Using four waves of China Health and Retirement Longitudinal Study(CHARLS)data, we investigated the associations between living arrangements and cognitive decline in older people in China. The gender-related difference in these associations was further examined. We found that participants living alone, living with adult children, living with spouse and adult children and living with others all had a faster rate of cognitive decline than those living with spouse. In addition, stratification to gender showed that living alone was related to faster cognitive decline only for male older people. Only in females was living with spouse and adult children or with others related to a faster rate of cognitive decline.
In China, the proportion of older people who lived with spouse had increased sharply, while the proportion of older people living with adult children had decreased substantially, due to increased preference for independent living, mobility of their offspring, lower mortality rates of their spouses, and higher remarriage rates among older persons . Our study found that all four other types of living arrangements were associated with faster cognitive decline in comparison to living with spouse, suggesting that living with spouse may be a better choice for maintaining cognitive function. Additionally, the finding supports the assertion that having a spouse provides the "best guarantee of support in old age" . Spouse may provide emotional support and intimate interaction to reduce the psychological stress and loneliness of older people, thereby slowing cognitive decline. Spouse also extends the older person's personal network by connecting with people such as the spouse's friends and family. Social engagement and a larger social network size could increase cognitive reserve and prevent cognitive decline [35, 36].
In comparison to older adults living with a spouse, those living alone experienced a faster rate of cognitive decline. Previous studies suggest those who live alone were more likely to experience greater social isolation and smaller social networks, which are predictive of negative impact on cognitive function[15, 37]. Living alone also means that this group of older adults had experienced the loss of a spouse. Losing a spouse through widowhood, divorce, or separation is an important stressful life event in old age, and it has a detrimental influence on cognitive performance in older persons [38, 39].
It is worth noting that in our study, we observed that older people living with adult children or with both spouse and adult children experienced a faster rate of cognitive decline than those who lived alone. Traditional Confucian values emphasise family and filial piety, and the practice of adult children living with their parents can be considered a part of filial piety. However, our finding indicates that living with adult children, as a traditional Chinese family concept, may not be conducive to the cognitive health of older people. The possible negative effects of living with children include the following. Although adult children got satisfaction in performing the duty of caring for their parents, they still got bad feelings and were physically and/or mentally stressed, which resulted in a high level of intergenerational conflict. In turn, this leads to cognitive decline in older people who received care from their children. Moreover, living with adult children may lead to an over-reliance on them for emotional or financial support, which can increase feelings of worthlessness and lead to impaired cognitive abilities . Influenced by traditional Chinese culture, people value interdependence within the family and most older people will stay with their adult children and provide the necessary support when asked to do so by their adult children . The burdens of helping their adult children during cohabitation might create long-term chronic stress. A study found that increasing levels of perceived stress were associated with worse initial cognitive status and a faster rate of cognitive decline among adults age 65 and over .
The stratified analysis revealed that the association between cognitive decline and living arrangements varied by gender. In the present study, for men, living alone and living with adult children were associated with cognitive decline. For women, cognitive decline was associated with living with adult children, living with spouse and adult children and living with others, but not related to living alone. Women are usually in charge of household affairs and family activities and are more likely to provide physical care and emotional support to their spouses, which could protect the cognitive function of their male partners [43–45]. Correspondingly, women may be able to live alone in old age as a result of their life experience managing a household. Also, women tend to enjoy more extensive social networks than men through their participation in social activities and intimate friendships [46, 47], which likely compensates for the loneliness and the lack of intimacy of older women living alone. In addition, previous studies reported that females are more emotional and express more negative exchanges than males . Therefore, they are more likely to be highly upset when living with others . Several studies found that experiencing psychological distress and negative emotions are associated with rapid cognitive in old age [50, 51]. This could partly explain why only in females was living with spouse and adult children or with others related to a faster rate of cognitive decline.
There are several limitations of this study. First, we used baseline living arrangements and covariates to determine the relationship between living arrangements and cognitive decline. Considering that the living arrangements of older people may change over time, further research needs to take into account the influence of time-varying living arrangements on cognitive function. Second, the detailed information on the living arrangements of the older people, such as the duration of current living arrangements, is not available, which also played an important role in exploring the relationship between living arrangements and cognitive decline in older people. Third, participants with missing key variates and less than four times follow-ups were excluded, which may lead to certain selection bias and limit the extrapolation of conclusions. Last, although this analysis covered an average of 5.3 years (range 2–7), it may not be long enough to evaluate the measurable change in cognitive function and the long-term influence of living arrangements as the cognitive decline is a chronic process. Thus, we will continue to follow up on the latest data from CHARLS and explore these associations over a longer time.
In conclusion, this study found that older people living alone, living with adult children, living with both spouse and adult children and living with others all had a faster rate of cognitive decline than those living with spouse. Also, the relationship between living arrangements and cognitive decline varies by gender. To slow cognitive decline with age, improve quality of life and promote successful ageing, the government should improve social security and community services and establish a variety of support systems for older people. In addition, more strategies to prevent cognitive decline should be proposed that take into account gender differences. More in-depth research is needed to better understand the mechanisms underlying the role of living arrangements in cognitive decline with age in the future.