key: cord-0945015-1robwl4r
authors: Atalay, Kadir; Staneva, Anita
title: The Effect of Bereavement on Cognitive Functioning among Elderly People: Evidence from Australia
date: 2020-10-20
journal: Econ Hum Biol
DOI: 10.1016/j.ehb.2020.100932
sha: 3960926b0785fb83528ab00290545f1c4bdb2fd4
doc_id: 945015
cord_uid: 1robwl4r

This paper explores the effects of experiencing the death of a spouse, relative or close friend on cognitive functioning of Australian elderly. Using rich longitudinal data, we show that experiencing a loss is associated with a modest decline in cognitive function. Our results show that on average the effects are more pronounced for males and the strongest effects are associated with the loss of the spouse or a close friend. These events have significant effects on working memory and speed of information processing. We show that the decrease in cognitive functioning is accompanied by decreases in engagement in cognitive activities and declines in socialization. Our results are suggestive that programmes to support grieving individuals, including support for socialization activities, and extending active ageing programmes could be important for promoting successful cognitive aging for the growing population of older adults.

Losing someone you care about has been considered the most stressful and emotionally devastating event an individual can experience in their lifetime (Holmes and Rahe, 1967) . Hence, either their scopes are limited and/or their findings are subject to issues related to unobserved individual heterogeneity. Importantly, these studies examine the memory cognitive domain only and overlook dimensions related to 'crystallized intelligence' due to lack of data. While specific dimensions of cognition, particularly applied to 'fluid intelligence', such as episodic memory, abstract reasoning and information processing speed, generally are in decline, other dimensions related to 'crystallized intelligence', such as the ability to draw on experiences, knowledge, skills acquired through socialization, have been found to remain stable into old age (McArdle et al., 2002) . Hence it is of interest to examine the association between bereavement (which potentially impact individual's social interactions) and crystallized intelligence. The data also allow us to examine different types of bereavement, e.g., the death of a spouse/children, relative or close friend. Furthermore, we provide novel evidence on the possible mechanisms through which bereavement could affect an individual's cognitive performance. Specifically, we explore a wide range of mental exercise activities and social behaviours that can potentially drive the cognitive effects of the observed adverse life events. We highlight the differences between men and women in estimated bereavement effects. Few studies in the recent literature focus on the relationship between bereavement and cognition with a gender focus, and the results are inconclusive (Wörn et al., 2020) . 2 Finally, our results highlight that establishing the link between bereavement and cognitive functioning is important for public policy. Given that spousal bereavement is associated with an excess risk of mortality (a well-documented phenomenon known as the 'widowhood effect', Sarah et al., 2016) , and in light of the recent COVID-19-related death tolls, more substantial preventive policy measures addressing bereavement-induced cognitive declines are needed.

We uncover a substantial heterogeneity in the effect of bereavement on cognitive functioning depending on the loss type and according to the cognitive domains.

Experiencing the death of a partner or a close friend was found to have a significant impact on individual's 'fluid intelligence', whereas no effect we observed in individual's 'crystallised ability'. These effects are stronger for males. We also show that the decrease in cognitive functioning is accompanied by decreases in engagement in mental exercise activities and declines in socialization and health behaviours.

The HILDA Survey contains a special module on human capital which includes cognitive assessment tasks. In particular, it measures three dimensions of cognition: (i) pronunciation reading test which is a 25-item version of the National Adult Reading Test 2 Support for the hypothesis that men are relatively more distressed than women by the loss of their spouse is provided in early studies. Stroebe et al., (2001) suggest that men suffer relatively greater health consequences than women. However, Gilbar and Dagan (1995) conclude that women have higher depression rates during bereavement than men. year. In the self-reported HILDA Survey, these questions have been included since wave 2 (2002). Respondents were asked whether they lost (i) their spouse or children, (ii) a close family member (other than children and spouse), or (iii) a close friend. We use these responses to construct our indicator variables for bereavement. We also combine all three separate life events in an indicator variable for experiencing any losses.

To analyse the mechanisms behind the cognitive effects of bereavement, we utilise various intensity measures of mental exercise activities, socialising, and physical activity available in the HILDA Survey. For the data on the change in mental exercise activities respondents state how often per week they go to museums, art galleries, or watch TV, do puzzles (such as crosswords or Sudoku) and board games; how often they write letters, reports, or stories and read books, magazines, attend educational courses or lectures. We count the number of activities that a person engages per week. We look at the change in the numbers of weekly mental exercise activities. We also consider indicator variables for individuals reporting that they feel lonelier in 2016 compared to 2012, less socially and physically active. 4 For the data on socialising respondents state how often they get together socially with friends/relatives and whether they are active members of community/sport clubs. The variable 'became less social' takes value 1 if they reduce their weekly meetings with their friends and relatives. The variable 'became less active' takes the value 1 if respondent reports no longer being an active member of community/sport or hobby clubs.

The resulting estimation sample consists of individuals aged 60-85 at the time of their first cognitive interview in 2012 who reported that they were partnered. We further restricted the sample to individuals who either did not change their marital status or became widowed. 5 Our final sample includes 842 women and 751 men assessed at two points in time. Table 1 reports that our male and female sample characteristics are similar, although men are slightly older, more educated and reported to be employed. The word reading test scores on both samples are similar; however, females score higher on the speed of information processing. In the 4-year period between 2012 and 2016, we observe that 69 % of women and 67 % of men either lost their spouse, close friend or relative. Approximately half of our sample loses their close friends during our observation period, and around 30 percent loss their close relatives. The least frequent event is the loss of a spouse.

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To investigate whether experiencing a loss of a spouse, close relative, or friend affects the cognitive outcomes of elderly men and women in Australia, we consider the following first difference (FD) model: given that couples share more unobservable riskshence common shocks are more plausible. Although in our data, we do not observe common accidents, we cannot rule out this possibility. Therefore, our spousal bereavement results should be interpreted within this limitation.

As an alternative to our FD method, we further consider difference-in-difference (Diff-in-Diff) with kernel propensity score matching (PSM). 7 To examine the potential mechanisms that could drive the association between bereavement and cognition, we rely on the same strategy and estimate the FD model by focusing on the role of mental exercise, socialisation, and physical activity. 7 We thank anonymous referee for their suggestion and insights on this matter. 8 For the matching we follow Tseng et al. (2017) and use socio-economic characteristics of the individual and their partner in 2012, as well as household and residential information in 2012. These covariates also include age, physical health, education, employment status, whether they have kids, outright or mortgage homeowner and household income. For the residential information, we include postcode level of house prices, LGA level average income and unemployment rates. In Online Appendix Figures A1 and A2 we present the overlap of the distribution of the propensity scores across bereaved and non-bereaved groups for men and women based on experienced any loss. We found the extent of the overlap to be satisfactory. 9 We do not find evidence that the loss of a close relative affects individual's cognition -for both men and women the effects are insignificant, though, for men, a decline in the speed of information processing is found for those who reported a death of close friend. The association remains significant at 10% significance level after including full controls.

Overall, our findings indicate a differential effect of the type of bereavement events on cognitive decline, where experiencing the death of a partner associates with the highest impact on cognition. This finding is consistent with the negative differential effects reported authors speculate that these differential effects may be due to the different amount of stress these events generate. Importantly, men are relatively more affected by the bereavement compared to women. We also find that the 'crystallized intelligence' remains unaffected, which confirms the existing knowledge that 'fluid' and 'crystallized' cognition exhibit [ In addition, we may expect the differential bereavement effects on cognitive functioning to depend on the length of time of this negative stressor is endured. We show the FD results for the associations between length of time of different bereavement events and cognition. We find stronger impacts of the recent bereavement events; however, the estimates are imprecise. We examine the younger age groups (40 to 60), and found consistent impacts, however the effects are smaller and less significant. We also showed that bereavement effects for men are stronger if the age difference between spouses are smaller (less than 5 years). This might be partly driven by that death of partner might be unexpected in this families. Alternatively, these couples might have a similar taste for social and daily routines and loss would be associated with bigger losses in social capital. Finally,

we check the single sample, and show that friend loss and relative loss have significant negative effects on single men's cognitive functions. 10 

In Table 3 we present the results of the kernel PSM Diff-in-Diff estimators for bereavement events. Our results are broadly consistent with the FD estimation and indicate the negative impact associated with the bereavement. The results from the kernel PSM Diff-in-Diff model show that losing someone is associated with a decrease of 0.18 standard deviations in the speed of information processing for men (compared to 0.08 standard deviations found in the FD). The main difference between the FD and Kernel PSM Diff-in-Diff is that in the latter method we find insignificant impacts of spousal bereavement on cognitive scores for both males and females. It is important to note that spousal bereavement is the least frequent event in our samplefor example, only 2 percent of men experienced this event. This may in part explain the differences we observe between the two models.

[ J o u r n a l P r e -p r o o f

One potential concern is possible non-random i) any loss; ii) spousal loss; iii) a close family member loss; iv) close friend. 11 We then use the inverse of the fitted probability to construct the weights that are used to adjust our main FD models. In Table 4 we present the weighted estimations for the three standardized cognitive outcomes. The results show that inverse probability weighted estimates are numerically similar, and qualitatively identical, to the unweighted estimates; therefore, we acknowledge the attrition is not likely to affect our estimates.

[ Figure 1 shows the coefficient estimates and 95% confidence intervals for the loss variables from that men are relatively more affected by the bereavement compared to women. We also examine the impact of the loss on mental health (measured by the SF-36) and overall stress levels; as expected, we observe negative impacts on these measures, we did not observe any significant impact of bereavement on the mental health.

[FIGURE 1]

This article presents Australian evidence on the effect of bereavement on cognitive functioning and adds to the literature by providing evidence on the possible mechanisms through which bereavement could influence individual's cognitive performance. Our data enable us to examine both fluid and crystalized cognitive dimensions. We find heterogenous impacts of bereavement on cognitive functioning. Importantly, men are relatively more affected by the bereavement compared to women. We also find that the 'crystallized intelligence' remains unaffected. While we cannot interpret these results as conclusively causal (due to potential time varying unobservables), our finding that the effect is more pronounced on working memory and speed of information processing 13 could be useful in development of intervention programs for targeting specific dimensions of cognitive decline.

Our findings further indicate that bereavement is associated with decreases in participation in mental exercises and social engagement activities. Many studies have supported these findings that physical activity and socialisation are preventive factors for cognitive decline (Read et al., 2020; Evans et al., 2018; Thomas, 2011 arts; going to museums) (b) Question is "How much do you agree or disagree with statement "I often feel very lonely"? The more you agree, the higher the number of the box you should cross. The more you disagree, the lower the number of the box you should cross " (c) This is indicating that individual meets with friends/relatives at least once a week. (d) Currently an active member of a sporting, hobby or community based-club or association. 

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