Our findings showed that providing intensive children care and co-habited with spouse was more positively associated with cognition compared with those who provided no children care or non-intensive children care. Moreover, social activities and depressive symptoms partially mediated the effect between taking grandchildren care and cognition of middle-aged and elderly people.
This study showed that grandparents played a key role in China’s childcare system. There was 40.8% middle-aged and elderly people provided varying degrees of intergenerational care. The result of this study was similar to those of the studies conducted in CLASS 2014 [14] and another study [30]. This trend is due to China’s traditional culture and the concept of filial piety, the grandparent has moral responsibility for his children and grandchildren [31]. Moreover, the conflict between work and child care for mothers is intense, and the high rate of women's labor force participation in China [32]. Therefore, Chinese parents need to rely on grandparents to help them balance work and childcare. Furthermore, in rural China, due to the surplus of agricultural labor [31], adult children often migrate to city in search of better employment opportunities and leaving their children with grandparents [33]. Additionally, there is a serious lacking of formal daycare facilities of children in China [34].
This study suggested that social activities and depressive symptoms played intermediary roles between caring for grandchildren and cognitive function in middle-aged and elderly people. Our finding was consistent with a study which demonstrated that higher frequency engaged in social interaction with lower risk of cognitive decline [35]. As well as consistent with some studies showed that providing grandchildren care could reduce the depressive symptoms [17, 30, 36] and improve the cognitive function of the older adults [7, 8, 10]. A cohort study showed that depression was a risk factor of dementia [37]. A study by Vinkers et al. also found cognitive impairment associated with exacerbation of depressive symptoms [24]. What’s more, some studies showed that caring for grandchildren can promote mental health in older adults [30, 36]. Thus, caring for grandchildren could help grandparent get the emotional support, reduce the depressive symptoms and then improve their cognition. Social activities also played a key role in the relationship of the provision of grandchildren care and cognition. Based on the role reinforcement theory, caring for grandchildren as a social role provided grandparents emotional support from grandchildren and made social connections, gaining social integration and satisfaction from social participation [38, 39]. One pilot RCT, which included social activities as an intervention component, the cognitive function of older adults was significant improved [40]. Another study showed that social engagement can be viewed as a cognitively stimulating form of daily activity [41]. Moreover, providing grandchildren care increased grandparents' opportunities for social engagement, made grandparents gain more social support, enhanced their emotional health and thus promoting their cognition in social interactions [25, 30].
Caring for grandchildren and co-habited with spouse could improve cognition in middle-aged and elderly Chinese people. Especially, providing intensive grandchildren care and co-habited with spouse was associated with better cognition. Grandparenting is a particularly good example of a social role. Cognition can be maintained due to its positive nature [42]. This is consistent with the earlier studies, which showed that caring for grandchildren was positively associated with cognition in middle-aged and elderly people [7, 8]. Moreover, a study showed that the intensive grandchildren care is associated with lower depressive symptoms [18]. In addition, A study suggests that older adults without a spouse are at greater risk for depression than those with a spouse [43]. The presence of a spouse can facilitate emotional communication and emotional support for older adults, thus counteracting some of the potential risks of depression [30]. Empirical researches provided the evidence that physiological stress and depressive symptoms are the risk factors of cognitive decline [44, 45]. Therefore, co-habiting with spouse and providing intergenerational care, the spouse could relieve some of the physical and psychological burden, reduce the risk of depression thus improve the cognition of the grandchild caregivers. In contrast, our findings suggested that providing intergenerational care but not co-habited with spouse was associated with a decline in cognitive function in middle-aged and older people. A study in Europe pointed that intensively engaged in grandchildren care had lower cognitive function than the others [16]. It can be physically and psychologically demanding that helping another person with daily activities [42], which may increase stress on caregivers, limit their social engagement, thus negatively affecting cognitive function [15].