Association between mid-life marital status and cognitive function in later life: population based cohort studyBMJ 2009; 339 doi: http://dx.doi.org/10.1136/bmj.b2462 (Published 02 July 2009) Cite this as: BMJ 2009;339:b2462
- Krister Håkansson, research fellow12,
- Suvi Rovio, research fellow2,
- Eeva-Liisa Helkala, neuropsychologist3,
- Anna-Riitta Vilska, lecturer4,
- Bengt Winblad, professor2,
- Hilkka Soininen, professor56,
- Aulikki Nissinen, professor7,
- Abdul H Mohammed, professor12,
- Miia Kivipelto, associate professor25
- 1School of Social Sciences, Department of Psychology, Växjö University, Sweden
- 2Aging Research Centre, Department of Neurobiology, Caring Sciences and Society, Karolinska Institute, Stockholm, Sweden
- 3Department of Public Health and General Practice, University of Kuopio, Kuopio, Finland
- 4Savonia University of Applied Sciences, Kuopio, Finland
- 5Department of Neuroscience and Neurology, University of Kuopio, Kuopio, Finland
- 6Department of Neurology, Kuopio University Hospital, Kuopio, Finland
- 7Department of Health Promotion and Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland
- Correspondence to: M Kivipelto, Department of NVS, KI - Alzheimer’s Disease Research Centre, Karolinska Institute, S-141 86 Stockholm, Sweden
- Accepted 10 March 2009
Objectives To evaluate whether mid-life marital status is related to cognitive function in later life.
Design Prospective population based study with an average follow-up of 21 years.
Setting Kuopio and Joensuu regions in eastern Finland.
Participants Participants were derived from random, population based samples previously investigated in 1972, 1977, 1982, or 1987; 1449 individuals (73%), aged 65-79, underwent re-examination in 1998.
Main outcome measures Alzheimer’s disease and mild cognitive impairment.
Results People cohabiting with a partner in mid-life (mean age 50.4) were less likely than all other categories (single, separated, or widowed) to show cognitive impairment later in life at ages 65-79. Those widowed or divorced in mid-life and still so at follow-up had three times the risk compared with married or cohabiting people. Those widowed both at mid-life and later life had an odds ratio of 7.67 (1.6 to 40.0) for Alzheimer’s disease compared with married or cohabiting people. The highest increased risk for Alzheimer’s disease was in carriers of the apolipoprotein E e4 allele who lost their partner before mid-life and were still widowed or divorced at follow-up. The progressive entering of several adjustment variables from mid-life did not alter these associations.
Conclusions Living in a relationship with a partner might imply cognitive and social challenges that have a protective effect against cognitive impairment later in life, consistent with the brain reserve hypothesis. The specific increased risk for widowed and divorced people compared with single people indicates that other factors are needed to explain parts of the results. A sociogenetic disease model might explain the dramatic increase in risk of Alzheimer’s disease for widowed apolipoprotein E e4 carriers.
We are grateful to Håkan Locking, Centre for Labour Market Policy Research (CAFO), Växjö University, for statistical advice.
Contributors: MK, E-LH, AN, and HS participated in the planning, conception and design of the CAIDE study. AN and E-LH were involved in the design of baseline surveys, including marital status and signs of depression, and data collection both at mid-life and re-examination. MK and E-LH were involved in diagnosing dementia and mild cognitive impairment at the re-examination, for which MK was the principal investigator. KH suggested the general concept and design of the present study, drafted the manuscript, and carried out statistical analyses. MK, SR, BW, and AHM contributed to further conceptual development of the study. Comments and suggestions were provided by SR, MK, BW, and AHM. All authors contributed in developing the manuscript further and interpreting the results. MK supervised the study and is guarantor.
Funding: This study was funded by EVO-grant of Kuopio University Hospital (5772720), Academy of Finland (grants 103334 and 206951), EU grant QLK-2002-172, the Swedish Council for Working Life and Social Research, the Finnish Cultural Foundation, the Foundation of Juho Vainio, the Gamla Tjänarinnor Foundation, the Helsingin Sanomain 100-vuotissäätiö, and the Gun and Bertil Stohne Foundation.
The funders had no role in study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the article for publication.
Competing interests: None declared.
Ethical approval: The CAIDE study has been approved by the ethics committee of Kuopio University Hospital (24/97, 07.02.97) and by the ethics committee of Karolinska Institutet (04-103).
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.