Rural Areas Of Northern China Research Articles

A matrix game‐based coordinated optimisation method of distribution networks with multiple flexible resources

AbstractThe ‘Electric energy substitution’ project in rural areas of northern China aims to replace coal‐fired heating with electric heating. However, this could potentially lead to congestion problems on the local distribution networks (DNs) due to an increase in heating loads. Instead of expanding the lines, flexible resources such as microgrids (MGs) and heat pumps (HPs) could provide auxiliary services in a more cost‐effective manner. A bi‐level optimisation model that coordinates DNs, MGs, and HP clusters is proposed to address this issue. In the lower level, MGs and HP clusters provide auxiliary services through competitive bidding to maximise their own income over multiple periods, considering a series of technical operational constraints and comfort constraints. In the upper level, DNs clear the market based on the bidding information to minimise its operational costs while guaranteeing network constraints. The bi‐level optimisation model is formulated as a multi‐agent matrix game problem, and the Win or Learn Fast‐Policy Hill‐climbing algorithm is used to achieve fast market equilibrium in a decentralised manner. Simulation results demonstrate that the proposed method can improve the revenue of MGs by up to 2.6 times compared to the single period matrix game method, and reduce the convergence time by up to 81.3% compared to the multi‐agent Q‐learning method.

Climate impact of coal-to-clean-energy shift policies in rural Northern China

China has implemented the coal-to-clean-energy shift policy in rural areas of northern China to improve air quality, optimize energy structure and reduce greenhouse gas emissions, resulting in a significant increase in natural gas and electricity consumption. The policies shifts can reduce CO2 emissions, but methane emissions from switching processes may contribute to short-term climate impacts. The climate impact during the policy transition is still unclear. Thus, this paper developed a lifecycle greenhouse gas (GHG) emissions framework for coal-to-clean-energy policies in rural northern China. The GHG emissions for heating and cooking, the two most energy intensive activities, were calculated. Four scenarios were designed based on energy types and equipment. Uncertainties in estimating lifecycle GHG emissions under different scenarios were analyzed. The technology warming potential values were calculated for the conversion of scenarios. Besides, the environmental benefits of natural gas versus electricity under emission reduction targets were compared. According to our findings, the total GHG emissions reduction of coal-to-clean-energy shift policies in rural northern China under global warming potential on a 100-year scale (GWP 100) is 1.83 million metric ton CO2 equivalent (MMT CO2 eq) in 2018. Since the climate benefits of policy shifts are driven by chosen technical routes, replacing coal with natural gas should be prioritized; heating with natural gas boilers can maximize GHG emissions reduction and climate benefits. By 2038, the climate benefits of electricity will be far superior to those of natural gas, based on emission reduction targets and electrical mix. There are numerous opportunities to reduce GHG emissions in China's energy sector, and there is a need for the energy industry to obtain better emissions data as well as to increase efforts to reduce GHG emissions.

Energy financing, energy projects retrofit and energy poverty: a scenario-analysis approach for energy project cost estimation and energy price determination.

The research aims to determine the nexus of energy projects retrofit and poverty under two scenarios: energy project cost estimation and energy price determination. Households in rural areas of northern China are now required to switch from coal to cleaner heating options, including natural gas and electricity, as part of a government-led clean heating initiative. This initiative significantly increased the heating expense for participating homes, even when substantial subsidies were applied. We surveyed a large number of northern Chinese households to learn more about the rise in energy insecurity that has been attributed to government action. Our research shows that switching to electricity and gas from coal considerably worsens energy poverty in several ways, whereas switching to clean coal improves the situation. According to an econometric study, changes in energy poverty reveal heterogeneity in several ways. There is little change in Beijing, while the considerably less developed province of Hebei to the north sees a 75% rise. Energy poverty is more common in families with poorer incomes, lower levels of education, and smaller sizes. People who lack resources to insulate their homes will feel the effects more acutely. These results support the idea that low-income families would suffer disproportionately under a "one policy for all" mandate. For policymakers working on energy transition strategies for a low-carbon economy, it highlights the need to consider the distributional impact.

Is solar heating an appropriate choice in rural areas of northern China? Evidence from numerical simulation and life cycle assessment

Solar heating is generally regarded as a clean and low-carbon heating method, while its high initial investment hinders its promotion in economically underdeveloped areas. With the implementation of the clean heating policy and the proposal of the carbon neutralization target, rural bulk coal heating in northern China is restricted. The Chinese government proposes to widely adopt solar heating to meet the heating demands of rural residents. In this research, the application of solar assisted heat pump systems in Beijing, Tianjin, Hebei and its surrounding areas in China is numerically simulated. A new evaluation method under the same initial investment constraint is proposed to verify its benefits throughout the entire life cycle. The results indicate that although solar thermal heating has the lowest environmental impact and carbon emissions among various heating methods, it is not the best solution to rural clean heating. The reason is that equal investment in other projects can bring much more benefits, such as roof solar photovoltaic. In contrast to the air source heat pump and photovoltaic panel scheme with the same initial investment, solar heating has obvious negative environmental impact, 53.3 % higher economic cost, 35.9 tons more carbon emissions, and 105.9 % higher roof area occupation. The sensitivity analysis of solar fraction, geographical coordinates, and energy price also supports the above findings. The recommendation is proposed to promote air source heat pumps or solar photovoltaic, rather than solar thermal collectors, so as to reduce the cost of rural clean heating and carbon emission reduction.

The association between physical activity and cognitive function in the elderly in rural areas of northern China.

Physical activity plays an important role in cognitive function in older adults, and the threshold effect and saturation effect between physical activity and cognitive function are unclear. The purpose of this study was to explore the threshold effect and saturation effect between physical activity and cognitive function in the elderly. The International Physical Activity Questionnaire (IPAQ) was used to measure moderate-intensity physical activity and vigorous-intensity physical activity and total physical activity in older adults. Cognitive function assessment uses the Beijing version of the Montreal Cognitive Assessment Scale (MoCA). The scale consists of seven parts: visual space, naming, attention, language, abstract ability, delayed recall and orientation, for a total of 30 points. The total score of the study participants < 26 was defined as the optimum cutoff point for a definition of mild cognitive impairment (MCI). The multivariable linear regression model was used to initially explore the relationship between physical activity and total cognitive function scores. The logistic regression model was used to assess the relationship between physical activity and cognitive function dimensions and MCI. The threshold effect and saturation effect between the total physical activity and the total cognitive function scores were investigated by smoothed curve fitting. This cross-sectional survey had a total of 647 participants aged 60 years and older (mean age: 73 years, female: 53.7%). Participants' higher level of physical activity were associated with higher visual space, attention, language, abstract ability, and delayed recall scores (P < 0.05). Physical activity was not statistically associated with naming and orientation. Physical activity was a protective factor for MCI (P < 0.05). Physical activity was positively correlated with total cognitive function scores. There was a saturation effect between total physical activity and total cognitive function scores, and the saturation point was 6546 MET × min/wk. This study showed a saturation effect between physical activity and cognitive function, and determined an optimal level of physical activity to protect cognitive function. This finding will help update physical activity guidelines based on cognitive function in the elderly.

Households' participation in energy transition and sustained use of clean energy: Evidence from China's clean heating program

Household energy transition is a critical tool for air pollution mitigation and energy inequality reduction. The effectiveness of the transition largely relies on not only households' decision to participate but also their sustained use of clean energy after participation. However, the sustained use of clean energy has not yet received sufficient attention in policy making and in literature. This study examines China's Household Clean Heating program, which has switched millions of households' heating energy sources from coal to electricity and gas. We focus on both households' adoption and coal substitution behavior in the program. Based on the large-scale household survey conducted in rural areas of Northern China, we find that both high subsidies and compulsory measures effectively increased the household adoption rate; however, the latter did not guarantee sustained use of clean energy. We also find that In-person and repeated dissemination of program information had a better effect on involvement than passive announcements. Moreover, lower-income households were less likely to participate. Our findings suggest effective implementation approaches and supplementary measures to promote household energy transition, with fewer negative consequences for participants, particularly for the participants with lower income.

Occupant Heating Patterns of Low-Temperature Air-to-Air Heat Pumps in Rural Areas during Different Heating Periods

Understanding the actual heating patterns of air-to-air heat pumps (AAHP) in rural areas is crucial for energy planning and clean-heating policy optimization. To explore the influence of outdoor climate change on occupants’ heating patterns when using AAHPs in rural areas, the heating season was classified into three periods: the early heating period (EH), the mid heating period (MH), and the late heating period (LH). The investigation was conducted in rural areas of northern China, and indoor environmental parameters were measured from December 2021 to March 2022. Occupants completed household questionnaires about their heating habits before heating and phone interviews at the end of heating. This paper proposes clustering analysis to identify the AAHP heating pattern in rural areas. The results revealed four typical heating patterns of AAHP utilization. Occupant heating behaviors were dominated by the outdoor temperature fluctuation. In particular, during the mid heating period, the heating operation time periods and the heating duration were longer than that of other heating periods. Moreover, the heating patterns in living rooms were different from that in bedrooms. Room occupancy had an impact on household heating demands. These results could provide guidance for energy planning and the development of clean heating policy in the rural area.

Polymorphisms of Placental Iodothyronine Deiodinase Genes in a Rural Area of Northern China with High Prevalence of Neural Tube Defects

Introduction: We have reported that high total homocysteine and the coexistence of inadequate thyroid hormones in maternal serum increase the risk of fetal neural tube defects (NTDs). Placental iodothyronine deiodinases (DIOs: DIO1, DIO2, and DIO3) play a role in regulating the conversions between different forms of maternal thyroid hormones. This study hypothesized that single nucleotide polymorphisms (SNPs) in placental DIOs genes could be related to NTDs. Methods: We performed a case-control study from 2007 to 2009 that included pregnant women from Lüliang, Shanxi Province, China. Nine distinct SNPs in DIOs genes were analyzed, and placental samples were obtained from 83 pregnant women with NTD fetuses and 90 pregnant women with normal fetuses. The nine SNPs were analyzed using the Cochran-Armitage test and the Fisher’s exact test. Results: There were no statistically significant differences between case and control in the nine SNPs of DIOs (p > 0.05). Conclusions: The results of this study suggested that SNPs of DIO genes in the placenta among pregnant women have no statistically significant difference between the two groups, suggesting that other factors might be involved in metabolism of maternal thyroid hormone provided to fetuses, such as epigenetic modification of methylation and homocysteinylation and genomic imprinting in the placenta. Further functional studies on placenta samples are necessary.

Recycling, disposal, or biodegradable-alternative of polyethylene plastic film for agricultural mulching? A life cycle analysis of their environmental impacts

Plastic mulching is widely used in croplands to improve yields, while its mismanagement leads to plastic pollution in rural areas. China has explored different approaches to manage post-use plastic mulching, while there is still inadequate research regarding their corresponding environmental impacts. This study establishes five plastic mulching management scenarios, i.e., plastic mulching disposed of in nature, substituting biodegradable plastic, recycling, incineration, and landfilling, and maize cultivation in rural areas of northern China was taken as the studied case. We determine the comprehensive environmental impacts through a life cycle assessment (LCA) approach and completed a field investigation to obtain local datasets. The impurity content of used polyethylene mulching (PEM), an essential parameter for the entire life-cycle environmental impact assessment, is 80.1% ± 9.5%, examined by on-site sampling and scanning electron microscope. Results show that: 1) the use of biodegradable mulching (BM) instead of traditional PEM reduces carbon emissions by 22.6%; 2) the increment of soil carbon flux caused in the application stage is more significant than that in the post-use stage; 3) incineration of post-use mulch causes relatively significant photochemical oxidant formation effect; furthermore, recycling of plastic mulching leads to negative impacts in terms of human toxicity effect, meanwhile the positive environmental impact of fossil depletion effect is 2.3 times higher than that of incineration. Reducing the rate of impurity content in wasted plastic mulching can reduce transportation costs and promote sustainable plastic pollution management in rural areas.

Evolutionary game analysis of clean heating governance in rural areas of Northern China

The attainment of clean heating in the rural areas of northern China is of great significance for environmental governance and the realization of the dual carbon goal. Based on the evolutionary game theory, this study constructs a three-party evolutionary game model of the central government, local government, and farmers, introduces key parameters, such as the local government’s governance strength, central government’s inspection strength, and two levels of government subsidy strength, into the model, systematically deduces different possible strategy combinations of the three parties, and analyzes the possible scenarios and stability conditions of each scenario. Finally, the study numerically simulates each scenario and analyzes the influence of the key parameters on the strategies of the three parties. The study conclusions are as follows. 1) The system is optimized in Scenario 6 (1,1,0). 2) The strategy of the local government has a decisive influence on farmers, and the central government’s inspector strength has a weak effect on farmers. 3) The cost of clean heating over coal-fired heating has a significant effect on farm households but not on the two levels of government. 4) The low perception that farmers hold regarding the benefits of the indoor environment weakens the government’s subsidy effect. This study provides effective practical guidance and policy references for governments to promote clean heating in rural areas.

Associations of personal exposure to domestic heating and cooking fuel emissions and epidemiological effects on rural residents in the Fenwei Plain, China

Solid fuel combustion for domestic heating in northern China in the wintertime is of great environmental and health concern. This study assesses personal exposure to particulate matter with different aerodynamic diameters and multiple gaseous pollutants from 123 rural residents in Yuncheng, the Fenwei Plain. The subjects are divided into groups based on the unique energy source applied, including biomass, coal, and electricity/no heating activities. The health effects of the exposures are expressed with four urinary biomarkers. The personal exposure levels to three different aerodynamic particle sizes (i.e., PM10, PM2.5, and PM1) of the electricity/no heating group are 5.1 % –12 % lower than those of the coal group. In addition, the exposure levels are 25 %–40 % lower for carbon monoxide (CO) and 10.8 %–20.3 % lower for ozone (O3) in the electricity/no heating group than the other two fuel groups. C-reactive protein (CRP) in the urine of the participants in biomass and coal groups is significantly higher than that in the electricity/no heating group, consistent with the observations on other biomarkers. Increases in 8-hydroxy-2 deoxyguanosine (8-OHdG), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) are observed for the exposures to higher concentrations of air pollutants. For instance, PMs and nitrogen dioxide (NO2) show significant impacts on positive correlations with 8-OHdG and IL-8, while O3 positively correlates with CRP. PM1 exhibits higher effects on the biomarkers than the gaseous pollutants, especially on VEGF and IL-8. The study indicates that excessive use of traditional domestic solid fuels could pose severe health effects on rural residents. The promotion of using clean energy is urgently needed in the rural areas of northern China.

The value of mobile magnetic resonance imaging in early warning for stroke: A prospective case-control study.

AimsTo evaluate the predictive value of mobile magnetic resonance imaging (MRI) in screening stroke.MethodsThis was a prospective case-control study performed on healthy residents over 40 years old in remote rural areas of northern China between May 2019 and May 2020. Multivariate logistic regression and receiver operator characteristic curve (ROC) analysis were used to evaluate the screening model.ResultsA total of 1,224 patients (500 [40.8%] men) enrolled, including 56 patients who suffered from stroke (aged 64.05 ± 7.27). The individuals who developed stroke were significantly older (P < 0.001), had a significantly higher occurrence of heart disease (P = 0.015), diabetes (P = 0.005), dyslipidemia (P = 0.009), and significantly increased waist circumference (P = 0.02), systolic blood pressure (SBP) (P = 0.003), glycosylated hemoglobin (HbA1c) level (P = 0.007), triglyceride (TG) level (P = 0.025), low density lipoprotein cholesterol (LDL-c) level (P = 0.04), and homocysteine (HCY) level (P < 0.001). Multivariate logistic regression analysis showed that age (OR = 1.055, 95% CI: 1.017–1.094, P = 0.004), HCY (OR = 1.029, 95% CI: 1.012–1.047, P = 0.001) and mobile MRI (OR = 4.539, 95% CI: 1.726–11.939, P = 0.002) were independently associated with stroke. The area under the curve (AUC) of the combined model including national screening criteria, mobile MRI results, and stroke risk factors was 0.786 (95% CI: 0.721–0.851), with a sensitivity of 69.6% and specificity of 80.4%.ConclusionMobile MRI can be used as a simple and easy means to screen stroke.

Study on sustainable defluoridization approaches for rural drinking water treatment in northern China

Groundwater for potable uses containing high fluoride is a worldwide threat to human health. Electrocoagulation is a sustainable approach for decentralized treatment. This study aims to analyse the economic and environmental impacts of electrocoagulation applied at different scale in rural area of northern China by life cycle cost (LCC) and life cycle assessment (LCA) methods. Decentralized treatment for defluoridization in rural Fangshan District, Beijing, where the groundwater quality is typical in northern China, is surveyed as a case study. Three scenarios were evaluated. In scenario 1 (S1) all domestic water is electrocoagulated at community scale without dual water supply system. In scenario 2 (S2) only water for potable uses is electrocoagulated at community scale and raw water and treated water are distributed via dual water pipeline systems. In scenario 3 (S3) water for potable uses is electrocoagulated at household scale. Life cycle assessment is performed with openLCA software and Ecoinvent database. S1 has the highest impacts for eutrophication and global warming. S2 has the lowest impact for toxicity but highest impact for ozone layer depletion. S3 has the lowest impact for global warming and acidification but highest impact for human toxicity. S2 is the costliest while S3 is the most economical. In this case, life cycle cost and global warming impact are the most restricted factors so electrocoagulation at household scale is recommended.

Application Prospect of Solar Water Heating System with Seasonal Thermal Storage in Rural Area of Northern China

In the past few decades, the traditional method of coal-fired heating in rural area of northern China has been exposed many environmental problems. Therefore, as a kind of clean and renewable energy, solar resource has attracted more and more attention. To ensure long-term domestic heating requirement in the countryside, seasonal thermal storage was developed to overcome seasonal variability, the main drawback of solar energy. However, the application prospect of this technology in rural area of northern China still remains to be discussion. This study selected six identical country seats (with 1800m 2 heating area) in Beijing as the model, and from three aspects of climate condition, thermal performance, economic and environmental impact, analyzed the application conditions of solar water heating system with seasonal thermal storage in space heating and domestic hot water. The results show that with 420m 2 solar collectors and 905m 3 seasonal storage tank, the proposed system can meet most demand of space heating and domestic hot water for six buildings, and its equivalent annual cost is acceptable compared to other heating systems despite high one-time cost may become the main problem of its advancement in the countryside of northern China.

Willingness to Have Total Knee Arthroplasty in Rural Areas of Northern China.

ObjectiveTo evaluate willingness and its potential predictors to have total knee arthroplasty (TKA) among residents in rural areas of northern China.MethodsData were collected from two population‐based studies on osteoarthritis (OA) in northern China. Residents aged ≥ 50 years in randomly selected rural communities were recruited using a cluster survey method. Participants completed a home interview (including social‐demographic characteristics, clinical information, 12‐Item Short Form Health Surveys [SF‐12], and Visual Analog Scale [VAS] of knee pain), a physical examination, and bilateral weight‐bearing posteroanterior semi‐flexed view of radiographs of knees. Willingness to have TKA was queried by asking: “If you need to undergo total knee arthroplasty as judged by orthopaedic surgeons, are you willing to accept this operation?” Two trained investigators read all radiographs independently and reached an acceptable intra‐reader agreement. We fitted univariate and multivariate regressions adjusting for potential confounders to examine predictors of willingness to have TKA stratified by sex.ResultsA total of 2172 participants were included. The overall rate of willingness to have TKA was 33.8%. Men were more likely to be willing to have TKA than women with an odds ratio (OR) of 0.73 (95% confidence interval [CI]: 0.60–0.89, P = 0.002). A higher household income (OR: 2.34 for men and 1.77 for women, both P < 0.001), higher SF‐12 Physical Component Summary (PCS) score (OR: 1.02 for both gender, P = 0.04 for men and P = 0.01 for women), and being aware of TKA (OR: 2.55 for men and 2.65 for women, both P < 0.001) were associated with a higher willingness to have TKA. Other predictors of higher willingness to have TKA were younger age (OR: 0.66 for 60–70 years, P = 0.01; and 0.48 for >70 years, P = 0.003, respectively) and lower level of physical activity (OR: 0.57 for moderate, p = 0.04; and 0.62 for heavy, p = 0.04, respectively) among men and a higher education (OR: 1.45 for Junior school, P = 0.04; and 1.66 for high school and above, P = 0.02, respectively) and being overweight among women (OR: 1.38, P = 0.008), respectively. No significant difference was observed between willingness to have TKA and frequent knee pain, VAS of knee pain and Kellgren and Lawrence grades in both men and women.ConclusionsThe willingness to have TKA among rural residents of northern China was relatively low. Younger age, women, educational level, household income, physical function, and awareness of TKA were positively associated with willingness to have TKA.

Exploration of Hydrogeochemical Characterization and Assessment of Organic Pollution Characteristics of Shallow Groundwater near a Chemical Plant That Discharged Sewage Illegally

Groundwater plays a significant role in domestic use and agricultural irrigation in rural areas of northern China. The untreated wastewater from the chemical plant was directly discharged into a seepage well, resulting in the pollution of groundwater. Assessing characteristics of groundwater organic pollution and identifying evolutionary mechanisms of hydrogeochemistry are beneficial for groundwater protection and sustainable management. Statistical methods (correlation analysis (CA) and principal component analysis (PCA)) combined with hydrogeochemical methods including Piper, Gibbs, Gaillardet, and ions binary diagrams and the chloride alkalinity index were employed to explore hydrogeochemical characteristics and evolutionary mechanisms. The results showed that cations were predominantly located at the Ca2+ end and anions were mostly close to the SO42− and Cl− end. The ion concentrations of groundwater were mainly affected by water–rock interactions. The weathering or dissolution of silicate (i.e., aluminosilicate minerals), evaporite (i.e., halite and gypsum), carbonate minerals (i.e., calcite and dolomite), cation exchange, and anthropogenic activities contribute to the chemical compositions of groundwater. Based on CA and PCA, the dissolution of halide minerals and the use of pesticides and fertilizers were the main factors controlling water chemistry. Additionally, the dissolution of sulfur-bearing minerals and gypsum was the key factor controlling the concentrations of Ca2+ and Mg2+. Application of mathematical statistical methods characterized that the exceedance rate of seven organic compounds with high detection rates were as follows: carbon tetrachloride (39.83%) &gt; 1,1,2-trichloroethane (28.81%) &gt; chloroform (10.17%) &gt; trichloroethene (6.78%) &gt; 1,1,2,2-tetrachloroethane (5.93%) &gt; perchloroethylene (5.08%) &gt; trichlorofluoromethane (0.85%). Simultaneously, pollution under the influence of volatilization and diffusion was significantly less than that in the direction of groundwater runoff.

Prevalence and risk factors of stroke in a rural area of northern China: a 10-year comparative study.

Stroke is currently the leading cause of death in China; however, the past decade has produced no new epidemiological studies of stroke. Therefore, the current study aimed to compare the prevalence and risk factors of stroke between 2010 and 2019. A comparative study was used to analyze the prevalence of risk factors for stroke in a population aged 65years or older between 2010 and 2019. Demographic characteristics, risk factors, medical history, and other clinical characteristics were collected for all participants via door-to-door interviews and inpatient hospital records. The standardized prevalence of stroke was 7.9% in 2010 and 14.2% in 2019 (p < 0.001). The prevalence of stroke was significantly higher in men than in women (p < 0.05) for all age groups. The risk factors of stroke were being male, hypertension, and diabetes mellitus in both 2010 and 2019. When comparing the risk factors between 2010 and 2019, these risk factors were statistically significantly more strongly associated with stroke in 2019 than in 2010. The current study suggests that the prevalence of stroke increased nearly by twofold in a population aged 65years or older within the past 10years. Hypertension, diabetes mellitus, and being male were the primary risk factors. In addition, these factors were more significantly associated with stroke in 2019 compared to 2010.

Nutritional Status of Selenium and Its Association with Diet and Indoor Air Pollution among Pregnant Women in a Rural Area of Northern China.

The nutritional status of selenium (Se) in pregnant women in rural areas of northern China and its association with diet and indoor air pollution are rarely reported. We recruited 273 pregnant women in early or middle term in Shanxi and Hebei province and detected their fasting blood selenium. Demographic characteristics, food habits, and indoor air pollution exposure were collected with a questionnaire. Multivariate logistic regression models were used to estimate the adjusted odds ratios (AORs) and their 95% confidence intervals for the factors and relatively low blood levels of Se (below the lower quartile). The median (interquartile range [IQR]) blood concentration of Se was 117.35 (103.90, 129.23) μg/L. The rate of Se deficiency was 4.8%, and the rate of overnutrition was 23.8%. The AORs for the risk for relatively low blood levels of Se were 2.26 (1.15, 4.44) for consuming less beef and pork/mutton; 0.39 (0.19, 0.80) for a lower frequency of vinegar consumption; and 1.41 (0.76, 2.60) and 1.18 (0.59, 2.36) for passive smoking and indoor coal pollution, respectively. In conclusion, the nutritional status of Se in pregnant women in a rural area of northern China was acceptable; diet was the main determinant; no conclusive association was found between indoor air pollution and Se nutritional status.

Co-existence and interrelationship between intracranial artery stenosis and extracranial carotid atherosclerosis in an asymptomatic rural population of 13 villages in northern China

ObjectiveWe investigated the characteristics and relationship of co-existing intracranial artery stenosis (ICAS) and extracranial carotid atherosclerosis in an asymptomatic rural population in northern China. MethodsAsymptomatic residents ≥ 30 years old in 13 villages underwent simultaneous cervical vascular and transcranial Doppler ultrasound. ICAS was defined as ≥ 50% stenosis. Extracranial carotid atherosclerosis severity was classified as increased intimal medial thickness (IMT), plaques, and a plaque with ≥ 50% extracranial artery stenosis (ECAS). Demographic details, medical history, and blood biochemistry results were collected. The relationship between ICAS and extracranial carotid atherosclerosis severity was determined using the chi-square trend test and binary logistic regression analysis. ResultsA total of 2598 asymptomatic participants were included; 122 (4.7%) had ICAS, 1071 (41.2%) had extracranial carotid atherosclerosis, and 84 (3.2%) had co-existing extracranial carotid atherosclerosis and ICAS. Those with co-existing ICAS and extracranial carotid atherosclerosis were older (P = 0.006) and had a higher hypertension (HTN) and diabetes mellitus (DM) prevalence (P < 0.001). HTN (95% confidence interval [CI]=1.31–3.55, odds ratio [OR]=2.15) and DM (95% CI=1.17–4.30, OR=2.24) were found to be independent risk factors for asymptomatic ICAS with extracranial carotid atherosclerosis. Among those with ICAS, 38/122 had no extracranial carotid atherosclerosis, 8/122 had increased IMT, 64/122 had a plaque, and 12/122 had ECAS. As extracranial carotid atherosclerosis severity increases, ICAS prevalence increases. ConclusionCo-existing ICAS and extracranial carotid atherosclerosis occurred in 3.2% of asymptomatic populations in rural areas of northern China. As extracranial carotid atherosclerosis severity increased, ICAS prevalence also increased. HTN and DM might be independent indicators of co-existing ICAS and extracranial carotid atherosclerosis.

Prenatal uranium exposure and risk for fetal neural tube defects: A case-control study in women living in a rural area of northern China

The adverse effects of uranium exposure on human health are well-known; less is known, however, regarding its association with congenital malformations. We conducted a case-control study to examine the association between prenatal exposure to uranium and risk for fetal neural tube defects (NTDs) using the concentration of uranium in placental tissue as an exposure marker in 408 NTD cases and 593 healthy controls. Uranium concentration was quantified with an inductively coupled plasma mass spectrometer. The odds ratios of NTDs for uranium exposure levels, categorized into quartiles, were estimated using logistic regression. The median concentration of uranium in the NTD group (0.409 ng/g) was significantly higher than that in the control group (0.218 ng/g). The risk for NTDs increased 2.52-fold (95% CI, 1.85–3.45) for concentrations of uranium above the median value for all participants. After adjusting for confounders, the risk for NTDs increased 1.36-fold (95% CI, 1.25–6.17), 1.77-fold (95% CI, 1.09–2.85), and 3.60-fold (95% CI, 2.30–5.64) for the second, third, and fourth quartiles of uranium concentrations compared to the lowest quartile, respectively. Prenatal exposure to uranium is a risk factor for NTDs in this population. Prospective studies are needed to further validate this finding.