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Marital status and dementia
- Rizaldy Pinzon (13 July 2009)
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Brain reserve or better strategic behaviour?
- Mairead Bartley, Desmond O'Neill (15 July 2009)
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Marital status and the risk of dementia
- Ruoling Chen (22 July 2009)
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On mid-life marital status and cognitive function in later life: notes inspired by a journal club discussion
- Adrian Loerbroks, Nasir Umar (23 July 2009)
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Re: Marital status and dementia
- Krister Håkansson, Miia Kivipelto (7 August 2009)
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Re: Brain reserve or better strategic behaviour?
- Krister Håkansson, Miia Kivipelto (7 August 2009)
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Re: Marital status and the risk of dementia
- Krister Håkansson, Miia Kivipelto (7 August 2009)
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Re: On mid-life marital status and cognitive function in later life: notes inspired by a journal club discussion
- Krister Håkansson, Miia Kivipelto (10 August 2009)
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Rizaldy Pinzon, Neurologist Bethesda hospital Yogyakarta Indonesia 55224
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The interesting study from Håkansson, et al showed that being unmarried will increase the risk of dementia. The association between marriage and health has been recognized in many studies. Married people consistently have lower rates of mortality than single. Married people suffer fewer accidents, have fewer acute and chronic conditions, and lower hospital utilization rates than those who are unmarried. In general, widowed, divorced and separated people have the highest number of health problems. The result of being unmarried directly increases the risk of dementia can be criticized because of confounding variables. 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. This study has slowed the consistent finding after adjustment for other risk factors of dementia. Those who were widowed in middle age also have higher risk of cognitive impairment compared with married/cohabiting people. The presence of the apolipoprotein E e4 allele further increased the risk of Alzheimer’s disease in people who were widowed. Good social activities and interaction should have positive impact on cognitive function. Competing interests: None declared |
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Mairead Bartley, Research Fellow Trinity Cantre for Health Sciences, Adelaide and Meath Hospital, Dublin 24, Ireland, Desmond O'Neill
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We read with interest Hakansson and colleagues’ study of mid-life marital status and cognitive function in later life (1). They acknowledge that factors other than the brain reserve hypothesis may account for the possible protective effect of a partner on cognition. Adaptive and coping strategies are an under-recognized component of successful cognitive ageing, and are worth considering in this study. For example, the theory of selection, optimization and compensation outlines strategies of adaptively responding to the challenges of ageing (2) which have been associated with successful ageing (3). Resource-rich (both internal and external) older adults have been shown to engage in these strategies more frequently, associated with the maintenance of higher levels of everyday functioning. The maintenance, renewal, and coping with loss of relationships with a partner may in some way reflect successful adaptive mechanisms. That the results for being widowed or divorced after mid-life had only borderline significance may be explained in part by the ongoing development of altered coping strategies of older people. In a review of coping strategies after stroke, a trend was seen towards the use of active problem-oriented coping strategies, which may be more effective in the long term (4). It may be reasonable to extrapolate this to the coping strategies of someone widowed in later life. Therapeutic advantage in the pursuit of better strategic thinking is supported by the effectiveness of reasoning training in later life in delaying the onset of functional decline among older people (5). 1. Hakansson K, Rovio S, Helkala EL, Vilska AR, Winblad B, Soininen H, et al. Association between mid-life marital status and cognitive function in later life: population based cohort study. BMJ. 2009;339:b2462. 2. Lang FR, Rieckmann N, Baltes MM. Adapting to aging losses: do resources facilitate strategies of selection, compensation, and optimization in everyday functioning? J Gerontol B Psychol Sci Soc Sci. 2002;57:P501-9. 3. Ziegelmann JP, Lippke S. Use of selection, optimization, and compensation strategies in health self-regulation: interplay with resources and successful development. J Aging Health. 2007;19:500-18. 4. Donnellan C, Hevey D, Hickey A, O'Neill D. Defining and quantifying coping strategies after stroke: a review. J Neurol Neurosurg Psychiatry. 2006;77:1208-18. 5. Willis SL, Tennstedt SL, Marsiske M, Ball K, Elias J, Koepke KM, Morris JN, Rebok GW, Unverzagt FW, Stoddard AM, Wright E; ACTIVE Study Group. Long-term effects of cognitive training on everyday functional outcomes in older adults. JAMA. 2006;296:2805-14. Competing interests: None declared |
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Ruoling Chen, Reader Centre for Health and Social Care improvement, School of Health and Wellbeing, University of Wolverh
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Hakansson et al (1) reported that for Finnish people in middle age losing a spouse would have a substantial increase in the incidence of cognitive impairment and dementia in later life, and the increased risk was higher than those never married. The authors suggested that other factors, not covered in the study, could partly explain this. The mid-life widowed, compared to those married without premature death in middle age, might have lived in a family environment with higher levels of risk factors, including low income, cardiovascular and psychosocial factors and low social support. Long-term widow status would make these situations worse, increasing the risk of ill health. In a population-based cohort study in China I examined the risk of dementia in relation to marital status. Using a standardised method of the Geriatric Mental State (GMS) interview (2), we recorded baseline mental status, physical health and risk factors among 3336 elderly living in urban and rural Anhui (3, 4). The prevalence of any depressive cases and subcases, diagnosed by the GMS-AGECAT (3, 4), was 6.7% in married people (n=2397), 10.1% in the widowed/divorcees (n=824, including 14 divorcees) and 11.3% in the never-married (n=115) (p=0.002). In 2007-9, we re- interviewed 1757 surviving cohort members. The incidence of dementia cases and subcases (mild cognitive impairment) were diagnosed over a 7 year period (5). Among participants with at least minimal educational levels, whose data on dementia diagnosis were comparable to those in western populations, I found that incident dementia (n=80) was related to baseline marital status. After adjustment for age, sex, body mass index, urban- rural region, educational levels, family income, smoking habits, hypertensive status, stroke, frequency of contacting neighbours and the GMS-AGECAT anxiety and depressions, odds ratio (OR) for dementia was 1.22 (0.67-2.25) in the widowed/divorcees and 5.32 (95%CI 1.14-24.8) in the never-married in comparison with those married. The matched figures for dementia subcases (n=169) were 1.31 (0.83-2.06) and 2.40 (0.63-9.22). In such an older population which were absolutely poor but had high levels of social support and low levels of depression and cardiovascular risk (4), the finding that the risk of dementia significantly increased with being single, but not being widowed (multiple adjusted OR 1.23, 0.67- 2.26), further supports the concept of the brain reserve hypothesis. The current data, together with an increasing proportion of never-married people in both developed and developing countries, additionally predicts a potential epidemic of dementia in the world. (1) Hakansson K, Rovio S, Helkala EL, Vilska AR, Winblad B, Soininen H et al. Association between mid-life marital status and cognitive function in later life: population based cohort study. BMJ 2009; 339:b2462. (2) Copeland JR, Prince M, Wilson KC, Dewey ME, Payne J, Gurland B. The Geriatric Mental State Examination in the 21st century. Int J Geriatr Psychiatry 2002; 17(8):729-732. (3) Chen R, Hu Z, Qin X, Xu X, Copeland JR. A community-based study of depression in older people in Hefei, China--the GMS-AGECAT prevalence, case validation and socio-economic correlates. Int J Geriatr Psychiatry 2004;19(5):407-413. (4) Chen R, Wei L, Hu Z, Qin X, Copeland JR, Hemingway H. Depression in older people in rural China. Arch Intern Med 2005; 165(17):2019-2025. (5) Chen R, Hu Z, Wei L, Qin X, McCracken C, Copeland JR. Severity of depression and risk for subsequent dementia: cohort studies in China and the UK. Br J Psychiatry 2008; 193(5):373-377. Competing interests: None declared |
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Adrian Loerbroks, Post-doc Mannheim Institute of Public Health, Social and Preventive Medicine, Mannheim, Heidelberg University, Nasir Umar
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We discussed with considerable interest in our monthly journal club presentation the implications of the study findings presented by Håkansson and colleagues in their article on mid-life marital status and cognitive function (1). We believe the interpretation of these findings needs take into account a number of considerations. Most important of these will be summarized here. First, cognitive assessments were only performed at the “follow-up”, but not at baseline. As the cognitive status of participants at age 50 is unknown, the study is, strictly speaking, not a prospective study. Thus, the authors cannot infer that being widowed for instance preceded cognitive dysfunction. Håkansson and colleagues argue that reverse causation seems unlikely as baseline measurements were taken at a mean age of 50 and 21 years before cognitive assessments. As they acknowledge, the pre-clinical period of dementia may span over nine years. However, it has been suggested that cognitive performance may be associated with the development of AD symptomatology over a period of 22 years (2) over even longer (3). Second, a previous study has suggested that the risk of Alzheimer’s disease associated with contact with children may be higher if those contacts are perceived as not satisfying (5). Satisfaction with one’s marriage may modify the association between being married and cognitive function in a similar fashion. Third, engagements in social activities, living arrangement, contact with friends or relative provide protective effect against dementia both for singles, widowed or divorced (5). However, the benefit is likely to be reduced in widowed and divorced. Being widowed is an imposed involuntary transition considered to be traumatic as stated by the authors (1), while being divorced though not involuntary imposed, is associated with divorced -related emotional difficulties (6). In contrast to singles, both widowed and divorced have experienced loss of their spouse. This might be a possible explanation for the specific increased risk for widowed and divorced reported by the authors. Finally, it seems likely that the public perception of and attitude towards singles or divorced adults was different in the 70s and 80s as compared to nowadays. It is likely that our present day society more readily accepts single life styles in mid-life. If so, then public health interventions targeted towards preventing the development of Alzheimer’s and dementia in later life need to take these into careful consideration. 1. Håkansson K, Rovio S, Helkala EL, Vilska AR, Winblad B, Soininen H, Nissinen A, Mohammed AH, Kivipelto M (2009) Association between mid- life marital status and cognitive function in later life: population based cohort study. BMJ 339; b2462. 2. Elias MF, Beiser A, Wolf PA, Au R, White RF, D'Agostino RB (2000) The preclinical phase of alzheimer disease: A 22-year prospective study of the Framingham Cohort. Arch Neurol 57: 808-813. 3. Snowdon DA, Kemper SJ, Mortimer JA, Greiner LH, Wekstein DR, Markesbery WR (1996) Linguistic ability in early life and cognitive function and Alzheimer's disease in late life. Findings from the Nun Study. 4. Berkman LF (2000) Which influences cognitive function: living alone or being alone? Lancet 355: 1291-1292 5. Fratiglioni L, Wang HX, Ericsson K, Maytan M, Winblad B (2000) Influence of social network on occurrence of dementia: a community-based longitudinal study. Lancet 355: 1315-1319. 6. Sbarra DA, Law RW, Lee LA, Mason AE (2009) Marital dissolution and blood pressure reactivity: evidence for the specificity of emotional intrusion hyperarousal and task-rated emotional difficulty. Psychosom Med. 71:532-540. Competing interests: None declared |
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Krister Håkansson, research fellow Växjö University, 35195 Växjö and the Karolinska Institutet, 14186 Stockholm, Sweden, Miia Kivipelto
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Rizaldy Pinzon, in response to our article about the association between midlife marital status and dementia in later life,(1) points out that married people not only seem to have less risk of dementia, but also can hope for a longer and more healthy life in general. We agree and there seems to be ample evidence for such a conclusion.(2) We also find Pinzon's point about self-selection and potential confounders especially relevant in evaluating associations of this kind, which is also discussed at length in our article. Even if the associations we found were not affected by adjustments for a number of variables, it can still be argued that people who enter into a couple relation do that for reasons that are also related to health – and that such variables were not taken into consideration. After all, you cannot adjust for “everything”. From a strictly methodological point we were however fortunate in this study to find the most dramatic difference between persons who were married and widowed. The widowed group were even significantly more at risk than the singles. This has some interesting implications in discussing the possibility of self-selection as a factor behind the results: Initially people in both these groups married, i.e. they were from the same “self-selected” group. It then seems far-fetched to assume that those who at a later time and involuntarily lost their partner under tragic circumstances were initially different from the ones who did not. We think that this methodological feature contributes to strengthen the case for a real and causal relation between losing a partner and cognitive health much later in life, especially for those who continue to live alone afterwards. 1. Hakansson K, Rovio S, Helkala E-L, Vilska A-R, Winblad B, Soininen H, et al. Association between mid-life marital status and cognitive function in later life: population based cohort study. BMJ 2009;339(jul02_2):b2462-. 2. Kiecolt-Glaser JK, Newton TL. Marriage and health: His and hers. Psychological Bulletin 2001;127(4):472-503. Competing interests: None declared |
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Krister Håkansson, research fellow Växjö University, 35195 Växjö and the Karolinska Institutet, 14186 Stockholm, Sweden, Miia Kivipelto
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Mairead Bartley, in response to our article on midlfe marital status and cognitive health in later life, (1) suggests that adaptive coping strategies in old age are related to successful aging and health. We have no reason to disagree, but the critical question is of course what is the hen and what is the egg behind this relation: Are more efficient coping strategies in later life a sign of better cognitive functioning or is it natural for people with better cognitive health to use more efficient coping strategies? It was for this reason we emphasized in the article the associations between variables we found already in midlife and cognitive health averagely 21 years later. One of the results we found, not mentioned in the article, was however the association with cognitive health for the group that had lost their partner in midlife, but were living in a partner relation at the follow-up. There were 23 persons in this category and none of them showed any signs of cognitive impairment at the follow-up. This result fits nicely with the point that M Bartleys makes in her response: “The maintenance, renewal, and coping with loss of relationships with a partner may in some way reflect successful adaptive mechanisms.” The reason we did not mention this result in the article was, besides the shaky statistical foundation with only 23 persons in this group, the point about reverse causation mentioned above: The decision and ability to form a new couple relation after midlife may be related to better health, including better cognitive health, already when these persons entered into the new couple relation. If so, and if these persons also manifest better cognitive health a few years later, this should not be surprising. On the other hand, even if not evidential, the results may still be of interest in discussing the possibility of a causal relation of the kind that Mairead Bartley suggests in her comment. 1. Hakansson K, Rovio S, Helkala E-L, Vilska A-R, Winblad B, Soininen H, Nissinen A, Mohammed AH, Kivipelto M. Association between mid-life marital status and cognitive function in later life: population based cohort study. BMJ. 2009;339(jul02_2):b2462-. Competing interests: None declared |
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Krister Håkansson, research fellow Växjö University, 35195 Växjö and the Karolinska Institutet, 14186 Stockholm, Sweden, Miia Kivipelto
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We were interested to read about these results based on a Chinese population, which confirms our main finding, that married people had a lower risk of dementia compared to non-married or non-cohabitant persons. Concerning the non-married subgroups, there are however some interesting differences between results, mainly that singles had a higher risk than in our population. We think that these differences may be related to both methodological and cultural differences between the studies. In the study by Chen et al, as reported in the comment, participants were already at baseline >65 years old, whereas our participants were relatively young, averagely 50.4 years.(1) In the most recent article referred to by Chen from 2008, the follow-up time for the Chinese sample seems to have been only one year,(2) although, as stated in the comment, the measurements were performed over a 5-7 year period. In our case the follow-up was averagely 21 years. The diagnosis we used was according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), combined with magnetic resonance imaging, whereas Chen et al used the Automated Geriatric Examination for Computer Assisted Taxonomy (AGECAT) to classify participants as cognitively impaired or healthy. Similar adjustments were made in both studies with the important exception that we also adjusted for carrying the apolipoprotein 4 allele (ApoE e4). We think it is important to have these differences in mind when comparing results. Chen reports, in comparison to our results, a lower and a statistically insignificant odds ratio for divorced and widowed (1.22, with a confidence interval of 0.67 to 2.25) and a higher odds ratio for singles (5.32, 1.14 to 24.8). If widowed and divorced at both midlife and late-life are combined in our study, as in the comment by Chen, the odds ratio amounts to a much higher 3.35 (1.8 to 6.1) - compared to cohabitants at both occasions. From the information we could obtain from a previous article,(3) we estimate that the participants in Chen’s study were averagely between 72-73 years old at baseline. For that reason, and also due to the very short follow-up time in their study, it might however be more appropriate to compare with the marital status data we have from the follow-up data in our study, rather than from midlife data. (Our participants were averagely 71 years at follow-up.) As we also have data from midlife, we can specifically calculate the odds ratio for those who were cohabitants at midlife but who either were widowed or divorced after midlife. The odds ratio for this group is a non-significant 1.57 (0.9 to 2.6), and thus not very different from the results that Chen reports in his comment. A possible interpretation of this difference is that losing a partner relatively early in life may be a more traumatic and health threatening event than when this occurs in later life, at least on a group level. As for the singles, this category is defined by Chen in the same way as we have, i.e. as never-married. We notice the high confidence interval in the results reported in the comment, but an odds ratio of 5.23 (1.14 to 24.8) still indicates that the risk increase of single-hood for dementia may be higher in China than we and others have found for a European population.(1, 4) This difference is interesting in speculating about the under-lying factors behind the association between marital status and dementia. We can only speculate about this, but perhaps the relatively low risk increase for singles in Europe is related to a difference in social status and integration in society of singles between cultures. It has been reported that singles in the US have a considerably lower social status than married. (5) In China, due to gender imbalance, single-hood also may have other social implications than in Europe, implications that may also be related to dementia risk. In conclusion, we think that cultural differences most probably exist in the way members of different groups of marital status are perceived and treated. If such differences can be related to differences in the association between marital status and dementia in different cultures, such data could be of potential value to help identifying mechanisms behind the disease. 1. Hakansson K, Rovio S, Helkala E-L, Vilska A-R, Winblad B, Soininen H, Nissinen A, Mohammed AH, Kivipelto M. Association between mid-life marital status and cognitive function in later life: population based cohort study. BMJ. 2009;339(jul02_2):b2462-. 2. Chen RL, Hu Z, Wei L, Qin X, McCracken C, Copeland JR. Severity of depression and risk for subsequent dementia: cohort studies in China and the UK. Br J Psychiatry. 2008;193(5):373-377. 3. Chen RL, Hu Z, Qin X, Xu XC, Copeland JRM. A community-based study of depression in older people in Hefei, China - the GMS-AGECAT prevalence, case validation and socio-economic correlates. Int J Geriatr Psychiatr. 2004;19(5):407-413. 4. Helmer C, Damon D, Letenneur L, Fabrigoule C, Barberger-Gateau P, Lafont S, Fuhrer R, Antonucci T, Commenges D, Orgogozo JM, Dartigues JF. Marital status and risk of Alzheimer's disease: a French population-based cohort study. Neurology. 1999;53(9):1953-1958. 5. DePaulo BM, Morris WL. Singles in society and in science. Psychol Inq. 2005;16(2-3):57-83. Competing interests: None declared |
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Krister Håkansson, research fellow Växjö University, 35195 Växjö and the Karolinska Institutet, 14186 Stockholm, Sweden, Miia Kivipelto
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Adrian Loerbroks and Nasir Omar present some very interesting ideas from a discussion on our article about marital status and cognitive impairment.(1) First we would like to point out that the outcome variables we used were diagnoses of mild cognitive impairment and dementia, including results specifically for Alzheimer’s disease. In other words, we did not use the level of non-pathological cognitive performance as outcome in this study. In addition the participants were relatively young, averagely 50.4 years at baseline. At the follow-up averagely 21 years later we used a random sample of survivors from the baseline measurements. These methodological features have important implications for the first issue raised in the comment: that we should have scanned participants for possible dementia already at baseline. We have not found reliable estimations for prevalence of dementia before the age of 60, but in the age group 60-64, the probably most reliable estimation is 0.9%.(2) Based on these estimations we feel safe in concluding that the prevalence of pathological cognitive impairment in our baseline sample must have been very close to 0. Another fact to consider is the median survival time after a diagnosis of either vascular dementia, possible Alzheimer’s disease or probable Alzheimer’s disease has been estimated to be 5.7 (4.54 to 6.86) years for the youngest group (65-74 years). For older persons, the corresponding expected survival period was even shorter.(3) So even if one or two of our subjects would have suffered from cognitive impairment already at baseline, how likely is it that any of them would have survived to be included in the follow-up, and thus in our study, averagely 21 years later? Another issue brought up by Loerbrok and Umar concerns the preclinical period and how it relates to reverse causation. We regret if we in some instances in the article used “sub-clinical” and “preclinical” synonymously, while the more adequate term should be sub-clinical in this case. We also think it is important to distinguish between what is sub- clinical and what is a risk factor in discussing reverse causation: A factor that increases the risk of triggering a disease process should be referred to as a risk factor and the changes that occur as a result of the disease process once it has started, but before the diagnostic criteria are fulfilled, should be referred to as a sub-clinical. Applying this distinction to Snowdons findings,(4) referred to by Loerbrok and Umar, means that certain cognitive/linguistic characteristics early in life should be regarded as possible risk factors for the development of dementia later in life, not as a sign of an underlying disease process that has already started. We think that careful reading of the referred article by Elias et al,(5) and especially the editorial comment to the same article,(6) supports the distinction we like to make. When we say that reverse causation is unlikely with a 21-year follow-up, this refers to changes during the sub-clinical phase (the latency phase) that might have affected behaviour already at baseline. We agree with the authors(5) and the editorial comment(6) that the findings by Elias et al(5) cannot be taken as evidence for sub-clinical changes 22 years before a diagnosis of dementia. How the quality of a couple relationship contributes to the potentially protective effect of living with someone is another interesting idea brought up in this comment. We are currently working on trying to identify such factors and hope to be able to report some interesting results on this issue in the near future. As for the last two points, we agree that the emotional consequences of losing a partner may be one of the critical and common dimensions for divorced and widowed in relation to singles. Another factor may be that singles form long-term social networks and activity patterns based on a single life style, while divorced and widowed might need to partly restructure their networks and activity patterns after having lost their partner. 1. Hakansson K, Rovio S, Helkala E-L, Vilska A-R, Winblad B, Soininen H, Nissinen A, Mohammed AH, Kivipelto M. Association between mid-life marital status and cognitive function in later life: population based cohort study. BMJ. 2009;339(jul02_2):b2462-. 2. Ferri CP, Prince M, Brayne C, Brodaty H, Fratiglioni L, Ganguli M, Hall K, Hasegawa K, Hendrie H, Huang Y, Jorm A, Mathers C, Menezes PR, Rimmer E, Scazufca M. Global prevalence of dementia: a Delphi consensus study. Lancet (British edition). 2005;366(9503):2112-2117. 3. Wolfson C, Wolfson DB, Asgharian M, M'Lan CE, Ostbye T, Rockwood K, Hogan DB. A reevaluation of the duration of survival after the onset of dementia. New England Journal of Medicine. 2001;344(15):1111-1116. 4. Snowdon DA, Kemper SJ, Mortimer JA, Greiner LH, Wekstein DR, Markesbery WR. Linguistic ability in early life and cognitive function and Alzheimer's disease in late life. Findings from the Nun Study. JAMA. 1996;275(7):528-532. 5. Elias MF, Beiser A, Wolf PA, Au R, White RF, D'Agostino RB. The preclinical phase of Alzheimer disease - A 22-year prospective study of the Framingham cohort. Archives of Neurology. 2000;57(6):808-813. 6. Mayeux R, Small SA. Finding the beginning or predicting the future? Archives of Neurology. 2000;57(6):783-784. Competing interests: None declared |
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