The Anyang Esophageal Cancer Cohort Study: study design, implementation of fieldwork, and use of computer-aided survey system

Disease burden and related risk factors of esophageal cancer in China and globally from 1990 to 2021, with forecast to 2035: An analysis and comparison

INTRODUCTION

In this study we estimate the burden of esophageal cancer (EC) in China and globally from 1990 to 2021, with a forecast to 2035, using Global Burden of Disease (GBD) data. We also analyze the related risk factors to investigate burden trends.

METHODS

Mortality, disability-adjusted life years (DALYs), crude rates, and age-standardized rates of EC were analyzed in China and globally from 1990 to 2035, utilizing GBD open data as a secondary dataset analysis of GBD data. Temporal change trends of EC risk factors were analyzed from 1990 to 2021. Joinpoint regression determined average annual percentage change (AAPC) of age-standardized rates. Descriptive analysis compared mortality and DALYs by age groups. Bayesian age-period-cohort (BAPC) predicted age-standardized mortality and DALYs rates for the next 14 years.

RESULTS

The ASMR and ASDR fluctuations in EC were significant in China, showing an overall downward trend. Globally, although there was also a downward trend, the fluctuations were relatively mild. The number of deaths and DALYs related to EC in China and globally showed a significant upward trend. Age-specific burden trends in China for EC indicated that the age group with the peak number of EC deaths shifted to the 70-74 years age group in 2021, while DALYs peaked in the 65-69 years age group. The crude mortality rate (CMR) peaked consistently in 1990 and 2021, both within the 90-94 years age range, while the crude DALY rate (CDR) shifted to the 85-89 years age group. Overall, the burden of EC deaths and DALYs in the population aged <40 years was relatively low, increasing rapidly after the age of 40 years, reaching a peak and gradually declining, and reaching a lower level after the age of 85 years. The predictive results of the BAPC model indicated that over the next 14 years, both ASMR and ASDR for EC in China and globally would show a slight overall increase. The GBD 2021 study identified smoking, high alcohol use, chewing tobacco, and diet low in vegetables as the main risk factors affecting EC mortality rate and DALYs. Among these, smoking and alcohol use were the most significant risk factors, with a higher impact on EC in China compared to the global level. From 1990 to 2021, the overall changes in ASMR and ASDR indicate a decreasing trend in the impact of these four risk factors on EC mortality rate and DALYs.

CONCLUSIONS

The burden of EC is expected to steadily increase in China and globally until 2035, posing a significant challenge. Targeted prevention and control policies, such as calling on people to quit smoking and reduce alcohol use, may help curb this upward trend.

Construction and validation of serum Metabolic Risk Score for early warning of malignancy in esophagus

Using noninvasive biomarkers to identify high-risk individuals prior to endoscopic examination is crucial for optimization of screening strategies for esophageal squamous cell carcinoma (ESCC). We conducted a nested case-control study based on two community-based screening cohorts to evaluate the warning value of serum metabolites for esophageal malignancy. The serum samples were collected at enrollment when the cases had not been diagnosed. We identified 74 differential metabolites and two prominent perturbed metabolic pathways, and constructed Metabolic Risk Score (MRS) based on 22 selected metabolic predictors. The MRS generated an area under the receiver operating characteristics curve (AUC) of 0.815. The model performed well for the within-1-year interval (AUC: 0.868) and 1-to-5-year interval (AUC: 0.845) from blood draw to diagnosis, but showed limited ability in predicting long-term cases (>5 years). In summary, the MRS could serve as a potential early warning and risk stratification tool for establishing a precision strategy of ESCC screening.

How should extra-large Lugol-unstained lesions of the esophagus be treated? Results from a population-based cohort study

BACKGROUND

Current guidelines recommend only severe dysplasia and above (SDA) lesions of the esophageal squamous epithelium for clinical intervention. However, the histopathologic diagnosis derived from tissue biopsies may be subject to underestimation of severity.

METHODS

1073 participants from whom biopsies were taken at baseline chromoendoscopic examination in a population-based screening trial were enrolled in this study. The size of the Lugol-unstained lesions (LULs) was mainly analyzed. The outcome was defined as SDA lesions either identified at baseline screening, or during follow-up, collectively referred to as the cumulative risk of SDA. Multivariable logistic regression models were used to evaluate the cumulative risk of SDA.

RESULTS

One hundred and forty-six SDA cases were identified in the study period. Participants with large LULs had a high cumulative incidence of SDA (cumulative incidence16-20mm : 55.88%; cumulative incidence>20mm : 76.92%) in the median of 7-year duration. LULs of large size were significantly associated with a higher cumulative risk of SDA, regardless of the pathologic diagnosis (adjusted OR16-20mmvs.≤5mm  = 21.02, 95% CI: 7.56-58.47; adjusted OR>20mmvs.≤5mm  = 33.62, 95% CI: 11.79-95.87).

CONCLUSIONS

Results from this study suggest physician-patient shared decision-making regarding clinical treatment or intensive surveillance should be carried out for LULs >20 mm in the esophagus, regardless of the histologic diagnosis. For those with LULs of 16-20 mm, intensive surveillance would also best be considered.

Esophageal cancer in China: Practice and research in the new era

China, as the one of the largest developing countries in the world and with about one-fifth of the global population, is bearing an increasing burden on health from cancer. In the area of esophageal cancer (EC), China accounts for more than 50% of the global cases, with this disease being a particularly worse for those in disadvantaged populations. Along with China's socioeconomic condition, the epidemiology, diagnosis, therapeutics and research of EC have developed throughout the 21st century. In the current review, existing control measures for EC in China are outlined, including the incidence, mortality, screening, clinical diagnosis, multidisciplinary treatment and research landscape. EC in China are very different from those in some other parts of the world, especially in Western countries. Core measures that could contribute to the prevention of EC and improve clinical outcomes in patients of less developed countries and beyond are recommended. International cooperation among academia, government and industry is especially warranted in global EC control.

Epidemiological landscape of esophageal cancer in Asia: Results from GLOBOCAN 2020

BACKGROUND

Esophageal cancer (EC) is a global health problem. Asia represents a huge burden of EC globally, and incidence and mortality vary considerably across different Asian regions.

METHODS

Data on incidence, mortality, and preference were extracted from GLOBOCAN 2020. Age-standardized incidence and mortality rates were calculated overall by sex, age, country, region, and continent. The predicted burden of incidence and mortality in 2040 was calculated based on global demographic projections.

RESULTS

It was estimated there were 481 552 new cases of and 434 363 deaths from EC in Asia in 2020, accounting for 79.7% and 79.8% of world EC cases and deaths, respectively. EC incidence and mortality in Asia ranked the highest among all continents. Eastern Asia represents the highest age-standardized world incidence rate (ASWIR) of 12.3 per 100 000 for all Asian regions. Western Asia represents the lowest ASWIR of 1.7 per 100 000, accounting for 0.7% of the globe. There exist obvious differences in epidemiological features in Asian countries, including incidence, mortality, prevalence, and mortality incidence ratio. There is forecast to be up to 781 000 new cases of EC in Asia by 2040, with increasing rates of 63% for incidence and 72% for mortality from 2020.

CONCLUSIONS

Asia has an increasing number of EC cases and deaths. Strategies for targeting in high-incidence areas, the elderly, and survival should be prioritized to reduce the global EC burden, especially in low- and middle-income countries in Asia.

Multiple Lugol-unstained lesions predict higher cumulative risk of malignance in the esophagus

BACKGROUND AND AIM

The impact of the presence of multiple Lugol-unstained lesions (LULs) in the esophagus on the risk of having severe dysplasia and above (SDA) lesions among asymptomatic individuals is unknown.

METHODS

We collected demographic factors, behavioral variables, and features of LULs from 1073 participants who were biopsied at baseline endoscopic screening in a population-based screening trial, and these individuals were followed over a median time of 7 years. Outcome events were defined as SDA identified at screening, at reexamination, or during follow-up. "Multiple LULs" were defined as ≥ 2 LULs found in the entirety of the esophagus. Multivariable logistic regression models were fitted to assess the effect of "multiple LULs" on the cumulative risk of SDA.

RESULTS

There were 147 SDA cases in the current study. After adjustment for potential risk factors and endoscopic features of LULs, the presence of "multiple LULs" slightly increased the cumulative risk of having SDA with no statistical significance (adjusted odds ratio [OR] = 1.26; 95% confidence interval [CI] [0.85, 1.88]). Further stratified analysis showed that this association was strong among subjects with small LULs (≤ 5 mm) (adjusted OR = 3.29; 95% CI [1.39, 7.79]). However, no such association was observed in subjects with larger LULs (adjusted OR = 0.99; 95% CI [0.63, 1.55], P _interaction  = 0.022).

CONCLUSIONS

The presence of "multiple small LULs (≤ 5 mm)" in chromoendoscopy indicates a higher cumulative risk of having SDA in the esophagus. We recommend biopsies be taken and surveillance be maintained at a more active level in individuals with relatively small but multiple LULs.

Update and validation of a diagnostic model to identify prevalent malignant lesions in esophagus in general population

BACKGROUND

Previous risk prediction models taking esophageal malignant lesions detected during endoscopy as the primary outcome are not always sufficient to identify prevalent cases which are "overlooked" at screening. We aimed to update and externally validate our previous risk prediction model for malignant esophageal lesions by redefining the predicted outcome.

METHODS

15,192 individuals from the Endoscopic Screening for Esophageal Cancer in China randomized controlled trial (ESECC trial, NCT01688908) were included as the training set, and 4576 participants from another population-based esophageal squamous cell carcinoma (ESCC) screening cohort (Anyang Esophageal Cancer Cohort Study, AECCS) served as the external validation set. Lesions with severe dysplasia or worse diagnosed at chromoendoscopy or identified via follow-up within 1 year after screening were defined as main outcome. Logistic regressions were applied to reconstruct the questionnaire-based prediction model using information collected before screening, with Akaike Information Criterion to determine the model structure.

FINDINGS

The final prediction model included age and its quadratic term, family history of ESCC, low body mass index (≤22 kg/m²), use of coal or wood as main fuel for cooking, eating rapidly, and ingestion of leftover food. The area under the curve was 0·77 (95% CI: 0·73-0·80) and 0·71 (95% CI: 0·65-0·78) in the training and validation set. When screening the top 50% or 10% of high-risk individuals within population, the detection rates can be increased in both cohorts, as compared to universal screening.

INTERPRETATION

The described tool may promote the efficiency of current national screening programs for ESCC and contribute to a precision screening strategy in high-risk regions in China.

FUNDING

This work was supported by the National Natural Science Foundation of China (82073626, 81773501), the National Science & Technology Fundamental Resources Investigation Program of China (2019FY101102), the National Key R&D Program of China (2021YFC2500405), the Beijing-Tianjin-Hebei Basic Research Cooperation Project (J200016), the Digestive Medical Coordinated Development Center of Beijing Hospitals Authority (XXZ0204) and the Beijing Nova Program (Z201100006820093). Sponsors had no role in the study design, data collection, analysis, and interpretation of data.

Tumor-associated autoantibodies in ESCC screening: Detecting prevalent early-stage malignancy or predicting future cancer risk?

BACKGROUND

To assess potential roles for tumor-associated autoantibodies (TAAs) in esophageal squamous cell carcinoma (ESCC) screening: detecting early-stage malignancy, and predicting future cancer risk.

METHOD

Thirteen candidate autoantibodies identified in previous literatures were measured using multiplex serological assays in sera from cases and matched controls nested in two population-level screening cohorts in China. To evaluate the role of TAAs in detecting prevalent esophageal malignant lesions, an identification set (150 cases vs. 560 controls) and an external validation set (34 cases vs. 121 controls) were established with pre-screening sera collected ≤ 12 months prior to screening-related diagnosis. To explore the role of TAAs in predicting future ESCC risk, an exploration set (105 cases vs. 416 controls) with pre-diagnostic sera collected > 12 months before clinical diagnosis was established. Two models, the questionnaire-based model and full model additionally incorporating TAA markers, were constructed. Area under the receiver operating characteristic curve (AUC) and net reclassification improvement (NRI) were calculated to compare the performance of the two models.

FINDINGS

In the identification set, NY-ESO-1 (OR=2·12, 95% CI=1·02-4·40) and STIP1 (OR=1·83, 95% CI=1·10-3·05) were positively associated with higher risk of esophageal malignancy. Elevated MMP-7 was associated with higher risk of malignancy in females (ORfemale=5·07, 95% CI=1·30-19·71). The estimates in validation set were consistent with these results, but were close to null in exploration set. Integration of selected TAAs improved the performance of questionnaire-based models in detecting prevalent esophageal malignancy (female: AUCfull model=0·745, 95% CI=0·675-0·814, AUCquestionnaire-based model=0·658, 95% CI=0·585-0·732, NRI=0·604, P<0·0001; male: AUCfull model=0·662, 95% CI=0·596-0·728, AUCquestionnaire-based model=0·619, 95% CI=0·548-0·690, NRI=0·357, P=0·0028). This improvement was also seen in validation set, but was not similarly effective in distinguishing long-term incident cases from healthy controls.

INTERPRETATION

Serological autoantibodies against NY-ESO-1, STIP1, and MMP-7 perform well in detecting early-stage esophageal malignancy, but are less effective in predicting future ESCC risks.

FUNDING

This work was supported by the National Science & Technology Fundamental Resources Investigation Program of China (2019FY101102), the National Natural Science Foundation of China (82073626), the National Key R&D Program of China (2016YFC0901404), the Beijing-Tianjin-Hebei Basic Research Cooperation Project (J200016), the Digestive Medical Coordinated Development Center of Beijing Hospitals Authority (XXZ0204), and the Natural Science Foundation of Beijing Municipality (7182033).

Size of Lugol-unstained lesions as a predictor for risk of progression in premalignant lesions of the esophagus

BACKGROUND AND AIMS

At present, the surveillance strategy for premalignant esophageal lesions in China is based solely on the pathologic diagnosis in Lugol's chromoendoscopy (LCE). In this study, we sought to determine the degree to which various unstained features under LCE may lead to improved ability to predict the risk of progression in esophageal lesions.

METHODS

We re-examined and followed up on 1058 subjects who had Lugol-unstained lesions (LULs) together with a pathologic diagnosis that was lower than severe dysplasia at baseline screening based on a population-based randomized controlled trial over a median time of 5.8 years. We established a logistic regression model and calculated the adjusted cumulative incidence of severe dysplasia or malignancy.

RESULTS

LUL size was predictive of progression to malignant lesions in individuals with a nondysplastic diagnosis (adjusted odd ratio_{6-10 mm vs ≤5 mm}, 6.7; 95% confidence interval, 1.7-25.7; adjusted odds ratio_{>10 mm vs ≤5 mm}, 27.9; 95% confidence interval, 7.3-105.7), and the corresponding adjusted cumulative incidence of malignant lesions was 3.6 and 13.2 per 100 persons. This is higher than that of small (≤5 mm) lesions, which showed mild dysplasia (2.7 per 100 persons), a condition for which surveillance every 3 years is recommended. Under the current approach, 65.3% of interval cancers missed at surveillance would be detected if individuals with medium (6-10 mm) and large (>10 mm) nondysplastic LULs were additionally monitored.

CONCLUSIONS

We propose a modified surveillance strategy that combines findings under LCE examination and the pathologic analysis, where follow-up endoscopy is recommended for individuals with relatively large nondysplastic lesions.

Estimating cancer survival and prevalence with the Medical-Insurance-System-based Cancer Surveillance System (MIS-CASS): An empirical study in China

BACKGROUND

We aimed to establish a new approach for surveillance of cancer prevalence and survival in China, based on the Medical-Insurance-System-based Cancer Surveillance System (MIS-CASS).

METHODS

We constructed a standard procedure for data collection, cleaning, processing, linkage, verification, analysis, and estimation of cancer prevalence and survival (including both actual observations and model estimates) by conjoint use of medical insurance claims data and all-cause death surveillance data. As a proof-of-principle study, we evaluated the performance of this surveillance approach by estimating the latest prevalence and survival for upper gastrointestinal cancers in Hua County, a high-risk region for oesophageal cancer in China.

FINDINGS

In Hua County, the age-standardised relative 5-year survival was 39·2% (male: 36·8%; female: 43·6%) for oesophageal cancer and 33·3% (male: 29·6%; female: 43·4%) for stomach cancer. For oesophageal cancer, better survival was observed in patients of 45-64 years compared with national average estimates, and women of <75 years had better survival than men. The 5-year prevalence rate in Hua County was 99·8/100,000 (male: 105·9/100,000; female: 93·3/100,000) for oesophageal cancer and 41·5/100,000 (male: 57·4/100,000; female: 24·5/100,000) for stomach cancer. For both of these cancers, the prevalence burden peaked at 65-79 years. The model estimates for survival and prevalence were close to the observations in real investigation, with a relative difference of less than 4·5%.

INTERPRETATION

This novel approach allows accurate estimation of cancer prevalence and survival with a short delay, which has great potential for regular use in general Chinese populations, especially those not covered by cancer registries.

FUNDING

The National Key R&D Program of China (2016YFC0901404), the National Science & Technology Fundamental Resources Investigation Program of China (2019FY101102), the National Natural Science Foundation of China (82073626), the Taikang Yicai Public Health and Epidemic Control Fund (TKYC-GW-2020), the Beijing-Tianjin-Hebei Basic Research Cooperation Project (J200016), and the Digestive Medical Coordinated Development Center of Beijing Hospitals Authority (XXZ0204).

Oral microbiome and risk of malignant esophageal lesions in a high-risk area of China: A nested case-control study

Objective

We aimed to prospectively evaluate the association of oral microbiome with malignant esophageal lesions and its predictive potential as a biomarker of risk.

Methods

We conducted a case-control study nested within a population-based cohort with up to 8 visits of oral swab collection for each subject over an 11-year period in a high-risk area for esophageal cancer in China. The oral microbiome was evaluated with 16S ribosomal RNA (rRNA) gene sequencing in 428 pre-diagnostic oral specimens from 84 cases with esophageal lesions of severe squamous dysplasia and above (SDA) and 168 matched healthy controls. DESeq analysis was performed to identify taxa of differential abundance. Differential oral species together with subject characteristics were evaluated for their potential in predicting SDA risk by constructing conditional logistic regression models.

Results

A total of 125 taxa including 37 named species showed significantly different abundance between SDA cases and controls (all P<0.05 & false discovery rate-adjusted Q<0.10). A multivariate logistic model including 11 SDA lesion-related species and family history of esophageal cancer provided an area under the receiver operating characteristic curve (AUC) of 0.89 (95% CI, 0.84−0.93). Cross-validation and sensitivity analysis, excluding cases diagnosed within 1 year of collection of the baseline specimen and their matched controls, or restriction to screen-endoscopic-detected or clinically diagnosed case-control triads, or using only bacterial data measured at the baseline, yielded AUCs>0.84.

Conclusions

The oral microbiome may play an etiological and predictive role in esophageal cancer, and it holds promise as a non-invasive early warning biomarker for risk stratification for esophageal cancer screening programs.

Effectiveness of Intensive Endoscopic Screening for Esophageal Cancer in China: A Community-Based Study

Evidence is required to evaluate the effectiveness of population-level endoscopic screening for esophageal cancer (EC). In this study, 5,632 permanent residents aged 25-65 years from 6 villages in Hua County, Henan Province, China, were defined as the screening cohort and were offered intensive endoscopic screening. Residents of all 914 remaining villages in Hua County were included as the control cohort, and age-sex standardization was used to calculate the expected numbers of EC and upper gastrointestinal (GI) tract cancer cases and deaths in the screening cohort. The effectiveness of screening was assessed by comparing observed numbers of cases and deaths with expected numbers after 9-year follow-up of these screened subjects (2007-2016). In the screening cohort, 23 upper GI cancers (including 16 ECs) and 10 upper GI cancer deaths (including 5 EC deaths) were identified, and 47% (standardized incidence ratio = 0.53, 95% confidence interval (CI): 0.33, 0.87) and 66% (standardized mortality ratio = 0.34, 95% CI: 0.14, 0.81) reductions in cumulative EC incidence and mortality were found. For upper GI cancers, incidence and mortality were lowered by 43% (standardized incidence ratio = 0.57, 95% CI: 0.38, 0.86) and 53% (standardized mortality ratio = 0.47, 95% CI: 0.25, 0.88), respectively. This study showed that upper GI tract endoscopy is an effective population-level screening test for EC in high-risk regions.

Efficacy of endoscopic screening for esophageal cancer in China (ESECC): design and preliminary results of a population-based randomised controlled trial

OBJECTIVE

Description of the design and preliminary results of baseline recruitment and screening in the endoscopic screening for esophageal cancer in China (ESECC), the first randomised controlled trial (RCT) assessing efficacy and cost-effectiveness of endoscopic screening for esophageal squamous cell carcinoma (ESCC).

DESIGN

ESECC trial is a cluster RCT, and 668 villages in rural Hua County, Henan Province, a high-incidence area of ESCC in China, were randomised into two arms at a ratio of 1:1. Screening arm participants were screened by Lugol chromoendoscopy; no screening was performed in the control arm. ESCC-specific and all-cause mortality, incidence of advanced ESCC and cost-effectiveness of screening will be evaluated in the next 10-year follow-up. Here, we report the performance of baseline recruitment and randomisation, prevalence of upper GI lesions and risk factors for ESCC.

RESULTS

A total of 17 151 and 16 797 participants were enrolled in screening and control arms from January 2012 to September 2016. The truncated prevalence (aged 45-69 years) of oesophageal and overall upper GI high-grade lesions was 744.0/100 000 and 902.0/100 000. 69.9% of the 113 patients with high-grade oesophageal lesions were of early stage. Risk factors for severe oesophageal dysplasia and more severe lesions in this population included higher age, family history of ESCC, lower body mass index, eating rapidly and frequent ingestion of leftovers.

CONCLUSION

This ESECC trial met the predesigned recruitment and randomisation requirements. Age, family history, undernutrition and unhealthy dietary habits increased the risk for high-grade oesophageal lesions in this high-risk population.

TRAIL REGISTRATION NUMBER

NCT01688908; Pre-results.

Serum levels of chemical elements in esophageal squamous cell carcinoma in Anyang, China: a case-control study based on machine learning methods

OBJECTIVES

Esophageal squamous cell carcinoma (ESCC) is the predominant form of esophageal carcinoma with extremely aggressive nature and low survival rate. The risk factors for ESCC in the high-incidence areas of China remain unclear. We used machine learning methods to investigate whether there was an association between the alterations of serum levels of certain chemical elements and ESCC.

SETTINGS

Primary healthcare unit in Anyang city, Henan Province of China.

PARTICIPANTS

100 patients with ESCC and 100 healthy controls matched for age, sex and region were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was the classification accuracy. Secondary outcome was the p Value of the t-test or rank-sum test.

METHODS

Both traditional statistical methods of t-test and rank-sum test and fashionable machine learning approaches were employed.

RESULTS

Random Forest achieves the best accuracy of 98.38% on the original feature vectors (without dimensionality reduction), and support vector machine outperforms other classifiers by yielding accuracy of 96.56% on embedding spaces (with dimensionality reduction). All six classifiers can achieve accuracies more than 90% based on the single most important element Sr. The other two elements with distinctive difference are S and P, providing accuracies around 80%. More than half of chemical elements were found to be significantly different between patients with ESCC and the controls.

CONCLUSIONS

These results suggest clear differences between patients with ESCC and controls, implying some potential promising applications in diagnosis, prognosis, pharmacy and nutrition of ESCC. However, the results should be interpreted with caution due to the retrospective design nature, limited sample size and the lack of several potential confounding factors (including obesity, nutritional status, and fruit and vegetable consumption and potential regional carcinogen contacts).

The epidemiological profile of hysterectomy in rural Chinese women: a population-based study

OBJECTIVES

Hysterectomy is one of the most common surgical procedures performed on women in developed countries; however, little is known about the epidemiology of hysterectomy in low-income to middle-income regions. This study seeks to evaluate the prevalence of hysterectomy and its risk factors in rural China.

METHODS

Questionnaires were collected from 3328 female adults aged 25â€"69 years in rural Anyang, China, in 2009â€"2011. Hysterectomy status was ascertained by the gynaecologist at the time of cytological test. Univariate and multivariate regression analyses were performed to assess the risk factors for hysterectomy.

RESULTS

The overall prevalence of hysterectomy was 3.31% (110/3328). Women above the age of 40 years had a higher prevalence of prior hysterectomy, compared with those aged 25â€"39 years (5.01% vs 0.33%). Obesity was marginally related with a higher risk of hysterectomy (adjusted OR=1.59; 95% CI 0.99 to 2.56; body mass index (BMI) ≥28.0 vs 18.5 ≤ BMI <24.0). History of prior pregnancy loss conferred a greater risk for hysterectomy (adjusted OR=1.51; 95% CI 1.02 to 2.23). Of the 75 (68.18%, 75/110) cases who provided further information on hysterectomy, 84.00% (63/75) had undergone total abdominal hysterectomy and 70.67% (53/75) had received surgery for leiomyoma.

CONCLUSIONS

Rural Chinese women had a relatively low prevalence of hysterectomy, and the majority of reported hysterectomies were performed abdominally for leiomyoma. Hysterectomy prevalence differed significantly by age, BMI and history of pregnancy loss. This study expands the current understanding of the epidemiology of hysterectomy in lower resource areas.

Epidemiology of self-rated health in rural China: a population-based cross-sectional study

Self-rated health (SRH) has been shown to be a good predictor of mortality. Data on SRH and its associated factors in the Chinese general population are limited. This study aims to assess the epidemiology of SRH in rural Anyang, China. SRH (categorized as "healthy", "fair" or "unhealthy") was measured in a population-based study of 2,814 adults (including 697 couples) aged 25 to 69 who were recruited from rural Anyang in 2014. Of 2,814 subjects, 63.1% rated their health as "healthy", whereas 28.1% and 8.8% rated their health as "fair" and "unhealthy". Compared to males, females had a higher likelihood of reporting a better SRH. Health ratings declined with increasing age, unmarried status, lower education levels. Poor SRH was positively correlated with medical history as well as high levels of fasting plasma glucose and total cholesterol, but not with unhealthy lifestyle indicators including smoking, drinking, and obesity. High household income was predictive of better SRH in men but not in women. Among couples, a positive spousal SRH concordance was observed, although the strength of this concordance was low. These findings will be useful for formulation of appropriate strategies for improving risk perception and promoting general health in economically developing regions.

Incidence and clearance of oral human papillomavirus infection: A population-based cohort study in rural China

The natural history of oral human papillomavirus (HPV) infection which is linked with the increased incidence of oropharyngeal squamous cell cancer (OPSCC) has been incompletely studied. Oral swab specimens and questionnaire data were obtained bi-annually for up to 6 visits from 4314 healthy adults aged 25-69 in rural Anyang, China. HPV infection status was evaluated with PCR-based sequencing. Participants with at least two consecutive valid HPV results within the study period were included in the incidence and clearance analysis. Among 3289 participants included in this analysis (median follow-up time 18.3 months), incidence rates of mucosal HPV, oncogenic mucosal HPV and cutaneous HPV were 0.53 (95% CI: 0.39-0.73), 0.30 (95% CI: 0.20-0.46), and 4.17 (95% CI: 3.70-4.70) per 1,000 person-months respectively. Most newly acquired infections were cleared within one year. Recent practice of oral sex increased the risk of incident infection with mucosal HPV (Adjusted HR, 5.03; 95% CI, 1.16-21.73) and oncogenic mucosal HPV (Adjusted HR, 10.13; 95% CI, 2.14-48.06). Newly acquired oral mucosal HPV infections are rare and most are cleared within one year in rural Chinese. This study expands understanding of the natural history of oral HPV in countries with a lower incidence of HPV-OPSCC.

Human papillomavirus and gastrointestinal cancer: A review

Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide. Exposure to HPV is very common, and an estimated 65%-100% of sexually active adults are exposed to HPV in their lifetime. The majority of HPV infections are asymptomatic, but there is a 10% chance that individuals will develop a persistent infection and have an increased risk of developing a carcinoma. The International Agency for Research on Cancer has found that the following cancer sites have a strong causal relationship with HPV: cervix uteri, penis, vulva, vagina, anus and oropharynx, including the base of the tongue and the tonsils. However, studies of the aetiological role of HPV in colorectal and esophageal malignancies have conflicting results. The aim of this review was to organize recent evidence and issues about the association between HPV infection and gastrointestinal tumours with a focus on esophageal, colorectal and anal cancers. The ultimate goal was to highlight possible implications for prognosis and prevention.

The Willingness to Change Risky Health Behaviors among Chinese Rural Residents: What We Learned from a Population-Based Esophageal Cancer Cohort Study

Background

The effectiveness of health interventions can be impaired by low socio-economic status and poor living conditions of the target population. However, the specifics of this problem in rural China are still unclear, and appropriate strategies should be explored.

Methods

In 2013, we conducted a questionnaire-based investigation among 410 participants from a population-based esophageal cancer cohort study in rural Anyang, China. Information regarding their demographic characteristics, levels of exposure to four health-risk behaviors, including smoking, alcohol consumption, risky dietary behaviors and poor hygiene, as well as willingness to change these behaviors, and data on potential predictors of willingness to change behaviors were collected.

Results

In this study, 33.3% (23/69), 25.0% (13/52), 60.7% (68/112) and 62.2% (237/381) of respondents reported that they were willing to change smoking, alcohol consumption, risky dietary behaviors and poor hygiene, respectively. Older people had higher exposure levels and less willingness to change these four health-risk behaviors. The levels of these four health-risk behaviors were negatively associated with willingness to change, while faith in people and behavioral change in surrounding people increased willingness to change risky behaviors.

Conclusions

In behavior-intervention-based health-promotion programs in rural China, the elderly and highly exposed populations should be the most difficult part and community- or household-based intervention would be more efficient.

Human papillomavirus DNA positivity and seropositivity in rural Chinese men and women: a population-based cross-sectional study

Data on simultaneous analysis of human papillomavirus (HPV) DNA and serology and the correlations within a single general population are limited. Among 1603 men and 2187 women enrolled from rural China, serum antibodies against bacterially derived GST-L1 fusion proteins of HPV were assessed with multiplexed serology and HPV DNA was evaluated with PCR-based sequencing. Few subjects were dually positive to HPV DNA and serum antibodies for any HPV (6.6% of men and 3.1% of women). The proportion of men ever having been infected with any HPV (DNA and/or antibody positive) was higher than that of women (71.0% vs. 65.2%, P < 0.001). Type-specific association was observed for genital HPV infection and HPV seropositivity among women but not among men. A positive correlation between the number of lifetime sexual partners and positivity for oncogenic HPV DNA and/or antibodies was found in men but was absent in women. Among 762 couples, the presence of HPV DNA and/or antibodies in one partner was positively associated with the identical HPV type in the other partner. These findings may reflect a site-specific natural course of HPV infection and further understanding of the epidemiology of HPV.

Prevalence and Associated Risk Factors of Human Papillomavirus in Healthy Skin Specimens Collected from Rural Anyang, China, 2006-2008

Skin infections with cutaneous human papillomavirus (HPV) have been linked to the development of non-melanoma skin cancer, in which mucosal HPV may also play a crucial role. However, systematic investigations of the distribution and associated factors of HPV infection in healthy skin of the general population are scarce. HPV DNA from palmar exfoliated cells of 2,087 individuals was detected by FAP6085/64 and SPF1/GP6+ primers followed by sequencing. A total of 338 papillomavirus types were detected, with HPV-3, HPV-57, and HPV-49 being the most dominant types. The overall prevalence for HPV DNA on skin was 79.92% and for alpha-, beta-, and gamma-HPV were 27.07%, 38.76%, and 29.56%, respectively. Having multiple lifetime sexual partners (adjusted odds ratio 1.60), being a migrant worker (adjusted odds ratio 2.05, reference: farmers), and frequent bathing (Ptrend = 0.001) were associated with alpha-HPV DNA presence. Advancing age increased the detection risk of beta-HPV (Ptrend = 0.001). Higher education (Ptrend = 0.017) and frequent bathing (Ptrend = 0.001) were positively related to gamma-HPV positivity. This study demonstrates that alpha-HPV commonly exists on healthy skin of the general population in rural China, and alpha- and gamma-HPV infections are related to certain behaviors, different from beta-HPV infection. These findings are crucial to better understanding the biology of HPV infection and may be suggestive of the potential transmission of these viruses.

Co-infection of Epstein-Barr virus and human papillomavirus in human tumorigenesis

Viral infections contribute to approximately 12% of cancers worldwide, with the vast majority occurring in developing countries and areas. Two DNA viruses, Epstein-Barr virus (EBV) and human papillomavirus (HPV), are associated with 38% of all virus-associated cancers. The probability of one patient infected with these two distinct types of viruses is increasing. Here, we summarize the co-infection of EBV and HPV in human malignancies and address the possible mechanisms for the co-infection of EBV and HPV during tumorigenesis.

Concurrence of oral and genital human papillomavirus infection in healthy men: a population-based cross-sectional study in rural China

Human papillomavirus (HPV) infection, a primary cause of genital cancer, is also related to the increasing incidence of oropharyngeal cancer among young men. Relatively little is known about the concurrence of oral and genital infection among healthy individuals. Oral and genital swab exfoliated cells were collected simultaneously from 2566 men in rural China. Using general primer-mediated (SPF1/GP6+) PCR and sequencing, HPV testing results were obtained from 2228 men with both valid oral and genital specimens (β-globin-positive). The prevalence of HPV infection was 6.7% in the oral cavity and 16.9% for the external genitalia. Among 43 men (1.9%, 43/2228) with oral-genital coinfection, 60.5% (26/43) harbored an identical HPV type at both sites. The risk of oral HPV infection was higher among men with genital infection than among uninfected men (11.4% vs. 5.7%, Adjusted OR = 2.3, 95% CI: 1.6-3.4). In addition, having multiple lifetime sexual partners was a significant risk for oral-genital HPV coinfection (Adjusted OR = 2.6, 95% CI: 1.0-7.0; 2 partners vs. 1 partner). These findings provide a basis for further understanding the natural history and transmission dynamics of oral HPV infection.

Transmission of genital human papillomavirus infection in couples: a population-based cohort study in rural China

HPV transmission dynamics have rarely been studied in the general population, especially in China. We followed the genital HPV infection status of both partners in 874 couples aged 25-65 years from rural China for up to 7 bi-annual visits during 2009-2013. The positive HPV concordance and transmission rate for partners in a couple were evaluated and relevant risk factors were assessed. The concordance of any, oncogenic, and non-oncogenic HPV was 15.52%, 16.18% and 10.41%, respectively. Male-to-female transmission rate was 7.11, 12.13 and 4.77/1000 person months for any, oncogenic and non-oncogenic HPV respectively. The female-to-male transmission rate was 5.56, 2.37, and 17.01/1000 person months for any, oncogenic and non-oncogenic HPV respectively. The risk of male-to-female transmission was significantly higher than that of female-to-male transmission for oncogenic types. However, for non-oncogenic types, the risk of male-to-female transmission was significantly lower than that of female-to-male transmission. Younger couples, persistent infection with HPV, higher numbers of sexual partners and higher frequency of sexual intercourse were positively associated with HPV transmission in couples. Our results indicate that men in rural China play a more important role than men in western populations as a source of cervical oncogenic HPV infection in women.

Association of genetic polymorphisms in PRKDC and XRCC4 with risk of ESCC in a high-incidence region of North China

BACKGROUND

The nonhomologous end-joining (NHEJ) pathway is the main mechanism repairing DNA double-strand breaks (DSBs) in human cells. This research was designed to study the association between selected variants in NHEJ members and esophageal squamous cell carcinoma (ESCC).

METHODS

Two single nucleotide polymorphisms (SNPs), PRKDC (rs7003908) and X-ray repair cross complementing group 4 (XRCC4; rs1805377), were genotyped in a total of 189 patients with ESCC and 189 unrelated control individuals in a high-risk area for ESCC in North China, and the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was applied.

RESULTS

A significantly different distribution was found in the frequency of PRKDC (rs7003908) genotype between the ESCC group and controls. Individuals homozygous for the C allele had a significant (3.185-fold) increased risk of ESCC. As for XRCC4 (rs1805377) polymorphism, no difference was found in distribution between the ESCC and control groups.

CONCLUSIONS

Our results suggest that variation in DNA repair genes may be associated with risk of ESCC.

Seroprevalence of 10 human papillomavirus types in the general rural population of Anyang, China: a cross-sectional study

OBJECTIVES

Data on the seroprevalence of human papillomavirus (HPV) in China are limited. The objective of this study was to characterise the serological profiles of HPV infection in a rural Chinese population and help establish effective vaccine policy.

METHODS

Serum antibodies against the major capsid protein L1 of 10 HPV types (HPV-3, 6, 11, 16, 18, 45, 52, 57, 58 and 75) were evaluated with Luminex-based multiplex serology in a population-based study of 5548 adults (including 1587 couples) aged 25-65 years enrolled from rural Anyang, China, in 2007-2009.

RESULTS

The seroprevalence for any HPV type and any of the types HPV-6/11/16/18 was 64.8% and 34.4%, respectively. 30.3% of adults were seropositive for any mucosal high-risk (HR) HPV, and HPV-58 (10.6%), HPV-16 (9.7%) and HPV-18 (9.3%) were the three most common types. 24.8% of seropositive individuals were positive for multiple mucosal HR-HPV serotypes. Seroprevalence for most HPV types was similar among men and women. While mucosal low-risk HPV seropositivity was found to significantly decrease with age, the prevalence of antibodies to mucosal HR antigens showed a general trend of increase with age. The lifetime number of sex partners was independently associated with mucosal HR-HPV seropositivity. Positive correlation of spousal seropositivity was observed for mucosal HPV but not for cutaneous HPV.

CONCLUSIONS

HPV infection was common in both men and women in rural China. HPV seroprevalence differed significantly with age, sexual behaviour and spousal infection status. These findings will be useful for evaluating and establishing HPV vaccination programmes.

Viruses, Other Pathogenic Microorganisms and Esophageal Cancer

BACKGROUND

Esophageal cancer (EC) is the eighth most prevalent malignant tumor and the sixth leading cause of cancer mortality throughout the world. Despite the technical developments in diagnosis and treatment, the 5-year survival rate is still low. The etiology of EC remains poorly understood; multiple risk factors may be involved and account for the great variation in EC incidence in different geographic regions.

SUMMARY

Infection with carcinogenetic pathogens has been proposed as a risk factor for EC. This review explores the recent studies on the association of human papillomavirus (HPV), Epstein-Barr virus (EBV), Helicobacter pylori and esophageal bacterial biota with EC.

KEY MESSAGE

Among the above-mentioned pathogens, HPV most likely contributes to esophageal squamous cell carcinoma (ESCC) in high-risk populations. New techniques are being applied to studies on the role of infection in EC, which will inevitably bring novel ideas to the field in the near future.

PRACTICAL IMPLICATIONS

Multiple meta-analyses support the finding of a higher HPV detection rate in regions associated with high risk for ESCC compared to low-risk areas. A potential role of HPV in the rise of esophageal adenocarcinoma (EAC) was proposed recently. However, further studies are required before a firm conclusion can be drawn. Less work has been done in studying the association between EBV and ESCC, and the results are quite controversial. H. pylori infection is found to be inversely related to EC, which is probably due to the reduced incidence of gastroesophageal reflux disease. Analysis of the esophageal bacterial biota revealed distinct clusters of bacteria in normal and diseased esophagi. A type II microbiome rich in Gram-negative bacteria potentially contributes to EAC by inducing chronic inflammation. Novel findings from such studies as these may benefit public health by justifying anti-infection measures to prevent EC.

Association of the Genetic Polymorphisms in XRCC6 and XRCC5 with the Risk of ESCC in a High-incidence Region of North China

Background

The XRCC6 and XRCC5 genes are part of the nonhomologous end-joining (NHEJ) pathway, which is the main mechanism repairing DNA double-strand breaks (DSBs) in human cells. Genetic variations of XRCC6 and XRCC5 might contribute to esophageal squamous cell carcinoma (ESCC) susceptibility.

Methods

ESCC patients (n = 189) and cancer-free controls (n = 189) were recruited in an ESCC high-risk area of north China. Then the rs2267437 (XRCC6), rs3835 (XRCC5) and rs16855458 (XRCC5) polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

Results

A significant difference in genotype distribution and allele frequency of rs2267437 (XRCC6) was observed between the cases and controls. The CG carriers were at higher risk of ESCC (p = 0.001, odds ratio [OR] = 2.040, 95% confidence interval [95% CI], 1.323-3.147). G allele carriers were also associated with an increased ESCC risk (p = 0.003, OR = 1.868, 95% CI, 1.230-2.836). In the 2 polymorphisms of XRCC5, no significant difference was found between both groups in the distribution of either genotype or allelic frequency. But in the haplotypes established by the single nucleotide polymorphisms (SNPs) of XRCC5, the haplotype AT and CC separately increased by 4.28- and 2.31-fold the risk ratio of ESCC (p = 0.01, OR = 4.28, 95% CI, 1.40-13.05; p = 0.03, OR = 2.31, 95% CI, 1.11-4.80, respectively). In addition, gene-smoking or gene-drinking interactions, and their effect on the risk of ESCC were observed, but no significant gene-environment interaction was demonstrated.

Conclusions

In conclusion, both the CG carriers/G allele carriers of rs2267437 (XRCC6) and the haplotype AT/CC established by the SNPs of XRCC5 are associated with ESCC susceptibility.

Seroprevalence of Merkel cell polyomavirus in the general rural population of Anyang, China

Background

Despite the probably causal link between Merkel cell polyomavirus (MCPyV) infection and Merkel cell carcinoma (MCC), a rare but aggressive skin malignancy, little is known about the seroepidemiology of MCPyV among healthy adults in China.

Methods

Serum antibodies against MCPyV were evaluated by multiplex serology in a population-based study of 5548 adults (including 1587 heterosexual couples) aged 25–65 years who were enrolled from rural Anyang, China in 2007–2009. Univariate and multivariate logistic regression analyses were performed to assess the risk factors for the seropositivity of MCPyV.

Results

The seroprevalence for MCPyV was 61.0%. MCPyV seropositivity was significantly higher in males than in females (64.5% vs. 57.7%, P<0.001), and for both genders, showed a trend of increase with age (Male: P_trend<0.001; Female: P_trend<0.001). Furthermore, among antibody positives, antibody levels of MCPyV increased with advancing age (P_trend = 0.017). MCPyV seropositivity of one spouse was significantly associated with that of the other partner (Adjusted OR = 1.32, 95% CI: 1.07–1.62). However, there was no association between sexual behaviors and the seropositivity of MCPyV.

Conclusions

High seroprevalence of MCPyV was observed in healthy Chinese individuals. Serological evidence suggests that nonsexual horizontal spread of MCPyV can occur among family members, and further research in this regard is needed.

The distribution and common amino acid polymorphisms of human papillomavirus (HPV)-31 variants in 2700 women from Northern China

To investigate the distribution of Human papillomavirus (HPV)-31 A, B and C variants as well as the common amino acid polymorphisms in Chinese women, all 14 HPV-31 positive cervical exfoliated cell specimens identified from a descriptive study including ∼2700 women from Northern China were analyzed. HPV-31 positive specimens were identified by Mass Spectrometry and the fragments of partial Long Control Region, E6 and E7 were amplified and directly sequenced or cloned into vector and then sequenced to confirm the variant information. HPV-31 prevalence in Northern Chinese female population was 0.52%. Six different sequences represented all 14 isolates, and these isolates were subsequently classified into variant lineage A (9), B (0) and C (5) by phylogenetic analysis. Five common amino acid polymorphism sites (2 in E6 and 3 in E7) and a novel non-synonymous mutation were detected in the current study. Our investigation suggested that HPV-31 was much less detected in Chinese women population than that in western countries. A and C variants were commonly detected while B variants were rarely detected in this population.

Human papillomavirus genital infections among men, China, 2007-2009

To determine prevalence of genital human papillomavirus (HPV) infection among men in rural China, we analyzed genital swab specimens. Among 2,236 male residents of rural Henan Province, HPV infection prevalence was 17.5%. The most common oncogenic and nononcogenic types were HPV-16 and HPV-3, respectively. Infection was associated with younger age and multiple sex partners.

Identification and characterization of eleven novel human gamma-papillomavirus isolates from healthy skin, found at low frequency in a normal population

Eleven novel human papillomavirus (HPV) types were isolated and characterized from healthy individuals in China. HPV163 belongs to the γ-1 species, HPV 164 and HPV 168 fit in the γ-8 species, HPV 165 and KC5 belongs to the γ-12 species, HPV 168 is closely allied with the γ-4 species, HPV 169 is closely related to the γ-11 species, and HPV 170 is related to the γ-12 species. In addition, HPV 161, HPV 162, and HPV 166 may form a new HPV species of the γ-PV genus. The prevalence of these HPV types in the normal population is low.