
Show HN: Four numbers can predict your lifetime risk of a heart attack - brandonb
http://knowyour4.com
======
brandonb
Hey HN!

This project was inspired by a personal experience I had--I put my numbers
into a spreadsheet provided by the American Heart Association and found I had
a 50% lifetime risk of a heart attack. Yikes!

I've gone to regular check-ups all my life and always been a little outside of
the cholesterol guidelines, but I never knew how seriously to take that. I
didn't know you could translate those numbers into percentage chance of
getting a heart attack, whether I was "high" or "low," or how much I could
improve by making lifestyle changes.

I figured there must be other people out there who are similarly ignorant
about their own health, so I built this. (Please don't take this as a
substitute for going to the doctor; there are all sorts of things your doctor
can tell you that a web page can't. This is just for education!)

Please let me know if you have questions!

~~~
GuiA
For those purposes, do you know how smoking marijuana maps to smoking
cigarette? E.g. is 1 "dose" of pot = 1 cigarette? 10 cigarettes? Or does it
not map at all?

What about electronic cigarettes?

~~~
doctorCoder
Real life doctor here. Your question sounds simple, but the answer is complex.
The heart disease risk from smoking probably stems from damage to blood
vessels caused by toxins generated in the tobacco burning. "Toxins" is really
the best word here, even though it's so general. I use it to encompass
thousands of different chemicals like free radicals, known carcinogens, etc.

Current thinking is the body repairs that damage with clots and cholesterol.
But, these repairs accumulate over time to occlude a blood vessel
(atherosclerosis). If red blood cells can't get through, oxygen can't either,
and heart cells downstream to the occlusion will die in minutes to hours.

Marijuana most likely generates a significant amount of toxins as well.
However, marijuana smokers generally smoke less than cigarette smokers. Given
that heart disease and cancer risk increases with the amount smoked, it would
be reasonable to assume marijuana smokers are much less at risk (though the
risk is nonzero). But, we don't have a clear conversion between marijuana and
cigarette smoke yet. You may also consider that marijuana may be contaminated
with other plants or chemicals.

Electronic cigarettes are possibly more safe than non-e cigarettes in terms of
cancer risk (this is theoretical as no significant study has been done yet).
However, some in vitro (cellular) research suggests nicotine may play a role
in atherosclerosis discussed above. Also, nicotine can precipitate a heart
attack if a heart is already diseased.

~~~
beachstartup
> Current thinking is the body repairs that damage with clots and cholesterol

does this imply that if there's very little damage (due to inflammation or
substance abuse) elevated cholesterol doesn't really matter?

~~~
doctorCoder
Damage accumulates with normal wear and tear, giving more chances for
atherosclerosis to form. Cholesterol matters in otherwise healthy patients
particularly as they age.

------
gear54rus
And none of these numbers can be expressed with proper measurement units most
of the world uses... Instead we have lbs feet and inches.

~~~
brandonb
Hey! Which units would you prefer?

For height/weight, I'd assume meters and kg?

When you get your cholesterol measurements, do use mg/dL, mmol/L, or something
else? What about blood pressure?

~~~
anigbrowl
Obviously metric, since that's what most of the world uses abd you're cutting
yourself from a large chunk of your potential audience. The cholesterol
measures are already metric.

~~~
vacri
The site is going to be limited to the US anyway. The data is calculated from
a US population for US lifestyles. And the racial information is US-centric.
Does 'Asian' mean Korean, Indian, or Palestinian? Is an African African-
American? Even if they're Moroccan? The medical term for that genotype is
'negro', but that word has far too much baggage to be used with a primarily US
audience.

------
whiddershins
Based on following the research, I don't believe all these risk factors have
been established scientifically. What i've gleaned over the years:

Total cholesterol: probably doesn't matter much

HDL: matters

Blood Pressure: I don't know

Smoking: matters

~~~
brandonb
If you're curious about the risk modeling research literature, here's a good
example of models built for 30-year risk prediction:
[http://circ.ahajournals.org/content/119/24/3078.abstract](http://circ.ahajournals.org/content/119/24/3078.abstract)

The models tend to be close to equivalent in their inputs: either total or LDL
cholesterol (small-particle LDL is the one that drives atherosclerosis, but if
the model includes HDL cholesterol, then it doesn't make a big difference in
accuracy whether the other variable is total or LDL cholesterol), HDL
cholesterol (seems to cause a protective effect, although randomized trials of
HDL-boosting drugs haven't shown improvements, so may not be causal), blood
pressure, and smoking. People also sometimes include newer biomarkers like
triglycerides or hs-CRP, but they don't consistently show accuracy gains (LDL,
triglycerides, and hs-CRP are highly correlated, so each one individually is a
good predictor but having all three doesn't necessarily give you a more
accurate model).

There's still a lot of active research to find out which of these variables
are causal and which are merely associated with heart disease. For example,
LDL-lowering drugs like statins do reduce the risk of heart attacks in
randomized trials.

------
nazgulnarsil
TC is less predictive than HDL:Triglyceride ratio by a significant margin.
people with "high" TC of 200-220 and a good HDL:Trig ratio outlive those with
"excellent" TC levels.

There are cases where BP matters less as well. For example the cochrane review
on sodium consumption indicated that while lowering sodium intake aggressively
did successfully lower BP, it resulted in worse mortality.

~~~
brandonb
Have a citation for a risk model that uses triglycerides?

"Predicting the Thirty-year Risk of Cardiovascular Disease: The Framingham
Heart Study"
([http://circ.ahajournals.org/content/119/24/3078.abstract](http://circ.ahajournals.org/content/119/24/3078.abstract))
reported that triglycerides were not statistically significant when added to a
model that already contains total and HDL cholesterol:

"Standard CVD risk factors (male sex, age, SBP, antihypertensive treatment,
total and HDL cholesterol, smoking and diabetes) were highly significant (0.01
level) in the multivariable model. DBP and triglycerides were not
statistically significant and inclusion of LDL in place of total cholesterol
did not improve model performance."

~~~
nazgulnarsil
Interesting, thanks for the citation I hadn't seen it before. It does look
like pretty solid evidence, so I'm less sure of the triglyceride hypothesis
than I was before.

A couple cites of interest:

[http://cpr.sagepub.com/content/3/2/213.short](http://cpr.sagepub.com/content/3/2/213.short)

[http://www.ahjonline.com/article/0002-8703(86)90296-6/abstra...](http://www.ahjonline.com/article/0002-8703\(86\)90296-6/abstract)

[http://circ.ahajournals.org/content/85/1/37.short](http://circ.ahajournals.org/content/85/1/37.short)

[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664115/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2664115/)

There is significant overlap in the explanatory power of these variables
because they are not independent. So it is possible that "high" cholesterol
has covariance with triglyceride:HDL ratio in the majority of the population
sample (seems likely). In that case we should see people with "high" TC still
have better mortality outcomes. Which we do see:
[http://www.ncbi.nlm.nih.gov/pubmed/11502313](http://www.ncbi.nlm.nih.gov/pubmed/11502313)

But like I said, the Framingham study does seem like reasonable evidence. I'll
look over the entire thing later.

There is also this interesting development, but I don't know enough to speak
intelligently about it:
[http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2796.2006....](http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2796.2006.01616.x/full)

It is interesting to note that apo-b levels VERY closely track HDL:Trig ratio.

~~~
brandonb
Sounds good. What I've mostly seen is that LDL, total cholesterol, and
triglycerides seem to be highly correlated, and adding in any one of those
three (assuming you also have HDL) gives the same accuracy, so the risk
modelers usually just stick with total cholesterol since more patients know
it.

For ratios, this particular model is log-linear: risk = b^(w0 + w1
_log(cholesterol) + w2_ log(hdl) + ...)

So adding in variables to represent ratios would change the coefficients, but
not the final risks.

For that last one, the "low cholesterol" bucket they allude to is people whose
total cholesterol is <180 mg/dL. 180 mg/dL is exceptionally low, particularly
for an older population. There's also a potential confounding effect when you
study only total cholesterol (ignoring HDL)--your "low cholesterol" group of
people includes a disproportionate number whose HDL ("good") cholesterol is
also low, and who thus are actually at a high risk of heart disease according
to models like the Framingham one.

------
HamSession
Right now QRISK2 is considered the most accurate when it comes to predicting
morbidity and mortality of cardiovascular events. This calculator is great,
but missing one important factor if either of your first degree parents had a
heart attack before 60 then you are at greater risk. This mostly ties into
things like homocystine levels, hrcp, and LDL particle size, but its a good
ballpark for the genetic variation.

My advice get genetically screened if you are worried and make changes. If you
carry alterations on the 9p21 chromosome chances are you are at higher risk.
If so you can simply eat more fruit and vegetables this has been shown in
multiple studies to dramatically lower rates independent of other factors.

------
sitkack
What a great way to get detailed demographic data of the HN crowd!

~~~
j_lev
I was thinking the exact opposite after having plugged in all sorts of crazy
numbers to see how they affect the results (incidentally the highest total
cholesterol it accepts is 400, way too low for anyone who regularly cooks with
coconut oil IMHO).

~~~
sitkack
The initial height/weight/sex/race/ip address/browser is a pretty good combo
and most likely the legit values.

------
pragone
One critical factor missing is immediately family history of early cardiac
disease, such as a parent or sibling having a heart attack before age 45

------
spindritf
Slick. I liked the additional prompts when entering information.

The graph animation was slow in my Firefox 33.

~~~
brandonb
Thanks for the report! I'll work on Firefox speed--it's sort of an all-around
problem with the Firefox experience.

------
cbr
If you don't enter height or weight into "debug my life" it says: "Your
current BMI is 23, which is in the healthy range" instead of "you didn't give
us what we need to calculate your BMI".

~~~
brandonb
Ah, thanks! Will fix.

------
SloopJon
The current risk in the graph doesn't update when I change a value and click
Calculate My Risk again; e.g., if I calculate with blood pressure blank then
recalculate with it set to 130.

I'm using Firefox 33 and Chrome 38-ish for Mac.

------
mapcars
Just wonder, do people know about kilograms, meters, international system of
units?

------
vikp
This is great, brandonb, and I love to see people making tools that raise
awareness. If anyone is looking for this in iOS app form, I made something a
few months ago: [https://itunes.apple.com/us/app/heartgram-physicians-cvd-
ris...](https://itunes.apple.com/us/app/heartgram-physicians-cvd-
risk/id885312924?mt=8) .

------
dabernathy89
Interesting that family history isn't included. I'd have thought that was a
pretty important factor.

------
kolev
Total cholesterol, really (which goes up with HDL, which has no upper limit)?
And no triglycerides?

~~~
jmhain
I closed the page immediately upon seeing total cholesterol. Being on a
ketogenic diet, it'd probably tell me I'm at risk because the diet increases
both HDL and big LDL particles (the harmless kind). Total cholesterol is
meaningless.

~~~
kolev
In fact, there was some study (can't find the link) showing that people with
moderately higher LDL lived longer than people with LDL that's in norm. I'm
also on a ketogenic diet and my HDL is over 100, triglycerides below 70, and
LDL is a bit high, but total cholesterol is way high due to high HDL. It's
totally unscientific to use LDL given it includes HDL and the higher the HDL,
the better with no set up limit (unlike many markers). HDL/triglycerides is
the only meaningful ratio in the standard lipid profile. Also, there's some
truth in doing subfractioning of LDL, which almost nobody does as it's
expensive and not part of official lipid profile testing as far as I know.
Edit: Grammar.

~~~
jmhain
> It's totally unscientific to use LDL given it includes HDL

I agree that total LDL is not a good indicator unless you do subfractioning,
but I think you meant total cholesterol here, as LDL does not include HDL
(that wouldn't even make sense!).

~~~
kolev
Yes, I made a mistake, but you got my point. As you may have in-norm LDL and
very HDL and then your TC will be in the danger zone, which doesn't make any
sense.

------
dr_
Interesting, but not exactly new. This has been promoted in various ways in
the past ([http://www.cvriskcalculator.com/](http://www.cvriskcalculator.com/)
\- which is updated with recent BP management data as well)

------
platz
There was also that thing in the news about some effects of smoking being
mitigated if one quit by about age ~32. Still I wonder (as someone who
previously smoked) how there couldn't be some kind of damage after several
years of smoking

------
rip747
This has got to be off.

"I had a 50% lifetime risk of a heart attack. Yikes!"

not for nothing, but I entered in my numbers and got 68% and I smoke about a
pack of day. If that's the case, then I'm not quitting any time soon.

~~~
lgas
You know higher numbers are worse, right?

------
arc_of_descent
A good metric would be the hours spent per week in doing cardio exercises.

------
cdjk
The sensitivity analysis being displayed automatically is a nice feature, as
it immediately shows the effects of changes. That's a clever bit of UI that
most similar apps don't have.

------
saryant
Minor bug: the heart icon gets clipped if the risk factor comes out to 12% in
the latest version of Chrome.

[http://imgur.com/l27HcXA](http://imgur.com/l27HcXA)

~~~
silencio
Actually, it's clipped _and_ it's overlapping with 'current risk'. I also see
the same on the other end of the chart with blood pressure:
[http://imgur.com/jaJHErm](http://imgur.com/jaJHErm)

(I'm also unclear as to why '90' systolic blood pressure is at an unexpected
end of the graph, but...)

------
lacker
This seems pretty neat. Are you considering turning this into a startup, then?
X for Y pitch of "machine learning for personal health"? I say go for it. :D

------
mathattack
Great app - thank you for sharing. Unfortunately the answer to this seems
similar to most health advice sent my way, "Lose some weight!"

~~~
brandonb
Unfortunately it's hard but true. I'm on a diet too and it's hard to keep it
up. But the benefits of losing weight are pretty clear--it basically improves
all four of your numbers except for smoking. :)

Feel free to email me if you have thoughts on what you've tried so far, and
what you'd like to see ideally. Address is in my profile.

------
kstenerud
Cool, but it doesn't take into account your drinking habits. 1-2 drinks per
day reduces the chances of coronary heart disease by up to 40%.

~~~
readerrrr
[research results needed]

Even if true, drinkings bring your other risk factors so high( >Σ40%) that you
are better of staying abstinent.

~~~
kstenerud
[http://pubs.niaaa.nih.gov/publications/arh23-1/15-24.pdf](http://pubs.niaaa.nih.gov/publications/arh23-1/15-24.pdf)

------
DanBC
So far there are only two links to published research in this thread.

That's suboptimal when discussing something where the science is moving.

------
ibarrajo
I don't know if you submitted your app to the Million Hearts challenge, but it
would have made a nice fit.

[http://www.health2con.com/devchallenge/one-in-a-million-
hear...](http://www.health2con.com/devchallenge/one-in-a-million-hearts-
challenge/)

Are you using the Archimedes Indigo back end?
[https://archimedesmodel.com/indigo-api](https://archimedesmodel.com/indigo-
api)

~~~
brandonb
Ah, I wish I had seen that challenge before submissions closed!

The risk models for heart disease are simple enough that I just implemented
them in Javascript based on the Framingham papers, although I did talk with
one of the risk modelers at Archimedes to understand which models to use.

------
hippich
How does BMI affect numbers when I do weight lifting? I.e. I assume I have
more muscles than average Joe?

~~~
ugh123
BMI has never been fully trusted. Partly for the reason you bring up.

[http://en.wikipedia.org/wiki/Body_mass_index#Limitations_and...](http://en.wikipedia.org/wiki/Body_mass_index#Limitations_and_shortcomings)

------
recusancy
Shouldn't alcohol intake be a major factor as well along with smoking?

------
kbenson
These numbers seem slightly off, or the way they are presented is a bit
confusing:

"Your lifetime risk of heart disease is 56% as of today. You can reduce that
to 38% if you ... That would make your risk about 34% lower. Not too shabby!"

~~~
jxf
It's measuring percent, not percentage points. 38% is ~34% less than 56%, but
about 18 percentage points.

If your risk was lowered from 2% to 1%, that's a 50% reduction, but a 1
percentage point reduction.

~~~
kbenson
I see what you are saying. I stand by the second part of my statement though.
Presenting a percentage you can lower a percentage can (and just did) lead to
some confusion.

------
jmulho
How might I increase my HDL (good cholesterol)?

------
markdown
> Your risk of heart disease is 25%

But the graph shows 26%

------
artmageddon
Does age play any part into one's risk?

~~~
brandonb
It does when calculating your 10-year-risk, but not for lifetime risk. I'd
like to add a feature to show you both 10-year and lifetime risks, but for
now, the NIH has a 10-year-risk calculator:
[http://cvdrisk.nhlbi.nih.gov/](http://cvdrisk.nhlbi.nih.gov/)

For most people, the 10-year-risk becomes important in your 50's, 60's, and
70's and is used to guide treatment for e.g., statin therapy or anti-
hypertensive medication.

If you're 30, your 10-year-risk is generally very low even if you treat your
body terribly. :) So part of the motivation for showing the lifetime risk is
to get people thinking about how to optimize their health for their life,
since by the time your 10-year-risk is significant it's often too late to
change your habits for diet/exercise.

------
vishnugupta
All I can say is big thank you :-)

------
in_sur_ance
Nice try, insurance company.

------
loqqus
Great domain name.

------
cperciva
Please add support for SI units (mmol/L) for cholesterol. Some of us live in
more enlightened countries...

~~~
brandonb
Working on it!

------
stefantalpalaru
There's an interesting controversy around the lipid hypothesis:
[http://en.wikipedia.org/wiki/Lipid_hypothesis#Minority_disag...](http://en.wikipedia.org/wiki/Lipid_hypothesis#Minority_disagreement)

~~~
brandonb
One warning--

"Cholesterol" tends to get used to mean two different things, and even
otherwise clear writers like Gary Taubes don't always explicitly denote which
one they mean: 1) the amount of cholesterol in your blood, which is mostly
produced by your liver. I.e., if my blood cholesterol is 300 mg/dL, should I
be worried? 2) cholesterol in your diet. I.e., should you avoid eggs?

I'd say the scientific consensus is that blood cholesterol (particularly
small-particle LDL) drives heart disease, but cholesterol (or saturated fat)
in your diet doesn't drive blood cholesterol (<10% effect).

So low-fat/high-carb diets were a fallacy and are not "heart-healthy," it's
fine to eat eggs, but you should still try to reduce your LDL cholesterol if
it's high and boost your HDL cholesterol if it's low.

~~~
tim333
>I'd say the scientific consensus is that blood cholesterol (particularly
small-particle LDL) drives heart disease

Blood cholesterol is a natural component of blood and is synthesized by all
animal cells because it is an essential component of cell membranes. If you
had no cholesterol in your blood you would be seriously ill.

Abnormal levels of cholesterol are associated with heart disease but it is not
clear if they are the prime cause. The heart disease and abnormal cholesterol
may both be caused by something else. There is evidence that excessive
activation of the bodies inflammatory system may be more of a root cause.

(see [http://www.sott.net/article/242516-Heart-surgeon-speaks-
out-...](http://www.sott.net/article/242516-Heart-surgeon-speaks-out-on-what-
really-causes-heart-disease) for example)

~~~
brandonb
Be careful about which sources you trust. Here's are a couple other articles
from sott.net's "Health and Wellness" page:
[http://www.sott.net/article/287460-Vaccine-wars-
Penalizing-t...](http://www.sott.net/article/287460-Vaccine-wars-Penalizing-
the-unvaccinated) [http://www.sott.net/article/287450-The-not-so-surprising-
ben...](http://www.sott.net/article/287450-The-not-so-surprising-benefits-of-
smoking)

I'll stick with Circulation, The Lancet, and JAMA, thank you very much. :)

~~~
tim333
Yeah I grabbed that link without checking up much. Although I still think
there is evidence for the inflammation hypothesis.

------
Dewie
So if I have relatively more muscle mass compared to my height, that means
that I am at a higher chance for getting a heart attack? Well, that could be
the case for all I know.

