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Association between mid-life marital status and cognitive function in later life: population based cohort study

BMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b2462 (Published 02 July 2009) Cite this as: BMJ 2009;339:b2462

Re: Marital status and dementia

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

Competing interests: No competing interests

07 August 2009
Krister Håkansson
research fellow
Miia Kivipelto
Växjö University, 35195 Växjö and the Karolinska Institutet, 14186 Stockholm, Sweden