cc >> Tom Zinnen: Welcome,
everyone, to Wednesday Nite at the Lab.
I'm Tom Zinnen. I work here at the UW Madison
Biotechnology Center and for UW Extension Cooperative Extension,
and on behalf of the Wisconsin Alumni Association and Wisconsin
Public Television, thanks again for coming to Wednesday Nite at
the Lab. We do this every Wednesday
night, 50 times a year. Tonight I'm delighted to be
able to introduce to you Barbara E.K. Klein
who's both a physician and a master of public health.
She's a professor in the Department of Ophthalmology and
Visual Sciences and is affiliated with the Department
of Population Health Sciences here at the University of
Wisconsin Madison. She is also the co-director of
the Beaver Dam Eye Study which will be the subject of her talk
tonight. This study collects information
on the prevalence and incidence of age-related cataract,
macular degeneration and diabetic retinopathy, which
are all common eye diseases in an aging population.
The study also has examined other aging issues such as
overall health, quality of life and environmental and medicinal
exposures. Please join me in welcoming
Dr. Klein to Wednesday Nite at the Lab.
[APPLAUSE] >> Barbara Klein: Thank you
very much for coming out this evening.
I know it wasn't fun walking through the ice and slush.
I'll get started and I think there will be plenty of time at
the end for questions. So here it goes.
This is the banner story in the Daily Citizen, the Beaver Dam
Daily Citizen, in 1987. After about two years of writing
and rewriting grant proposals to the NIH, the Beaver Dam Eye
Study was funded, and the newspaper's been a very
wonderful supporter of this study.
Let's see, the reason that the Beaver Dam Eye Study was
conceived and designed was because at the time, 1985 or so,
there was very, very little information on the common
chronic eye conditions, not esoteric things but things all
of us will likely face with regard to how common they were,
what was the incidence or new development after so many years
of life and then what were risk factors in particular for these
common conditions. In particular, we looked at the
functional end point, which is visual impairment and severe
visual impairment or legal blindness, but then we looked at
the causes which are cataracts, glaucoma, age-related
degeneration or macular degeneration, and, as was
pointed out by Tom also, diabetic retinopathy.
We got a lot of information about other things as well, some
of which I'll share with you this evening.
Retinal vein occlusion as it turned out was more common than
we had anticipated, and this is also a big problem.
Well you may be quite familiar with where Beaver Dam is.
It's about 39 miles northeast of Madison, not far from Milwaukee
as well. It's about equal distance
between the two. We painted this in Badger red
because of the Rose Bowl. So why Beaver Dam?
I've been asked this question innumerable times.
We chose Beaver Dam because it was very representative of other
small communities throughout the Midwest.
It had the appropriate size population for adequate sample
sizes to test the hypotheses we were interested in.
Beaver Dam had a high participation rate in an earlier
study that we had done. And the community leaders from
all walks of life as well as the physicians and eye care
providers, including eye doctors and optometrists which at the
time was unusual, all cooperated and were supportive.
Also very important was that it was close to Madison, and if
something happened at the field center in Beaver Dam and I was
at my office in the WARF building, I could get there
within an hour. So this is a picture of the
gazebo in Swan Park, and in times past there used to be
springs, excuse me.
People would come to take the waters in Beaver Dam
and they'd be dealt this Swan Park gazebo.
Pardon me for a minute.
Sorry. Well, a very important part of
the project was getting an accurate census.
This is one of our census takers in action.
[LAUGHTER] The census was done between
1987 and 1988 to determine the actual number of people in the
target age range as well as to ascertain or confirm
their current addresses. We had estimates from the
previous census, the national census, but this was many years
after and we had to update it. We also wanted to introduce
ourselves to the community, in particular each household where
we would be recruiting study participants.
We also collected some very basic information about vision
and self-reported eye conditions.
By doing this, we identified 5,924 people 43 to 84 years of
age. That was our target range.
Each participant received an invitation to the study followed
up by a call and then a scheduling of appointments.
We did a study evaluation which took about two and a half hours
for each participant. Then we collated all the
information, and those who wanted the information back
received it as well as their healthcare providers, if they
chose to do that. And then, of course, the big
part is the analysis of the wealth of information that came
in after that. Took us about two and a half
years the first time through with the arduous recruitment
back and forth, but the participation rate has been
tremendous in Beaver Dam. It's been a wonderful community
to work in, and we're still working there.
And I'll tell you a little bit more about that in a moment.
I'm sort of cutting to the chase here, and this is a summary of
the prevalence. Prevalence is a cross-section of
the population at the time of the first exam.
So this is prevalence of visual impairment.
Visual impairment means visual acuity of 20/40 or worse after
an in depth refraction and using that optimal correction.
So we call this the best corrected visual acuity.
And you can see from the slide that visual impairment is very
uncommon in the youngest age group, the 43- to 54-year-olds,
and it stays very low until that last decade or so when it
increases to about 20% of people.
Excuse me again.
This plots the data for legal blindness which is about 2200
or worse in the better eye.
You can see that woman are disproportionately
disadvantaged compared to men. Once again, you notice that the
scale is different but, again, it's that big increase
after age 65. Oops, sorry.
I'll go now through the individual eye conditions.
So the first one would be cataract.
A picture of me at an earlier stage in my career.
[LAUGHTER] In front of a slit lamp, which
we use to examine for cataract, and right next to it is a camera
that we use to take photos of the lens.
I'm also pointing out to one of the study participants where
we're looking at when I look at the lens of the eye.
There are three kinds of age-related cataract: nuclear
cataract, cortical cataract, and posterior subcapsular cataract.
These photographs are taken after the pupil is dilated with
dilating eye drops, and a light beam comes in at 45 degrees from
where the camera is angled so that you get a sort of a
cross-section and you get the impression of sort of layers or
like layers of an onion. And on your left is a relatively
young lens, very little nuclear sclerosis.
And on your right is someone where the nucleus, which is the
center part, is dense or less clear.
That's a nuclear cataract. This photograph was taken, or
this set, through a dilated pupil but with a different sort
of camera. Here, it's called a
retroillumination camera, a bright light is shown into the
eye, and the reflected light from the retina gives it that
orange appearance. On your left is a clear lens,
no cataract. On your right is cortical
cataract. Excuse me again.
I'm so sorry. This is another form.
This is the posterior subcapsular cataract.
The one on your left again is clear.
This opacity is in the back part of the lens, and it tends to be
very visually disabling. Why is preventing cataract
important? Cataract is the leading cause of
blindness worldwide. It's more common as the cause of
blindness than a variety of parasitic infections that used
to be quoted as being the most important.
It's also the leading cause of loss of vision in the US.
It's responsible for about 60% of all Medicare costs related to
vision. So it's a big problem.
Cataract surgery which is relatively easy to come by in
this country can be complicated, there are always complications
for surgery or at least you have to anticipate they could happen,
it can be uncomfortable, it's expensive and it may not be able
for those with limited or no healthcare coverage.
I think this is going to be a bigger and bigger problem.
It's also not widely available in some Third World countries.
This again is a summary of the data from the first Beaver Dam
study. And you can see the tall bars
are the prevalence of cataract, and you can see once again that
inexorable increase with increasing age but by the time
we got there, there were a number of people who had already
had some cataract surgery, usually with implants in place.
Rises to be about, cataract is about 80% of the population 75
or older. When I group together the three
kinds of cataract you can see, again, the increase with
increasing age because they are all age related, and once again
you can see that women are disproportionately affected.
This is just a summary of the prevalence of the three
different kinds. So you can see that 17% of the
people had nuclear cataract, not rare.
Cortical, about 16%. Posterior subcapsular, the most
visually disabling, about 6%, and cataract surgery had been
done in about 3.6% of people. Well, what are the causes of
this? Are there environmental causes
to these problems? It looks like smoking increases
the risk of cataract quite significantly, most
significantly for nuclear cataract.
I would point out that for the others it's not statistically
significant all the time. And this may be a sample size
issue. But that 1.09 means that smokers
who smoke 10 pack-years will have a 9% increase in risk.
But most smokers or many smokers have smoked more than
10 pack-years in their lives. So you can see it becomes quite
a significant cause for increase in nuclear cataract which is the
most common cause of cataract surgery.
A little bit less and not statistically significant for
cortical and a smaller effect on posterior subcapsular cataract.
I'm going the wrong way. Past heavy drinking it appears
is also associated with cataract.
And you can see it appears to increase the risk of all three
kinds of cataract. I have a colleague in Rotterdam
doing the Rotterdam Eye Study that was patterned after Beaver
Dam, and when I told him we consider heavy drinking to be
four or more drinks per day on a regular basis.
And he said, that's not heavy drinking, everybody drinks that
much. [LAUGHTER]
But that's not true in Beaver Dam.
And so we have relatively few heavy drinkers, but they are
apparently at increased risk. Well there are other factors
that are environmental factors that are associated with
cataract. There's evidence that UVB is
associated with cortical cataract in men.
UVB is the common UV radiation that comes in with blue light
when you're outdoors, and we found an increased risk in
Beaver Dam and also there have been other studies to
corroborate this. And there may be an association
with CAT scans to the head but that's less clear.
So what have we learned about cataract from the Beaver Dam Eye
Study or from the prevalence data at any rate?
We found that more than 80% of people who were over the age of
75 had cataracts, that's pretty prevalent.
Women were more likely to be affected than men.
Smoking, heavy drinking were associated with nuclear
cataract. UVB exposure, diabetes, past
heavy drinking were associated with cortical cataract.
Diabetes, steroid use, past heavy drinking were associated
with posterior subcapsular cataract.
So they seem to have slight differences in their risk
factors. Do we know anything about
protection? Of course the idea is to find
things that you can intervene on to protect people from getting
this. Well, the data about
multivitamins is tenuous. We found a significant effect
but not strong for cortical cataract.
Some studies find it, some don't.
Something that we found five years ago and reported was
statistically significant protective effect of statin
drugs for cataract, in particular for nuclear cataract.
We have yet to see this replicated, although the Blue
Mountains Eye Study, sister study right now, the Blue
Mountains of Australia right outside of Sydney, found a very
similar protective rate but it wasn't statistically
significant. So we have yet to see.
It hasn't been tested in a trial.
I'm going to move along to another common condition in
Beaver Dam, age-related macular degeneration.
And you all may know something about this.
There really was very little information about this disease
when we started. So we were interested in both
the incidence and progression when evidence of some of the
disease was already there. Its risk factors and then we
have some information about treatments to prevent or restore
vision in the late stage. So this is one of our field
examiners using this camera. This is a particular camera
designed to take photographs of the retina.
It's a fundus camera. Not easy to use for the
examiner, not so easy for the patient either, the participant
either. So this montage shows you just a
quick glimpse of fundus, that is retinal photos of eyes that have
different degrees of this lesion, or this condition.
On the top we see early age-related macular
degeneration, and you see that there are a lot of yellow spots
there. The blood vessels are normal,
the optic nerve looks good, but those yellow spots, if you want,
are called drusen, and they're excrescences in the deep layers
of the retina, and this person would likely have no symptoms at
all. On the bottom you see two
pictures of late age-related macular degeneration.
The one on your left is called geographic atrophy, the bottom
is cut off, and essentially the retina is missing in what
appears to be a geographically defined area.
And of course you can't see in that area.
The other one is called neovascular or wet AMD and that
red stuff is blood. There's been new growth of
vessels from the choroid, a vascular layer under the retina,
and this new vessel membrane is very friable and fragile, and it
often breaks, bleeds and people can go to sleep seeing and wake
up and see nothing. Fortunately, you can see that as
early age-related macular degeneration occurred in only
16% of people, the late AMD occurred in only .6%, and the
neovascular in 1.1%. Let me back up for a minute here
and tell you just a little bit about the risk factors.
Of course age is a risk factor, and I'll show you that again
graphically. Gender, again we'll see women
are disproportionately affected for neovascular.
Smoking seems to be the most important obvious environmental
factor that's related to it. And hypertension.
It takes a while but before it rears its ugly head is a risk
factor that you can find to be statistically significant.
This is a graph of the prevalence data.
Again, the tall bars are early age related macular
degeneration. You can see that monotonic
increase with increasing age. The difference between men and
women is not so obvious, but it is statistically significant
when you divide them by the wet and the dry type.
And along the bottom, the smaller bars, the yellow and
green, are late lesions. Again, very clearly age related.
I'm sorry. So, aside from the smoking that
I talked about in hypertension, there's also heavy alcohol
consumption appears to increase risk.
Chronic inflammation that's ascertained by doing studies,
inflammatory markers in the blood appear to increase risk.
For reasons that are not clear at all, sedentary lifestyle is
associated with it in Beaver Dam.
And the biggest thing that I put in larger font is genetic
factors. And you may have heard about
this recently. There was a big explosion about
three or four years ago when a particular gene was found to be
responsible. Estimates of how many cases it's
actually responsible for is not known, but it's clear that will
are many different genetic factors that increase the risk.
Are there protective factors? Well, antioxidant multivitamins
may reduce the incident and progression of late wet and dry
AMD, and of course avoiding known risk factors will do it
too. The antioxidant multivitamin
preparations were tested in a clinical trial called the AREDS,
the Age-Related Eye Disease Study, where there is random
assignment to antioxidant nutrients and zinc or not, a
placebo. And those people who had
moderate degrees of age-related macular degeneration but no
symptoms before, those people who took the experimental
supplement had a 25% decrease in progressing to late stage
disease. Not a miracle.
About 27 people in the group who didn't get the medications went
on, about 21 and the group that got it went on, but it's about a
25% reduction. You may know these preparations.
They're commonly sold in any drug store.
There are new treatments that have come on even while we've
been in Beaver Dam over the last now 20 years.
Avastin and Lucentis, which were drugs that were initially
designed for and used for metastatic cancer, are used now
by intravitreal injection, that's a needle to the eye, for
wet AMD. This has provided some success.
Now, it's often true that people need to come back for repeated
injections which isn't fun and can be associated with infection
or inflammation. There are other, they call them
vascular endothelial growth factor inhibitors, or
anti-drugs, but currently there's no treatment for dry
AMD. It's an area of hot research, I
can tell you, but there's nothing on the market now.
So that's the end for macular degeneration, and I hope if you
have questions we'll talk about it after.
I'll talk a little bit about glaucoma.
Now, glaucoma in Beaver Dam, which is very largely a white
population, over 99% of the population is white.
And glaucoma is a much more common disease in people of
African heritage, African Americans or African Caribbean
background. Nevertheless, it occurs in
Beaver Dam. You can see once again the age
trend, but of course if you notice the scale it's not nearly
as common as the other conditions.
In people who were 75 and older, about 5% of them had glaucoma.
This is just a grand summary of the diseases that I talked about
so far. So you can see that cataract is
by far the most common condition.
Cataract surgery was also fairly common, but it doesn't occur
until later. Maculopathy, that's the same
thing, the names vary by the time we made up the slide
because of the trends in what you call things.
It used to be called senile macular degeneration and that
word was bad. [LAUGHTER]
So now it's maculopathy or age-related
macular degeneration, that's the same thing.
It's the next most common. You can see glaucoma is not very
common. And then just to show you how
common visual impairment is and that has importance for quality
of life and so on. So I'm jumping ahead now 15
years because the Beaver Dam Eye Study, the first round of exams
was completed in 1990, but just in November, the last November,
we finished the 20-year follow up.
We don't have that data ready to go yet.
So I'm presenting just a little bit of the findings from the
previous exam which would be 15-year interval from the
baseline for the follow up, 15-year incidence.
So at the 15-year point, these were the primary causes of
severe visual impairment in Beaver Dam.
Now, incident means they didn't have this at the baseline exam.
They may have had some impairment but they weren't
blind. But 15 years follow up, 180 eyes
had become blind or had visual acuity poorer than 2200.
That's the big E on the top of the doctor's eye chart.
You can see that at 52%, cataract leads the league.
I'm sorry, AMD leads it for severe visual impairment.
That's the 52%. Sorry.
12% were due to cataract which is very easy to obtain, if you
will, in Beaver Dam. That's sort of a middle-class
community, it's right here near Madison.
12% of those with severe impairment had a retinal vein
occlusion. As I was mentioning before, it
turned out to be much more common than we thought because
this is quite severe visual loss.
So that was news to everybody. 5% were due to a macular hole.
Again, we didn't realize that was going to be so common.
And then there are a variety of other things.
What's notable is that diabetic retinopathy, which we thought
was going to be a much more common cause of visual loss, is
now responsible for about the same amount of severe visual
impairment as is the retinal vein occlusion, and that's
probably because there have been great strides, as you may know,
in the care for people with diabetes.
And tight glycemic control has really improved things
remarkably for all complications of diabetes, including diabetic
retinopathy but also cataract that occurs more commonly in
people with diabetes. So this is a real giant step
forward in medical care. At 15 years we were able to look
at the incidence. We measured things at the
baseline, we looked at the incidence of the new development
of poor vision and we looked at the risk factors for it.
Actually, I guess here I'm just going to tell you what happened
to those people over the course of time.
Not the risk factors for poor vision, we may get to that.
But people who had lost vision were more likely to be placed in
a nursing home. They were more likely, as you
might expect, to have falls and fractures.
We've got good history on that. They were more likely to give up
driving. Many people give up driving
because they know themselves that it's not a smart idea.
But that's a big problem in Beaver Dam which is a rural
community. Once you stop driving, you give
up your independence. So that's a hard thing.
It's a big change in life. And they were more likely to
have a host of other medical problems.
I want to just show you just a tiny smidgen about what happens
disease wise over the course of time and why it's so important
to have a longitudinal follow up.
At the top you can see that when we first saw this person they
had some early lesions of AMD. They had drusen, those are the
yellow spots. The coloration of the photo is a
little different compared to the others, but you have to just
accept that people with different pigmentations have
different color in their fundus. There's a little bit more at
your lower left. And by the time you get to the
picture on the right, which is in this case only 10 years from
the baseline exam, there's a big patch where the retina isn't
anymore but you can see a sort of white area and you can see
atrophic lesions and you can also see some blood and that's
from the new vessel. So this poor person has dry
macular degeneration and wet. And what happens is that the
central vision is lost. They tend to keep peripheral
vision, side vision is good, but when you want to read something
or if you're trying to track something you have a bad time of
it. So, there was a very high
incidence of late AMD of both varieties in people who were 75
years or older at the baseline exam.
So in other words, it really gets to be a very significant
cause of loss of vision as you get older.
But it's not all bad news. At any specific age people who
are born more recently were at less risk for developing AMD
than those people born at an earlier time.
And I'll try and walk you through a slide of this, but let
me just talk this part out. For example, the five-year
incidence, over a five-year course of early AMD in people
examined when they were 65 to 69 was 14% among people who were
born in 1918 to 1922, 10% in those people born just four
years more recently than that, 6% again in those born in more
recently, and 4% amongst those who were born in 1933 to '37.
So there's a very step wise decrement in the incidence of
new disease. That's a good thing.
In other words, the way you would look at it here is that
you can see the increased incidence with increasing age
but at each age group in each set of four bars the people to
the right-hand side in the group of four were born most recently
compared to those at the other side.
And you can see until about the last group when we run out of
numbers that people who were born more recently have a
systematic decrease in incidence.
We don't know why that's true, we don't know what everybody is
doing, presumably living better is good for everything, and it's
probably true that many, many things have improved since the
earliest decades. And we don't have any idea
really what exposures in life, except for the few I mentioned
to you, are increasing or have increased the risk.
Well, I sort of gave you a whirlwind trip through some of
the eye diseases, but the Beaver Dam Eye Study protocols have
been borrowed by many, many studies around the world.
There's the age study which is in Iceland, Andhra Pradesh in
India, the ARIC which is an atherosclerosis study in this
country, the Baltimore Eye Study, Barbados Eye Study,
I could go on and on and on. I only gave you a partial list
of studies that have borrowed protocols and other things and
people who have come to work with us.
So more data is available around the world.
In the most recent Beaver Dam exam phase we have added an
interesting new examination tool.
Excuse me once again.
This is called an OCT. It's a really fancy gizmo.
But it shows you, it's painless. You take essentially what's like
a photograph, and you sit still and it shows you, in depth, the
layers of the retina. So you can get a better idea of
what's going on really. Let's see if I can get this to
work. So you get a photograph like
this and then using this fancy new technology, it takes what
looks like histologic sections through the retina.
Let's see, there you go. So it's taking five slices
through the retina at different levels.
And you can see, this happens to be a picture of macular edema or
swelling in the macular area. And you can see where it
balloons up that there are cysts that are filled with fluid,
edema fluid. So we think this is going to be
very important in trying to understand the development of
some of these diseases.
Pardon me. This really concludes the part
that I have about eye disease. I have a little bit more that I
can present to you about a few of the other facets of Beaver
Dam. If that's okay with you,
I'll go on. So here's just something else
about Beaver Dam. Falls are a big problem
as I noted to you before. It costs about $19 billion
annually for the healthcare budget to take care of the
variety of things that are incurred after a fall.
It's a sixth of the cost of the Iraq war.
It causes fractures and all sorts of disability and, on
occasion, even death. So falls are a big problem.
Here are some of the causes that in the literature have been
associated with falls. Some of them are just
environmentally related. Some are gait and balance
disorders. Some seem to be associated with
vertigo or dizziness. Others, some people just have
what are called drop attacks, they just lose consciousness.
Some confusion. Some postural hypotension.
In other words, you stand up quick, your blood pressure
drops, boom, you go over. And then there are visual
disorders that are associated with falls.
As well as your garden variety fainting.
And then some, they call them other, they can't identify the
particular cause. But what are the risk factors
for falls? It seems as though the weakness
and balance deficits are the most common or the strongest
risk factors, while the postural hypotension is less common.
And then there are various things in between including
cognitive disorders and mobility limitation.
So it is my purpose to quantitate the risk of falls
with respect to vision and other potentially modifiable functions
in Beaver Dam. I used data from the 15-year
follow up and, at that time, there were about nearly 2400
survivors from the original group and that was 77% of people
who were still alive to come in. And we had complete data on some
of the things I'll show you for about 2,256.
We asked people, during the past 12 months have you fallen and
landed on the floor or ground or fallen and hit an object like a
table or a stair? If they said yes we asked, them
how many times have you fallen in the past 12 months?
We give them one fall for nothing.
You live in Wisconsin, falling is not a rare event and it may
have nothing to do with your disability but you could have an
icy sidewalk like mine. So we give them one for nothing.
But we used as our outcome two or more falls.
And we looked at a variety of vision measures.
Here are the ones that we had in Beaver Dam.
We had what's called the logMAR, it's just a variation of the
Snellen chart. Big dark letters at the top,
small ones at the bottom. Then we used something called
contrast sensitivity. And this gives you an idea of
how people function in less than perfect lighting.
And then we have a near vision chart which is also good to
measure certain things. It certainly tells you a lot
about how vision affects people's quality of life if they
have trouble reading. We considered these all as
measures of frailty. And we did a bunch of measures
of frailty in the people of Beaver Dam.
We did a timed walk. We had a course that was marked
out, same for everybody, and we timed how long it took them to
walk there. We did a chair stand.
These, incidentally, are standard measures in studies of
aging. We asked people to stand up
without using their hands from a chair at a certain height
of 19 and a half inches. We used a dynamometer to get
grip strength. It's a very good measure in
cardiovascular disease and other studies of subsequent cardiac
events and also mortality. And then we did a peak
expiratory flow rate, which is a poor man's pulmonary function
test. And in Beaver Dam we are poor
men and women. We depend on the largess
of your Uncle Sam. Other things that are important,
of course, are age and sex. We also looked at things that we
thought would be related and they appear to be which were
blood pressure, height, weight, waist and hip diameter,
glycosylated hemoglobin. And we asked a bunch of other
questions about other conditions.
We asked about physical activity, cancer, cardiovascular
disease, arthritis, other diseases and medication status.
I won't walk you through all of this.
These are just giving you an idea of some of the risk
variables that we were interested in in Beaver Dam.
Now, I want to walk you through this.
These are four vision measures. Now I only showed you three of
them before. The fourth vision measure that I
include here is the walking around vision.
In other words, people came in with their own glasses, the
first thing we did was say read our eye chart.
So we call that the walking around vision.
Many people's vision could be improved, and that's the best
corrected vision. We did that for distance and
near, but we wanted to know how many people were actually
walking around with suboptimal vision.
At any rate, what you can see are four sets of three bars.
The black bar in each is poor vision, and what you can see
when you look up the axis, the Y axis, is that the black bar is
taller than the others. In other words, people who did
poorly on the best corrected vision far and near, the poorest
walking around vision, and the poorest contrast sensitivity,
all had a higher risk of two or more falls.
We also looked to see if there was a discrepancy in the vision
between the two eyes which we defined in a certain way, and we
found that lo and behold if the two eyes did not see equally,
the risk for falling was greater.
It may be intuitive to some of you if you've had to deal with
that, but not everybody is aware of that.
We then showed here the different measures of frailty
that I showed you before, and it shows that in each case they are
bona fide risk factors for falls.
People who could not stand up from a chair without help,
people who took the longest time to walk our very short course,
people who had the poorest hand grip strength, and those with
the poorest pulmonary function all were at increased risk of
falls. We put together an index of all
these measures and we called this a frailty index and you got
one point for each bad thing you had.
So either if you had a poorer measure on any one of the vision
tests, if you couldn't stand from the chair without using
your hands, if you had the slowest time to walk the course,
the poorest hand grip strength and the poorest pulmonary
function. So we had a scale that went from
nothing wrong to all five of them wrong, and you can see that
the greater the number of frailties the more likely you
were to have a fall. Other things that were also
related to falls are things that you might find intuitive.
People who are older were more likely to fall.
Women were more likely to fall than men.
If they had two or more what we call co-morbidities, other
illnesses that we could identify, cardiovascular
disease, cancer, arthritis, whatever, two or more had
increased risk. And then medications, this is a
very interesting one, but people in Beaver Dam take a lot of
medications. And you can see that there's an
increased risk of falling with an increased number of
medications. Now I don't know if it's the
medications or the reason that they're taking them, I can't be
sure. We didn't have enough in any one
class to be sure. Things you worry about of course
are sedatives and things of that sort, but there are many others,
blood pressures medications and on and on.
Things that we thought might be related that weren't were use of
vitamin supplements, some specific medications like
sedatives, statins were not protective, hormone replacement
therapy which some women were still taking at the time,
physical activity didn't come in, neither did portliness, body
mass index or the waist/hip ratio, and blood pressure didn't
either. Well, in any study you do there
are limitations, things that you would liked to have done better
or you couldn't afford to but you thought was bad.
We, for example, didn't have a measure of cognition, which I
think is quite important. And also people who had very bad
diseases didn't participate. You had to be able to do all
these tests in order to get counted, and people who were
quite severely disabled couldn't do all of them.
So my conclusion is that people with poor visual function had a
higher frailty score and had an increased risk of history of
falls. I think the frailty score may be
a good measure to evaluate persons at increased risks of
falling. And something can be done for
some of these. Physical therapy can help for
some of them, not for everything.
But also doctors paying attention to medications and so
on and counseling patients would be helpful.
So longitudinal follow up, I can't emphasize enough how
important having long-term measures is for understanding
many of the problems here. As I said, we had baseline
evaluation from '88 to '90 and we had reexaminations these many
times. And we're very excited about
getting to the data analysis, but that's a big step yet.
We still have a lot of work to do.
This will allow us to calculate change over time, incidence of
new diseases, we add other risk factors that have become more
and more important over the years.
We've added some protocols that will give us more information
like the OCT. Did we do anything good for the
people in Beaver Dam? They've been very good to us.
They've been a wonderful population to work in.
But we did diagnose 90 people with diabetes who didn't know
they had it, 947 people with increased cholesterol, 124 with
significant carotid narrowing, that is not done directly in the
Beaver Dam study. There's a parallel study on
hearing where they got funded, we didn't, to measure the
carotid artery narrowing. And we found that 729 people had
hearing loss, all of whom did not know that they had the
condition. So the border implications of
the Beaver Dam Eye Study is that we have estimates that are used
nationally for disease frequency, and they've been
published in a variety of ways. As I told you, we freely share
our protocols so there can be international collaborations and
also we can compare across countries which sometimes is
very insightful. And the incidence studies and
the cohort have provided increased information on the
incidence and changes over time, as I mentioned before.
The Beaver Dam Eye Study has expanded.
It started out as an eye study. Now, as I mentioned, we have a
hearing loss component which is also where they do the IMT or
the carotid measurements. There's also a health outcome
study, finding how sort of quality of life issues amongst
these people. We are hot now on genetic
studies of all the age-related eye conditions, and this is
really a very, very promising area of research.
And I guess that's about it. I thank you very much for your
attention, and I'm more than happy to take any questions you
might have. [APPLAUSE]