and cognitive function was found, and the association was more pronounced in participants with poor self-rated health.
    Annals of epidemiology 07/2011; 21(11):857-63. · 2.95 Impact Factor
  • Article: Short or long sleep duration is associated with memory impairment in older Chinese: the Guangzhou Biobank Cohort Study.
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    ABSTRACT: To examine the association between sleep-related factors and memory impairment. Cross-sectional study Community-based study in Guangzhou, China. 28,670 older Chinese (20,776 women and 7,894 men) aged 50 to 85 years. Demographic and socioeconomic data, sleep-related factors, and cognitive function were collected by face-to-face interview. Potential confounders, such as employment and occupational status, smoking, alcohol and tea use, physical activity, self-rated health, anthropometry, blood pressure, and fasting plasma glucose and lipids were measured. After adjusting for multiple potential confounders, an inverted U-shaped association between sleep duration and delayed word recall test (DWRT) score, a validated measure of memory impairment, was found, with 7 to 8 h of habitual sleep duration showing the highest score (P-values for trend from 3 to 7 h and from 7 to ≥ 10 h were all ≤ 0.001). Compared to sleep duration of 7 h, the adjusted odds ratio for memory impairment from the sleep duration of 3 to 4 or ≥ 10 h was 1.29 (95% confidence interval 1.07-1.56) and 1.52 (1.25-1.86), respectively. Subjects with daily napping, morning tiredness, or insomnia had significantly lower DWRT scores than those without (P ranged from < 0.001 to 0.01). Short or long sleep duration was an important sleep-related factor independently associated with memory impairment and may be a useful marker for increased risk of cognitive impairment in older people.
    Sleep 05/2011; 34(5):575-80. · 5.05 Impact Factor
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    Article: Depressive symptoms and suicide in 56,000 older Chinese: a Hong Kong cohort study.
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    ABSTRACT: To examine dose-response associations between depressive symptoms and suicide and modification effects of sex, age and health status in older Chinese. We used the Chinese version of the 15-item Geriatric Depression Scale (GDS) to measure depressive symptoms (GDS score ≥ 8) and Cox regression to examine association with suicide mortality in a population-based cohort of 55,946 individuals, aged 65 years or above, enrolled from July 1998 to December 2000 at one of 18 Elderly Health Centres of Hong Kong Department of Health. The cohort was followed up for suicide mortality till 31 March 2009 (mean follow-up 8.7 years). Depressive symptoms were associated with suicide in men [hazard ratio (HR) 2.03, 95% confidence interval (CI) 0.96-4.29] and women (HR = 2.36, 95% CI 1.31-4.24) after adjusting for age, education, monthly expenditure, smoking, alcohol drinking, physical activity, body mass index, health status, and self-rated health. There was no threshold for GDS score and suicide in either sex. Age, sex and health status did not modify the association. Depressive symptoms predict higher suicide risk in older Chinese in a dose-response pattern. These associations were not attenuated by adjustment for health status, suggesting that depressive symptoms in older people are likely to be an independent causal factor for suicide. The GDS score showed no threshold in predicting suicide risk, suggesting that older people with low GDS scores deserve further attention and those with very high scores need urgent intervention.
    Social Psychiatry 03/2011; 47(4):505-14. · 2.05 Impact Factor
  • Article: Aortic arch calcification and vascular disease: the Guangzhou Biobank Cohort Study.
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    ABSTRACT: To examine the association between aortic arch calcification (AAC) and vascular disease in an older Chinese sample. For this study, 30,203 Chinese aged 50-85 years were recruited with baseline information on socioeconomic position, lifestyle and vascular risk factors. The presence and severity of AAC were diagnosed independently from chest X-ray by two radiologists. The age-adjusted prevalence of AAC was significantly higher in women than men [34.6% (95% CI 33.9-35.3) vs. 27.9% (95% CI 26.8-28.8), p < 0.001]. Severity of AAC was significantly associated with physician-diagnosed ischemic heart disease (adjusted OR = 1.55, 95% CI 1.35-1.79) and combined vascular disease (OR = 1.48, 95% CI 1.30-1.69) after adjusting for multiple potential confounders. Increasing severity of AAC was associated with increased risk for ischemic heart disease and vascular disease (p for trend = 0.02 to <0.001). No association between AAC and stroke was found. AAC was strongly and independently associated with vascular disease, suggesting that assessment of AAC from chest X-ray, which is noninvasive and relatively inexpensive, can provide useful information for risk stratification of vascular disease, and should be routinely incorporated in chest X-ray examination.
    Cardiology 01/2011; 117(4):260-4. · 1.71 Impact Factor
  • Article: Plasminogen activator inhibitor-1 and HbA1c defined prediabetes: the Guangzhou Biobank Cohort Study-CVD.
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    ABSTRACT: To examine the association between plasminogen activator inhibitor-1 (PAI-1) and diabetes status. 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. 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). 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.
    Clinical Endocrinology 12/2010; 74(4):528-31. · 3.17 Impact Factor
  • Article: [Dose-response relationship between smoking status and carotid atherosclerosis].
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    ABSTRACT: To examine the dose-response relationship of smoking status with carotid atherosclerosis in 959 relatively healthy Chinese men. 959 older Chinese men were selected from Guangzhou Biobank Cohort Study (GBCS) on cardiovascular disease. Personal histories were collected and fasting plasma glucose and lipids, blood pressure, and common carotid artery intima-median thickness (CCA-IMT) were measured. (1) Composition of the cases: 39.1% were non-smokers, 25.7% were former smokers and 35.2% were current smokers. The mean (95% confidence interval) carotid IMT was 0.78 (0.77 - 0.79) mm. 18.4% of the subjects had carotid IMT equal to or thicker than 1.0 mm while 34.1% had carotid plaque. (2) After adjusting for age, sex, physical activity, body mass index, fasting glucose, triglyceride, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, compared to never smokers, current smokers had significantly increased risk for thicker IMT and carotid plaque [odds ratio (OR) = 1.82, 95%CI: 1.30 - 2.55 and OR = 1.95, 95%CI: 1.38 - 2.75, respectively, all P < 0.001]. The risk for thicker IMT and carotid plaque increased with the increasing amount (cigarettes/day) and duration of smoking (years) as well with cigarette pack-years (P for trend all ≤ 0.01). An elevated risk with a clear dose-response relationship was found between cigarette smoking and carotid atherosclerosis. Quitting smoking or reducing the amount of smoking may lower the risk of atherosclerosis, preventing and controlling the occurrence of cardiovascular diseases, and reducing the related cardiovascular mortalities.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 09/2010; 31(9):983-7.
  • Article: The metabolic syndrome is associated with subclinical atherosclerosis independent of insulin resistance: the Guangzhou Biobank Cohort Study-CVD.
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    ABSTRACT: We examined whether the association of the metabolic syndrome (MetS) and subclinical atherosclerosis is independent of insulin resistance in a Chinese community sample with no history of type 2 diabetes. Five hundred and ninety-six men and 526 women from a substudy of the Guangzhou Biobank Cohort Study (GBCS-CVD) had carotid intimal-medial thickness (IMT) measured by B-mode ultrasonography, and brachial-ankle pulse wave velocity (PWV) and ankle-brachial systolic blood pressure index (ABI) measured simultaneously by a noninvasive automatic waveform analyser. Fourteen percentage had MetS as defined by the International Diabetes Federation. Obesity indices, systolic and diastolic blood pressure and pulse pressure, lipids, fasting and postload glucose and insulin, homeostatic model assessment of insulin resistance, glycosylated haemoglobin A1c, leptin, high-sensitivity C-reactive protein, IMT and PWV increased and high-density lipoprotein-cholesterol, adiponectin and ABI decreased significantly with increasing number of MetS components after adjusting for age and sex (P for trend from 0.004 to <0.001). After adjusting for traditional cardiovascular risk factors and insulin resistance, the odds ratios [OR (95% CI)] of thicker IMT (> or =1.0 mm), higher PWV (> or =14.0 m/s) and low ABI (< or =1.0) for MetS were significantly increased [2.28 (1.19-4.38), 2.17 (1.36-3.46) and 1.72 (1.14-2.59), respectively, all P < 0.01] but were lower than the adjusted OR for those with three or more MetS components. MetS was associated with subclinical atherosclerosis independent of insulin resistance. The presence of increasing number of MetS risk factors appeared to be more important than the diagnosis of MetS in predicting subclinical atherosclerosis. Early screening for MetS risk factors might identify those at greater cardiovascular risk.
    Clinical Endocrinology 08/2010; 73(2):181-8. · 3.17 Impact Factor
  • Article: [Study on the association between gene polymorphism of ENPP1 and left ventricular hypertrophy: a Guangzhou Biobank Cohort Study-CVD].
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    ABSTRACT: To examine the association between genetic polymorphism of rs1409181 in ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and left ventricular hypertrophy (LVH) among older Chinese in Guangzhou. 390 subjects aged ≥ 50 years were randomly selected from the Guangzhou Biobank Cohort Study-CVD. Information on personal history, blood pressure, fasting plasma glucose and lipids were collected. Color Doppler ultrasound was used to measure the indicators of LVH, including left ventricular internal diastolic diameter (LVIDD), thickness of the interventricular septum diastolic wall (IVSD) and the posterior wall diastolic diameter (LVPWD). LVIDD was calculated using Devereux ventricular mass (LVM) equation while the Left ventricular mass index (LVMI) equation was used to estimate LVH. The genotype of rs1409181 was determined by Taqman SNP genotyping kits using the ABI 7900HT real time PCR system. In the GG, CG and CC genotype groups, the proportions of LVH were 21.5%, 28.2% and 37.5% respectively. Compared with GG, the adjusted odds ratios (95% confidence interval) for the LVH were 1.39 (0.78 - 2.50) and 2.36 (1.21 - 4.60) for CG genotype and CC genotype of ENPP1 respectively (P for trend = 0.01). Polymorphism of ENPP1 gene rs1409181 was associated with LVH in the older Chinese people in Guangzhou.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 07/2010; 31(7):742-6.
  • Article: Brachial-ankle pulse wave velocity and cardiovascular risk factors in the non-diabetic and newly diagnosed diabetic Chinese: Guangzhou Biobank Cohort Study-CVD.
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    ABSTRACT: Increased arterial stiffness is an important cause of cardiovascular disease (CVD). We examined determinants of arterial stiffness in subjects across strata of glycaemic status. A total of 1249 subjects from a sub-study of the Guangzhou Biobank Cohort Study (GBCS-CVD) had brachial-ankle pulse wave velocity (baPWV) measured by automatic oscillometric method. Major cardiovascular risk factors including glycosylated haemoglobin A1c (HbA(1c)), high sensitivity C-reactive protein (hsCRP), fasting triglyceride, low- and high-density lipoprotein cholesterol and both fasting and post 2-h oral glucose-load glucose, systolic and diastolic blood pressure were assessed. In all, 649, 479 and 121 subjects were classified into normoglycaemia, impaired glucose metabolism (IGM) and newly diagnosed diabetes groups, respectively. Both age and systolic blood pressure were significantly associated with increased baPWV in all three groups (all p < 0.001). In both normoglycaemic and IGM groups, hsCRP and HbA(1c) were positively associated with baPWV (p from 0.04 to < 0.001), whereas current smoking and triglyceride were associated with baPWV in the normoglycaemic and IGM group, respectively (p = 0.04 and 0.001). No gender difference in baPWV was observed in the normoglycaemic or IGM groups. However, in the newly diagnosed diabetes group, men had higher baPWV than women (p = 0.01). In the normoglycaemic and IGM subjects, after adjusting for age, blood pressure and other confounders, increasing HbA(1c) was associated with increased baPWV, suggesting a pathophysiological role of chronic glycaemia that can contribute to vascular disease risk in persons without diabetes.
    Diabetes/Metabolism Research and Reviews 02/2010; 26(2):133-9. · 3.37 Impact Factor
  • Article: [Relation of serum leptin and adiponectin to cardiovascular risk factors in older adults: a Guangzhou biobank cohort study-CVD].
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    ABSTRACT: To study the serum leptin and adiponectin levels among relatively healthy older people and their association with traditional cardiovascular risk factors. Personal medical history and blood sample were collected from 1515 older people of Guangzhou. Fasting serum glucose, lipids, leptin and adiponectin were measured. (1) In relatively healthy older adults aged 50 or above, from Guangzhou, the following data were seen: serum leptin levels (x(-) ± s) in men and women were (3.90 ± 2.36) ng/ml and (12.17 ± 2.01) ng/ml respectively; serum adiponectin levels in men and women were (5.33 ± 2.78) mg/L and (7.18 ± 2.58) mg/L respectively. (2) Serum leptin and adiponectin level increased with age. After adjusting for body mass index, the trend for serum leptin level in men (P < 0.001) and adiponectin level in women (P < 0.05) were significantly associated with age. (3) No association was found between cigarette smoking and levels of leptin or adiponectin in both men and women after adjusting for age (P from 0.09 to 0.76). (4) In both men and women, serum leptin and adiponectin levels were positively associated with waist circumference/body mass index, systolic blood pressure, low-density lipoprotein cholesterol and triglyceride (P from 0.04 to < 0.001). In men, leptin was also significantly associated with the increase of diastolic blood pressure and glucose but decreased with high-density lipoprotein cholesterol (P from 0.03 to 0.02). (5) Decreased adiponectin level was associated with increased waist circumference and triglyceride in both men and women (P from 0.003 to < 0.001) and with the increased body mass index, fasting plasma glucose as well as with decreased high-density lipoprotein cholesterol in men (P from 0.05 to < 0.001) but with increased systolic blood pressure and total cholesterol in women (P from 0.05 to 0.006). In Guangzhou city, among relatively healthy older adults aged 50 or above, their serum leptin and adiponectin levels were lower in men than in women. Serum leptin level in men and adiponectin level in women were significantly associated with the increase of age. Increased leptin and decreased adiponectin levels were associated with increased traditional cardiovascular risk factors.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 02/2010; 31(2):121-5.
  • Article: Atrial fibrillation and obesity among older Chinese: the Guangzhou Biobank Cohort Study.
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    ABSTRACT: Atrial fibrillation (AF) is the most common form of arrhythmia, and its prevalence is increasing. Few studies have examined its association with obesity as defined by different criteria, particularly in developing countries. We investigated the association between atrial fibrillation (AF) and obesity indices among older Chinese. We conducted a community-based nested case control study using cross-sectional data of 5882 men and 14,548 women aged 50 or above from Phases I and II (September 2003 to May 2006) of the Guangzhou Biobank Cohort Study (GBCS). AF cases were identified by the 12-lead body surface electrocardiogram. 159 AF cases (65 men and 94 women) were identified from 19,964 participants with ECG records. 9249 participants with other abnormal ECG findings were excluded, resulting in a case control comparison on 159 AF cases and 10,369 controls. After multivariate adjustment, BMI (adjusted odds ratio (OR) 1.06 per kg/m(2), 95% confidence interval (CI)=1.01-1.11) and waist circumference (adjusted OR 1.02 per cm (1.00-1.04)) were significant risk factors. The adjusted OR per Z-score [(individual value-mean)/standard deviation] for BMI and waist circumference was 1.21 (1.03-1.41) and 1.18 (1.01-1.38) respectively. This is the first report showing that both general and central obesity are associated with increased risk of AF in an Eastern population with much lower level of obesity than in the West. As both AF and obesity are increasing in developing countries, the results should have important public health implications.
    International journal of cardiology 11/2009; 148(1):48-52. · 7.08 Impact Factor
  • Article: Passive smoking and aortic arch calcification in older Chinese never smokers: the Guangzhou Biobank Cohort Study.
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    ABSTRACT: To study whether passive smoking is a risk factor for aortic arch calcification (AAC) among never smokers. We have previously reported that active smoking increases the risk of AAC, but the effect of passive smoking has not been reported. We used baseline data of the Phase 1 Guangzhou Biobank Cohort Study (GBCS). 7702 older Chinese never smokers from the Phase 1 GBCS were included. Information on passive smoking and potential confounders were collected by standardized interviews and laboratory assays. AAC was diagnosed from chest X-ray by two experienced radiologists. Unconditional logistic regression was used to estimate odds ratios of AAC for passive smoking with adjustment for potential confounders. In women, the risk for aortic arch calcification (AAC) increased significantly with increasing duration of adulthood passive smoking exposure at home, at work and total duration of adulthood home and work exposure [adjusted odds ratio 1.24 (95% confidence interval 1.09-1.41) for high level of total exposure] (P for trend from 0.012 to 0.001). For passive smoking at home, at work and total exposure, significant trends of increasing severity of AAC with increasing duration of exposure were observed in men and women combined (P for trend from 0.05 to 0.002). Passive smoking is a risk factor for aortic arch calcification. Studies of passive smoking and AAC, especially in developing countries can generate important local evidence to raise awareness and to support public health measures to protect non-smokers from second-hand smoke.
    International journal of cardiology 11/2009; 148(2):189-93. · 7.08 Impact Factor
  • Article: Impact of impaired fasting glucose and impaired glucose tolerance on arterial stiffness in an older Chinese population: the Guangzhou Biobank Cohort Study-CVD.
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    ABSTRACT: The aim of the study was to compare the impact of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) on vascular function among older Chinese people. A random sample of 671 men and 603 women aged 50 to 85 years without known diabetes from the Guangzhou Biobank Study-CVD was examined in a cross-sectional study. Subjects with no previously confirmed or treated diabetes but with both fasting plasma glucose less than 5.6 mmol/L and 2-hour glucose from 7.8 to less than 11.0 mmol/L were classified as having isolated IGT, and those with no previously confirmed and treated diabetes but with both fasting plasma glucose from 5.6 to less than 7.0 mmol/L and 2-hour glucose less than 7.8 mmol/L were classified as having isolated IFG. A total of 11.0% of the men and 8.6% of the women had isolated IFG, and 17.7% of the men and 18.6% of the women had isolated IGT. The brachial-ankle pulse wave velocity and pulse pressure were increased in both the isolated IFG and isolated IGT subjects compared with the normoglycemia group (both Ps < .001). Compared with subjects with isolated IFG, those with isolated IGT appeared to have a higher age- and sex-adjusted brachial-ankle pulse wave velocity (1543 +/- 22 vs 1566 +/- 17, P = .07) and to be more insulin resistant (2-hour postload insulin: 54.2 +/- 2.13 vs 26.8 +/- 2.99 muU/mL, P < .001), had a worse lipid profile (apolipoprotein [apo] B: 1.07 +/- 0.02 vs 0.97 +/- 0.02 g/L, P < .001; apo B/apo A-1 ratio: 0.80 +/- 0.02 vs 0.69 +/- 0.02, P < .001), but had lower glycosylated hemoglobin levels (6.03% +/- 0.06% vs 5.86% +/- 0.04%, P < .001) (values are mean +/- SE). Subjects with isolated IGT had greater arterial stiffness, probably as a result of being more insulin resistant, with a worse lipid profile than those with isolated IFG. The sole use of fasting glucose level to identify prediabetic people would fail to identify a significant proportion of the at-risk population.
    Metabolism: clinical and experimental 10/2009; 59(3):367-72. · 2.59 Impact Factor
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    Article: Smoking cessation and carotid atherosclerosis: the Guangzhou Biobank Cohort Study--CVD.
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    ABSTRACT: Smoking has been shown to be associated with carotid atherosclerosis in cross-sectional and prospective studies in Western populations. However, few studies have examined the reversal of risk resulting from quitting smoking, and the results are conflicting. 959 men aged 50-85 years were randomly selected from phase III (2006-2007) of the Guangzhou Biobank Cohort Study into this cross-sectional study. Common carotid artery intima-media thickness (CCA-IMT) was measured by B-mode ultrasonography, and carotid artery plaques were identified. Major cardiovascular risk factors, including fasting triglyceride, low-density and high-density lipoprotein (LDL and HDL) cholesterol and glucose, and systolic and diastolic blood pressure, were assessed. CCA-IMT and the number of carotid plaque increased from never to former to current smokers (both p≤0.001). Among former smokers compared to current smokers, after adjustment for cigarette pack-years and other potential confounders, the adjusted ORs (95% CI) for quitting for 1-9, 10-19 and 20+ years were 0.77 (0.47 to 1.26), 0.45 (0.26 to 0.79) and 0.37 (0.17 to 0.77) for the presence of CCA atherosclerosis, and 0.69 (0.43 to 1.12), 0.47 (0.27 to 0.82) and 0.45 (0.23 to 0.96) for the presence of carotid plaques, respectively. Longer duration of quitting smoking was also significantly associated with decreasing risk of the severity of CCA atherosclerosis and carotid plaques (all p≤0.001). Smoking cessation was beneficial in attenuating the risk of carotid atherosclerosis associated with cigarette smoking. The short duration of cessation in earlier studies is a likely explanation for the inconsistent results.
    Journal of epidemiology and community health 10/2009; 64(11):1004-9. · 3.04 Impact Factor