April 18, 2025 • 21 mins
In this #StudyFinds episode of #ProveItPod, Dr. Matt Law digs into a study that suggests married folks are at a higher risk of dementia. Is it true? Listen now to find out!
Episode Resources:
George, J. (2025, March 25). Surprising findings from new research about dementia and marriage - U.S. study could challenge the belief that marriage protects against cognitive decline. MedPage Today. https://www.medpagetoday.com/neurology/dementia/114820
Karakose, S., Luchetti, M., Stephan, Y., Sutin, A. R., & Terracciano, A. (2025, March 20). Marital status and risk of dementia over 18 years: Surprising findings from the National Alzheimer's Coordinating Center. Alzheimer's & Dementia, 21(3). https://doi.org/10.1002/alz.70072
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
My dearest listener,
(00:01):
from the moment we met,
I knew my life would never be the same.
Would you do me the honor of making me
the happiest researcher in the, the,
um, wait, what was I saying?
Ah, screw it.
Never mind.
It's an all new prove it to me.
(00:47):
Hello, everyone,
and welcome to prove it to me.
I'm your host, Dr.
Matt Law.
When I first started doing these study
finds episodes,
they were meant to be quick,
one-off filler episodes between the
guest appearances.
I mean,
the guest appearances seem to be what
folks really care about.
No one actually wants to hear me rattle
(01:09):
on endlessly about the things that I
find interesting, right?
I have to be honest though,
I've become an addict.
There's a real catharsis I feel that's
associated with diving deeper behind
the headlines.
Every time I see the words study finds,
I get butterflies in my stomach.
It's Pavlovian.
(01:30):
I start to anticipate the inevitable
buzz I get from doing the search,
clicking the links,
and getting into the nitty gritty
details to find out if this new study
is really a game changer,
or if it's just a little bit of
something somebody wrote up that got
blown out of proportion.
Or maybe it was slightly misconstrued
(01:50):
when the morning news wrote up their
summary of a summary.
Either way,
I find myself almost drooling at the
chance to geek out over the details of
this new research.
And I promise,
I have more guests on the way.
The thing is,
my guests so far have been researchers.
Researchers spend a lot of time…
(02:10):
No, that's actually it.
Researchers spend a lot of time,
period.
It takes so much time and effort to
answer a question thoroughly and
definitively.
There is no yes or no.
There is no black or white.
It's all gray,
and there are many shades of gray.
(02:31):
They spend months looking at the
factors they want to study and figuring
out all the possible confounding
factors.
They put so much effort into developing
models and modifying models to measure
relationships between variables.
They pore over statistical analyses and
try to explain the data and why the
outcomes are the way they are.
(02:52):
That's just the quantitative
researchers.
The qualitative researchers are even
more screwed.
They have to try to make sense of
paragraph after paragraph of text from
focus groups and interviews and loosely
guided observations to try to pull
themes that create a story for further
quantitative analysis.
(03:12):
Sometimes these studies take years.
They want to get it right.
That's how good research is done,
with an aim to get it right,
not with the intention to push an
agenda.
So it's no surprise that my guest
researchers will reach out months in
advance to schedule an appearance on
the podcast.
They want to make sure they have time
(03:34):
to get it right.
Honestly, I can't blame them.
I would too.
In fact,
my own pet research projects are taking
much longer than I expected because I
want to make sure I get them right.
So until then, you are stuck with me.
But I promise we're only a few weeks
away from the next guest appearance.
(03:55):
Now, for this episode,
I'm going back to sort of everyday
health topics rather than a workplace
safety topic.
I mean,
this is the stuff that ends up on the
news,
so that's what I tend to latch onto
first.
We've been able to do some workplace
safety stuff over the last few
episodes,
so I think it's fair that we have some
(04:15):
fun and get into an everyday health
topic.
And boy, this is a fun one.
This is a topic that is just begging
for some tongue-in-cheek, cynical,
comedic takes.
I don't know if you all are able to
appreciate my sense of humor,
but I really hope you enjoy going
through this one with me.
From MedPage Today,
(04:36):
an article dated March 25th,
2025 entitled,
Surprising Findings from New Research
about Dementia and Marriage.
With the tagline, U.S.
study could challenge the belief that
marriage protects against cognitive
decline.
(04:59):
a sacred institution.
But you and I both know that this can
be a divisive and emotional topic for
many, many folks.
So,
MedPage today had access to the entire
study article because the article is
open access.
So let's just read what their key
takeaways were and we'll jump into the
(05:19):
study.
Key takeaways.
Number one,
unmarried people in a US study had
lower risk of dementia than married
people.
Number two, the study followed 24,000
older adults through the National
Alzheimer's Coordinating Center.
And number three,
findings were similar for men and
women.
(05:40):
I mean, really folks,
you ever run into that old married
heterosexual couple and the wife is
super naggy and opinionated and the
husband is totally aloof.
And it's not really clear if he's
always been that way or if it's just an
act or Maybe he became this way just
because it's easier and more peaceful
than trying to fight it?
(06:00):
Like seriously,
this is a classic troupe in comedy
movies and sitcoms.
I won't be sexist here either because
I've seen it the other way around too
where the wife is the one that's aloof
and the husband is just a grumpy
asshole.
Honestly, you can ask my wife.
She probably thinks I already have
dementia.
Seriously,
since like year 5 of our marriage,
(06:21):
the only words I hear my wife say are,
were you listening to what I just said?
I don't do this intentionally or
maliciously.
I really suck at active listening.
In fact,
the only difference between my college
professors and my wife is the fact that
my wife holds an immediate oral exam
after the lecture and I don't have time
to go back to the textbook or my study
(06:41):
notes to make sure I had total
comprehension.
I may have a 4.0 GPA associated with my
doctorate,
but I'm sitting at a D average with the
classes I get from my wife.
Don't worry everybody, I love my wife,
as far as I know she still loves me,
even though she rolls her eyes at me
when I space out.
There's no trouble in paradise.
(07:01):
But man,
for those of you who may have trouble
in paradise,
it sounds like divorce might save you
from dementia.
Not to say I'm endorsing that,
I'm just reading this study summary on
MedPage today.
I mean,
maybe there is something medically
wrong with me already and that's my
excuse for spacing out during my
conversations with my wife.
(07:22):
Alright, enough of that.
Ready to get into the study and figure
out what's going on?
Let's do it.
This study was published by Karakose
and colleagues in March 2025 in
Alzheimer's and Dementia,
the journal of the Alzheimer's
Association.
It is titled,
Marital Status and Risk of Dementia
(07:42):
over 18 Years,
surprising findings from the National
Alzheimer's Coordinating Center.
Okay,
surprising findings is actually a little
risque for a journal article title.
I mean...
I would do that for a presentation
title,
just to get folks to come to my session
at a conference.
It's like these researchers wrote up
this study like, oh,
(08:03):
guess what we found?
Like,
they're pretending to be these conniving
gotcha artists instead of the droll
geeks we all know they are.
I'm putting myself in that category,
by the way, not trying to be a dick.
We researchers are, in fact,
geeks and nerds,
but we make the world a better place
for it.
Okay, first,
funding disclosures and conflicts of
(08:25):
interest.
The authors declare no competing
interests.
In the supplemental information,
the lead author declares the only
funding provided was from a grant to
their institution from the US National
Institutes of Health.
So,
no funny business there that we know
of.
Let's go through how the authors set up
their problem statement.
The authors start by referencing
(08:46):
evidence that being married has
traditionally been related to better
health and longevity.
They also discuss the marital resource
model,
which suggests that marriage provides
social, psychological,
and economic benefits unavailable
through other relationships that,
in turn,
support healthier and longer lives.
(09:07):
They also say there is conflicting
evidence on marital status as it
relates to Alzheimer's disease and
dementia.
Some studies have said that unmarried,
never-married, divorced,
and widowed folks are at higher risk
and others are inconclusive.
There has also been contradiction in
studies on whether this affects
unmarried men more than unmarried
(09:28):
women,
with some reporting higher risk of poor
health outcomes for men than women.
They also note that married individuals
are more likely to engage in
preventative medical care than
unmarried individuals,
citing that individuals may be made
aware that something is wrong because
their partner told them.
This is why if I keep not listening to
(09:50):
my wife,
she's probably going to put me in a
home.
So their justification for doing this
study is that they are using data from
the National Alzheimer's Coordinating
Center, one of the largest cohorts,
with annual clinical evaluation of
dementia over one of the longest follow
-ups, which is up to 18 years.
(10:12):
When you do a longitudinal study like
this,
a study that makes multiple observations
over a period of time,
it makes it easier to identify and
measure all the other stuff that could
be causing a certain outcome.
Cross-sectional studies,
or those that only grab a snapshot at
one period in time,
don't show changes over time,
obviously.
(10:32):
Again,
this is a way to get better correlations
that get closer to causation.
Additionally,
this study is supposed to separate out
different types of dementia,
including Alzheimer's disease,
Lewy body dementia, vascular dementia,
and frontotemporal lobar degeneration,
as well as mild cognitive impairment.
(10:53):
Lastly,
the authors say they will look at
potential moderating factors such as
sex, age, race, education, depression,
diagnostic form,
participants' referral source,
primary reason for visiting the
research centers,
and genetic vulnerability.
Yeah,
so this is set up to be a pretty comprehensive
(11:13):
study.
Let's check out the methods to see how
they did it.
Sample methods.
They started with a little over 50,000
participants.
They excluded almost 10,000
who withdrew from the study after the
baseline observation,
about 600 who were younger than 50
years old, almost 17,000
(11:34):
who had already had dementia at
baseline,
and 300 who responded other/unknown to
marital status at baseline.
I have so many questions.
How do you not know your marital
status?
You know what?
Maybe I shouldn't ask.
Anyway, final sample size was 24,107,
(11:55):
59.6% female and average age 71.79
years at baseline.
There's some other stuff in here about
how they combined groups of marital
status.
There was a small group of folks who
said they were separated,
and they were combined with the larger
group of folks who said they were
divorced.
(12:15):
Similarly,
there was a small group who said they
were living as married or had a
domestic partner.
Those folks were combined with the
married group.
Now,
the reason you do this for statistical
analysis is because when you have a
widely varied size groups,
it can throw off the outputs of the
results.
Remember, the bigger the sample size,
(12:35):
the more accurate the correlation will
be.
If you compare a tiny group to a large
group,
it doesn't give you a realistic comparison
in the results.
I actually had to do this during my
dissertation as well.
Now again,
I try not to get too deep into
statistics on this podcast,
but I want to point out a different
(12:56):
type of analysis that was used here.
They used Cox Proportional Hazards
Regression.
So we're looking at regression models,
but it's a different type than we've
looked at in the past,
like linear regression or logistic
regression.
Now,
I have never used Cox regression myself,
but basically this type of regression
(13:16):
is used when you are looking at the
association between a predictor
variable or independent variable and
survival time as your dependent
variable.
In this case,
that "survival time" is the time it takes for the onset of dementia. So in the output of the Cox model, you get this number called a hazard ratio, which compares the hazard or risk of an event between two groups.
(13:43):
The hazard ratio greater than one
indicates an increased risk,
while a hazard ratio less than one
indicates a reduced risk.
You also get a confidence interval,
which shows a range that hazard ratio
falls in at a certain percentage of
confidence.
Basically,
the closer those numbers are together,
the more sure we are that hazard ratio
(14:05):
is correct.
Hey, did you fall asleep?
Come on, stick with me.
I promise, no more statistics.
Just know that this is an appropriate
statistical test for this study.
So,
they compared the risk of dementia for
unmarried groups, meaning the widowed,
divorced, or never married,
compared to the married group as their
(14:26):
reference group.
They ran two different models.
The first included age and sex as
covariates.
The second added race, ethnicity,
education, living alone,
physical health, depression,
smoking behavior, diagnostic form,
referral source,
primary reason to visit the research
center, and genetic vulnerability.
(14:47):
The second model that includes all this
other stuff is called their fully
adjusted model.
Again,
all of this is done to try to paint a
more complete picture of the
correlations.
Now, at this point,
I've hopefully given you enough about
the statistical modeling that if you
want to go through all of the
(15:07):
individual calculations in the results
section, you are more than welcome to.
And you can feel a little bit more
confident about what you're looking at.
At this point,
I'll put everyone to sleep for sure if
I go through each one of these
individually.
So,
I'm going to jump down to the discussion
and get the most important parts of
(15:28):
these results.
Accounting for age and sex,
that was the first model,
the authors found that widowed,
divorced,
and never married individuals had about
50% or lower dementia risk relative to
their married counterparts.
That held true in the second model when
they included all of these other
factors as covariates.
That held true in the second model when
(15:50):
they included all of those other
factors as covariates.
All unmarried groups were also at lower
risk of Alzheimer's disease and Lewy
body dementia with a pattern of mixed
findings for frontotemporal lobar
degeneration.
There were no associations found with
risk of vascular dementia or mild
cognitive impairment.
(16:11):
Now,
on that mild cognitive impairment piece,
they did a follow-up analysis because
some individuals already had mild
cognitive impairment at baseline.
When they excluded those folks,
unmarried groups were at lower risk for
all causes of dementia.
When they included those folks,
the unmarried groups were at lower risk
of that mild cognitive impairment
(16:32):
progressing into dementia.
Okay, is everybody still with me?
What we have so far is a pretty good
longitudinal study with a large sample
size that says unmarried folks are at
lower risk of dementia than married
folks,
even when accounting for all of these
other potential factors like age and
sex.
(16:53):
The authors state this is contrary to
most previous longitudinal studies,
so we're at a bit of a crossroads.
Now we get to the fun part of the
discussion where the authors start to
speculate why this might be the case.
I'm going to pull out the best ones.
They start looking at other studies
that examine health relative to marital
status.
There is some evidence in previous
(17:15):
studies of cognitive improvement,
happiness,
and life satisfaction after divorce,
and social participation after a
partner dies.
That's a little dark, but okay.
Also,
never married individuals are more
likely to socialize with friends and
neighbors and engage in healthier
behaviors,
(17:35):
while married individuals are less
likely to engage in high quality
socialization in their networks.
Also,
there is some evidence to suggest that
the health benefits associated with
marriage are only evident in high
-quality marriages.
This is a point to examine for future
research, they say,
(17:55):
since this study did not look at
marriage quality, only marital status.
There's also a potential in this sample
of what they call ascertainment bias.
Remember,
this data came from the National
Alzheimer's Coordinating Center,
and earlier we talked about married
individuals being more likely to have
partners who notice and report
(18:15):
cognitive issues.
So there could be a little bit of bias
here where the unmarried folks have
underreported diagnoses of cognitive
issues.
So what are the limitations to this
study?
The first thing is where this data came
from.
These participants are referral-based
or voluntary,
they do not fully represent the U.S.
(18:36):
population,
and because of the nature of what this
research center is,
they have worse subjective cognition
overall.
The authors state that black
individuals and unmarried individuals
may be underrepresented relative to the
entire U.S.
population.
There is also room to look at nuances,
such as the role of relationship
(18:56):
factors like marital quality and
relationship duration.
The authors conclude by restating the
overall findings.
Unmarried folks are at lower risk of
dementia,
but qualify that by also restating the
potential for delayed diagnoses because
they don't have partners who would be
more likely to notice they possibly
(19:16):
have dementia.
So there it is.
Those are the parts that the news
reports miss.
Those limitations and potential biases.
What did we learn?
Well,
if you were in the unmarried group,
you might be at lower risk of dementia.
Also,
if you don't have someone living with
you to notice your potential onset of
dementia,
(19:37):
you're probably less likely to get
diagnosed anyway.
If you are married,
you apparently have a have two options.
You can either try to actively listen
to your partner and have a healthy
relationship where your partner will
make sure you get the care you need
when you need it or you can ignore your
partner and risk them sending you to
get a brain scan out of spite.
(19:58):
Either way,
you'll know for sure if you have
dementia or not, I guess.
That's all I got.
Until next time, I'm Dr.
Matt Law.
This has been another episode of Study
Finds on the Prove It To Me podcast.
Take care and stay safe everyone.
(20:28):
Prove It To Me is produced by me,
Matt Law.
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(20:49):
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Examples of research and data analysis
discussed within this podcast are only
(21:10):
examples.
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Assumptions made within this discussion
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No part of this podcast may be
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(21:31):
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the host.
My dearest listener,
(00:01):
from the moment we met,
I knew my life would never be the same.
Would you do me the honor of making me
the happiest researcher in the, the,
um, wait, what was I saying?
Ah, screw it.
Never mind.
It's an all new prove it to me.
(00:47):
Hello, everyone,
and welcome to prove it to me.
I'm your host, Dr.
Matt Law.
When I first started doing these study
finds episodes,
they were meant to be quick,
one-off filler episodes between the
guest appearances.
I mean,
the guest appearances seem to be what
folks really care about.
No one actually wants to hear me rattle
(01:09):
on endlessly about the things that I
find interesting, right?
I have to be honest though,
I've become an addict.
There's a real catharsis I feel that's
associated with diving deeper behind
the headlines.
Every time I see the words study finds,
I get butterflies in my stomach.
It's Pavlovian.
(01:30):
I start to anticipate the inevitable
buzz I get from doing the search,
clicking the links,
and getting into the nitty gritty
details to find out if this new study
is really a game changer,
or if it's just a little bit of
something somebody wrote up that got
blown out of proportion.
Or maybe it was slightly misconstrued
(01:50):
when the morning news wrote up their
summary of a summary.
Either way,
I find myself almost drooling at the
chance to geek out over the details of
this new research.
And I promise,
I have more guests on the way.
The thing is,
my guests so far have been researchers.
Researchers spend a lot of time…
(02:10):
No, that's actually it.
Researchers spend a lot of time,
period.
It takes so much time and effort to
answer a question thoroughly and
definitively.
There is no yes or no.
There is no black or white.
It's all gray,
and there are many shades of gray.
(02:31):
They spend months looking at the
factors they want to study and figuring
out all the possible confounding
factors.
They put so much effort into developing
models and modifying models to measure
relationships between variables.
They pore over statistical analyses and
try to explain the data and why the
outcomes are the way they are.
(02:52):
That's just the quantitative
researchers.
The qualitative researchers are even
more screwed.
They have to try to make sense of
paragraph after paragraph of text from
focus groups and interviews and loosely
guided observations to try to pull
themes that create a story for further
quantitative analysis.
(03:12):
Sometimes these studies take years.
They want to get it right.
That's how good research is done,
with an aim to get it right,
not with the intention to push an
agenda.
So it's no surprise that my guest
researchers will reach out months in
advance to schedule an appearance on
the podcast.
They want to make sure they have time
(03:34):
to get it right.
Honestly, I can't blame them.
I would too.
In fact,
my own pet research projects are taking
much longer than I expected because I
want to make sure I get them right.
So until then, you are stuck with me.
But I promise we're only a few weeks
away from the next guest appearance.
(03:55):
Now, for this episode,
I'm going back to sort of everyday
health topics rather than a workplace
safety topic.
I mean,
this is the stuff that ends up on the
news,
so that's what I tend to latch onto
first.
We've been able to do some workplace
safety stuff over the last few
episodes,
so I think it's fair that we have some
(04:15):
fun and get into an everyday health
topic.
And boy, this is a fun one.
This is a topic that is just begging
for some tongue-in-cheek, cynical,
comedic takes.
I don't know if you all are able to
appreciate my sense of humor,
but I really hope you enjoy going
through this one with me.
From MedPage Today,
(04:36):
an article dated March 25th,
2025 entitled,
Surprising Findings from New Research
about Dementia and Marriage.
With the tagline, U.S.
study could challenge the belief that
marriage protects against cognitive
decline.
(04:59):
a sacred institution.
But you and I both know that this can
be a divisive and emotional topic for
many, many folks.
So,
MedPage today had access to the entire
study article because the article is
open access.
So let's just read what their key
takeaways were and we'll jump into the
(05:19):
study.
Key takeaways.
Number one,
unmarried people in a US study had
lower risk of dementia than married
people.
Number two, the study followed 24,000
older adults through the National
Alzheimer's Coordinating Center.
And number three,
findings were similar for men and
women.
(05:40):
I mean, really folks,
you ever run into that old married
heterosexual couple and the wife is
super naggy and opinionated and the
husband is totally aloof.
And it's not really clear if he's
always been that way or if it's just an
act or Maybe he became this way just
because it's easier and more peaceful
than trying to fight it?
(06:00):
Like seriously,
this is a classic troupe in comedy
movies and sitcoms.
I won't be sexist here either because
I've seen it the other way around too
where the wife is the one that's aloof
and the husband is just a grumpy
asshole.
Honestly, you can ask my wife.
She probably thinks I already have
dementia.
Seriously,
since like year 5 of our marriage,
(06:21):
the only words I hear my wife say are,
were you listening to what I just said?
I don't do this intentionally or
maliciously.
I really suck at active listening.
In fact,
the only difference between my college
professors and my wife is the fact that
my wife holds an immediate oral exam
after the lecture and I don't have time
to go back to the textbook or my study
(06:41):
notes to make sure I had total
comprehension.
I may have a 4.0 GPA associated with my
doctorate,
but I'm sitting at a D average with the
classes I get from my wife.
Don't worry everybody, I love my wife,
as far as I know she still loves me,
even though she rolls her eyes at me
when I space out.
There's no trouble in paradise.
(07:01):
But man,
for those of you who may have trouble
in paradise,
it sounds like divorce might save you
from dementia.
Not to say I'm endorsing that,
I'm just reading this study summary on
MedPage today.
I mean,
maybe there is something medically
wrong with me already and that's my
excuse for spacing out during my
conversations with my wife.
(07:22):
Alright, enough of that.
Ready to get into the study and figure
out what's going on?
Let's do it.
This study was published by Karakose
and colleagues in March 2025 in
Alzheimer's and Dementia,
the journal of the Alzheimer's
Association.
It is titled,
Marital Status and Risk of Dementia
(07:42):
over 18 Years,
surprising findings from the National
Alzheimer's Coordinating Center.
Okay,
surprising findings is actually a little
risque for a journal article title.
I mean...
I would do that for a presentation
title,
just to get folks to come to my session
at a conference.
It's like these researchers wrote up
this study like, oh,
(08:03):
guess what we found?
Like,
they're pretending to be these conniving
gotcha artists instead of the droll
geeks we all know they are.
I'm putting myself in that category,
by the way, not trying to be a dick.
We researchers are, in fact,
geeks and nerds,
but we make the world a better place
for it.
Okay, first,
funding disclosures and conflicts of
(08:25):
interest.
The authors declare no competing
interests.
In the supplemental information,
the lead author declares the only
funding provided was from a grant to
their institution from the US National
Institutes of Health.
So,
no funny business there that we know
of.
Let's go through how the authors set up
their problem statement.
The authors start by referencing
(08:46):
evidence that being married has
traditionally been related to better
health and longevity.
They also discuss the marital resource
model,
which suggests that marriage provides
social, psychological,
and economic benefits unavailable
through other relationships that,
in turn,
support healthier and longer lives.
(09:07):
They also say there is conflicting
evidence on marital status as it
relates to Alzheimer's disease and
dementia.
Some studies have said that unmarried,
never-married, divorced,
and widowed folks are at higher risk
and others are inconclusive.
There has also been contradiction in
studies on whether this affects
unmarried men more than unmarried
(09:28):
women,
with some reporting higher risk of poor
health outcomes for men than women.
They also note that married individuals
are more likely to engage in
preventative medical care than
unmarried individuals,
citing that individuals may be made
aware that something is wrong because
their partner told them.
This is why if I keep not listening to
(09:50):
my wife,
she's probably going to put me in a
home.
So their justification for doing this
study is that they are using data from
the National Alzheimer's Coordinating
Center, one of the largest cohorts,
with annual clinical evaluation of
dementia over one of the longest follow
-ups, which is up to 18 years.
(10:12):
When you do a longitudinal study like
this,
a study that makes multiple observations
over a period of time,
it makes it easier to identify and
measure all the other stuff that could
be causing a certain outcome.
Cross-sectional studies,
or those that only grab a snapshot at
one period in time,
don't show changes over time,
obviously.
(10:32):
Again,
this is a way to get better correlations
that get closer to causation.
Additionally,
this study is supposed to separate out
different types of dementia,
including Alzheimer's disease,
Lewy body dementia, vascular dementia,
and frontotemporal lobar degeneration,
as well as mild cognitive impairment.
(10:53):
Lastly,
the authors say they will look at
potential moderating factors such as
sex, age, race, education, depression,
diagnostic form,
participants' referral source,
primary reason for visiting the
research centers,
and genetic vulnerability.
Yeah,
so this is set up to be a pretty comprehensive
(11:13):
study.
Let's check out the methods to see how
they did it.
Sample methods.
They started with a little over 50,000
participants.
They excluded almost 10,000
who withdrew from the study after the
baseline observation,
about 600 who were younger than 50
years old, almost 17,000
(11:34):
who had already had dementia at
baseline,
and 300 who responded other/unknown to
marital status at baseline.
I have so many questions.
How do you not know your marital
status?
You know what?
Maybe I shouldn't ask.
Anyway, final sample size was 24,107,
(11:55):
59.6% female and average age 71.79
years at baseline.
There's some other stuff in here about
how they combined groups of marital
status.
There was a small group of folks who
said they were separated,
and they were combined with the larger
group of folks who said they were
divorced.
(12:15):
Similarly,
there was a small group who said they
were living as married or had a
domestic partner.
Those folks were combined with the
married group.
Now,
the reason you do this for statistical
analysis is because when you have a
widely varied size groups,
it can throw off the outputs of the
results.
Remember, the bigger the sample size,
(12:35):
the more accurate the correlation will
be.
If you compare a tiny group to a large
group,
it doesn't give you a realistic comparison
in the results.
I actually had to do this during my
dissertation as well.
Now again,
I try not to get too deep into
statistics on this podcast,
but I want to point out a different
(12:56):
type of analysis that was used here.
They used Cox Proportional Hazards
Regression.
So we're looking at regression models,
but it's a different type than we've
looked at in the past,
like linear regression or logistic
regression.
Now,
I have never used Cox regression myself,
but basically this type of regression
(13:16):
is used when you are looking at the
association between a predictor
variable or independent variable and
survival time as your dependent
variable.
In this case,
that "survival time" is the time it takes for the onset of dementia. So in the output of the Cox model, you get this number called a hazard ratio, which compares the hazard or risk of an event between two groups.
(13:43):
The hazard ratio greater than one
indicates an increased risk,
while a hazard ratio less than one
indicates a reduced risk.
You also get a confidence interval,
which shows a range that hazard ratio
falls in at a certain percentage of
confidence.
Basically,
the closer those numbers are together,
the more sure we are that hazard ratio
(14:05):
is correct.
Hey, did you fall asleep?
Come on, stick with me.
I promise, no more statistics.
Just know that this is an appropriate
statistical test for this study.
So,
they compared the risk of dementia for
unmarried groups, meaning the widowed,
divorced, or never married,
compared to the married group as their
(14:26):
reference group.
They ran two different models.
The first included age and sex as
covariates.
The second added race, ethnicity,
education, living alone,
physical health, depression,
smoking behavior, diagnostic form,
referral source,
primary reason to visit the research
center, and genetic vulnerability.
(14:47):
The second model that includes all this
other stuff is called their fully
adjusted model.
Again,
all of this is done to try to paint a
more complete picture of the
correlations.
Now, at this point,
I've hopefully given you enough about
the statistical modeling that if you
want to go through all of the
(15:07):
individual calculations in the results
section, you are more than welcome to.
And you can feel a little bit more
confident about what you're looking at.
At this point,
I'll put everyone to sleep for sure if
I go through each one of these
individually.
So,
I'm going to jump down to the discussion
and get the most important parts of
(15:28):
these results.
Accounting for age and sex,
that was the first model,
the authors found that widowed,
divorced,
and never married individuals had about
50% or lower dementia risk relative to
their married counterparts.
That held true in the second model when
they included all of these other
factors as covariates.
That held true in the second model when
(15:50):
they included all of those other
factors as covariates.
All unmarried groups were also at lower
risk of Alzheimer's disease and Lewy
body dementia with a pattern of mixed
findings for frontotemporal lobar
degeneration.
There were no associations found with
risk of vascular dementia or mild
cognitive impairment.
(16:11):
Now,
on that mild cognitive impairment piece,
they did a follow-up analysis because
some individuals already had mild
cognitive impairment at baseline.
When they excluded those folks,
unmarried groups were at lower risk for
all causes of dementia.
When they included those folks,
the unmarried groups were at lower risk
of that mild cognitive impairment
(16:32):
progressing into dementia.
Okay, is everybody still with me?
What we have so far is a pretty good
longitudinal study with a large sample
size that says unmarried folks are at
lower risk of dementia than married
folks,
even when accounting for all of these
other potential factors like age and
sex.
(16:53):
The authors state this is contrary to
most previous longitudinal studies,
so we're at a bit of a crossroads.
Now we get to the fun part of the
discussion where the authors start to
speculate why this might be the case.
I'm going to pull out the best ones.
They start looking at other studies
that examine health relative to marital
status.
There is some evidence in previous
(17:15):
studies of cognitive improvement,
happiness,
and life satisfaction after divorce,
and social participation after a
partner dies.
That's a little dark, but okay.
Also,
never married individuals are more
likely to socialize with friends and
neighbors and engage in healthier
behaviors,
(17:35):
while married individuals are less
likely to engage in high quality
socialization in their networks.
Also,
there is some evidence to suggest that
the health benefits associated with
marriage are only evident in high
-quality marriages.
This is a point to examine for future
research, they say,
(17:55):
since this study did not look at
marriage quality, only marital status.
There's also a potential in this sample
of what they call ascertainment bias.
Remember,
this data came from the National
Alzheimer's Coordinating Center,
and earlier we talked about married
individuals being more likely to have
partners who notice and report
(18:15):
cognitive issues.
So there could be a little bit of bias
here where the unmarried folks have
underreported diagnoses of cognitive
issues.
So what are the limitations to this
study?
The first thing is where this data came
from.
These participants are referral-based
or voluntary,
they do not fully represent the U.S.
(18:36):
population,
and because of the nature of what this
research center is,
they have worse subjective cognition
overall.
The authors state that black
individuals and unmarried individuals
may be underrepresented relative to the
entire U.S.
population.
There is also room to look at nuances,
such as the role of relationship
(18:56):
factors like marital quality and
relationship duration.
The authors conclude by restating the
overall findings.
Unmarried folks are at lower risk of
dementia,
but qualify that by also restating the
potential for delayed diagnoses because
they don't have partners who would be
more likely to notice they possibly
(19:16):
have dementia.
So there it is.
Those are the parts that the news
reports miss.
Those limitations and potential biases.
What did we learn?
Well,
if you were in the unmarried group,
you might be at lower risk of dementia.
Also,
if you don't have someone living with
you to notice your potential onset of
dementia,
(19:37):
you're probably less likely to get
diagnosed anyway.
If you are married,
you apparently have a have two options.
You can either try to actively listen
to your partner and have a healthy
relationship where your partner will
make sure you get the care you need
when you need it or you can ignore your
partner and risk them sending you to
get a brain scan out of spite.
(19:58):
Either way,
you'll know for sure if you have
dementia or not, I guess.
That's all I got.
Until next time, I'm Dr.
Matt Law.
This has been another episode of Study
Finds on the Prove It To Me podcast.
Take care and stay safe everyone.
(20:28):
Prove It To Me is produced by me,
Matt Law.
Original music by West London.
You can find this podcast on Podbean,
Apple Podcasts, Spotify, YouTube,
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Like what you've heard so far.
Please like, subscribe,
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podcasts,
and leave a five-star review on Apple
Podcasts.
Got questions about what we talked
(20:49):
about or research that you want to
share?
Send an email to contact@proveitpod
.com.
The views and opinions expressed in
this podcast are those of the host and
its guests,
and do not necessarily represent the
official position, opinion,
or strategies of their employers or
companies.
Examples of research and data analysis
discussed within this podcast are only
(21:10):
examples.
They should not be utilized in the real
world as the only solution available,
as they are based on very limited,
often single-use case,
and sometimes dated information.
Assumptions made within this discussion
about research and data analyses are
not necessarily representative of the
position of the host, the guests,
or their employers or companies.
No part of this podcast may be
reproduced,
(21:31):
stored in a retrieval system,
or transmitted in any form or by any
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The presentation of the content by the
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the host.
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