Betsy Kristjansson, Barbara Helliwell, William F Forbes and Gerry B Hill

Abstract

The association between marital status and mortality is well known; marital status has also been related to morbidity. In this paper, we examine the importance of marital status in relation to the presence or absence of dementia and to institutional residence, using data from the Canadian Study of Health and Aging. Three groups are compared: married, single and previously married. We show that the age-standardized prevalence of dementia and the proportions of elderly Canadians living in institutions with and without dementia are highest among single people and are also high for those who were previously married. These associations hold true for both women and men, but the relation between marital status and institutionalization is much stronger for men. Possible explanations and implications for the future care of the elderly are discussed.

Key words: aging; Canada; dementia institutionalization; marital status

Introduction

The association between marriage and longevity has been recognized for at least a century.¹ Married people consistently have lower rates of mortality than single, widowed and divorced people of the same age and sex; these longevity benefits are greater for men than for women.^2–6

A similar differential has been found for morbidity. Married people suffer fewer accidents and assaults,⁷ have fewer acute and chronic conditions, fewer activity limitations, a lower probability of becoming disabled, less psychiatric morbidity, and lower physician and hospital utilization rates than those who are unmarried.^1,3,8–11 In general, widowed, divorced and separated people have the highest number of health problems, whereas people who remain single are only slightly more unhealthy than married people.^3,11 A person’s sex confounds this relation: single men have more health problems than married men, but single women are no different than married women. Some studies have found that single women are healthier than married women.³

There is continuing debate as to whether this differential is due to the protective effect of marriage or to selection of healthy people into marriage and remarriage. Most researchers maintain that a combination of selection and causative factors are involved in producing this health differential.^2,3,9,12,13 Married people generally have more material resources, and the association between health and socio-economic status (SES) is well known.  Marriage may also influence health through the provision of social support, which buffers the effects of stress. The presence of a caregiver may speed recovery after illness, reduce time in hospital and prevent admission to an institution.² Marriage also provides social control and regulation: married people indulge in fewer risk-taking behaviours, such as smoking and drinking.^2–4,13 Departures from the married state are extremely stressful.^2–4,9

The greater health and longevity of married people are probably also due, in part, to the selection of healthy people into marriage and to the selection of unhealthy people out of marriage.¹² People who are seriously ill or disabled are less likely to marry because they are less desirable as partners;^3,4 chronic illness and disability may lead to marital dissolution.¹ Indirect selection through characteristics associated with health, such as SES, obesity and appearance, may also be at work.¹²

The relation between marital status and health is particularly important for Canada’s elderly population because this group is at high risk for morbidity¹⁴ and for cognitive and functional impairment, including dementia.^15,16 Dementia is a debilitating disease that impairs intellectual and functional capacity, and results in behaviour disturbance and personality change.¹⁷ Because it is so debilitating, dementia is one of the most important reasons for institutional placement of older people.^18,19 Institutional care is often the only appropriate alternative for elderly people with severe cognitive and functional disabilities, but it is costly in both individual and societal terms.²⁰ As Canada’s aging population increases, there will be growing pressure for institutional beds and increased interest in reducing or delaying admission to an institution.¹⁴

We know that institutionalization is largely due to severe declines in health, but it is also affected by a number of social factors, including SES and the availability of a caregiver. The study of social risk factors for institutionalization can help to identify people most at risk and suggest appropriate interventions. One risk factor may be the unmarried state; this is important because only 43% of elderly Canadian women and 77% of elderly Canadian men are married.¹⁶

Unmarried people are far more heavily represented in health care institutions than married people. In 1994 in Canada, fewer than 15% of the residents of health care institutions were married, whereas 60% of community residents in the same age group were married or living with a partner.²¹ In the United States, single people have the highest rates of institutionalization and married people, the lowest; widowed, divorced and separated people are in between.¹¹ Multivariate analyses of the risks of institutionalization have generally shown an increased risk among the unmarried,^22,23 although results are inconsistent.^5,24 Many of these studies were limited to small clinical samples. As well, almost all of them dichotomized marital status, ignoring the distinction between single and previously married that has been so important in studies of other health states.

Most studies on the risks of institutionalization in patients with dementia have concentrated on behavioural, functional and cognitive risk factors; few have considered marital status. Two that did include marital status came from registries in the United States.^18,19 In one, the risk of institutionalization of unmarried patients with Alzheimer’s disease was 2.7 times higher than that of those who were married.¹⁸ In the other study,¹⁹ marital status was significant for men only.

In this article we use data from the 1991 Canadian Study of Health and Aging (CSHA) to examine the importance of marital status in relation to institutionalization of elderly Canadians with and without dementia; we also consider differences in the prevalence of dementia. Three different marital states are studied: married, never married and previously married.

Methods

As mentioned, the data studied come from the CSHA. Between February 1991 and May 1992, the CSHA recruited a sample of Canadian residents aged 65 and over: 9,008 living in the community and 1,255 living in institutions. The primary objective of the study was to estimate the prevalence of dementia in Canada. People living in the community were screened for cognitive impairment. Those failing the screening test and all those in institutions were offered a clinical and psychometric examination to determine the presence or absence of dementia. A description of the methods used has been published.¹⁵

The study produced estimates of the numbers of elderly women and men with and without dementia in Canada in 1991, by age group (65-74, 75-84 or 85+) and type of residence (community or institution). Marital status was one of the demographic characteristics included in the study, and we have used this to estimate, for those married, never married and previously married, the prevalence of dementia and the proportions of the populations with and without dementia living in institutions. The married group included people who were in common-law relationships. Because the numbers of divorced or separated people were too small to allow precise estimates, we combined them with the widowed to form a group labelled “previously married.”

The sample for the present analyses included the entire CSHA sample (n = 10,263), with the exception of community residents who were found to be cognitively impaired on screening but refused clinical examination (n = 508). People for whom marital status or age was missing (n = 21) were also excluded. Thus, the total sample size for these analyses was 9,734; 8,496 were community residents and 1,238 were institutional residents.

To obtain age-standardized rates of dementia, the proportions by marital status, cognitive status, sex, age and residence were projected onto estimates of the corresponding 1991 Canadian population by cognitive status, sex, age and residence (estimated from CSHA-1). Age-standardized rates per 1,000 were calculated using the indirect method. This standardization was carried out separately for women and men, so that their rates are not completely comparable; however, the comparison of interest was between the rates for the married, never married and previously married, and the ratio of these rates. Although age-standardized rates were calculated, differences in dementia prevalence and institutionalization by marital status were in the same direction in each age group.

Results

Table 1 shows that the prevalence of dementia among the never married (i.e. single) was higher than among the married and previously married for both sexes. The prevalence of dementia among the previously married was between that of the never married and the married. These findings are true for both women and men, but the ratios of the rates for the unmarried to the married are slightly higher for men than for women.

Table 2 shows the proportions of subjects with dementia who were living in institutions. The institutionalization rate of married people who had dementia was higher among women than men; this was reversed for single and previously married people. Institutionalization ratios were higher among the unmarried than the married, particularly for men. Among the people with dementia, the proportion of single men in institutions was higher than that of previously married men.

Table 3 shows the proportions of subjects without dementia living in institutions. Although the rate of institutionalization was much lower among people without dementia, the pattern by marital status was qualitatively the same as that among subjects with dementia. The unmarried-to-married ratios were much higher, however. For example, the rate among single men was 13.4 times that among married men, and among single women it was 6.8 times higher than the rate among married women.

Discussion

In the present study, the prevalence of dementia was highest among single men and women and was also elevated among previously married people when compared with married people. Women had higher rates in general, but the differentials in rate ratios were greatest for men. A few other studies have also found an increased prevalence or incidence of dementia among unmarried people.^25,26

It seems unlikely that being unmarried directly increases the risk of dementia, but this relation could be due to factors that are related to both marital status and dementia risk. For example, married people exhibit fewer risk behaviours; they also have higher income and education levels. Those with higher education have lower mortality rates and hence lower rates of widowhood, as well as lower rates of divorce.²⁷ In some studies education has been shown to protect against Alzheimer’s disease.²⁸ On the other hand, selection is plausible. Indirect selection may operate in young adulthood and middle age, since the presence of risk behaviours that may lead to dementia would reduce the likelihood of marriage. In the elderly, direct selection may occur because the presence of cognitive impairment or dementia would also impede marriage. Marriage rates are much higher among elderly men than elderly women,²⁹ which could partly explain the sex difference in the prevalence ratio.

The association between marital status and institutional residence is consistent with other studies.^5,21–24 Again, the selection hypothesis is plausible, but it seems unlikely that it could produce such a marked difference in the rates, and spousal support is a more likely explanation. It is reasonable to suppose that such support would be less effective in preventing institutionalization for those who have dementia, and that husbands would be less able to provide support than wives. The higher rates for the never married compared with the previously married could be due to the presence of adult children.

Longitudinal studies are needed to determine the relative importance of selection and support. If support plays a major role, then the implications for the future need for institutional care are enormous. Fortunately, the proportion of elderly Canadians who are married is currently increasing, as a result of the decrease in mortality rates and widowhood.²⁹ This may change as younger cohorts with higher rates of divorce enter the ranks of the elderly. If they are to remain in the community, then methods should be found to provide support for those who are unmarried.

Acknowledgements

The data reported in this article were collected as part of the Canadian Study of Health and Aging. This was funded by the Seniors Independence Research Program, administered by the National Health Research and Development Program of Health Canada (Project No 6606-3954-MC[S]). The study was co-ordinated through the University of Ottawa and Health Canada’s Laboratory Centre for Disease Control. The first author is supported by a doctoral fellowship from the Alzheimer Society and also by the Social Sciences and Humanities Research Council.

References

1. Wyke S, Ford G. Competing explanations for associations between marital status and health. Soc Sci Med 1992;34:523-32.

2. Lillard LA, Panis CWA. Marital status and mortality: the role of health. Demography 1996;33:313-27.

3. Goldman N, Korenman S, Weinstein R. Marital status and health among the elderly. Soc Sci Med 1995;40:1717-30.

4. Smith KR, Waitzman NJ. Effects of marital status on the risk of mortality in poor and non-poor neighborhoods. Ann Epidemiol 1997;7:343-9.

5. Young JE, Forbes WF, Hirdes JP. The association of disability with long-term care institutionalization of the elderly. Can J Aging 1994;13:15-29.

6. Boyd M. Marriage and death. In: Ishwaran K, ed. Marriage and divorce in Canada. Toronto: Methuen, 1983:89-106.

7. Cheung YB. Accidents, assaults, and marital status. Soc Sci Med 1998;47:1325-9.

8. Bosworth HB, Schaie KW. The relationship of social environment, social networks, and health outcomes in the Seattle longitudinal study: two analytical approaches. J Gerontol 1997;52B(5):P197-P205.

9. Joung IMA, Van de Mheen D, Stronks K, Van Poppel FWA, Mackenbach JP. Differences in self-reported morbidity by marital status and by living arrangement. Int J Epidemiol 1994;23:91-7.

10. Joung IMA, Van der Meer JBW, Mackenbach JP. Marital status and health care utilization. Int J Epidemiol 1995;24:569-75.

11. Verbrugge LM. Marital status and health. J Marriage Fam 1979;41:267-85.

12. Joung IM, Van de Mheen D, Stronks K, Poppol FWA, Mackenbach JP. A longitudinal study of health selection in marital transitions. Soc Sci Med 1998;46:425-35.

13. Waldron I, Hughes ME, Brooks TL. Marriage protection and marriage selection—prospective evidence for reciprocal effects of marital status and health. Soc Sci Med 1996;43:113-23.

14. Moore EG, Rosenberg MW, McGuinness D. Growing old in Canada: demographic and geographic perspectives. Scarborough (Ont): ITP Nelson, 1997.

15. Canadian Study of Health and Aging Working Group. Canadian Study of Health and Aging: study methods and prevalence of dementia. Can Med Assoc J 1994;150:899-913.

16. Elliot G, Hunt M, Hutchison K. Facts on aging in Canada. Hamilton (Ont): McMaster University, Office of Gerontological Studies; 1996.

17. American Psychiatric Association. Diagnostic and statistical manual of mental disorders, third edition—revised. Washington, DC: American Psychiatric Association, 1987.

18. Severson MA, Smith GE, Tangalos EG, et al. Patterns of predictors of institutionalization in community-based dementia patients. J Am Geriatr Soc 1994;42:181-5.

19. Wilkins R, Adams OB. Healthfulness of life: a unified view of mortality, institutionalization, and non-institutionalized disability in Canada. Montreal: The Institute for Research on Public Policy, 1978.

20. Shapiro E, Tate R. Who really is at risk of institutionalization? Gerontologist 1988;28:237-45.

21. Tully P, Mohl C. National Population Health Survey 1995. Residents of health care institutions. Paper presented at the Annual Conference of the Canadian Association on Gerontology, 1995.

22. Rockwood K, Stolee P, McDowell I. Factors associated with institutionalization of older people in Canada: testing a multifactorial definition of frailty. J Am Geriatr Soc 1996;44:578-82.

23. Lagergren M. Transferring to an institution—an analysis of factors behind the transfer to institutional long-term care. Can J Aging 1996;15:427-41.

24. Glazebrook K, Rockwood K, Stolee P, Gray JM. A case-control study of the risks for institutionalization of elderly people in Nova Scotia. Can J Aging 1994;13:104-17.

25. Bickel H, Cooper B. Incidence and relative risk of dementia in an urban elderly population: findings of a prospective field study. Psychol Med 1994;24:179-92.

26. Freidl W, Schmidt R, Stronegger WJ, Irmler A, Reinhart B, Koch M. Mini Mental State Examination: influence of sociodemographic, environmental and behavioral factors and vascular risk factors. J Clin Epidemiol 1996;49:73-8.

27. Boyd M. The social demography of divorce in Canada. In: Ishwaran K, ed. Marriage and divorce in Canada. Toronto: Methuen, 1983:248-68.

28. Canadian Study of Health and Aging Working Group. The Canadian Study of Health and Aging: risk factors for Alzheimer’s disease in Canada. Neurology 1994;44:2073-80.

29. Nault F. Twenty years of marriages. Health Rep 1996;8(2):39-47.

Betsy Kristjansson and Barbara Helliwell, Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario

William F Forbes (deceased), formerly in Research Department, Sisters of Charity of Ottawa Health Service Inc., Ottawa, Ontario

Gerry B Hill, Department of Epidemiology and Community Medicine, University of Ottawa; and Research Department, Sisters of Charity of Ottawa Health Service Inc., Ottawa, Ontario

Correspondence: Betsy Kristjansson, Canadian Study of Health and Aging, Department of Epidemiology and Community Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario  K1H 8M5; Fax: (613) 562-5441; E-mail: krist@zeus.med.uottawa.ca

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