Institute of Psychiatry, Kings College London, UK
Institute for Population and Social Research, Mahidol University, Nakhon Pathom, Thailand
Faculty of Medicine, Thammasat University, Rangsit Campus, Pathumani, Thailand
Institute for Population and Social Research, Mahidol University, Nakhon Pathom, Thailand
Institute of Psychiatry, Kings College London, UK
Correspondence: Melanie A. Abas, PO 60, HSPRD, Institute of Psychiatry, Kings College London, London SE5 8AF, UK. Email: m.abas{at}iop.kcl.ac.uk
This work was funded by the Wellcome Trust (WT 078567).
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It has been suggested that rural–urban migration will have adverse consequences for older parents left behind.
Aims
To describe correlates of outmigration and to estimate any association between outmigration of children and depression in rural-dwelling older parents.
Method
Population-based survey of 1147 parents aged 60 and over in rural Thailand. We randomly oversampled parents living without children. We defined an outmigrant child as living outside their parents district, and measured depression as a continuous outcome with a Thai version of the EURO–D.
Results
Outmigration of all children, compared with outmigration of some or no children, was independently associated with less depression in parents. This association remained after taking account of social support, parent characteristics, health and wealth. Parents with all children outmigrated received more economic remittances and they perceived support to be as good as that of those with children close by.
Conclusions
Outmigration of children was not associated with greater depression in older parents and, after taking account of a range of possible covariables, was actually associated with less parental depression. This could be explained by pre-existing advantages in families sending more migrants and by the economic benefits of migration.
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A commonly held view is that outmigration of young people has starkly negative consequences for ageing rural parents, with loneliness, isolation and even loss of basic instrumental and economic support.3 A contrasting position is that non-migrant family members benefit through remittances4 and that families find adaptive ways to maintain contact.5 If this is true, older people with some of their children migrated may be in a better position than those with all children migrated, having remittances but also local support.
The setting for the current study is Thailand, where traditionally children take responsibility for older parents and older parents continue to support children. With declining co-residence and increase in urbanisation of young adults, older people may be at risk of being left behind in rural Thailand if all their children migrate. Given that depression in older adults is associated with loss of close contacts6 our hypothesis was that Thai parents aged 60 and over, living without at least one child in the district, would have more depression than those living with some or all children living in the district.
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Sampling
Historical data from 2004 showed which older adults in the surveillance
system were living without at least one child in the same household. We did
not know which of these had some or all of their children migrated outside the
district, or which were childless. We therefore established a sampling frame
that over-sampled older adults living without a child in the same household
with the aim of capturing parents who had some or all children migrated beyond
the district. We would then be able to use the whole sample we obtained to
compare parents with all children migrated, parents with some children
migrated and parents with no children migrated. There was a potential sample
of 3916 households with at least one older adult aged 60 and above, of whom
2432 (62%) had at least one child of the older adult in the same household,
and 1484 (38%) did not. For each sampling unit we used simple random sampling
to select 60% of households where an older adult was living without at least
one child and 30% of households where an older adult was living with at least
one of their children, a total of 1593 households. We used random selection to
select the participant in situations where there was more than one eligible
parent living in a household. Data were collected from November 2006 to
January 2007.
Definitions
We defined an outmigrant child as a child living outside the parents
district of
residence5 for a
minimum of the past 3 months. We used minimum of 3 months to avoid temporary
absences. A district is a well-recognised administrative boundary, with a
radius of approximately 15 km in this province. Our a priori measure
of exposure was having all children migrated outside the district. Given our
conceptual model we compared this separately with having some children
migrated or having no children migrated.
Recruitment
The interviewing team visited each sampling unit and made contact with the
village headman or appropriate administrator prior to visiting each selected
household. The populations were mostly already well acquainted with the
demographic surveillance system. If the selected older adult and the household
head gave consent, the interviewer first interviewed the household head with
the household questionnaire and then the older adult with the individual
questionnaire.
Inclusion criteria
Fluent Thai-speaking; aged 60 or over; parent of at least one living child
(biological, adopted or step-child); living in a demographic surveillance
system village since at least 2004.
Exclusion criteria
Change in living arrangement between 2004 and 2006 from living without a
child to living with a child (or vice versa). We excluded these to minimise
error in measuring duration of exposure and did not consider it would
introduce bias as during piloting we found that fewer than 5% of older adults
had changed this status between 2004 and 2006.
Exposure
The exposure of interest was location of children inside or outside the
district. Early in the interview we established the location of all the
participants children (biological, adopted and step-children) by asking
their names, where they lived and length of time living at that location. To
assist precision we asked older adults if their child was in the household,
the village (or for urban dwellers within average walking distance), the
subdistrict/neighbourhood (tambon), or the district
(amphoe), all of which are well-recognised. In Kanchanaburi
province the average radius of a tambon is 6 km and of a district 15 km. We
then stipulated which children we were referring to when we asked subsequently
about support exchanges and remittances, cross-checking with the participant
and/or another informant to ensure that we were rating contact with the
correct child. For the few participants who performed poorly on cognitive
tests or who gave vague or inconsistent answers, an informant gave this
information.
Dependent variable
We measured depression using a Thai version of the EURO–D
questionnaire.8 The
EURO–D is a 12-item screen for depression using items from standardised
validated measures of depression that can be used by lay interviewers,
including the Geriatric Mental
State/AGECAT.9 It is
strongly correlated with its parent diagnostic instruments and shows high
criterion validity against
DSM–IV10
major depression.8
In studies from low- and middle-income countries the EURO–D has a
similar factor structure to that in high-income European
countries.11 Thai
mental health professionals, including two non-English speaking locally
trained providers, considered that it covered symptoms recognised locally as
common in psychological disorders in older adults. A team of bilingual mental
health professionals, bilingual social scientists and English psychiatrists
with relevant experience developed the first translation, paying particular
attention to conceptual and semantic equivalence. We validated the Thai
EURO–D in an out-patient setting against structured diagnostic interview
by a Thai psychiatrist. The sample size was 150 and the number of people with
gold-standard depression was 51. The area under the receiver operating
characteristic (ROC) curve was 0.78 (95% CI 0.70–0.85), the kappa
(
) was 0.4 and internal consistency for the total scale measured by
Cronbachs alpha was 0.72.
Covariables
Socioeconomic position. We considered years of education, number of
household assets (up to 24) and household wealth index. We used principal
components analysis to develop a household wealth index comprising 14
household assets (such as ownership of a fridge, motorcycle and mobile
telephone) and interviewers global rating of household quality.
Social network and social support. We modified existing measures, taking into account the importance in the Thai context of the family and of children. We measured size of neighbourhood family network; frequency of talking to a child; frequency of talking to friends; received support (instrumental, emotional, financial), and perceived adequacy of support from and to children; and received support from others.12–14 We also measured financial transfers from children in three separate ways: remittances defined as amount of money per year transferred to parents to use as they chose;15 substantial gifts valued above the equivalent of US$50 such as a television; and household expenses defined as amount of money per year paid by children directly to cover parents household bills, for example payment to electricity company or health insurers.
Cognitive function. We used immediate recall and delayed recall of a ten-word list learning task from the Consortium to Establish a Registry of Alzheimers Disease16,17 and the animal-naming verbal fluency task, also from the Consortium to Establish a Registry of Alzheimers Disease. We defined significant cognitive impairment as performance at or below 1.5 standard deviations below the norm for the individuals age group and educational level.
Physical illnesses and impairments. We used a modified version of the Burvill physical illness scales18 covering the presence of 13 common health problems affecting different systems, including breathlessness, blackouts, arthritis, weakness, hearing difficulties and heart trouble. If the person said they had such a problem we rated it as impairment if they also said yes when asked if it affects your function a lot.
Disability. We used the brief version (12-items) of the World Health Organizations Disability Assessment Schedule to rate disability over the past 30 days.19 Domains included understanding and communicating with the world, getting around, self-care, getting along with people, activities and participation in society. One item (any difficulty with learning new tasks) was deleted as it was not found relevant for older rural people.
Life events and difficulties. We adapted the List of Threatening Experiences20 in the light of qualitative work and following advice from experts in measuring life events in older people. The adaptations included adding difficulties as well as events, restricting rating of events and difficulties to those remaining severe for over 3 weeks that occurred to the participant, an immediate family member or someone perceived as very close, and adding events to do with caring for grandchildren and to do with problems at school or work for children or grown-up grandchildren.
We used a short version of the questionnaire in situations where information had to be gathered from an informant if the older adult had apparent significant cognitive impairment or was too unwell to complete a full interview.
Questionnaire development
We carried out focus group discussions to explore experiences of rural
ageing and outmigration of children, exchanges with family members and
expectations surrounding children. This informed the development of the
questionnaire that was pre-tested by a team of ten experienced interviewers on
three separate occasions. After each pre-test we made modifications by
consensus. The final version was back-translated to English and checked for
consistency by a bilingual psychiatrist and a bilingual social scientist.
Data collection
The data collection team of 4 supervisors and 12 interviewers each had at
least a bachelors degree. Most had previous experience with
interviewing for the demographic surveillance system. Residential training
took 10 days and included presentations, role play and practice in pilot
villages.
The data collection team stayed in the villages at the headmans house or the temple. Quality control included checks on data completeness and consistency. Interviewers had to return to the participant if data were inadequate, which happened six times. Researchers were in frequent telephone contact and regularly visited the data collection teams. We conducted all interviews in Thai and gathered informed consent from all participants. We gained ethical approval from Kings College Research Ethics Committee (No. 05/05-68) and from Mahidol University Institutional Review Board.
Sample size calculation
We initially calculated this based on a comparison of prevalence of
depression in those with all children migrated v. those with some
children migrated and needed a total sample size of 954 given the proportions
expected of those exposed and not exposed to having all their children
migrate. In the analyses currently presented the interest was the level of
depression in three groups (all/some/no children migrated). With the attained
sample size in these three groups, we achieved 90% power to detect a
difference of 0.75 on the EURO–D scale given the standard deviation in
our sample of 2.8.
Analysis
We used Stata version 9 for Windows (Release 9, College Station, TX: Stata
Corporation. 2003). Because of the oversampling the sample was not
representative; however, the analyses were reweighted to take this into
account. We weighted the data using the product of two sets of probability
weights to take account of differential sampling at village and household
levels, and used the survey commands in Stata (svyset) for analyses. We
analysed the univariate associations between continuous depression score,
exposure to outmigration of all children (compared with some or none) and
covariables. We used multiple regression to assess the effect of outmigration
on depression and taking account of confounding variables, carrying out a Wald
test to test the effect of the exposure after adding in potential confounding
variables. We adjusted first for variables known to be associated with
depression that might confound any association, for example sociodemographic
characteristics, physical and cognitive impairment and severe life events. We
then adjusted for variables more specific to the outmigration situation that
could be mediators, for example time since last child left, social support
from children and economic remittances from children. We checked the residuals
for normality; there was some skewness that appeared to be related to the
small number of participants from whom data were gathered from an informant.
We re-ran the model excluding these and there was only negligible difference
in the effect size of explanatory variables. We explored interaction between
outmigration and variables for which there was some a priori reason
to suspect this might exist, for example demographic factors, wealth and
support. Interaction terms were tested by putting them into the multivariable
model. All tests were Wald tests.
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Out of the 1300 eligible, 153 (12%) were non-responders of whom 110 were unavailable for an interview (despite up to ten visits to the household), 21 refused to take part and 22 were too unwell. Those unavailable were mostly away visiting their children. Of the 1147 (88%) who agreed to participate, data were complete for 1104 and incomplete for 43 because the older adult was unwell or cognitively impaired.
In the study sample of 1147 parents, 48% lived with at least one child and 52% lived without at least one child. Of the total, 16% had all children migrated from the district, 68% had some children migrated from the district and 16% had no children migrated from the district (i.e. all children living in the district). Taking into account the weighting, this extrapolates to a province estimate of 4966 parents with all children migrated from the district, 28 522 with some children migrated and 7862 with no children migrated from the district.
The mean age of the study participants was 70 years (the range was 60–93), 55% were female, 55% were married, and 29% had no education (Table 1). Fourteen per cent lived alone, a further 19% lived with a spouse only and 48% lived with at least one child with or without a spouse or others (data not shown). There were no significant differences from non-responders in terms of age (non-responders 69 years), gender (55% female), living alone (12%), being currently married (54%), or education (27% no education). Weighted estimates of the characteristics extrapolated for the wider province population from which the sample was drawn revealed few differences between the study sample and the estimated province population (Table 1, col. 2). Because we oversampled those not co-resident with a child, the study population has a lower proportion living with a child (48%) than did the estimated province population (63%) and is slightly more likely to have outmigrant children (data not shown). Otherwise there are few differences between the study sample and the estimated province population. The average time living in the district was nearly 50 years.
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View this table: [in a new window] | Table 1 Characteristics of parents |
Most older parents had at least one child living inside the district and at least one living outside the district. Three-quarters either lived with a child or saw a child daily (79% for the weighted province population).
The distribution of remittances given by children in the previous year was skewed and broad, ranging from none to 300 000 baht with a median of 9000 baht (about US$300). The amount paid directly by children for expenses in the previous year was also skewed and broad, ranging from none to 350 000 baht with a median amount of zero baht.
Table 2 shows that those parents with all children living out of the district differed in many ways from those with some children living beyond the district or with all children living inside the district. They were more likely to be younger, male, currently married, working, to have higher education, to live in a skip-generation family (i.e. live with a grandchild but without the grandchilds mother or father) and to get a greater amount in remittances. They were less likely to have household expenses paid by their children. Although they got less overall support from children living anywhere and they talked far less frequently to their children, they were equally as likely to perceive very good support from their children as those with some or all children living close by. They got more support from others (not children or grandchildren) and they gave less support to their children. They scored lower for depression and disability than those with some or all children in the district.
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View this table: [in a new window] | Table 2 Weighted characteristics of 1147 parents: with all children living outside the district; with some children living outside the district; and with no children living outside the district |
Table 3 shows the multivariate association between outmigration and depression score. Having all children living outside the district is crudely associated with less depression. However, this association is positively confounded by sociodemographic characteristics. After adjusting for all these, the coefficient for having some children migrated fell from 1.05 to 0.45 and the coefficient for having no migrant children fell from 0.76 to 0.21 with a fall in P from <0.001 to 0.134. The association between having all children living outside the district and less depression was negatively confounded by health and social adversity, by social support from children and by payment of expenses by children. After adjusting for these, the coefficient for depression among those having some children migrated rose to 1.01 and among those with no migrant children rose to 1.15 (P = 0.004). There was a slight drop in the effect of migration after taking account of support to children. Even after adjusting for all the variables shown in Table 3, having all children living outside the district remained independently associated with less depression.
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View this table: [in a new window] | Table 3 Association between depression score and migration of children beyond the district (n = 1147): weighted regression |
We found an interaction between poverty and location of children. Depression in parents was highest when the household was poorer. Depression was especially high when the household was poor and no children had migrated (mean EURO–D level 4.8, 95% CI 3.9–5.6) compared with when the household was wealthier and no children had migrated (mean EURO–D level 3.5, 95% CI 2.5–3.6) or compared with when the household was poor and all children had migrated. The interaction term F(2,95) was 4.02, P = 0.021. Depression in parents was also especially common when support from children was low and no children or only some had migrated (Wald test for interaction term F(2,95) = 3.15, P = 0.047).
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Our findings also do not support the hypothesis that depression is more common in older parents living without any of their children in the same district. In contrast, depression was less common among older parents with all children living outside the district, compared with those living either with some or all children in the same district.
Chance is an unlikely explanation for the finding as the crude and adjusted associations were highly significant. Because the sample was obtained through stratified random sampling and the sampling design was built into the analysis, and because the response rate was good, the likelihood of major biases is small. We were unable to interview those who were travelling to visit their children at the time of the study. It is possible that these were more depressed and seeking support. However, non-responders did not differ on demographic characteristics, hence this is unlikely to explain our findings. We were able to adjust for a large range of confounders that were selected carefully at the outset, although there could be residual confounding, for example measurement of remittances is likely to be prone to non-systematic error. There could be uncontrolled confounding by several factors on which we lacked data, including premorbid mental health and autonomy of the older person that might both encourage migration of family members and promote good mental health. We were however able to adjust for education and household assets, which may to some extent control for prior achievements and capabilities. The construct of depression, and our approach to measurement, were seen as valid by the local mental health providers who were trained locally in psychiatry and are non-English speaking. Also, the EURO–D scale has been validated internationally and in Thailand. It was applied by lay interviewers who were masked to the study hypothesis. Any measurement error should bias towards the null so should not explain our findings. We adjusted for factors that could have been mediators, such as social support and economic remittances, but the effect remained robust.
The findings regarding depression are very interesting and challenge popular notions of the consequences for older people of family separation.3,6,23 We propose two reasons to explain them.
Pre-existing advantages in families
First, households sending a large proportion of migrants may have
advantages at outset from households from where migration is less common.
Migration is known to be a selective process, described as
movement of the brightest and more
advantaged.24 In
our study, parents with all children migrated were more likely to be male,
better educated and married – all variables that would reduce risk for
depression – and to have better educated children. Households enabling
all children to migrate may have greater personal resources, for example
facilitating social networks for their children in the destination area.
Although migration can be a response to poverty it is also a search for
prosperity by those coming from households able to take up the challenge.
Rather than seeing the left behind as passive
recipients25
it is likely that they contributed to the decision to migrate as part of
family diversification. In contrast having few children migrate could be
linked to failed aspirations, increasing the risk for family conflict and
parental depression. It is notable that well-planned migration, including
family involvement, has been associated with better mental health in Irish
migrants to the
UK.26 Furthermore,
in the Thai context, migrant households adapted to separation by keeping
contact through telephones (increasingly available and affordable and often
shared with relatives and neighbours) and through short visits at crucial
times. These approaches enabled children to respond to emergency situations.
Although parents with all children migrated received less overall social
support from children, they were as likely to perceive very adequate support
from children and more likely to receive support from others. Many older
people continued to live with a grandchild, which has been shown to be
protective against depression in
China.27 For
special festivals it was standard for children to travel back for 24 h. Knodel
has called this the modified extended family, which he describes
as dynamic and unbound by the solid traditional family structure
relationship, with parents linked into their childrens migration
processes.5
Economic and health benefit v. social cost
Second, the benefits of migration may outweigh the social costs. Many
families with migrant members moving within and between low- and middle-income
countries tend to benefit
economically15 and
to have improved general
health.28 Benefits
for those who stay behind are influenced by remittances received and by
factors for the migrant such as improved income, shared language in the host
setting and lower distance between home and host
setting.15 For
low-skilled migrants from and within low-income settings there is an emphasis
on sacrifice, strong family ties and strong
obligation.29,30
In our setting, having outmigrant children was strongly associated with
receiving more remittances. This will provide not only short-term aid but may
give security and
well-being.27 Very
few older Thais receive a pension but instead rely on children as a main
source of income.22
The ability to lift households out of poverty may be an important influence on
better mental health of those left behind. We found that those with all
children migrated gave less support to children and that this in turn was
associated with less depression. Having one less mouth to feed or one less to
support may reduce parental
burden.29 Another
consideration could be that successful outmigrant children raise the social
standing of the family. Parents in our study indicated their pride and relief
when children found employment and advanced their careers in urban centres, in
contrast to the heavy work in the fields for less-educated young people.
Reverse causality of return or non-migration
A contrasting explanation for a higher level of depression in parents with
children living close by could be reverse causality. It is possible that
children return in response to concerns about parents mental state and
to the onset of disability. We did not have data on return migration. If this
was a key explanation we might have seen more evidence of confounding by
impairment, disability and life events, which we did not.
Strikingly we found that depression was particularly high in poorer households with no outmigrant children. This inequality raises questions about barriers to migration in poorer households, and potential benefits of interventions and policies to support migration from poorer households. Low socioeconomic status was strongly related to worse depression among older people in rural China.21
Study limitations
The limitations of our study include that it is cross-sectional hence many
of the links we propose are speculative. Data from our 1-year follow-up of the
same parents will be available later and may allow us to show how having
migrated children influences chronicity of depressive symptoms in parents but
these data may not have the power to address questions about onset. We did not
have enough power to study the differential effect of migrant gender, given
the concerns about the feminisation of migration, which may adversely affect
health of parents left
behind.3 It is not
possible to say how much our findings can be generalised to other populations
given that migration is context-dependent. However, this study complements
other work on migration and
depression,1,26
and may have implications for the families of migrants moving within other
developing and restructuring countries. Future prospective research should
test the hypothesis that poor mental health in the parents of young migrants
and in young migrants themselves may adversely influence migration decisions
or impair successful migration.
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