With the rapid development of Chinese economy, life expectancy increased from 67.9 years in 1981 to 76.5 years in 2016,1 people aged 65 years and over accounted for 8.87% of the total.2 However, the evaluation of the health of population should focus on the length of life and the health-related quality of life (HRQoL) and its differences. A large number of studies have found that a huge disparity in HRQoL exist among urban and rural middle-aged and elderly adults,3–5 and the overall HRQoL of urban residents is better than that of rural residents.6 It may be due to the large gap of development between urban and rural areas in China. Some relevant factors may contribute to the difference of HRQoL between urban and rural residents, such as demographic factors, marital status, level of education, socioeconomic status (SES)7 8 and social support, especially frequency of contact with children, which acts as the core of social relationship.9 10 Some researchers found that SES had a positive impact on HRQoL in China, Korea and many other countries.11 12

It has been well demonstrated that weak social ties could result in physical and mental health problems among the elderly.13 14 The scope of the social network usually shrinks as the elderly grow older15 and elderly parents’ relationship with children becomes a greater proportion of their social relationships. Especially in China, blood relations were emphasised by the traditional culture; relationships between children and elderly parents have usually been considered a core element of the family structure.16 17 Elderly people who got support from their family members had an enhanced quality of life (QoL).18 Some studies have proposed that older adults who are less connected to their children exhibit the higher risk of developing depression.19 However, urbanisation in recent years has led to an increase in the number of empty nesters in rural areas and weakening of family function in rural areas.20

Although it has been demonstrated that urban–rural areas, SES and frequency of contact with children have association with HRQoL of the middle aged and elderly,21 few studies has explored the mediating effects of SES and frequency of contact with children as mediators between urban–rural area and HRQoL of older adults in China. Therefore, we hope to study the possible mediating effect of SES and frequency of contact with children on the overall health status of older adults. Based on previous research, we hypothesise that: (1) Urban participants have higher level of HRQoL than rural participants, (2) Older adults with higher SES have higher HRQoL, (3) The participants who have more contacts with children may have higher HRQoL and (4) SES and frequency of contact with children may possibly mediate the difference of HRQoL between urban and rural elderly population.

HRQoL, a comprehensive index, is selected as the independent variable to evaluate and compare the health status of the middle aged and elderly in both urban and rural areas. Our results explicitly reveal a huge gap, even after controlling known confounders, in the HRQoL among urban and rural individuals who are aged over 45 years and indicate that living in urban areas leads to better health status of older adults than rural areas. Moreover, the current study provides vital information about the relationship of urban–rural disparity in HRQoL with SES and frequency of contact with children among the middle aged and elderly in China. SES and frequency of contact with children play positive mediating roles in the difference of HRQoL between urban and rural older residents.

The mediation analysis indicates that the difference of HRQoL between urban and rural areas is partly mediated by SES. According to our analysis, families or individuals living in rural areas have lower level of SES, which will correspondingly contribute to the significantly worse self-perceived HRQoL of the middle-aged and elderly than those in cities. As shown in previous studies, the disparity mediated by SES may credit to the correlation between the level of health self-management and consciousness of the middle aged and elderly.33 Many studies have shown that high SES is indeed an advantage in promoting healthy behaviours and health service utilisation that further promote health status.34–36 Therefore, it is necessary for improving well-being of Chinese older adults to accelerate the process of balanced economic development and to enhance the equity of health service utilisation between urban and rural areas.

Another discovery of this study is that the frequency of contact with children plays an intermediary role in the relationship between urban/rural areas and HRQoL. We found that urban middle-aged and elderly residents have more contact with children than rural ones. The more frequent contact with children elderly residents have, the higher the index score of HRQoL they received. Considering the stage of China country’s social development and demographic transition related with population policy, it may be ascribed to the migration to cities of many rural young workers for a better life.37 Rural-to-urban migration is an important reason that decreases the frequency of contact between children and parents. The previous researches put forward that the elderly’s social network affects their physical and psychological well-being by buffering stress and promoting health relevant behaviours.38–40 Meanwhile, other researches also stand the point that family and social support can affect the mental health of the elderly, children could play a key role in positively affecting the social network of their elderly parents15 and among elderly population, the risk of suffering from depression was negatively correlated with frequency of contact with adult children.19 Compared with the group of frequent face-to-face and phone contact with adult children, the risk of suffering from depression was higher in the other three groups, which lack of either face-to-face contact or phone contact or both. From the above, young people should give more care and support to the elderly. Meanwhile, the government should also encourage more young people to return to work in the countryside and support the development of rural economy in our country.

However, SES and frequency of contact with children merely explained partial disparity in HRQoL of urban and rural elderly participants in multiple mediation analysis. This may remind us that there are still many other mediation factors to be explored. Concerning the two mediators we studied, SES has greater mediating effect on the relationship between urban–rural disparity in HRQoL of middle-aged and elderly participants compared with frequency of contact. It is possible that SES as a synthetic index covers more extensively. In some ways, it is suggested that reducing the unfairness of economic development between urban and rural areas is the most important task for the country to improve the national health.

The current study has three major limitations. First, we employed the cross-sectional data that cannot distinguish cause and effect between mediators and HRQoL. The longitudinal mediation analysis will be a good choice in the future study. Second, the two mediators we chose only explained about 70% indirect effect, and the current study is not to further explore the relationship between the mediators and HRQoL. Some other researchers found the positive effects of SES on HRQoL of older adults might credit to some additional factors such as social functioning. Maybe a more complex mediation model or more mediation variables could be applied to explore the relevant relationship. Third, urban and rural respondents may have different performance in different dimensions of HRQoL.41 Further investigation could be conducted in each dimension separately to study the mediating effects of SES and frequency on urban–rural disparity among middle-aged and elderly people.

Our findings prove the fundamental influence of SES on health status of the middle aged and elderly. Therefore, this study is of great significance for the government to carry out future healthcare policies and promote the health equality for middle-aged and elderly residents in urban and rural areas.42 Moreover, it also provides the adequate foundation that young people need to provide financial support for our parents and to establish close relationships with them to maintain their QoL when they get older.