Systematic differences among never, occasional and moderate alcohol users in southern China, and its use in alcohol research: a cross-sectional study

BACKGROUND

Western observational studies show moderate alcohol use, compared with never use, positively associated with health. Moderate users differ systematically from others, making these observations vulnerable to confounding. Observations from other contexts may help distinguish whether these associations are confounded. To assess whether southern Chinese would provide a more suitable setting to examine the association of moderate alcohol use with health, we compared never alcohol users with moderate alcohol users and occasional users in this setting.

METHODS

We used age-adjusted multinomial regression to assess sex-stratified associations of alcohol use (never, occasional (<1 occasion/week), moderate (≤140 g ethanol/week for women and ≤210 g for men)) with health attributes and indicators in the Guangzhou Biobank Cohort Study (2003-2008) (n=26 361).

RESULTS

Among men, moderate alcohol users, when compared with never users, had slightly lower socioeconomic position and unhealthier lifestyle. Conversely, occasional alcohol users, when compared with never users, had higher socioeconomic position and healthier lifestyle. Among women, when compared with never users, both occasional and moderate users had higher socioeconomic position and healthier lifestyle. However, all alcohol users for both sexes, when compared with never users, were more likely to be ever smokers and to be exposed to secondhand smoke.

CONCLUSIONS

Observations in alcohol epidemiology may be affected by confounding due to contextually specific systematic differences. Results from a particular setting should not be interpreted as causal unless they are verified in different populations and, preferably, in non-observational studies.

Artifact properties of carbon nanotube yarn electrode in magnetic resonance imaging

OBJECTIVE

Deep brain stimulating (DBS) is a rapidly developing therapy that can treat many refractory neurological diseases. However, the traditional DBS electrodes which are made of Pt-Ir alloy may induce severe field distortions in magnetic resonance imaging (MRI) which leads to artifacts that will lower the local image quality and cause inconvenience or interference. A novel DBS electrode made from carbon nanotube yarns (CNTYs) is brought up to reduce the artifacts. This study is therefore to evaluate the artifact properties of the novel electrode.

APPROACH

We compared its MR artifact characteristics with the Pt-Ir electrode in water phantom, including its artifact behaviors at different orientations as well as at various off-center positions, using both spin echo (SE) and gradient echo (GE) sequences, and confirmed its performance in vivo.

MAIN RESULTS

The results in phantom showed that the CNTY electrode artifacts reduced as much as 62% and 74% on GE and SE images, respectively, compared to the Pt-Ir one. And consistent behaviors were confirmed in vivo. The susceptibility difference was identified as the dominant cause in producing artifacts.

SIGNIFICANCE

Employing the CNTY electrode may generate much less field distortion in the vicinity, improve local MR image quality and possibly be beneficial in various aspects.

Evaluation of moderate alcohol use and cognitive function among men using a Mendelian randomization design in the Guangzhou biobank cohort study

Observational studies usually show that moderate alcohol use is associated with better cognitive function. Such studies are vulnerable to residual confounding arising from systematic differences between moderate alcohol users and others. A Mendelian randomization study carried out in a suitable population, such as southern Chinese men, in which alcohol use is low to moderate and is influenced by genotype, offers an alternative and superior approach for clarifying the causal effect of moderate alcohol use on cognitive function. The authors used aldehyde dehydrogenase 2 (ALDH2) genotype (AA, GA, or GG) as an instrumental variable in 2-stage least squares analysis to obtain unbiased estimates of the relation of alcohol consumption (measured in alcohol units (10 g ethanol) per day) with cognitive function, assessed from delayed 10-word recall score (n = 4,707) and Mini-Mental State Examination (MMSE) score (n = 2,284), among men from the Guangzhou Biobank Cohort Study (2003-2008). ALHD2 genotype was strongly associated with alcohol consumption, with an F statistic of 71.0 in 2-stage least squares analysis. Alcohol consumption was not associated with delayed 10-word recall score (-0.03 words per alcohol unit, 95% confidence interval: -0.18, 0.13) or MMSE score (0.06 points per alcohol unit, 95% confidence interval: -0.22, 0.34). Moderate alcohol use is unlikely to be cognitively protective.

Intergenerational influences on diabetes in a developing population: the Guangzhou Biobank Cohort Study

OBJECTIVES

Intergenerational "mismatch" and/or growth conditions may be relevant to the epidemic of diabetes in developing populations. In a rapidly developing southern Chinese population, we tested whether maternal environment, proxied by maternal literacy, or family socio-economic position (SEP), proxied by paternal literacy, were associated with fasting glucose and diabetes. To assess if intergenerational mismatch contributed, we tested whether the associations varied by life course SEP.

METHODS

In 19,818 older (≥50 years) adults from the Guangzhou Biobank Cohort Study (phases 2 and 3), we used censored and logistic regression to assess the associations of maternal and paternal literacy with fasting glucose, elevated fasting glucose and diabetes and whether these associations varied by sex, age or life course SEP.

RESULTS

Maternal, but not paternal, literacy was negatively associated with fasting plasma glucose (β-coefficient -0.06 mmol/l, 95% confidence interval (CI) -0.11 to -0.01) and elevated fasting glucose (odds ratio (OR) 0.92, 95% CI 0.86-0.99) adjusted for age, sex, study phase, life course SEP, childhood growth, adiposity, number of offspring, and birth order. Associations of maternal and paternal literacy with fasting glucose, elevated fasting glucose and diabetes did not vary by sex, age or life course SEP.

CONCLUSION

Offspring of literate mothers had lower risk for impaired glucose tolerance than offspring of illiterate mothers. Being raised by literate mothers may increase the likelihood of children with higher SEP and lower long-term disease risk, or better maternal conditions over generations may be associated with lower fasting glucose.

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.

Childhood meat eating and inflammatory markers: the Guangzhou Biobank Cohort Study

BACKGROUND

We hypothesized that socio-economic development could, via nutritionally driven levels of pubertal sex-steroids, promote a pro-inflammatory state among men but not women in developing countries. We tested this hypothesis, using recalled childhood meat eating as a proxy for childhood nutrition, in southern China.

METHODS

We used multivariable linear regression in the Guangzhou Biobank Cohort Study phase 3 (2006-8) to examine the adjusted associations of recalled childhood meat eating, <1/week (n = 5,023), about once per week (n = 3,592) and almost daily (n = 1,252), with white blood cell count and its differentials among older (≥ 50 years) men (n = 2,498) and women (n = 7,369).

RESULTS

Adjusted for age, childhood socio-economic position, education and smoking, childhood meat eating had sex-specific associations with white blood cell count and lymphocyte count, but not granulocyte count. Men with childhood meat eating almost daily compared to <1/week had higher white blood cell count (0.33 109/L, 95% confidence interval (CI) 0.10 to 0.56) and higher lymphocyte count (0.16 109/L, 95% CI 0.07 to 0.25). Adjustment for obesity slightly attenuated these associations.

CONCLUSION

If confirmed, this hypothesis implies that economic development and the associated improvements in nutrition at puberty may be less beneficial among men than women; consistent with the widening sex differentials in life expectancy with economic development.

Estimated birth weight and adult cardiovascular risk factors in a developing southern Chinese population: a cross sectional study

Background

Birth weight is negatively associated with cardiovascular diseases and diabetes, but the associations are less well-established in developing populations where birth weight is often unavailable. We studied the association of birth weight and cardiovascular risk, using birth rank as an instrumental variable, in Southern China.

Methods

We used published data on birth weight by birth rank from an appropriate population and baseline data from the Guangzhou Biobank Cohort Study phases 2 & 3 (2005-8) to examine the adjusted associations, using instrumental variable analysis, of birth weight with clinically measured cardiovascular risk factors and the metabolic syndrome in older (≥ 50 years) men (n = 5,051) and women (n = 13,907).

Results

Estimated birth weight was associated with lower blood pressure (systolic -0.25 mm Hg 95% confidence interval (CI), -0.53 to 0.03 and diastolic -0.33 mm Hg 95% CI -0.48 to -0.18 per standard deviation higher birth weight), but had little association with glucose, lipids, waist-hip ratio, body mass index or the metabolic syndrome, adjusted for age, sex, early environment and number of offspring.

Conclusion

Birth weight may impact blood pressure; however associations of birth weight with other cardiovascular risk factors may not be related to foetal exposures, but speculatively could be an historical co-incidence, with corresponding implications for prevention.

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.

Airflow obstruction and metabolic syndrome: the Guangzhou Biobank Cohort Study

There is some evidence that chronic obstructive pulmonary disease (COPD) and metabolic syndrome may be related, perhaps through systemic inflammation, which is common to both. However, the association between the two conditions has not yet been clearly shown. The present study involved 7,358 adults aged > or =50 yrs from a population-based survey who underwent spirometry, a structured interview and measurement of fasting metabolic marker levels. Airflow obstruction (forced expiratory volume in 1 s/forced vital capacity ratio of less than the lower limit of normal) was present in 6.7%, and the International Diabetes Federation metabolic syndrome criteria were met by 20.0%. The risk of metabolic syndrome was higher in those with airflow obstruction than in those without (odds ratio (OR) 1.47; 95% confidence interval (CI) 1.12-1.92), after controlling for potential confounders. Of the five components of metabolic syndrome, only central obesity was significantly associated with airflow obstruction (OR 1.43; 95% CI 1.09-1.88) after adjusting for body mass index. A similar association was observed in both never and current smokers. In this Chinese sample, airflow obstruction was associated with metabolic syndrome, and, in particular, its central obesity component. This may help explain the increased risk of cardiovascular diseases in COPD, and so could guide future clinical practice.

What causes H5N1 avian influenza? Lay perceptions of H5N1 aetiology in South East and East Asia

BACKGROUND

Health education to reduce population poultry exposures has limited effect. Lay beliefs about H5N1 highly pathogenic avian influenza (HPAI) causes could provide insights helpful for improving public health interventions.

METHODS

Qualitative interviews of poultry farmers, retailers, market stall holders and consumers in Hong Kong (n = 20), Guangzhou (n = 25), Vietnam (n = 38) and Thailand (n = 40) were conducted using purposive sampling and analysed using ethnographic principles.

RESULTS

Each location produced three comparable themes: 'viruses': HPAI exemplified a periodic, natural, disease process therefore, deserving little concern. For some, science had 'discovered' something long known to farmers and lived with for generations. Others believe the virus to be new. Viral ecology was reasonably well understood among farmers, but less so by retailers and consumers; 'husbandry practices' included poor hygiene, overcrowding and industrial farming, modern commercial feed and veterinary drugs; 'vulnerability factors' included uncontrollable 'external' explanations involving the weather, seasonal changes, bird migrations and pollution.

CONCLUSIONS

Lay explanations were generally ecologically consistent. Nonetheless, beliefs that HPAI is a normal, recurrent process, external factors and roles of industrialized poultry rearing countered health worker claims of H5N1 seriousness for smallholders. These causal beliefs incorporate contemporary models of H5N1 ecology, but in a manner that contradicts public health efforts at control.

Are height and leg length universal markers of childhood conditions? The Guangzhou Biobank cohort study

OBJECTIVE

In developed western populations longer legs have been shown to be a marker of better early childhood conditions. In the first generations to experience the epidemiologic transition and associated economic development, epigenetic constraints on growth might preclude improved childhood conditions from increasing leg growth or height.

DESIGN, SETTING AND PARTICIPANTS

Multivariable linear regression was used to assess the association of parental growth environment, proxied by parental literacy, and childhood conditions, proxied by parental possessions, with leg length, sitting height and height in a cross-sectional sample from 2005-6 of 9998 Chinese people aged at least 50 years from phase 2 of the Guangzhou Biobank Cohort Study.

MAIN RESULTS

Adjusted for age and sex, the association of childhood conditions with leg length and height varied with parental literacy (interaction p values <0.01 and 0.03), but not for sitting height (p value 0.43), with statistically significant trends (p values <0.01) for parental possessions to be associated with longer legs and greater height only in the offspring of two literate parents where legs were longer by 0.56 cm (95% CI 0.27 to 0.86) and height greater by 1.16 cm (95% CI 0.74 to 1.58) for participants with most, compared with least, parental possessions in childhood.

CONCLUSIONS

Epigenetic influences originating in earlier generations may constrain growth during the infancy and/or childhood phases in very recently developed populations. Neither height nor leg length should be assumed to be consistent proxies of early life environment with corresponding implications for economic history, the aetiology of some chronic diseases and the monitoring of population health.

Alcohol use and fasting glucose in a developing southern Chinese population: the Guangzhou Biobank Cohort Study

BACKGROUND

In observational studies, mainly from Western Caucasian populations, moderate alcohol use has been shown to be associated with a lower risk of diabetes. However, whether the protection is due to the attributes of alcohol or to those of moderate alcohol users is difficult to disentangle. A population with a different distribution of alcohol consumption and diabetes prevalence from Western populations was studied as a counterfactual comparison.

METHODS

Baseline data from the Guangzhou Biobank Cohort Study phases 1 and 2 (2003-6) were used to examine the adjusted associations, using multivariable censored linear regression, of alcohol use with fasting blood glucose in older (> or =50 years) men (n = 5740) and women (n = 14 274) from southern China. Moderate alcohol use was defined as weekly drinking of < or =210 g alcohol in men and < or =140 g in women. The expected associations of alcohol with high-density lipoprotein (HDL) cholesterol and blood pressure were also checked.

RESULTS

Moderate alcohol users had very similar fasting glucose levels to never users, adjusted for age, sex, socioeconomic status, smoking and physical activity. In contrast, moderate alcohol users had higher HDL-cholesterol by 0.05 mmol/litre (95% CI 0.02 to 0.07). Excessive (more than moderate) alcohol users had higher fasting glucose.

CONCLUSIONS

In an understudied population with a different pattern of alcohol use from the populations usually studied, the biologically expected effects of moderate alcohol use were seen, but there was little effect on fasting glucose. Although cross-sectional studies cannot be conclusive, this pattern of findings, if confirmed, suggests that moderate alcohol use may not affect fasting glucose, although excessive use may be a risk factor.

Is leg length a biomarker of childhood conditions in older Chinese women? The Guangzhou Biobank Cohort Study

OBJECTIVE

In developed western populations longer legs have been shown to be a biomarker of better early childhood conditions. It was hypothesised that in transitioning populations better childhood conditions may bring forward puberty and thus decrease leg length, counteracting the overall positive effect of a favourable childhood environment on leg growth.

DESIGN

Structural equation modelling was used to assess the interrelationship of age, education, father's job, age of menarche and leg length in a cross-sectional sample of 7273 Chinese women aged at least 50 years from the Guangzhou Biobank Cohort Study.

RESULTS

Leg length had no significant association with education or father's occupation on bivariable testing. After including age of menarche in the model, education was associated with longer legs (0.45 cm longer per 10 years of education, 95% CI 0.20 to 0.71). Education was also associated with younger age of menarche (1.21 years younger per 10 years of education, 95% CI 1.09 to 1.34), which was in turn associated with shorter legs (0.23 cm shorter per year of menarche earlier, 95% CI 0.18 to 0.27).

CONCLUSIONS

In older Chinese women leg length is not a universal biomarker of childhood conditions, when proxied by her educational level and father's occupation. Nutritionally driven epigenetic influences operating over generations may constrain growth in very recently developed populations. Given the impact of childhood conditions on health, and the dearth of long-term records outside the industrialised world, a greater understanding of the influences on growth in the developing world is required.

Life-course origins of social inequalities in metabolic risk in the population of a developing country

In countries that have been industrialized for a long time, but not always elsewhere, low socioeconomic position (SEP) is associated with ischemic heart disease in men. The authors hypothesized that socioeconomic development could, via pubertal sex steroids, promote an atherogenic lipid profile and body shape in men but not in women. Therefore, they examined the associations of SEP with ischemic heart disease risk in a developing-country population. The authors used multivariable regression to examine the associations of SEP with the metabolic syndrome and its components in 9,746 Chinese adults aged >/=50 years from the Guangzhou Biobank Cohort Study, phase 2, recruited in 2005-2006. After adjustment for age, smoking, alcohol use, and physical activity, high SEP at each of three life stages, proxied by parental possesions in childhood, education, and longest held-occupation, was inversely associated with the metabolic syndrome in women but not in men. Higher SEP in men was associated with lower pulse pressure and fasting plasma glucose level but also with greater waist circumference and a lower high density lipoprotein cholesterol level. With socioeconomic development, diet-related hormonal changes at puberty may outweigh the usual protective effect of social advantage in men, with corresponding implications for boys currently undergoing the nutrition transition in the developing world.

c-Reactive protein and the metabolic syndrome in older Chinese: Guangzhou Biobank Cohort Study

OBJECTIVE

To examine the association between serum c-reactive protein (CRP) concentration and the metabolic syndrome (MS) using the International Diabetes Federation Metabolic Syndrome Guidelines (April, 2005) definition in an older Chinese population.

METHODS

Three thousand and fourteen men and 7275 women aged 50-85 years were recruited and received a full medical check-up including measurement of blood pressure, obesity indices, fasting total, LDL-, HDL-cholesterol, triglycerides, glucose and c-reactive protein. Data describing socioeconomic and lifestyle factors was also collected.

RESULTS

Vascular risk factors including waist circumference, weight gain and waist gain since the age of 18, body mass index, waist-hip-ratio, triglyceride, HDL-cholesterol, and systolic and diastolic blood pressures were positively associated with CRP in both men and women (p from <0.001 to 0.016). Compared to those without MS components, adjusted odds ratios for having elevated CRP increased in those with the MS or its components compared those without MS or components (all p<0.001), except for the low HDL-cholesterol in both genders and raised fasting glucose in men. Similarly, the risk of elevated CRP increased with escalating MS components even after adjustment of a range of potential confounders.

CONCLUSIONS

There is a strong relationship between CRP and the constellation of MS components and associated vascular risk in this older Chinese population.

Implications of increased weight and waist circumference on vascular risk in an older Chinese population: the Guangzhou Biobank Cohort Study

BACKGROUND

The relationships between weight and waist on vascular risk are well described, but the long-term impact of these parameters is less clearly defined, particularly in Chinese populations.

METHODS

Ten thousand four hundred and ten older subjects (50-85 years) were recruited and blood pressure, anthropometric, and fasting vascular risk factors measured. Socioeconomic and demographic data, including self-reported weight and waist gain since 18 years. The association of weight and waist gain with these vascular risk factors was analysed.

RESULTS

Weight, and particularly waist gain were associated with a more adverse vascular risk factor profile, with the most adverse profile associated with gains in both weight and waist. Anthropometric gains were associated with increased risk even in non-obese subjects (p<0.05). Even after adjustment for a range of demographic and socioeconomic factors, waist gain was associated with additional risk of having the metabolic syndrome and its components and self-reported vascular disease in those centrally obese subjects (p<0.05 for all).

CONCLUSION

Increased weight and waist increased the level of vascular risk factors and self-reported disease in both non-obese and obese subjects. The high prevalence of vascular risk factors in this population forewarns of a major developing health burden in the rapidly modernising 1.2 billion Chinese population.

Passive smoking exposure and risk of COPD among adults in China: the Guangzhou Biobank Cohort Study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality in China, where the population is also exposed to high levels of passive smoking, yet little information exists on the effects of such exposure on COPD. We examined the relation between passive smoking and COPD and respiratory symptoms in an adult Chinese population.

METHODS

We used baseline data from the Guangzhou Biobank Cohort Study. Of 20 430 men and women over the age of 50 recruited in 2003-06, 15,379 never smokers (6497 with valid spirometry) were included in this cross-sectional analysis. We measured passive smoking exposure at home and work by two self-reported measures (density and duration of exposure). Diagnosis of COPD was based on spirometry and defined according to the GOLD guidelines.

FINDINGS

There was an association between risk of COPD and self-reported exposure to passive smoking at home and work (adjusted odds ratio 1.48, 95% CI 1.18-1.85 for high level exposure; equivalent to 40 h a week for more than 5 years). There were significant associations between reported respiratory symptoms and increasing passive smoking exposure (1.16, 1.07-1.25 for any symptom).

INTERPRETATION

Exposure to passive smoking is associated with an increased prevalence of COPD and respiratory symptoms. If this association is causal, we estimate that 1.9 million excess deaths from COPD among never smokers could be attributable to passive smoking in the current population in China. Our findings provide strong evidence for urgent measures against passive smoking in China.

Impact of smoking and smoking cessation on lung cancer mortality in the Asia-Pacific region

Cigarette smoking is becoming increasingly common in Asia while quitting remains rare, in part because of a lack of knowledge about the risks of smoking. This study compared the risk of death from lung cancer associated with smoking habits in Australia and New Zealand and in Asia by using data from the Asia Pacific Cohort Studies Collaboration: 31 studies involving 480,125 individuals. Cox regression models were used. The hazard ratios for lung cancer mortality associated with current smoking were, for men, 2.48 (95% confidence interval (CI): 1.99, 3.11) in Asia versus 9.87 (95% CI: 6.04, 16.12) in Australia and New Zealand; p for homogeneity <0.0001. For women, the corresponding estimates were 2.35 (95% CI: 1.29, 4.28) in Asia versus 19.33 (95% CI: 10.0, 37.3) in Australia and New Zealand; p for homogeneity <0.0001. Quitting was beneficial in both regions; the hazard ratios for former compared with current smokers were 0.69 (95% CI: 0.53, 0.92) in Asia and 0.30 (95% CI: 0.22, 0.41) in Australia and New Zealand. The lesser effect in Asia was partly explained by the fewer number of cigarettes smoked and the shorter duration of follow-up in Asian studies. These results suggest that tobacco control policies in Asia should not solely concentrate on preventing the uptake of smoking but also attend to cessation.

Association of the metabolic syndrome with vascular disease in an older Chinese population: Guangzhou Biobank Cohort Study

OBJECTIVE

To assess the prevalence of the metabolic syndrome (MS) and relative associations with vascular disease in an older Chinese population using the US National Cholesterol Education Program: Adult Treatment Panel (NCEP: ATP III) and International Diabetes Federation (IDF) definitions.

DESIGN

Cross-sectional study.

SUBJECTS

A total of 3035 men and 7291 women aged 50 to 85 yr recruited from Guangzhou, China.

MEASUREMENTS

All participants received a full medical check-up including measurement of blood pressure, obesity indices, fasting total, LDL-, HDL-cholesterol, triglycerides (TG) and glucose levels. Demographic information and self-reported history of physician-diagnosed coronary heart disease (CHD), stroke and myocardial infarction (MI) were collected through standardized interview.

RESULTS

The estimates under the two definitions differed substantially, with the age standardized prevalence of MS 15.57% using the NCEP: ATP III definition and 25.81% using the IDF definition. Among all participants, 80.23% were similarly classified using both definitions. The association between self-reported CHD, stroke and MI and the MS defined by the IDF definition was stronger than that by the NCEP: ATP III.

CONCLUSIONS

The IDF compared to the ATP III definition shows a stronger association with the MS and associated vascular disease in Chinese. The prevalence of the MS is alarmingly high in this older Chinese population. Comprehensive strategies are needed for prevention and treatment of the MS to reduce the increased societal burden of cardiovascular disease in China.

Parity and the metabolic syndrome in older Chinese women: the Guangzhou Biobank Cohort Study

OBJECTIVE

To examine whether parity or gravidity contributes to the development of the metabolic syndrome (MS).

METHODS

The first phase of the Guangzhou Biobank Cohort Study recruited 7352 women and 3065 men aged 50-93 years in 2003-4. Data on the number of live births and pregnancies, other reproduction-associated factors and socioeconomic and lifestyles factors were collected by standardized interview. The MS components were determined through physical examination and measurement of fasting blood samples. MS was identified if waist circumference was >or= 90 cm for men or >or= 80 cm for women, plus any two of: (a) raised triglyceride (TG) level (1.7 mmol/l) or specific treatment for this lipid abnormality; (b) reduced high density lipoprotein (HDL)-cholesterol (< 1.03 mmol/l in males or < 1.29 mmol/l in females) or specific treatment for this lipid abnormality; (c) raised blood pressure (BP, systolic BP >or= 130 mmHg or diastolic BP >or= 85 mmHg) or hypertension therapy; and (d) raised fasting glucose (>or= 5.6 mmol/l) or previously diagnosed type 2 diabetes.

RESULTS

Before adjustment for potential confounders, we found associations between the number of births and lifestyle and socioeconomic factors in both sexes. However, in women, but not in men, body mass index (BMI), waist-hip ratio, triglyceride and glucose were positively associated with the number of birth after adjusting for a range of potential confounders. The age-adjusted prevalence of the MS increased with the number of births and pregnancies in women, but the gradient for birth was steeper than that for pregnancies [odds ratio change per birth 1.16, 95% confidence interval (CI) 1.11-1.22, P < 0.001; odds ratio change per pregnancy 1.11, 95% CI 1.06-1.16, P < 0.001], although attenuating the association adjustment did not affect the significance of these findings. There was no association in men with regard to the number of their partners' live births given the same analysis and similar shared living background with the women.

CONCLUSION

Higher parity or gravidity was associated with a consistent increase in the risk of MS in Chinese women. As the association persisted after adjustment for lifestyle factors and there was no association between the risk of MS and the number of births associated with the partners of the males, the association in women may represent a biological response to pregnancy.

Snoring and vascular risk factors and disease in a low-risk Chinese population: the Guangzhou Biobank Cohort Study

STUDY OBJECTIVE

Snoring is a common condition, but data describing the relationship between snoring and vascular disease is very limited in Asian populations. We therefore describe the association between snoring and vascular disease and associated risk factors.

DESIGN

Cross-sectional study of baseline data from the Guangzhou Biobank Cohort Study.

SETTING

Community-based elderly association from Guangzhou, China.

PARTICIPANTS

10413 Chinese subjects (50-85 years of age).

MEASUREMENTS

Self-reported snoring status and frequency and frequency of daytime tiredness were collected by questionnaire, as were demographic and socioeconomic data, disease histories, and potential confounders, such as smoking and alcohol consumption. Anthropometry, blood pressure, and fasting glucose and lipid profile were also measured.

RESULTS

Self-reported snoring frequency was identified in 8325 (80.0%) subjects, with 51.6% reporting that they snored, of whom 15.5% were daily snorers. Increasing prevalence of snoring showed a clear positive relationship with cardiovascular risk factors, including age, obesity, blood pressure, and lipid levels (p < .001 for all). The prevalence of self-reported vascular-disease history was low but significantly associated with increasing snoring frequency. Logistic regression showed that snoring frequency was an independent predictor of vascular-disease history (odds ratios [95% confidence intervals] 1.68 [1.32-2.13] for daily snorers compared with the never-snorer reference group), of the metabolic syndrome (2.16 [1.88-2.49]) and each of its components (hypertension [1.37 (1.20-1.56)], and of dyslipidemia [1.22 (1.07-1.40)], central obesity [2.39 (2.08-2.76)], and diabetes [1.30 (1.09-1.56)]) after adjustment for potential confounders.

CONCLUSION

Increasing snoring frequency was associated with an increasing prevalence of risk factors and self-reported vascular disease. Snoring may a useful marker for increased risk of vascular disease.

Dysbaric osteonecrosis by X-ray and CT scan in Chinese divers

OBJECTIVE

To compare the results of X-ray and CT scan for dysbaric osteonecrosis in Chinese divers.

METHODS

Both shoulders, hips and knees of 66 asymptomatic divers with diving duration of more than one year were examined by X-ray and CT scan.

RESULTS

The most frequent locations of dysbaric osteonecrosis were the upper femurs, followed by the upper humerus, lower femurs and upper tibias, and the most frequent radiographic lesions were calcification spots and cystic changes. Of the lesions detected, 38% (27/71) and 42% (95/229) werejuxta-articular of the femoral and humeral heads by X-ray and CT respectively. The detection rates of dysbaric necrosis (juxta- and/or other lesions) of X-ray and CT scan were 42.4% (95% confidence interval: 30.5%-54.3%) and 81.8% (95% CI: 72.4%-91.2%) respectively (p<0.05). If CT scan was used as the gold standard, the sensitivity of X-ray was 100% and the specificity was 31.6%.

CONCLUSION

CT scan showed a higher detection rate of dysbaric necrosis than X-ray. We recommend that CT scan be used for early diagnosis of dysbaric osteonecrosis.