Introduction

With the socio-economic development, the biomedical model has undergone change to a biopsychosocial model(1). Traditional health indicators, such as morbidity,mortality and survival do not fully reflect overall health status (2). Health related quality of life (HRQOL) refers to the overall impact of physical, mental, and social well-being on an individual, and reflects mainly on the individual’s life itself rather than on the length of survival (3). This has been increasingly recognized to be an endpoint which can serve to measure health needs (4).

China is an agricultural country with 1.3 billion people and 70% of Chinese people live in rural areas (5). There is an obvious gap between the levels of urban and rural health, and the health level of rural residents is still relatively low (5). In 2016 the Chinese central government proposed the “The Thirteenth Five-Year Plan” and improving life quality and eliminating poverty in rural areas is one of the major goals of this plan (6). There has been a growing acceptance of the need for understanding the current status of the life quality and risk factors in rural populations, which can help to establish and regulate relevant health policy and effectively eliminate factors which adversely impact health equity between rural and urban populations, and thus improve the overall level of health for rural Chinese people.

这是沙盘实训课程中最易出现也较难控制的一个问题，严重影响了课程的实施效果。团队中的个别成员在学习前期一旦松懈，进入不了角色，对经营规则、经营思路一知半解，则极易被边缘化，后面即便想加入也比较困难。因此，为了达到实训效果，使得全员参与，有必要引入激励理论对学生学习积极性进行激励。

Unfortunately, there have been few population-based studies evaluating HRQOL in rural populations in China,and defects in study design of most previous studies such as inadequate sample size, flawed sampling sources and statistical analysis (7,8) have limited the reliability of the conclusions and the comparability among studies.Moreover, these studies focused predominantly on exploring the association of socio-economic status and HRQOL, which is insufficient for fully understanding the risk factors which may impact HRQOL.

In this study, we investigated current HRQOL findings in over 12,000 rural adults aged 45—69 years, and explored risk factors for low HRQOL on the basis of a large randomized trial in rural Hua County, Henan Province,China (9). The goal of this study was to identify the vulnerabilities and principal risk factors which impact life quality in this population, and to provide intervention targets for health promotion programs in rural China.

Materials and methods

Study subjects

As shown in Figure 1, the total EQ-5D index score decreased with age in both males and females, and men had

A computer aided one-on-one questionnaire was also completed by all participants in the interview to investigate potential risk factors associated with low HRQOL, which included demographic factors (age, gender), socioeconomic status (educational level, job type, household annual per capita income), household factors (living arrangement, source of drinking water, family members smoking), behavioral and mental factors (cigarette smoking,alcohol drinking, testiness), dietary habits (regularity of eating, eating speed, dietary pattern) and health status[body mass index (BMI), upper gastrointestinal cancer related symptoms, chronic diseases] (Supplementary File S1).

In January 2012, we initiated the Endoscopic Screening for Esophageal Cancer in China (ESECC) randomized controlled trial (ClinicalTrials.gov identifier: NCT 01688908) in Hua County to evaluate the efficacy and costeffectiveness of population level endoscopic screening for ESCC. The inclusion criteria in the ESECC trial were: 1)permanent residency in a target village; 2) age 45—69 years(with ＞5 years of life expectancy) and no history of endoscopic examination within 5 years prior to the initial interview; 3) no history of cancer or mental disorder; 4)negative for hepatitis B virus, hepatitis C virus and human immunodeficiency virus; and 5) agreement to complete all phases of the trial (9).

Based on the ESECC trial, from November 2015 to September 2016, we interviewed 12,085 residents from 257 target villages with total population sizes ranging from 500 to 3,000 which were randomly selected from 18 towns in Hua county.

EQ-5D instrument

The EQ-5D-3L was developed as a standardized nondisease-specific measure of HRQOL by the EuroQoL Group, a voluntary multinational collaboration of European investigators (11). This instrument consists of five dimensions, mobility, self-care, usual activities,pain/discomfort and anxiety/depression. Each dimension has three levels of severity ranked as no problem, some/moderate problems, and severe/extreme problems (coded 1,2 and 3 respectively). For example, state 11111 represents full health (no problems on any dimension), whereas state 33333 represents an extreme problem on all five dimensions. The EQ-5D-3L has 245 kinds of health conditions, including “unconscious” and “death” which are considered as health states.

In this cross-sectional study, we investigated 12,085 rural residents aged 45—69 years from Hua County and found that up to 30.62% reported problems in at least one EQ-5D dimension. A series of risk factors for low quality of life in this rural population were also evaluated. This is the first population-based study using random sampling to evaluate the HRQOL status and risk factors which impact HRQOL in a rural population in China.

HRQOL results measured by the EQ-5D-3L were converted to index scores (health utility scores) using the China time trade-off value sets (ranging from —0.149 for the worst health status to 1.00 representing the best health rating) which were developed by Liu et al. in 2014 (14).

Questionnaire investigation

Hua County of Henan Province, with a rural population of 1.1 million, is an agricultural region in northern part of China, and the per capita GDP was $2,430 in 2013 (10).The mortality for esophageal squamous cell carcinoma(ESCC) in this area is among the highest in the world (9).

Statistical analysis

We transformed the continuous EQ-5D-3L index scores into binary variable and respondents who were below the tenth percentile of index scores were defined as having a poor quality of life (coded 1), others were good (coded 0).In addition, due to the ceiling effects of EQ-5D-3L (15),we regrouped the three response levels (no problem,some/moderate problems and extreme problems) into two categories, namely no problem and any problem (coded 0 and 1, respectively).

All variables were first evaluated with unconditional univariate logistic regression analysis. Age, gender and variables with P＜0.05 were subjected to multivariate logistic regression model analysis and backward selection with P＜0.05 was used to explore potential risk factors for low quality of life. Odds ratio (OR) and 95% confidence interval (95% CI) were estimated taking village cluster into account (16), and pairwise interactions were exhaustively tested in multivariate models. Due to rigorous logic checking of our computer-based investigation system, there were few missing data in this study. The living arrangement information and body mass index (BMI) were not available in 3 (0.02%) and 41 (0.34%) subjects respectively, and they were excluded from the regression analysis. There were 1,002 (8.29%) respondents who refused to declare their income, so we conducted sensitive analysis by including and not including the household annual per capita income variable in the multivariate logistic regression analysis. As the results were similar, only results from the analysis based on the models not including the household annual per capita income variable were presented.

All statistical analysis was performed using STATA(Version 13.1; StataCorp LLC, TX, USA). All tests were two-sided and had a significance level of 0.05.

Ethics statement

Research protocols were approved by the Institutional Review Board of Peking University Cancer Hospital,Beijing, China. All participants provided written informed consent before the survey.

Results

Proportion of full health by selected sociodemographic and health characteristics

Table 2 (continued)of low quality of life in the 56—69 year group than in the 45—55 year group (OR56—69y=1.80, OR45—55y=1.27,Pinteraction=0.006), which was mainly resulted from the usual activities dimension (OR56—69y=2.20, OR45—55y=1.18,Pinteraction=0.028).

Health status distribution in five dimensions of EQ-5D

Among the five dimensions under evaluation, pain/discomfort was the most frequently reported problem(25.52%, 95% CI: 24.75%—26.30%), followed by anxiety/depression (7.98%, 95% CI: 7.51%—8.47%),mobility (5.82%, 95% CI: 5.41%—6.25%), usual activities(2.61%, 95% CI: 2.34%—2.91%) and self-care (1.00%,95% CI: 0.84%—1.20%). The prevalence of severe problems in all dimensions was less than 0.50% (Supplementary Table S1).

数据全面 应用广泛 共享顺畅（施继业） ........................................................................................................5-14

HRQOL by age and gender

同理,以B′为顶点,以为起始搜索方向,可构造出A′B′和B′C′的点集SAB和SBC;以S为顶点,以为起始搜索方向,可构造出C′D和FA′的点集SCD和SFA;最后对所有的P∈SAB∪SBC∪SCD∪SDE∪SEF∪SFA,若P同时存在于多个点集,将P从所在的点集中删除,以消除线段端点区域内的点对相邻直线的影响。

Table 1 Selected demographic and behavioral characteristics and EQ-5D index scores among 12,085 residents from rural Hua County,China, ESECC trial, 2015—2016

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Table 1 (continued)a higher mean score than women in all age groups (0.956 vs. 0.941, P＜0.001). The proportion of participants with EQ-5D identified problems increased with age in all dimensions except for the anxiety/depression dimension.Women tended to have more problems than men with mobility (P=0.01), pain/discomfort (P＜0.001) and anxiety/depression (P＜0.001). Although men and women had no differences in usual activities on the whole(P=0.185), we found that women had a significantly higher proportion of reported activity related problems than men after 55 years old (P＜0.001).

Table 1 (continued)

ESECC, Endoscopic Screening for Esophageal Cancer in China; IQR, inter-quartile range; BMI, body mass index; SD, standard deviation; a, proportion of respondents with no problem in any EQ-5D dimension; b, P values were derived from the chi-square test;c, the standard deviation could not be estimated; d, unhealthy dietary pattern refers to low intake of vegetables, fruit and meat/egg/milk (Supplementary File S1); e, the number of upper gastrointestinal cancer-related symptoms including dysphagia, chest pain, heartburn reflux, indigestion, black stool, upper abdominal pain and weight loss; f, one “chronic disease” represents a system disease that may contain more than one kind of specific disease (Supplementary File S1).

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Risk factors for HRQOL

Figure 1 Mean EQ-5D index score and problem proportion in each EQ-5D dimension by age group and gender among 12,085 residents from rural Hua County, China, Endoscopic Screening for Esophageal Cancer in China (ESECC) trial, 2015—2016.

As shown in Table 2 and Supplementary Table S2, lower EQ-5D-3L index scores were associated with older age(Ptrend＜0.001), female gender (OR=1.29, 95% CI:1.11—1.50), lower levels of household annual per capita income (Ptrend＜0.001), living alone (Ptrend＜0.001), using shallow wells as main source of drinking water (OR=1.53,95% CI: 1.23—1.89), exposure to family members smoking(OR=1.28, 95% CI: 1.10—1.49), testiness (OR=1.56, 95%CI: 1.31—1.85), irregular eating (OR=1.48, 95% CI:1.01—2.17), eating slowly (OR=1.28, 95% CI: 1.07—1.53),unhealthy dietary pattern (Ptrend＜0.001), overweight or obesity (OR=1.57, 95% CI: 1.38—1.80), upper gastrointestinal cancer related symptoms (Ptrend＜0.001) and chronic diseases (Ptrend＜0.001). Among these factors, living alone, unhealthy dietary pattern, upper gastrointestinal cancer related symptoms and chronic diseases had a significantly negative impact on all of the five dimensions which were evaluated. Although job type and alcohol drinking did not impact the overall HRQOL, respondents who engaged in farming reported more problems with pain/discomfort, and alcohol drinking had slight protective effects in mobility and self-care dimensions.

Interaction evaluation

As is shown in Table 3, we found the modification effect of age on the relationship between BMI and quality of life.Overweight or obese subjects had a significantly higher risk

Table 2Multivariate logistic analysis of risk factors for lowHRQOL among12,085residents from rural Hua County, China, ESECC trial, 2015—2016

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Table 2 (continued)

Table 2 (continued)

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From 2015 to 2016, a total of 12,085 permanent residents(median age 56 years; male-female ratio 0.96) from rural Hua County were interviewed. Selected demographic and behavioral characteristics of the participants are shown in Table 1. All respondents were of Han ethnicity and 91.28%of the respondents were farmers. The respondents had an average EQ-5D-3L index score of 0.948 (standard deviation=0.089), and 69.38% of the respondents reported full health status. The proportion of full health varied with the demographic and behavioral characteristics of the participants. Older age, female gender, lower educational level, farming as occupation, lower levels of household annual per capita income, living alone, using shallow wells as main source of drinking water, exposure to family members smoking, testiness, irregular eating, eating slowly,unhealthy dietary pattern, overweight or obesity, upper gastrointestinal cancer related symptoms and chronic diseases were associated with a lower proportion of full health (P＜0.001). In addition, smokers and drinkers had a higher proportion of full health than who did not smoke or drink (P＜0.001).

Table 2 (continued)

ORand 95%CI were derivedafter accounting for villagecluster; HRQOL, health relatedquality of life; ESECC, Endoscopic Screeningfor Esophageal Cancer in China; BMI,bodymassindex; OR, odds ratio; 95%CI, 95%confidenceinterval; a, educational level andcigarette smokingwerenot in this table, as atwo-stepvariableselection method was used in this study. Ageand gender were forced to all models, other variablesinTable 1werefirstly evaluatedinunivariatelogisticregressionmodelsand variableswith P＜0.05wereretainedand subjectedtomultivariatelogisticregressions; b, EQ-5Dindex scores were dividedintobinaryvariable, andrespondents whowerebelow thetenth percentileof indexscores were definedas having apoor qualityof life; c, variables whichwerenot significant in themultivariatelogisticmodels were excluded from themodels and showed using“–”; d, living arrangement was not availablein3 (0.02%) subjects whowereexcludedfromthe models containing thelivingarrangement variable; e, BMI was not availablein41(0.34%) subjects whowereexcludedfromthe models containing theBMI variable.

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Table 3 Interaction analysis between age and BMI for HRQOL among 12,085 residents from rural Hua County, China, ESECC trial,2015—2016

BMI, body mass index; HRQOL, health related quality of life; ESECC, Endoscopic Screening for Esophageal Cancer in China; OR,odds ratio; 95% CI, 95% confidence interval; ＊, each dimension adopts the same multivariate models as EQ-5D index scores,including variable age, gender, household annual per capita income, living arrangement, source of drinking water, family members smoking, testiness, regularity of eating, eating speed, dietary pattern, BMI, upper gastrointestinal cancer related symptoms, and chronic diseases; ＊＊, OR and 95% CI were derived after accounting for village cluster; ＊＊＊, EQ-5D index scores were divided into binary variable, and respondents who were below the tenth percentile of index scores were defined as having a poor quality of life.

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Discussion

In practical terms, the EQ-5D-3L has the advantage of being a simple instrument, which is easy to use with good response rates, so it has been one of the most commonly applied generic HRQOL instruments, particularly in lesseducated elderly population (12). The validity and reliability of the EQ-5D-3L scale have been tested in China (13).

尽管相比机构分布图谱、作者分布图谱，该网络密度已有所提升，但总体上看，关键词共现网络结构仍较松散，密度较低，建议相关研究者避免只追求成果量而追求广度，面面俱到，在考虑适当的课题合作外，还得专注于某一主题方向，展开纵深研究，使得政府机构改革的研究氛围朝良性方向发展。剔除有关标识性不强的关键词，可以看出“政府机构改革”“机构改革”“政府体制改革”“行政管理”“管理体制改革”“机构编制”等成为政府机构改革研究领域高频热点词汇，这些关键词在共现网络图中表现出较高的中心度，由此可初步判断该网络舆情中的“政府机构改革”“机构改革”“政府体制改革”“行政管理”“管理体制改革”“机构编制”是研究热点。

(1)做好水资源总量消耗和强度控制。深入推进实行最严格水资源管理制度考核。按照国家要求，加强规划水资源论证工作。全面实施水资源消耗总量和强度“双控行动”，抓紧完成呼兰河等河流水量分配。进一步推进黑龙江省地下水压采工作，严格控制地区水田发展，坚决遏制农业生产无序开采地下水的势头。强化取水许可审批，对水资源超载，尤其是严重超载的地区，要坚决采取水资源管控措施。

People living alone had the poorest quality of life than those living with their offspring or spouse in this rural population. Studies from Japan (25), the UK (26) and the US (27) also reported that living alone was significantly and negatively correlated with mental health, life satisfaction and self-rated health among the elderly. Similarly, China’s 4th National Household Health Survey in 2008 reported that Chinese urban elders who lived with their offspring or spouse had better HRQOL than those living alone (28).Lack of financial and social support, companionship and daily care from family members may be principal reasons.In addition, we found that the elderly living only with spouse reported more physical problems than those living with their offspring. The explanation for this finding may be economic independence. The majority of rural residents in China do not have unemployment insurance or retirement pension, and their social and health security is dependent largely on their family, particularly their offspring. There has been an increasing trend of migration among the young labor force from rural to urban areas because of urbanization in China (29), which may leave more and more elderly people living on their own with less physical and emotional support. Strengthening the social support system and basic medical services among the rural elderly is likely to be measures for improving their quality of life.

Pain/discomfort and anxiety/depression were the most commonly reported dimensions with moderate or severe health problems, which is consistent with previous studies from other regions of China (5,7,17). International studies among general populations aged 60 years and older from Asia (18) and Europe (19,20) also identified pain/discomfort as the most common problem with a prevalence ranging of 29.4%—61.3%. Thus, relieving of physical discomfort should be a global priority in prevention of HRQOL deterioration in community level health care programs.

The mean EQ-5D index score in this population was 0.948, which is lower than the scores reported in two previous studies of urban populations in China using the same health utility weights for calculating health index scores. A community based study in Suzhou, which is an urban metropolis in East China, investigated 5,557 inhabitants aged 60 years and older and reported a mean EQ-5D index score of 0.959 (17). For purposes of comparison, we also calculated the health index score in our rural population of individuals aged 60—69 years, and the mean score was 0.941. Another cross-sectional survey in 13 provinces across China from 2013 to 2014 which was a part of the Cancer Screening Program in Urban China(CanSPUC) reported that the mean EQ-5D index score was 0.96 for 11,699 participants with an age range similar to participants in our study (21). The urban-rural health inequality in China has been reported to be associated not only with natural conditions and socio-economic development, but also with allocation of health care resources and health services (5). The quality and accessibility of primary health care services play an important role in the health of the population in rural Chinese areas, and these factors should be targets of the health promotion programs to eliminate the urban-rural disparities in the overall quality of life.

北京在多个领域创新政策亮点突出，尤其是社区居家养老服务政策全面领先。此外，北京也位列医养结合政策创新首位，确定了开展省级医养结合试点，出台了相关服务标准，明确提出发展社区居家老年人慢性病管理，并出台促进中医药健康养老服务发展的政策、规划。

We found that the EQ-5D index scores decreased with age, and women reported lower quality of life than men.This was also consistent with previous studies both from China (7,17) and other countries (18-20). Older people were more likely to experience problems in the physical domains of EQ-5D than their younger counterparts in this study. This finding may further serve to explain that more severe disabilities in activity, cognitive impairment and poor physical functioning may be the main causes of poor quality of life among the elderly (17,22). Lower quality of life among women was mainly due to problems with pain/discomfort and anxiety/depression in this study.Possible explanations for this gender difference are as follows. First, women may be more sensitive to pain and other physical discomfort than men (23). Second, women in Asia-pacific countries are more vulnerable to the conditions of lower socio-economic status including fewer job opportunities, lower wages and discriminatory attitudes and so on (24), which may lead to negative psychologic pressure.

鉴于“互联网+”时代游客需求的变化，传统的乡村旅游产品已不能满足当前游客的需求，因此，乡村旅游管理者要保持创新意识，积极融合新技术，升级乡村旅游产品。

According to the Fresnel diffraction theory, the radii of a Fresnel zone plate can be defined as follows18:

例如：在学习《24时计时法》这一节时，我会先向学生介绍一下在我国古代人们都是怎样计时的，这样就调动起了学生的积极性，这样做可以让同学们了解到我们虽然现在可以方便地利用钟表看时间做出时间安排，但在这之前古人做出了长久的探索。古人最初计时是利用杆子在地面上的影子的长度来计算时间，到后来慢慢出现了曰晷和滴漏等计算时间的工具。要让学生深刻意识到古代人民的智慧与创新，从而引导培养学生热爱祖国，热爱祖国的灿烂文化，体现出数学文化强大的教学功能。学生们了解了课外知识后还可以拓宽眼界，增强数学知识储备。

2.校企之间的合作与联动。学校与酒店应当共同注重实习生的心理状况，并安排合适的心理辅导教师以及有经验的酒店工作人员，为学生提供心理健康辅导，便于学生更好地适应岗位需求，发挥自身的工作热情。

Water source has not been a commonly reported factor which impacts HRQOL, especially in developed countries.Since the 1980’s, the Chinese government has committed significant resources to an extensive water improvement project, and deep groundwater (＞100 meters) has become the main water source for most of the inhabitants of rural Hua county (30). We found that 7.81% of the residents who still used shallow wells as main water source had a lower quality of life and more problems in physical health than those who did not. A previous cross-sectional survey in mid-east rural China also reported that the quality of a water source (deep groundwater or public water system vs.surface or shallow well water) was positively associated with the HRQOL score (31). The shallow ground water source was more likely to result in exposure to chemical and biological pollution (32), which may be potential risk factors to physical health, and thus lead to a decline in quality of life. From a more macroscopic perspective, the quality of a water source may reflect the individual’s level of socio-economic status, which is also a crucial determinant of life quality (33).

Obesity, which is a clear risk factor for physical health,also leads to a decrease in the physical domain of HRQOL in our study, especially in individuals of 55 years or older.The obesity epidemic in low-income and middle-income countries is mainly a result of unhealthy dietary habits and physical inactivity (34). This low-income, less-educated population tended to use low-protein high-energy pasta as main dietary staple, and at the same time poor social resources limited their chances of physical activity. Comprehensive life style intervention for weight control and improvement of physical fitness such as dietary education and establishment of physical exercise facilities would likely play an important role for improvement of quality of life in this rural population, especially for older people.

Cancer has become a major public health problem in China since 2010 (35). The ESCC incidence and mortality vary by economic level and geographic location, which have brought about extremely heavy burden to the “highrisk” regions (36,37). We found that esophageal cancer related symptoms had a stable negative impact on life quality in this high prevalence population for ESCC, which suggested that physical symptoms due to the highprevalence disease might lead to the decline of general quality of life. We found that chronic diseases, which are worldwide risk factors for quality of life in the elderly (38),were also strongly associated with low HRQOL in this population, and this further demonstrated that primary health care services and chronic disease management are crucial for improving the overall health status in this rural population.

This study has two limitations that should be acknowledged.First, we could not conclude a causal relationship between these factors and HRQOL due to the nature of crosssectional investigation. Second, although high-grade sampling method was adopted, respondents of this study were restricted to those from Hua County, Henan Province,which might limit the generalizability of our findings to other rural population in China.

Conclusions

This large population-based survey reports the current HRQOL status and describes a series of risk factors which impact HRQOL in this rural population in China using random sampling methodology. The overall quality of life among Chinese rural residents was relatively low by objective measurement. Health intervention and promotion programs in rural China are needed, and more attention should be given to the elderly, especially to elderly women and the elderly living alone. Alleviation of poverty,improvement of basic living conditions and primary medical care should be priorities for improvement of the overall HRQOL in rural China. Results of this study are crucial for generating health promotion strategy in rural population in China, and will also serve as the fundamental basis for the cost-utility evaluation in our ESECC screening trial in the future.

Acknowledgements

This work was supported by the Charity Project of National Ministry of Health (No. 201202014), the Natural Science Foundation of China (No. 81473033), the National Key R&D Program of China (No. 2016YFC0901404), the Science Foundation of Peking University Cancer Hospital(No. 2017-4) and the Open Project funded by Key Laboratory of Carcinogenesis and Translational Research,Ministry of Education/Beijing (No. 2017-10).

Footnote

Conflicts of Interest: The authors have no conflicts of interest to declare.

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