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.

[Study design and the preliminary results on the modes of smoking cessation in general hospitals]

To study the intervention programs on smoking cessation in a general hospital and to evaluate its effects of the programs. Four methods including: a) the intervention through specialists in the smoking cessation clinic, b) short-time intervention in the out-patient department, c) free medical intervention, d) group intervention, were adopted for different smokers, with health counseling, psychological intervention and drug treatment. Intervention effect was evaluated by standard methods. During the 20-month period of the project, we treated 690 cases and 402 completed 6-month follow-up. Preliminary results in 402 cases showed that the three methods of smoking cessation interventions could reduce the amount of cigarette smoking and increase the quitting rate. Motivation to quit smoking, intervention methods and intensity of intervention seemed the main factors. The quit rate of 6-month follow-up in the 'specialist intervention' in the smoking cessation clinic (31.6%) and in the group intervention (30.9%) was higher than short-time intervention in free medical events (15.1%). The successful rate of smoking cessation depended on the motivation of quitters, and the attitude, methods and intervention skills of the physicians. Therefore, it is necessary to explore and develop smoking cessation service models suitable to national context and individual intervention methods in China.

Replication study of SNP associations for colorectal cancer in Hong Kong Chinese

BACKGROUND

Recent genome-wide association studies of colorectal cancer (CRC) have identified common single-nucleotide polymorphisms (SNPs) mapping to 10 independent loci that confer modest increased risk. These studies have been conducted in European populations and it is unclear whether these observations generalise to populations with different ethnicities and rates of CRC.

METHODS

An association study was performed on 892 CRC cases and 890 controls recruited from the Hong Kong Chinese population, genotyping 32 SNPs, which were either associated with CRC in previous studies or are in close proximity to previously reported risk SNPs.

RESULTS

Twelve of the SNPs showed evidence of an association. The strongest associations were provided by rs10795668 on 10p14, rs4779584 on 15q14 and rs12953717 on 18q21.2. There was significant linear association between CRC risk and the number of independent risk variants possessed by an individual (P=2.29 × 10(-5)).

CONCLUSION

These results indicate that some previously reported SNP associations also impact on CRC risk in the Chinese population. Possible reasons for failure of replication for some loci include inadequate study power, differences in allele frequency, linkage disequilibrium structure or effect size between populations. Our results suggest that many associations for CRC are likely to generalise across populations.

A pilot double-blind randomised placebo-controlled trial of the effects of fixed-dose combination therapy ('polypill') on cardiovascular risk factors

AIM

Our objective was to investigate the effects and tolerability of fixed-dose combination therapy on blood pressure and LDL in adults without elevated blood pressure or lipid levels.

METHODS

This was a double-blind randomised placebo-controlled trial in residents of Kalaleh, Golestan, Iran. Following an 8-week placebo run-in period, 475 participants, aged 50 to 79 years, without cardiovascular disease, hypertension or hyperlipidaemia were randomised to fixed-dose combination therapy with aspirin 81 mg, enalapril 2.5 mg, atorvastatin 20 mg and hydrochlorothiazide 12.5 mg (polypill) or placebo for a period of 12 months. The primary outcomes were changes in LDL-cholesterol, systolic and diastolic blood pressure and adverse reactions. Analysis was by intention-to-treat basis.

RESULTS

At baseline, there were differences in systolic blood pressure (6 mmHg). Taking account of baseline differences, at 12 months, polypill was associated with statistically significant reductions in blood pressure (4.5/1.6 mmHg) and LDL-cholesterol (0.46 mmol/l). The study drug was well tolerated, but resulted in the modest reductions in blood pressure and lipid levels.

CONCLUSION

The effects of the polypill on blood pressure and lipid levels were less than anticipated, raising questions about the reliability of the reported compliance. There is a case for a fully powered trial of a polypill for the prevention of cardiovascular disease.

Mechanisms of recurrence of Ta/T1 bladder cancer

INTRODUCTION

Bladder cancer recurrence occurs via four mechanisms - incomplete resection, tumour cell re-implantation, growth of microscopic tumours, and new tumour formation. The first two mechanisms are influenced by clinicians before and immediately after resection; the remaining mechanisms have the potential to be influenced by chemopreventive agents. However, the relative importance and timing of these mechanisms is currently unknown. Our objective was to postulate the incidence and timing of these mechanisms by investigating the location of bladder cancer recurrences over time.

PATIENTS AND METHODS

The topographical locations of tumours and their recurrences were analysed retrospectively for 169 patients newly-diagnosed with Ta/T1 bladder cancer, with median follow-up of 33.8 months. Tumours were assigned to one or more of six bladder sectors, and time to recurrence and location of recurrences were recorded.

RESULTS

Median time to first tumour recurrence was 40 months. Median times between subsequent recurrences were 6.6, 7.9, 8.0 and 6.6 months for recurrences 1 to 2, 2 to 3, 3 to 4, and 4 to 5, respectively. The risk of first tumour recurrence in any given bladder sector increased by nearly 4-fold if the primary tumour was resected from that sector (P < 0.001); this association was not significant for subsequent recurrences. The proportion of tumour recurrences in multiple bladder sectors increased from 13% for the first recurrence to 100% for recurrence seven onwards.

CONCLUSIONS

First tumour recurrence appears different to subsequent recurrences; incomplete resection and tumour cell reimplantation may dominate at this time-point. Only later does genuine new tumour formation appear to increase in importance. This has important implications for clinical trials, especially those involving chemopreventive agents.

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.

The West Midlands Bladder Cancer Prognosis Programme: rationale and design

OBJECTIVE To describe the rationale and design of the Bladder Cancer Prognosis Programme (BCPP), and to demonstrate the capability of this design. METHODS There is a need to understand the determinants of bladder cancer to help reduce recurrence, progression, morbidity, mortality and related costs. We previously showed that lifestyle factors are important for determining the risk of bladder cancer, but little is known about their importance in determining the risk of recurrence or progression after diagnosis. Also, histopathological factors alone provide only crude prognostication; the analysis of molecular markers represents a method for refinement but research in this area has not been useful in informing therapeutic decisions or prognostication. The BCPP is a prospective longitudinal cohort study of all patients with newly diagnosed bladder cancer within the West Midlands (UK), investigating the influence of lifestyle factors on recurrence and progression, health-related quality of life, the predictive effect of a panel of molecular markers on recurrence or progression, and the establishment of Europe's largest comprehensive bladder cancer bio-repository. It also incorporates the first randomized clinical trial on the efficacy of selenium and vitamin E on bladder cancer. The numbers and proportions of eligible patients recruited, questionnaires completed and specimens obtained were all recorded. RESULTS Since December 2005, 771 patients have been recruited (68% of eligible patients) and of these, 331 are currently being followed up by questionnaires. We have obtained blood, urine and tumour tissues from 92%, 80% and 80% of patients, respectively. CONCLUSIONS The design of the BCPP has allowed this study to be incorporated into routine clinical work throughout the West Midlands, achieving high levels of recruitment, and data and specimen collection. This might represent a model for the future investigation of urological and other malignancies.

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.

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.

Refinement of the basis and impact of common 11q23.1 variation to the risk of developing colorectal cancer

The common single-nucleotide polymorphism (SNP) rs3802842 at 11q23.1 has recently been reported to be associated with risk of colorectal cancer (CRC). To examine this association in detail we genotyped rs3802842 in eight independent case-control series comprising a total of 10 638 cases and 10 457 healthy individuals. A significant association between the C allele of rs3802842 and CRC risk was found (per allele OR = 1.17; 95% confidence interval [CI]: 1.12-1.22; P = 1.08 x 10(-12)) with the risk allele more frequent in rectal than colonic disease (P = 0.02). In combination with 8q21, 8q24, 10p14, 11q, 15q13.3 and 18q21 variants, the risk of CRC increases with an increasing numbers of variant alleles for the six loci (OR(per allele) = 1.19; 95% CI: 1.15-1.23; P(trend) = 7.4 x 10(-24)). Using the data from our genome-wide association study of CRC, LD mapping and imputation, we were able to refine the location of the causal locus to a 60 kb region and screened for coding changes. The absence of exonic mutations in any of the transcripts (FLJ45803, LOC120376, C11orf53 and POU2AF1) mapping to this region makes the association likely to be a consequence of non-coding effects on gene expression.

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.

An assessment of the quality of randomised controlled trials conducted in China

Background

Despite the rapid increase in research in China, little is known about the quality of clinical trials conducted there.

Methods

A systematic review and critical appraisal of randomised controlled trials (RCTs) conducted in China and published in 2004 was undertaken to describe their characteristics, assess the quality of their reporting, and where possible, the quality of their conduct. Randomised controlled trials in all disease areas and types of interventions, which took place in China and included Chinese citizens were identified using PubMed and hand searching the Journal Series of the Chinese Medical Association. Quality was assessed against a subset of criteria adapted from the CONSORT statement.

Results

Three hundred and seven RCTs were included. One hundred and ninety-nine (64.8%) failed to report methods of randomization and 254 (82.4%) did not mention blinding of either participants or investigators. Reporting of baseline characteristics, primary outcome and length of follow-up was inadequate in a substantial proportion of studies. Fewer than 11% of RCTs mentioned ethical approval and only 18.0% adequately discussed informed consent. However, dropout rates were very favourable with nearly 44% of trials reporting a zero dropout rate.

Conclusion

Reporting of RCTs in China requires substantial improvement to meet the targets of the CONSORT statement. The conduct of Chinese RCTs cannot be directly inferred from the standard of reporting; however without good reporting the methods of the trials cannot be clearly ascertained.

A genome-wide association study identifies colorectal cancer susceptibility loci on chromosomes 10p14 and 8q23.3

To identify colorectal cancer (CRC) susceptibility alleles, we conducted a genome-wide association study. In phase 1, we genotyped 550,163 tagSNPs in 940 familial colorectal tumor cases (627 CRC, 313 high-risk adenoma) and 965 controls. In phase 2, we genotyped 42,708 selected SNPs in 2,873 CRC cases and 2,871 controls. In phase 3, we evaluated 11 SNPs showing association at P < 10(-4) in a joint analysis of phases 1 and 2 in 4,287 CRC cases and 3,743 controls. Two SNPs were taken forward to phase 4 genotyping (10,731 CRC cases and 10,961 controls from eight centers). In addition to the previously reported 8q24, 15q13 and 18q21 CRC risk loci, we identified two previously unreported associations: rs10795668, located at 10p14 (P = 2.5 x 10(-13) overall; P = 6.9 x 10(-12) replication), and rs16892766, at 8q23.3 (P = 3.3 x 10(-18) overall; P = 9.6 x 10(-17) replication), which tags a plausible causative gene, EIF3H. These data provide further evidence for the 'common-disease common-variant' model of CRC predisposition.

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.

The importance of anaemia in diagnosing colorectal cancer: a case-control study using electronic primary care records

Although anaemia is recognised as a feature of colorectal cancer, the precise risk is unknown. We performed a case–control study using electronic primary care records from the Health Improvement Network database, UK. A total of 6442 patients had a diagnosis of colorectal cancer, and were matched to 45 066 controls on age, sex, and practice. We calculated likelihood ratios and positive predictive values for colorectal cancer in both sexes across 1 g dl⁻¹ haemoglobin and 10-year age bands, and examined the features of iron deficiency.In men, 178 (5.2%) of 3421 cases and 47 (0.2%) of 23 928 controls had a haemoglobin <9.0 g dl⁻¹, giving a likelihood ratio (95% confidence interval) of 27 (19, 36). In women, the corresponding figures were 227 (7.5%) of 3021 cases and 58 (0.3%) of 21 138 controls, a likelihood ratio of 41 (30, 61). Positive predictive values increased with age and for each 1 g dl⁻¹ reduction in haemoglobin. The risk of cancer for current referral guidance was quantified. For men over 60 years with a haemoglobin <11 g dl⁻¹ and features of iron deficiency, the positive predictive value was 13.3% (9.7, 18) and for women with a haemoglobin <10 g dl⁻¹ and iron deficiency, the positive predictive value was 7.7% (5.7, 11). Current guidance for urgent investigation of anaemia misses some patients with a moderate risk of cancer, particularly men.

[Electrocardiogram change of workers after disengaging occupational noise exposure]

OBJECTIVE

To examine electrocardiogram (ECG) change of workers after leaving occupational noise exposure.

METHODS

In the first phase of the Guangzhou Biobank Cohort Study, 10413 Guangzhou residents aged 50 years or more received a face-to face interview including noise exposure history, a full medical check-up and laboratory tests in 2003 - 4. ECG examination was carried out using 12-lead MAC-CS ECG machine made in HP Ltd, Shanghai, China. ECG of every subject was independently diagnosed by two doctors who had obtained ECG diagnosis qualification.

RESULTS

(1) Among 10413 subjects, 70% were female, and more than half were aged 60-69 years. The mean age and education level in males were higher than those in females. (2) 2119 subjects (21.0%) were previously exposed to noise and were retired now. (3) The prevalence of ECG abnormality was respectively 82.4% and 79.1% in females and males. Rate of ECG abnormality increased with age in both females and males (P = 0.000), and was lower in females with higher education level (P = 0.000). There was not significant difference in ECG abnormality between workers previously exposed or unexposed to noise in both females and males (P > 0.05). 4 Comparing workers previously exposed to those unexposed to noise in both females and males, after adjusting for age, educational level and smoking status, the rates of arrhythmia, axes deviation, atria and ventricle hypertrophy, ST-T change and coronary artery syndrome were not significantly different (P > 0.05).

CONCLUSION

Our study showed that the prevalence of ECG abnormality was not significantly increased in workers previously exposed to noise and had left exposure now compared to those never exposed to noise. Because our study was cross section and occupational history was obtained from a questionnaire but was not confirmed by the companies, further study is needed.