Physical examination service utilization among seasonal immigrants in Sanya, China: a cross-sectional study

Backgroud this paper is to explore the influencing factors on utilizing physical examinations (PE) for the seasonal immigrants who moved from their home town to Sanya city in Hainan province in China during the winter . Methods A total of 1342 seasonal immigrants (aged 50 or over) were randomly selected and surveyed through a standardized questionnaire. Using an adjusted logistic regression model to identify the factors associated with the use of PE for those immigrants. Results We found the utilization rate of PE among seasonal immigrants is 26.80%. The level of education, living time, the availability of health insurance, and the attitude to the quality of health service were influencing factors( p < 0.05) . Conclusion The results imply seasonal immigrants have a low utilization rate of physical examination. To improve the availability of health insurance and the quality of health service will be helpful to keep the health of the seasonal immigrants in Sanya .


Introduction
The impact of climate change on the health has become a worldwide phenomenon, it may increase the frequency or severity of extreme weather. 1,2 The extreme weather have led to great threaten to human health especially for the elder. The risk of mortality and morbidity during heatwaves and cold spell are particularly high for older people in care homes 3,4 . Some studies showed that increasing in temperature above the 90th percentile of maximum temperature would increase respiratory admissions for the 75 plus age group and in New York people over 75 were found to have a higher rates of respiratory and cardiovascular morbidity compared to the younger population in heatwave days 5,6 . The morality also high in extreme weather among the older. Heat waves in London, Budapest and Milan were associated with increases in all-cause, respiratory and cardiovascular mortality for those aged over 75 and this result was consist with other studies 7,8 . In the cold spell days the main affected objects also are those elder. S Hajat found a mean relative risk was1.06 if per degree decrease below the cold threshold (set at the 5th centile) and elderly people, were most vulnerable 3 .
For adapting those extreme weather, increasing retiree choose to migrate in different season. This phenomenon of seasonal immigration first appeared in the United State. They moved from the cold districts to the warm sunshine zones during winter and in summer they would immigrant from the hot area to the cool region. 9 This phenomenon also appeared in Australia and Sweden. 10,11 There are also large-scale floating population in China, especially for the elderly who take seasonal leisure and keep health as the main purpose. 12 One research reported Hainan Province has attracted about 450,000 seasonal immigrants during the winter. 13 Most seasonal immigrants are the elderly 10,14, . Once they moved to a new area, it will mean they have to spend time to adapt the new environment and may be exposure to new risk factors. Early examine the level of physical health will found the risk factors in time and to lower the chance of getting illness. And lots of studies have demonstrated that periodic physical examination is an effective measure to prevent illness and keep health. 15,16 The most elderly have one or more chronic diseases, such as cerebrovascular disease, hypertension, diabetes, respiratory disease. 17 So they need more regular physical examination. But seasonal immigrants were not like the local residents who could get a regular physical examination, which make them into a weak position of not getting full health service. Therefore, utilization rate of physical examination is an effective index which could help to assess the level of health service for the seasonal immigrants. Once there is a lower rate of physical examination for the immigrants in the destination, they will have to face a higher risk than the local residents or Economic losses.
Some studies have analyzed the factors which effected the utilization rate of physical examination, such as health knowledge, income level, education background 18,19 . Xi Sun found above 65.50% people aged 60 or over in rural China taking annual physical examinations 20 . Another study found the utilization rate of annual physical examinations in urban elderly is 76.20% in Shandong Province and residents with basic health insurance are more likely to use PE 21 . However, most studies focused on long-term residents, there are almost no studies about the use of PE among the group of seasonal immigrants. This present study aims to explore the utilization rate of the PE among those seasonal immigrants and identify the risk factors associated with the use of PE. Finally the study will make some suggestions to government and improve the level of health services for the seasonal immigrants 2. Methods

Participants
The participants was selected through the local 'Migratory Birds Association' which recorded where have the most number of migrants and we got the data of the floating population through the sixth national census which recorded the number of the population in the city and village. Multistage sampling method was used to selected participants. First, there are four districts in Sanya and one community in each district were selected randomly (Teng hai community, Li zhigou community, Jin jiling community, Dong guan community) as study sites. Second, selecting participants by randomly sampling method from the selected sites. The objects must be not the local residents and over 50 years old. And before survey, we will further check the object whether she or he is a migrant from other province through inquiry and ask several leading number from their identity card. In each site, we calculate the number by the formula of random sampling. In total, 1342 participants aged 50 or over were sampled and completed the survey.

Procedures
Participants were asked about their demographic background, hospital experience and general opinions about health care, and to answer the questions on the questionnaire. We ask whether they got the physical examination during the trip as the object variable. The study was approved by the ethics committee of the university. All participants were provided with informed consent and obtained monetary compensation.

Variables
Social demographic characteristics included gender (male vs female), age (50-59; 60-69; 70-79; 80+), household registration (rural vs. urban), education (junior high school or below; senior school; college or above), marital status (single vs. couple), economic status(poor; normal; good), working status (working vs retired), living time (1 or 2months; 3 or 4 month; 5months above) in Sanya, time with friends (little time; Once in a while; often), health insurance (None; Urban Employee Basic Medical Insurance, UEBMI; Urban Resident Basic Medical Insurance, URBMI; New Cooperative Medical System, NCMS; Public Medical C-are, PMC), health insurance whether can be used in Sanya (yes vs.no), and the attitude to quality of health service (worse than origin; same as origin; better than origin). The major information about physical health including long-term medication (yes vs. no), number of chronic disease (none; 1 or 2; 3 or 4; 5 or above).PE was measured by a question of "Did you have any physical examinations during the past month you came here". The answer included "yes" and "no".

Statistical analysis
We employed a logistic regression model to identify the factors associated with utilization of PE in seasonal immigrants. The dependent variable was PE, independent variables are other variables we discussed above. Statistical significance level was 0.05.

Social demographic characteristics
Most seasonal immigrants (92.30%) were Urban residents and more than half(56.80%) of participants were female. Participants were aged 60-69 (56.60%) and more than 75% participants had educational level above high school. Other social demographic characteristics are presented in Table1.

Utilization of Physical examination
Among 1342 participants, only 26.80% seasonal immigrants were the user of PE(Table1). Results from the unadjusted model shown those who age exceed 70 (p<0.05), who have retired (p<0.05), who have a long time living in Sanya (p<0.05), who have long-term medication (p<0.05), whose health insurance can be used in Sanya, who have more types of chronic disease (p<0.05) are more likely to use PE.

Predictors of utilization of physical examination among seasonal immigrants.
Adjusted binary logistic regression model is conducted to identify the factors associated with the use of PE (Table2). Four factors are found to be statistically associated with the use of PE (p<0.05) , including education level, living time in Sanya, health insurance whether can be used and quality of health service. Those who living in Sany more than 5 months (AOR =1.67, p=0.005), health insurance can be used in Sanya (AOR=2.14, p=0.000), and who thinking Sanya had a better quality of health service (AOR=1.43, p=0.000) are more likely to use PE. Comparing with the local residents, most immigrants were the elder, they have to spend more time to In this study we don't find the difference in the use of PE between rural and urban. This is different from the previous studies, which reported the utilization rate of PE among urban residents was higher than residents in rural residents. 21,22 That maybe due to there are huge differences in health resources between city and country, but those seasonal immigrants use the same health resources in Sanya which reduced the impact from differences of medical resource between city and country 23 .
We had not found evidence for the impact of genders, age, marital status, economic status, working status on the utilization of physical examination and this is not consistent with previous studies. [24][25][26][27] Gong CH et al. found PE increased significantly by age and those who had higher household expenditure were also more likely to have PE. 28  interval. In addition to this, we find the percent of age over 80 was only 2.50%, which may effect on the final analysis. So a further research is needed to understand whether the age effect the use of PE.
Consisting with one previous study 30 , we found seasonal immigrants with lower education compared with those college or advanced degrees, would be more like to use PE. But there also have some studies got the contrary conclusion. Some studies found people with higher education will be more positive to have PE and high education mean high economic status and more active to search for PE 28,21 . People with high education also mean they may have a high awareness of self-care, they could use more way to find self-health status like smart phone, family doctor which could decrease the frequency of going to the hospital for PE. 32 In this study we find the time with living in Sanya is one influencing factor for the use of PE, which could be explained that when immigrants come into a new place with the living-time going, they maybe exposure more harmful factors. Especially Hainan belongs to the largest tropical monsoon region 33  we could analyze subjective influences to get PE. The higher the degree of evaluation, the more likely to participate in the PE (Same as origin: AOR = 1.51, p = 0.005; Better than origin: AOR = 1.74, p = 0.002) which consist with another research 38 . When people believe the level of health services, they may be willing to accept the relevant treatment with a positive attitude.
Seasonal immigrants is becoming more common due to climate change around the world and improve the level of health services for the immigrants in the immigrant land is very important to keep their heath. And through this study in China we found the level of physical examination is low for the seasonal immigrants which give an information that government need to pay more attention to the immigrants and take effective measures to meet health demand of immigrants.

Conclusions
Seasonal immigrants in Sanya had a low physical examination utilization, which may effect on their health especially for the elderly. This study emphasized the importance of improving the availability of health insurance in Sanya, which could expand the health effects of health insurance, and enhance the utilization rate of PE. This study also implied local medical system need to improve the quality of health service in Sanya, indirectly increasing satisfaction and confidence of seasonal immigrants for local health service.

Ethical Approval and Consent to participate
This research have got the Ethical Approval and Consent to participate.

Consent for publication
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Availability of data and materials
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