Status of Two-week Prevalence Rate in Tibet: Data Base on the Sixth Health Service Survey of Tibet, China

Background Tibet is located in the high altitude area of southwest China, which health level is influenced by specific factors. However, there was little research on Tibetan health condition. And the two-week prevalence rate is an important indicator to health status of residents. The purpose of this study was to understand the two-week prevalence rate and its influencing factors in Tibet. Methods Two-week prevalence rate was calculated using data from a population of 10493 aged 15 and above obtained from the sixth Health Service Survey of Tibet in 2018. Multivariate logistic regression analysis was used to further screen factors for gender, age, marital status, employment status and so on. Results The two-week illness prevalence rate was 20.1% in Tibet. According to the Multivariate logistic regression analysis the two-week prevalence rate was associated with gender, age, residence, marital status, employment status, respectively. Digestive system diseases are given priority, hypertension is the most common disease. Besides, the severity of two-week illness has differences in different groups. Conclusion This study identified a number of factors that appear to have a significant relationship with the two-week illness prevalence. Moreover, the two-week prevalence rates of women and older people were significantly higher, which should be paid attention to in the utilization of health services.


Background
The Tibet Autonomous Region is located in the southwestern part of China. It covers an area of 1.23 million square kilometers and has a population of about 3.3 million. As the average altitude is over 4,000 meters [1].The natural environment and living habits are significantly different from those in other parts of China. Therefore, the health status of 3 local residents has seldom reported before. Besides, two-week prevalence rate is also an important index for evaluating medical and health services, which can reflect the health status and social health status of the population. Many countries in the world attach importance to health services in order to establish effective health service systems, such as the United States, Ethiopia and Kenya, et al [2][3][4]. In China, there are huge differences of the two-week prevalence among different regions [5] [6]. The Fourth National Health Service Survey of China showed that Chengguan District in Lahsa, Tibet has a minimal two-week prevalence rate of 5.2%, while the Dongcheng District in Beijing has a maximal two week prevalence rate of 53.2% [7]. Here this study reported the two-week prevalent rate and the factors based on the data from the Sixth Healthy Service Survey of Tibet, China which completed in 2018.

Data source
Data were collected or obtained from the Sixth Health Service Survey of Tibet, China in 2018. Therefore, according to the level of economic development, geographical location, population distribution and other factors, a total of 24 counties were selected for this survey according to multi-stage stratified cluster random sampling method.
Face-to-face survey using a tablet (PAD), the investigator inquired all members of the household one by one, filled in the electronic questionnaire offline, then reported the survey data online after the survey instructors examined each person. A total of 10493 valid cases were finally included. Subjects were eligible to participate in the current study if they: (1) were≥15 years; (2) were the permanent residents of the sample households. In principle, all the contents of the survey should be answered by themselves. People are not at home or unable to respond during the survey period may be replaced by those who are 4 familiar with their situation.
This study was part of the Sixth National Health Service Survey of China, which has been approved by National Health and Family Planning Commission of the People's Republic of China and Health and Family Planning Commission of Tibet autonomous region. Oral consent was obtained before the survey from the eligible residents.
The definition of outcome variables Two-week illness was defined as the respondents had any of the following three circumstances before two weeks when interviewed: 1) visit a doctor 2) receive medical treatment for the illness or injury or 3) being bedridden or being off work due to illness (including obvious abnormal depression and loss of appetite in elderly people) for at least one day.
Two-week prevalence rate was calculated by the following formula: Two-week prevalence rate = (Number of respondents with two-week illness) * 100 % / (The total number of respondents).
Besides, we measure the severity of two-week illness by calculated the average days of duration of the disease, the days of being bedridden and the days of being off work.
Among them, "the duration of disease", "being bedridden" were applied to the residents aged 15 years and above.

Statistical analysis
Data was double typed in by Epidata 3.0. The Chi-square test was performed to examine the significance of differences in two-week prevalence rates from demographic variables.
Whether sick within two weeks was used as a dichotomous variable. Multivariate logistic regression analysis was further conducted, and variables with statistical significance were included in the analysis. With respect to there are a number of subjects suffered from chronic diseases, multivariate regression analysis was performed to adjust the confounding factors, including gender, age, residence, economic level, education level, marital status, employment status, smoking status and drinking status. Besides, one way analyze of variance was used to analyze the severity of two-week prevalence rate in different groups. Data analysis was completed using SPSS20.0 statistical software. 0.05 as the test level.

Results
Overall, 10,493 residents aged 15 and above were included in this study. The proportion of women (53.1%) was higher than men. The age of the objects in this study was (44.1 + 15.7) years old. The two-week prevalence rate was 20.1% in Tibet in 2018(Table1). The Tibetan ethic accounted for the highest proportion (97.0%).
Among the patients, the two-week prevalence rate of female was higher than that of male with significant difference. The two-week prevalence rate was positively associated with age, and inversely associated with educational level. Urban residents had a higher twoweek prevalence rate than rural residents (27.7 % vs. 18.0 %). The two-week prevalence of widows was the highest, reaching 35.8%. Among the people with different employment status, the two-week prevalence rate of the unemployed was the highest, reaching 41.7%, followed by the retired population, which was 37.2%. Characteristics of survey participants were present in table 1.  regression method based on maximum likelihood) was used to adjust confounding factors In addition, duration of the two-week illness was positively associated with age. There were differences among urban-rural residents, education levels, marital status, employment status, smoking and drinking. For the time of being bedridden of the two- week illness, age, residence, education level, and employment status were also different.
Rural versus urban residents had longer time of being off work. (Table3).  [8,9],which was difficult to digest and absorb in human body.
Moreover, the prevalence of hypertension was 14.4% among the patients which is lower than national average (27.8%) [10]. Nevertheless, hypertension was the most popular chronic diseases in Tibet, which may be related to the diet and awareness of Tibetan [11,12]. High salt in diet, insufficient awareness of hypertension might lead to poor control of hypertension, and the greater possibility of adverse reactions to hypertension, which leads to an increase of medical treatment [13,14].In addition, this study found that the prevalence of hypertension in females was higher than that in males which was consistent with Yichong Li [10].
In this study, we found that there was a significant difference in the two-week prevalence rate between genders. The risk of female population was higher than that of men. The reason may be that women had special physiological periods, mainly affected by menstruation, pregnancy, childbirth, puerperium and breastfeeding, which resulted in special needs [15,16]. Compared with men, women had lower immunity and more delicate emotions which were more likely to pay attention to their own health needs. Therefore, the two-week morbidity rate is higher than men. According to the founding of Anna Ruggieri [17], it appears that hormonal, genetic and environmental factors between males and females may affect the immune.
With the increase of age, the two-week prevalence rate showed an linear increasing trend, which supported for an explanation comes from studies [18] that have shown various kinds of physical diseases are gradually increasing with the increase of age. For most older people, physical and social activities are showing a downward trend, which will weaken the immunity the body. Therefore, the possibility of exposure to risk factors is greater, coupled with a relatively weak awareness of health care, which increased the risk of disease. Otherwise, most women over 60 are in menopause, whose health might be affected by hormone levels [19].
Besides, we also identified factors that rural-urban was different to two-week prevalence rate. The two-week disease risk of urban residents is higher than rural residents, which may be that the education level and health awareness of urban residents are higher than farmers and herdsmen [20,21]. Moreover, the distance between medical treatment in agricultural and pastoral areas is relatively longer, which might affect the accessibility of farmers and herdsmen in medical treatment to a certain extent. Therefore, the reported prevalence rate is low, which is similar to the results from Tian, D [22].Compared with married people, the two-week prevalence of widowed and divorced people is higher than others in urban. The reason may be that the people who undergone widowhood or divorce, to a certain extent, the past way of life or environment will be changed. On the other hand, the widowed were also more likely older, the results were consistent with age.
Therefore, they may have a certain negative psychological impact, thus affecting health.
In different employment situations, unemployment and loafer are the risk factors leading to two-week illness which came to the same conclusion with Fifth National Health Service Survey [23].To a certain extent, Irregular daily life and realistic pressure are the negative factors of illness [24]. Happy marriage and good family care are conducive to reducing the occurrence of illness and accelerating the recovery of illness. As a special social group, school students were at a young stage, who have relatively low life pressure and regular living habits, and most of them are energetic in their youth with good physical immunity, so the risk of two-week illness was lower.
There are several limitations in this study. We did not obtain detailed information on the frequency of smoking and drinking. This discrepancy can attribute to the limited the questionnaire design. Secondly, we did not consider the difference in disease severity for two-week illness due to the size of specific diseases and injuries caused by sample limitations. In addition, due to the lack of longitudinal data, we were unable to examine changes in the two-week prevalence rate.

Conclusions 13
In conclusion, the two-week prevalence rate of Tibetan was generally associated with Because the subjects of this study were Tibetan residents with a low educational level and a large sample size, the investigators use oral informed consent to inform the respondents of the purpose of the survey in accordance with the prepared electronic version of the informed consent. Oral consent was obtained before the survey from the eligible residents. And all the participants are Chinese, and they resided in China.

Consent for publication
Not applicable

Availability of data and materials
The data that support the findings of this study are available from Medical College of Tibet University but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of Medical College of Tibet University.
Competing interests