Epidemiologic application of verbal autopsy to investigate the high occurrence of cancer along Huai River Basin, China

Thyroid-disrupting effects caused by exposure to alternative flame retardants from groundwater contamination in rural central China

Accumulating evidence reveals that exposure to alternative flame retardants (AFRs) results in defective thyroid functions. AFRs are detectable in various environmental media in developed cities in China. However, few studies have reported the contamination levels of AFR in groundwater in rural areas, indicating an urgent need to investigate exposure of AFRs and perform health risk assessment for populations that use groundwater as the main source of drinking water. This study investigated the concentrations of AFRs in groundwater in rural areas of central China. Moreover, Nthy-ori-3-1 cells were used to determine the thyroid cytotoxicities and thyroid-interfering effects of a single AFR as well as the mixtures of AFRs based on the AFR contamination levels in real-world. The results revealed that all classes of AFRs were detectable in rural areas in central China. Dechlorane plus, hexabromocyclododecane, bromophenols (BPs), novel brominated flame retardants (NBFRs) and organophosphate flame retardants (OPFRs) exhibited spatial contamination patterns, with an average concentrations (median) of 157.89 ± 88.61 (185.47) pg/L, 0.09 ± 0.29 (not detectable) ng/L, 5.20 ± 5.92 (3.43) ng/L, 3338.11 ± 3758.78 (2836.72) pg/L, and 79.35 ± 97.19 (53.62) ng/L, respectively. The half maximal effective concentrations (EC₅₀) of BPs, OPFRs, and NBFRs ranged 98.4-4012 μM, 42.0-2506 μM, and 10.1-203.7 μM, respectively. Several AFRs exhibited more cytotoxic effects than did traditional brominated flame retardants. It is intriguing that several single AFRs and mixtures at environmentally-relevant exposure levels promoted the viability of Nthy-ori-3-1 cells. Taken together, our study demonstrates that AFRs are present in the groundwater in rural areas in central China and AFRs exhibit thyroid disrupting effects.

Impact of environmental factors on gastric cancer: A review of the scientific evidence, human prevention and adaptation

Globally, gastric cancer (GC) ranks fifth in prevalence and third in fatalities, and shows a distinct geographical distribution in morbidity and mortality. Such a spatial pattern indicates that environmental factors could be an important contributor to GC. We reviewed a total of 135 relevant peer-reviewed articles and other literature published 1936-2019 to investigate the scientific evidence concerning the effects of environmental factors on GC worldwide. Environmental factors affect GC from the aspects of water, soil, air, radiation, and geology. Risk factors identified include water type, water pollution, water hardness, soil type, soil pollution, soil element content, climate change, air pollution, radiation, altitude, latitude, topography, and lithology; and most of them have an adverse impact on GC. Furthermore, we found that their effects followed five common rules: (1) the leading environmental factors that affect GC incidence and mortality vary by region, (2) the same environmental factors may have different effects on GC in different regions, (3) some different environmental factors have similar effects on GC in essence, (4) different environmental factors often interact to have combined or synergistic effects on GC, and (5) environmental factors can affect human factors to have an impact on GC. Environmental factors have a great impact on GC. Human beings may prevent GC by controlling carcinogenic factors, screening high-risk populations and providing symptomatic and rehabilitative treatments. Furthermore, adaptation measures are recommended to reduce GC risk on private and public levels. Future studies should transcend existing empirical studies to develop causal relationship models and focus on vulnerable population analysis.

Spatiotemporal Variations in Gastric Cancer Mortality and Their Relations to Influencing Factors in S County, China

Increasingly stricter and wider official efforts have been made by multilevel Chinese governments for seeking the improvements of the environment and public health status. However, the contributions of these efforts to environmental changes and spatiotemporal variations in some environmental diseases have been seldom explored and evaluated. Gastric cancer mortality (GCM) data in two periods (I: 2004⁻2006 and II: 2012⁻2015) was collected for the analysis of its spatiotemporal variations on the grid scale across S County in Central China. Some environmental and socioeconomic factors, including river, farmlands, topographic condition, population density, and gross domestic products (GDP) were obtained for the exploration of their changes and their relationships with GCM's spatiotemporal variations through a powerful tool (GeoDetector, GD). During 2004⁻2015, S County achieved environmental improvement and socioeconomic development, as well as a clear decline of the age-standardized mortality rate of gastric cancer from 35.66/10⁵ to 23.44/10⁵. Moreover, the GCM spatial patterns changed on the grid scale, which was spatially associated with the selected influencing factors. Due to the improvement of rivers' water quality, the distance from rivers posed relatively larger but reversed impacts on the gridded GCM. In addition, higher population density and higher economic level (GDP) acted as important protective factors, whereas the percentage of farmlands tended to have adverse effects on the gridded GCM in period II. It can be concluded that the decline of GCM in S County was spatiotemporally associated with increasingly strengthened environmental managements and socioeconomic developments over the past decade. Additionally, we suggest that more attentions should be paid to the potential pollution caused by excessive pesticides and fertilizers on the farmlands in S County. This study provided a useful clue for local authorities adopting more targeted measures to improve environment and public health in the regions similar to S County.

Cause-specific mortality estimates for Malaysia in 2013: results from a national sample verification study using medical record review and verbal autopsy

Background

Mortality indicators are essential for monitoring population health. Although Malaysia has a functional death registration system, the quality of information on causes of death still needs improvement, since approximately 30% of deaths are classified to poorly defined causes. This study was conducted to verify registered causes in a sample of deaths in 2013 and utilise the findings to estimate cause-specific mortality indicators for Malaysia in 2013.

Methods

This is a cross-sectional study involving a nationally representative sample of 14,497 deaths distributed across 19 districts. Registered causes of deaths were verified using standard medical record review protocols for hospital deaths, and locally adapted international standard verbal autopsy procedures for deaths outside hospitals. The findings were used to measure the validity and reliability of the registration data, as well as to establish plausible cause-specific mortality fractions for hospital and non-hospital deaths, which were subsequently used as the basis for estimating national cause-specific mortality indicators.

Results

The overall response rate for the study was 67%. Verified causes of 5041 hospital deaths and 3724 deaths outside hospitals were used to derive national mortality estimates for 2013 by age, sex and cause. The study was able to reclassify most of the ill-defined deaths to a specific cause. The leading causes of deaths for males were Ischaemic Heart Disease (15.4%), Cerebrovascular diseases (13.7%), Chronic Obstructive Pulmonary Disease (8.5%) and Road Traffic Accident (8.0%). Among females, the leading causes were Cerebrovascular diseases (18.3%), Ischaemic Heart Disease (12.7%), Lower Respiratory Infections (11.5%) and Diabetes Mellitus (7.2%).

Conclusions

Investigation of registered causes of death using verbal autopsy and medical record review yielded adequate information to enable estimation of cause-specific mortality indicators in Malaysia. Strengthening the national mortality statistics system must be made a priority as it is a core data source for policy and evaluation of the public health and healthcare sectors in Malaysia.

Assessment of the cytotoxic and mutagenic potential of the Jialu River and adjacent groundwater using human-hamster hybrid cells

The Jialu River in China has been seriously polluted by the direct discharge of industrial and domestic wastewater. The predominant contaminants of the Jialu River and its adjacent groundwater were recently investigated. However, the potential genotoxic impact of polluted water on human health remains to be clarified. Here, we used human-hamster hybrid (A_L) cells, which are sensitive for detecting environmental mutagens. We found that the cytotoxicity and mutagenicity of the groundwater in the Jialu River basin were influenced by the infiltration of the Jialu River. Hydrological periods significantly affected the cytotoxicity, but not the mutagenic potential, of surface and groundwater. Further, the mutagenic potential of groundwater samples located <1km from the Jialu River (S_M-2 water samples) was detected earlier than that of groundwater samples located approximately 20km from the Jialu River (S_N water samples). Because of high cytotoxicity, the mutagenic potential of water samples from the Jialu River (S_M-1 water samples) was not significantly enhanced compared with that of untreated controls. To further assess the mutagenic dispersion potential, an artificial neural network model was adopted. The results showed that the highest mutagenic potential of groundwater was observed approximately 10km from the Jialu River. Although further investigation of mutagenic spatial dispersion is required, our data are significant for advancing our understanding of the origin, dispersion, and biological effects of water samples from polluted areas.

Delivery of public health services by community health workers (CHWs) in primary health care settings in China: a systematic review (1996-2016)

BACKGROUND

Community Health Workers (CHWs) have been widely used in response to the shortage of skilled health workers especially in resource limited areas. China has a long history of involving CHWs in public health intervention project. CHWs in China called village doctors who have both treatment and public health responsibilities. This systematic review aimed to identify the types of public health services provided by CHWs and summarized potential barriers and facilitating factors in the delivery of these services.

METHODS

We searched studies published in Chinese or English, on Medline, PubMed, Cochrane, Google Scholar, and CNKI for public health services delivered by CHWs in China, during 1996-2016. The role of CHWs, training for CHWs, challenges, and facilitating factors were extracted from reviewed studies.

RESULTS

Guided by National Basic Public Health Service Standards, services provided by CHW covered five major areas of noncommunicable diseases (NCDs) including diabetes and/or hypertension, cancer, mental health, cardiovascular diseases, and common NCD risk factors, as well as general services including reproductive health, tuberculosis, child health, vaccination, and other services. Not many studies investigated the barriers and facilitating factors of their programs, and none reported cost-effectiveness of the intervention. Barriers challenging the sustainability of the CHWs led projects were transportation, nature of official support, quantity and quality of CHWs, training of CHWs, incentives for CHWs, and maintaining a good rapport between CHWs and target population. Facilitating factors included positive official support, integration with the existing health system, financial support, considering CHW's perspectives, and technology support.

CONCLUSION

CHWs appear to frequently engage in implementing diverse public health intervention programs in China. Facilitators and barriers identified are comparable to those identified in high income countries. Future CHWs-led programs should consider incorporating the common barriers and facilitators identified in the current study to maximize the benefits of these programs.

Reporting of ethics in peer-reviewed verbal autopsy studies: a systematic review

Introduction

Verbal autopsy (VA) is a method that determines the cause of death by interviewing a relative of the deceased about the events occurring before the death, in regions where medical certification of cause of death is incomplete. This paper aims to review the ethical standards reported in peer-reviewed VA studies.

Methods

A systematic review of Medline and Ovid was conducted by two independent researchers. Data were extracted and analysed for articles based on three key areas: Institutional Review Board (IRB) clearance and consenting process; data collection and management procedures, including: time between death and interview; training and education of interviewer, confidentiality of data and data security; and declarations of funding and conflict of interest.

Results

The review identified 802 articles, of which 288 were included. The review found that 48% all the studies reported having IRB clearance or obtaining consent of participants. The interviewer training and education levels were reported in 62% and 21% of the articles, respectively. Confidentiality of data was reported for 14% of all studies, 18% did not report the type of respondent interviewed and 51% reported time between death and the interview for the VA. Data security was reported in 8% of all studies. Funding was declared in 63% of all studies and conflict of interest in 42%. Reporting of all these variables increased over time.

Conclusions

The results of this systematic review show that although there has been an increase in ethical reporting for VA studies, there still remains a large gap in reporting.

Disparity of nitrate and nitrite in vivo in cancer villages as compared to other areas in Huai River Basin, China

Saliva and Urine samples were collected for the study on how nitrate and nitrite concentration in human body may be related to the corresponding health risk in a high cancer incidence area. The study area includes three known cancer villages in Huai River basin, China. The results of analyzing collected sample show that there are higher levels of nitrate and nitrite concentration in human saliva and urine sample collected in the study area as compared to those collected in other areas. In addition, levels of nitrate and nitrite concentration in saliva and urine sample change significantly with the ages of sampled population. NO3-concentrations in saliva and urine sample are the most outstanding among the middle-aged and elderly populations. It means that the middle-aged and elderly populations have relatively high vivo nitrate reductive transformation rates and they also have higher N-nitroso compounds synthesis risks in the studied cancer villages.

Deep challenges for China's war on water pollution

China's Central government has released an ambitious plan to tackle the nation's water pollution crisis. However, this is inhibited by a lack of data, particularly for groundwater. We compiled and analyzed water quality classification data from publicly available government sources, further revealing the scale and extent of the crisis. We also compiled nitrate data in shallow and deep groundwater from a range of literature sources, covering 52 of China's groundwater systems; the most comprehensive national-scale assessment yet. Nitrate pollution at levels exceeding the US EPA's maximum contaminant level (10 mg/L NO₃N) occurs at the 90th percentile in 25 of 36 shallow aquifers and 10 out of 37 deep or karst aquifers. Isotopic compositions of groundwater nitrate (δ¹⁵N and δ¹⁸O_NO3 values ranging from -14.9‰ to 35.5‰ and -8.1‰ to 51.0‰, respectively) indicate many nitrate sources including soil nitrogen, agricultural fertilizers, untreated wastewater and/or manure, and locally show evidence of de-nitrification. From these data, it is clear that contaminated groundwater is ubiquitous in deep aquifers as well as shallow groundwater (and surface water). Deep aquifers contain water recharged tens of thousands of years before present, long before widespread anthropogenic nitrate contamination. This groundwater has therefore likely been contaminated due to rapid bypass flow along wells or other conduits. Addressing the issue of well condition is urgently needed to stop further pollution of China's deep aquifers, which are some of China's most important drinking water sources. China's new 10-point Water Pollution Plan addresses previous shortcomings, however, control and remediation of deep groundwater pollution will take decades of sustained effort.

Polycyclic Aromatic Hydrocarbons Concentrations in Drinking Water in Villages along the Huai River in China and Their Association with High Cancer Incidence in Local Population

This study aims to evaluate the carcinogenic risk of PAHs in the drinking water of counties along the Huai River in China and study their associations with high cancer incidence in local population. We investigated 20 villages with high cancer incidence rates as the risk group and 20 villages with low rates as the control group. Water samples from each village were collected in the winter and summer seasons to analyze the concentrations of 16 PAHs. The carcinogenic risks of the PAHs were calculated for each village using a health risk assessment approach. Results showed that PAHs concentrations in 27.2% of the water samples were higher than the allowable values in China. However, no significant difference in water PAHs concentrations was observed between the risk and control groups (P > 0.05), and no correlation was found between water PAHs concentrations and cancer incidence in these villages. The average upper bound carcinogenic risks were less than 1 × 10⁻⁴ in both groups. In conclusion, PAHs were present in the drinking water of the studied villages, but their carcinogenic risks remained within acceptable limits. PAHs in local drinking water might not be the major environmental cause of the high cancer incidences.

Predicting cytotoxicity of complex mixtures in high cancer incidence regions of the Huai River Basin based on GC-MS spectrum with partial least squares regression

Complex mixture exposures, such as those associated with water sources, are an important issue in health risk assessment. This study assessed the cytotoxicity of chemical mixtures extracted from water sources in regions of the Huai River Basin with high cancer incidences and built statistical models of cytotoxicity based on pollution profiles that were measured with gas chromatography-mass spectrometry (GC-MS). Both surface and ground waters were collected from rural water sources of Shenqiu County, Henan Province of China from 2008 to 2011 and extracted with XAD-2 resigns. Cytotoxicity was evaluated with Chinese hamster ovary K1 (CHO-K1) cells and compared against the pollution profiles of the extracts. IC50 of water samples ranged from 0.023 to 0.338L-eq/mL. The pollutants in waters determined by GC-MS are complex and some of the compounds that contributed to cytotoxicity lack toxicity data. A partial least squares (PLS) regression model of cytotoxicity was built based on linear aggregation of predictor variables (i.e., peaks for single compounds in the gas chromatograms). The PLS model contains 2 PLS factors extracted from 141 variables. The model was validated internally with training data permutation and externally with a test sample. The model explained 92% of the cytotoxicity in the training samples and 40% in the test sample. This approach provides a general, rapid method for relating water toxicity to GC-MS chromatograms and for predicting the compounds that contribute most to toxicity.

Characterisation of gastric cancer and its relation to environmental factors: a case study in Shenqiu County, China

This article presents the results of spatial analysis of gastric cancer and its relation to environmental conditions in Shenqiu County, China. Retrospective data on gastric cancer mortality (GCM) were analysed at various spatial scales, with its relation to environmental factors explored at an appropriate scale. The results considered 2 × 2 km(2) grid as the optimal level for characterising GCM due to the highest Moran's I (I = 0.68, p < 0.01). Then, three clustering regions were clearly identified. Meanwhile, GCM was obviously associated with topography (r = -0.11, p < 0.10), farmland (r = 0.11, p < 0.10), population density (r = 0.10, p < 0.10) and river density (r = 0.11, p < 0.10) in the buffered zones. It indicates that spatial grid technique is suitable for characterising GCM in Shenqiu County, and that GCM was geographically associated with environmental conditions. We suggest that preventive measures for controlling the environment-related malignant neoplasm should not be limited in the regions suffering from this disease but be reasonably extended to surrounding areas.

Application of human cell transformation assay on assessment of carcinogenic potential of river organic pollutants

A human cell transformation assay was used to evaluate the carcinogenic potential of organic extracts of water pollutants collected from the Jialu River.

Association between changing mortality of digestive tract cancers and water pollution: a case study in the Huai River Basin, China

The relationship between the ever-increasing cancer mortality and water pollution is an important public concern in China. This study aimed to explore the association between serious water pollution and increasing digestive cancer mortality in the Huai River Basin (HRB) in China. A series of frequency of serious pollution (FSP) indices including water quality grade (FSP_WQG), biochemical oxygen demand (FSP_BOD), chemical oxygen demand (FSP_COD), and ammonia nitrogen (FSP_AN) were used to characterize the surface water quality between 1997 and 2006. Data on the county-level changing mortality (CM) due to digestive tract cancers between 1975 and 2006 were collected for 14 counties in the study area. Most of investigated counties (eight) with high FSP_WQG (>50%) distributed in the northern region of the HRB and had larger CMs of digestive tract cancers. In addition to their similar spatial distribution, significant correlations between FSP indices and CMs were observed by controlling for drinking water safety (DWS), gross domestic product (GDP), and population (POP). Furthermore, the above-mentioned partial correlations were clearly increased when only controlling for GDP and POP. Our study indicated that county-level variations of digestive cancer mortality are remarkably associated with water pollution, and suggested that continuous measures for improving surface water quality and DWS and hygienic interventions should be effectively implemented by local governments.