Guangzhou, China
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Kucharski A.J.,London School of Hygiene and Tropical Medicine | Kucharski A.J.,Imperial College London | Read J.M.,University of Liverpool | Zhu H.,Shantou University | And 5 more authors.
PLoS Biology | Year: 2015

The immunity of a host population against specific influenza A strains can influence a number of important biological processes, from the emergence of new virus strains to the effectiveness of vaccination programmes. However, the development of an individual’s long-lived antibody response to influenza A over the course of a lifetime remains poorly understood. Accurately describing this immunological process requires a fundamental understanding of how the mechanisms of boosting and cross-reactivity respond to repeated infections. Establishing the contribution of such mechanisms to antibody titres remains challenging because the aggregate effect of immune responses over a lifetime are rarely observed directly. To uncover the aggregate effect of multiple influenza infections, we developed a mechanistic model capturing both past infections and subsequent antibody responses. We estimated parameters of the model using cross-sectional antibody titres to nine different strains spanning 40 years of circulation of influenza A(H3N2) in southern China. We found that “antigenic seniority” and quickly decaying cross-reactivity were important components of the immune response, suggesting that the order in which individuals were infected with influenza strains shaped observed neutralisation titres to a particular virus. We also obtained estimates of the frequency and age distribution of influenza infection, which indicate that although infections became less frequent as individuals progressed through childhood and young adulthood, they occurred at similar rates for individuals above age 30 y. By establishing what are likely to be important mechanisms driving epochal trends in population immunity, we also identified key directions for future studies. In particular, our results highlight the need for longitudinal samples that are tested against multiple historical strains. This could lead to a better understanding of how, over the course of a lifetime, fast, transient antibody dynamics combine with the longer-term immune responses considered here. © 2015 Kucharski et al.


Read J.M.,University of Liverpool | Riley S.,Imperial College London | Wang S.,Guangzhou No 12 Hospital | Tan L.J.,Guangzhou No 12 Hospital | And 4 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2014

A dense population, global connectivity and frequent human-animal interaction give southern China an important role in the spread and emergence of infectious disease. However, patterns of person-to-person contact relevant to the spread of directly transmitted infections such as influenza remain poorly quantified in the region. We conducted a household-based survey of travel and contact patterns among urban and rural populations of Guangdong, China. We measured the character and distance from home of social encounters made by 1821 individuals. Most individuals reported 5-10 h of contact with around 10 individuals each day; however, both distributions have long tails. The distribution of distance from home at which contacts were made is similar: most were within a kilometre of the participant's home, while some occurred further than 500 km away. Compared with younger individuals, older individuals made fewer contacts which tended to be closer to home. There was strong assortativity in age-based contact rates. We found no difference between the total number or duration of contacts between urban and rural participants, but urban participants tended to make contacts closer to home. These results can improve mathematical models of infectious disease emergence, spread and control in southern China and throughout the region. © 2014 The Authors.


Riley S.,Imperial College London | Read J.M.,University of Liverpool | Wang S.,Guangzhou No 12 Hospital | Zhu H.,Shantou University | And 5 more authors.
PLoS Pathogens | Year: 2012

A key observation about the human immune response to repeated exposure to influenza A is that the first strain infecting an individual apparently produces the strongest adaptive immune response. Although antibody titers measure that response, the interpretation of titers to multiple strains - from the same sera - in terms of infection history is clouded by age effects, cross reactivity and immune waning. From July to September 2009, we collected serum samples from 151 residents of Guangdong Province, China, 7 to 81 years of age. Neutralization tests were performed against strains representing six antigenic clusters of H3N2 influenza circulating between 1968 and 2008, and three recent locally circulating strains. Patterns of neutralization titers were compared based on age at time of testing and age at time of the first isolation of each virus. Neutralization titers were highest for H3N2 strains that circulated in an individual's first decade of life (peaking at 7 years). Further, across strains and ages at testing, statistical models strongly supported a pattern of titers declining smoothly with age at the time a strain was first isolated. Those born 10 or more years after a strain emerged generally had undetectable neutralization titers to that strain (<1:10). Among those over 60 at time of testing, titers tended to increase with age. The observed pattern in H3N2 neutralization titers can be characterized as one of antigenic seniority: repeated exposure and the immune response combine to produce antibody titers that are higher to more 'senior' strains encountered earlier in life. © 2012 Lessler et al.


Yeung S.L.A.,University of Hong Kong | Jiang C.,Guangzhou No 12 Hospital | Cheng K.K.,University of Birmingham | Liu B.,Guangzhou No 12 Hospital | And 5 more authors.
International Journal of Epidemiology | Year: 2013

Background Mendelian randomization studies provide a means of assessing causal relations without interventions, but require valid genetic instruments. We assessed the credibility of aldehyde dehydrogenase 2 (ALDH2) as a genetic instrument for alcohol use in Southern Chinese men. Methods We genotyped the single nucleotide polymorphism rs671 of ALDH2 in 4867 men from the Guangzhou Biobank Cohort Study. We used linear regression to assess the strength of the association of ALDH2 variants with alcohol use, whether ALDH2 variants were independently associated with socio-economic position or other potential confounders and whether associations of ALDH2 variants with cardiovascular risk factors (systolic and diastolic blood pressure, HDLand LDL-cholesterol, fasting glucose), triglycerides, body mass index, self reported cardiovascular disease, self-reported ischaemic heart disease, cognitive function (delayed 10-word recall and Mini Mental State Examination score) and liver function (alanine transaminase and aspartate transaminase) were fully mediated by alcohol use. Results The minor allele frequency (A) of ALDH2 was 0.29. The F statistic for ALDH2 variants was 75.0, suggesting that substantial weak instrument bias is unlikely. ALDH2 variants were not associated with socio-economic position, smoking or physical activity. ALDH2 variants were only associated with diastolic blood pressure and HDL-cholesterol, but these genetic associations with blood pressure and HDL-cholesterol were attenuated after adjusting for alcohol use, suggesting the apparent genetic associations were possibly mediated by alcohol use. Conclusions ALDH2 variants are a credible genetic instrument for Mendelian randomization studies of alcohol use and many attributes of health in Southern Chinese men.© The Author 2012; all rights reserved.


Xu L.,University of Hong Kong | Jiang C.Q.,Guangzhou No 12 Hospital | Lam T.H.,University of Hong Kong | Zhang W.S.,Guangzhou No 12 Hospital | And 3 more authors.
Sleep | Year: 2014

Study Objectives: Previous cross-sectional studies showed that short or long sleep duration was associated with memory impairment (MI), but longitudinal studies are scarce. We examined whether sleep duration was associated with memory decline or development of MI.Design, Setting, Participants: We conducted a prospective analysis based on the Guangzhou Biobank Cohort Study on 13, 888 participants aged 50+ years without MI at baseline and with a follow-up for a mean of 4.1 years.Measures and Results: Memory decline was assessed using the Delayed 10-Word Recall Test (DWRT), and in a subset (n = 6, 020) with the Mini-Mental State Examination (MMSE). Short and long sleep duration was defined as ≤ 5 hours/day and ≥ 9 hours/day, respectively. Data were analyzed both continuously for memory decline and dichotomously for MI (independently defined as DWRT, < 4; MMSE, < 25). After adjusting for multiple potential confounders, both short and long sleep durations were associated with memory decline using DWRT or MMSE score changes (all P < 0.001). Seven percent (n = 980) developed DWRT-defined MI and 4.0% (n = 194) MMSE-defined MI during the follow-up. Only those with a short (≤ 5 h/day) sleep duration had a significantly increased risk of DWRT-defined MI (odds ratio = 1.53 (95% confidence interval; 1.21-1.93); P < 0.001) relative to normal sleepers (7 h/day). The association remained significant after excluding those with poor self-reported health. No associations were observed with MMSE-defined MI for both long and short sleep durations.Conclusions: This is the largest study to date addressing the association between extremes of sleep duration and memory decline. The observed adverse relationships provide support for an intervention study to examine the potential benefits of normalizing sleep duration in attenuating memory decline.


Xu L.,University of Hong Kong | Jiang C.Q.,Guangzhou No 12 Hospital | Lam T.H.,University of Hong Kong | Liu B.,Guangzhou No 12 Hospital | And 5 more authors.
Sleep | Year: 2011

Study Objectives: To examine the association between sleep-related factors and memory impairment. Design: Cross-sectional study Setting: Community-based study in Guangzhou, China. Participants: 28,670 older Chinese (20,776 women and 7,894 men) aged 50 to 85 years. Measurements and Results: 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).Conclusions: 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. © Copyright 2011 Associated Professional Sleep Societies, LLC.


Xu L.,University of Hong Kong | Jiang C.Q.,Guangzhou No 12 Hospital | Lam T.H.,University of Hong Kong | Zhang W.S.,Guangzhou No 12 Hospital | And 2 more authors.
Annals of Epidemiology | Year: 2011

Purpose: To examine, via cross-sectional analysis, the dose-response association between physical activity and cognitive function in Chinese subjects. Methods: 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). Results: 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. Conclusions: 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. © 2011 Elsevier Inc.


Lin Q.-H.,Guangzhou No 12 Hospital | Jiang C.-Q.,Guangzhou No 12 Hospital | Lam T.H.,University of Hong Kong
Journal of Occupational Health | Year: 2013

stress and social support were strong predictors of emotional exhaustion. Psychoticism, passive coping, occupational stress, objective support, utilization of support, male gender and job satisfaction were strong predictors of depersonalization. Active and passive coping and job satisfaction were strong predictors of personal accomplishment. Job dissatisfaction and emotional exhaustion were strong predictors of turnover intention. Conclusions: High occupational stress and low job satisfaction were associated with high burnout, particularly in the emotional exhaustion and depersonalization dimensions. Low job satisfaction and high emotional exhaustion were associated with high turnover intention among employees. Personality traits, social support and coping style were also found to be associated with burnout.


Wu M.,Southern Medical University | Mao C.,Southern Medical University | Chen Q.,Southern Medical University | Cu X.-W.,Southern Medical University | Zhang W.-S.,Guangzhou No 12 Hospital
Molecular Biology Reports | Year: 2010

The aim of this study to determine whether serum p53 protein and antibodies are associated with malignant tumors. A case-control study was conduct in 569 patients with various types of malignant tumors and 879 healthy controls. Serum p53 protein and antibodies were analyzed by enzyme-linked immunosorbent assay (ELISA).The rate of positive p53 protein in patients with various malignant tumors was 4.22% compared with 0.34% in healthy controls (P < 0.001). The rate of anti-p53 antibodies in patients with various malignant tumors was 14.59% compared with 1.02% in healthy controls (P < 0.001). The adjusted odd ratio (OR) for p53 protein was 17.55 (95% CI = 4.98-61.94). The adjusted odd ratio for anti-p53 antibodies was 14.27 (95% CI = 6.75-30.16). The study strongly suggested that serum p53 protein and antibody are associated with increased cancer risk and can be used as early serological markers in the diagnosis of malignancies tumors. © 2009 US Government Employee.


Bao B.,Guangzhou No 12 Hospital
Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi | Year: 2010

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.

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