Monday, May 21, 2018

Coffee, Acrylamide, and Proposition 65 - Part 5


In the case of acrylamide in coffee, how do we establish there is a "significant amount" of acrylamide "in the products they purchase?"

Based on what we know so far, California has established a "Safe Harbor" concentration of 0.2 micrograms per day. Any thing that is at this concentration or less in the "products they purchase" would never have to be disclosed.

That is, California has determined that your need to be warned ends when the concentration of the chemical presents a cancer risk of less than one additional cancer in 100,000. Less than 0.2 micrograms that would be consumed when using the product, would not require the warning:
“This product can expose you to a chemical [or chemicals] known to the State of California to cause cancer."
let's make sure we are all clear on this. 0.2 micrograms presents a cancer risk that California tells us that y'all don't need to worry yer perduy lil' head about this here chemical. Which means we go back to that proverbial line in the sand...




That line - threshold - for acrylamide is 0.2 micrograms per day. We don't say that less than 0.2 micrograms is "safe" what California claims is this:
...such chemical shall be deemed to pose no significant risk within the meaning of Section 25249.10(c) of the Act.
Section 25249.10(c):
 An exposure for which the person responsible can show that the exposure poses no significant risk assuming lifetime exposure at the level in question for substances known to the state to cause cancer...
So on the "Safe" side of the line in the sand lies acrylamide at a 0.2 micrograms/day concentration that "pose no significant risk."

Which means what for the other side of the line? If on one side it poses "no significant risk" does the other side of that line therefore pose a "significant" risk? If less than one in 100,000 is "no significant risk", is 1.01 in 100,000 a "significant" risk? What about two in 100,000?

Oh what a corner Proposition 65 painted us into.

This now requires us to get back into some math. That risk calculation of one in 100,000, or 1.01 in 100,000, or 2 in 100,000 is calculated based on that linear line we have discussed. Remember, that line is forced so that zero dose = zero risk.



Let's look at a recognized definition of cancer risk:
A slope factor is an estimate of a chemical’s carcinogenic potency, or potential, for causing cancer. If adequate information about the level of exposure, frequency of exposure, and length of exposure to a particular carcinogen is available, an estimate of excess cancer risk associated with the exposure can be calculated using the slope factor for that carcinogen.
...an estimate of excess cancer risk can be calculated...
 Specifically, to obtain risk estimates, the estimated chronic exposure dose (which is averaged over a lifetime or 70 years) is multiplied by the slope factor for that carcinogen.
So that number of 0.2 micrograms per day for acrylamide was determined as the dose that would get an “excess cancer risk” of one cancer above the background chance would appear in a population of 100,000 people.

Here is how the ATSDR guys define it for a cancer risk of one in 1,000,000:
Cancer risk is the likelihood, or chance, of getting cancer. We say “excess cancer risk” because we have a “background risk” of about one in four chances of getting cancer. In other words, in a million people, it is expected that 250,000 individuals would get cancer from a variety of causes.
This is a bit misleading here. Acrylamide risk is based on cancer from acrylamide exposure. We would need to know the background risk of the cancer associated with acrylamide. However, this still works as they are telling us that if you did not drink coffee your chance of cancer is 25,000 in 100,000. If you drink coffee with 0.2 micrograms each day, for 70 years, your chance of cancer is 25,001 in 100,000.

Here is how the ATSDR explains it based on the one in 1,000,000 cancer risk:
If we say that there is a “one in a million” excess cancer risk from a given exposure to a contaminant, we mean that if one million people are exposed to a carcinogen at a certain concentration over their lifetime, then one cancer above the background chance, or the 250,000th cancer, may appear in those million persons from that particular exposure. In order to take into account the uncertainties in the science, the risk numbers used are plausible upper limits of the actual risk based on conservative assumptions. In actuality, the risk is probably somewhat lower than calculated, and in fact may be zero. [ATSDR]
Here is what that calculation looks like for determining the Safe Harbor NOEL for a chemical "known to the State of California to cause cancer." This is how 0.2 micrograms per day for acrylamide was calculated. Note: The term "potency value = slope factor.



Now that we have that out of the way, let's look at the calculated cancer risk that California would claim is in one delicious cup of Pikes.


Next Post: Coffee, Acrylamide, and Proposition 65 - Part 6

Coffee, Acrylamide, and Proposition 65 - Part 4


My last post ended with this graph:

Source
Let's focus on that last statement in blue type.

Because we (us public health people who look at chemical exposure) have decided that any exposure to a chemical known, or suspected, to cause cancer presents a risk, once we force the data of the doses we use and the cancers we see to form a straight line from zero through our splatter of data points, we now get the ability to assign risk.

Yay for us!

Only problem is, this forced line from zero dose = zero risk, tells us that at some dose above zero we will have some particular risk.

Remember that this is based on the assumption that all exposure to a carcinogen presents a risk.

Some of us say horse feathers! Lest you think I am the only one, let's look at what this guy from the Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, writes:
The linear plot for dose is very deceptive and compresses low doses so that evaluation in that range is impossible; however, this has not heretofore been clearly recognized. This paper is an attempt to demonstrate that deception and the difficulty in evaluating effects at low doses. 
Deception...

Interesting word choice, but that's what guys like me think about using a linear plot where zero exposure = zero risk and anything above that - even one molecule - presents a risk.

If that line we produce is deceptive, then the statement in blue presents a situation whereby the "Safe Harbor" dose may be deceptive. From that paper:
The thresholds that are demonstrated from the animal experiments can be used to calculate safety factors for human exposure. In some instances human exposures are at or very near the thresholds in animal experiments. This indicates that humans are more resistant to the carcinogenic effect of at least some chemicals.
What he is arguing is that we can look at carcinogens in a similar manner (non-linear) as we do non-carcinogens.

This means that the safe harbor Proposition 65 has come up for acrylamide - 0.2 micrograms per day - is only applicable if that straight line starting at zero is correct.

That concentration of 0.2 is derived using the slop of the line that they plot starting at zero does/zero response.

That concentration of 0.2 is considered Safe Harbor because it is the highest concentration per day where the cancer risk is less than one in 100,000.

Any situation whereby a person could consume more than 0.2 micrograms of acrylamide in a single dose (one cup of coffee) would therefore trigger the Proposition 65 warning notice:

Unless Starbucks et. al. could make an argument that a concentration above 0.2 micrograms per day is okay as an Alternative Significant Risk Level (ASRL) because the benefits of drinking coffee exceed the increase risk of cancer above one in 100,000.

Hopefully you can start to see the absurdity in this, although to be fair, we have not yet determined how much acrylamide could be consumed in that one cup of coffee and what the increase in cancer risk would be.

More math...yay!



Next Post: Coffee, Acrylamide, and Proposition 65 - Part 5

Thursday, May 17, 2018

Coffee, Acrylamide, and Proposition 65 - Part 3

California's Proposition 65 does two things:
  1. Proposition 65 requires businesses to notify Californians about significant amounts of chemicals in the products they purchase, in their homes or workplaces, or that are released into the environment. 
  2. By providing this information, Proposition 65 enables Californians to make informed decisions about protecting themselves from exposure to these chemicals. 
Therefore, I want to focus on two things as I move through this. First, is the acrylamide a "significant amount" and second, does knowing that there is acrylamide in a cup of coffee above the "safe harbor concentration of 0.2 micrograms per day" protect the individual?

Where to start on this...

Okay, so we need to get a bit sciencey here. Then we will bring in some math (or "maths" as the kids seem to call it these days).

Two questions:
  1. What is the risk of cancer if you drink Starbucks coffee?
  2. Should you be concerned?
I am going to say "trivial" to the first and "no" to the second. However, I need to show my work as to why.

Let's first define what a risk for cancer is. We need to understand the definition as that's the foundation on which the number is derived. It's that number that determines if Starbucks must place a Proposition 65 warning for those who enter their store to drink their coffee. 

Full disclosure here, I drink Starbucks and it is my favorite coffee. So there's my bias front and center...

Let's look at the definition we use in the biz of protecting public health because of chemical exposure have decided on for Cancer Risk:
The potential for exposure to a contaminant to cause cancer in an individual or population is evaluated by estimating the probability of an individual developing cancer over a lifetime as the result of the exposure. This approach is based on the assumption that there are no absolutely “safe” toxicity values for carcinogens.
Here is where it gets messy. We (them scientists looking at chemical exposure and cancer) decided that there is always a risk of cancer when you are exposed to a chemical where cancer is an outcome.

I think this model is incorrect, but it is what we decided on when determining a "safe" level for exposure of a chemical suspected of causing cancer.

For most chemicals that we classify as carcinogenic, we assume a "linear response," that is, at zero dose there will be zero risk:
What does “linear responses at low doses” mean? These chemicals are assumed to have no threshold for effects, and even one molecule of the substance is assumed to confer some increase in the risk of contracting a cancer. [Source]
 As I have pointed out in previous posts, when we talk about non-carcinogen chemicals, we assume a "non-linear" dose response curve.

Basically, what this curve shows is that there is a dose that a person (child, adult, elderly) could receive where we would see no observed adverse effects. We call that a NOAEL.
The highest exposure level at which there are no biologically significant increases in the frequency or severity of adverse effect between the exposed population and its appropriate control; some effects may be produced at this level, but they are not considered adverse or precursors of adverse effects.
When we graph this non-linear dose-response out, it looks like this:


You will notice that the graph starts at a dose of 7 mg before we start to see a response. Based on what we accept for non-carcinogens, in this graph, there is no difference between an exposure of a dose of zero mg up to 7 mg. This is know as the "threshold."
The threshold is the dose below which no effect is detected or above which an effect is first observed.
With carcinogens, there is assumed to be no threshold. Therefore, as stated previously, exposure to one molecule of the chemical produces a risk for cancer.

As this is the case, we assume that at zero exposure there will be zero risk. Since it is impossible to measure that, we take the data for cancer and dose that we see, and we force the non-linear dose-response curve into a straight line so that zero dose = zero cancer.


Pay attention to that last bit there in blue type. That's important as we look at Starbucks coffee, cancer risk, and California's Proposition 65.

Next Post: Coffee, Acrylamide, and Proposition 65 - Part 4


Wednesday, May 16, 2018

Coffee, Acrylamide, and Proposition 65 - Part 2

In the court case, Starbucks et. al. made an argument for an Alternative Significant Risk Level (ASRL).
Specifically, Prop 65 allows an exemption to warning requirements even where the NSRL is exceeded if "sound considerations of public health support an alternative level" – for example, where "chemicals in food are produced by cooking necessary to render the food palatable or to avoid microbiological contamination." [Source]
The judge took issue with Starbucks on this matter stating that their claim was not supported by a "quantitative risk assessment" for acrylamide in coffee.

As I understand it, the ASRL is for situations where the potential harm of not consuming the materials because of the Prop 65 warning, outweighs the risk of cancer when consumed.

An example of this is arsenic that is naturally occurring in rice. A quantitative risk assessment could show that the benefits of consuming rice that may contain arsenic over the NSRL outweighs the elevated risk of cancer from one in 100,000 to maybe two in 100,000. I don't think I could make an argument where coffee has benefits that exceed a similar increased risk (from one to two). Starbucks did try:
Defendants argue there is no increased risk of any chronic diseases, including cancer, associated with coffee consumption.  In fact, defendants contend there is strong evidence that drinking coffee is associated with a decreased risk of several major chronic diseases, such as cardiovascular disease, Type 2 diabetes, liver disease, liver cancer and endometrial cancer. [Source]
How then, should Starbucks et. al. have approached this? I think it best to point out what is not going to fly.

First, if your stuff has more than the“no significant risk level” (NSRL) concentration that would be consumed in one unit, then you are out of luck. If you can reduce that concentration to below the NSRL, then Proposition 65 a "safe harbor level" and notification is not required.

Now this is where it gets a bit silly. The logic we use is this. There is a risk of cancer for any amount of a carcinogen one is exposed to. And by "any" we mean one molecule.

There is a risk from one molecule up to some hypothetical concentration where it becomes a 100% risk (yeah...not possible because some folks will not get the cancer, but work with me here...).

Now this "there is always a risk" is what we have decided on, but there are some of us (myself included) that think it creates more concern then is warranted. Look at the money being spent on this issue involving coffee. Look at how many people may - may - stop drinking coffee because the news media just wrote about Starbucks and their coffee containing a chemical that causes cancer.
Toxicologists have also used that scale for noncancer experiments but, for some unexplained reason, most authors of chemical carcinogenesis experiments have instead preferred a linear scale for dose. [Source]
I will get more into this in the following posts. For now, let's look at this.

If one molecule presents a cancer risk, and Proposition 65 allows for a "Safe Harbor" concentration and gives a company the ability to exceed this amount with an Alternative Significant Risk Level (ASRL), then in certain situations, California has decided you don't need to know that the chemical is present.

In other words, if a risk of one additional cancer in 100,000 is worth a warning, why isn't a risk of say three in 100,000 no longer needing to be stated just because the chemical is from a natural source or the benefit of consuming the product containing that chemical is seen as better for you than not consuming it (eat your veggies!)?

Remember that the cancer risk is based on the contaminant alone, not where the contaminant comes from or what benefits form other stuff in addition to the cancer chemical is there.

This then, begs the question of what is more important, knowledge of the risk or adherence to the letter of the law?

Next post: Coffee, Acrylamide, and Proposition 65 - Part 3

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Tuesday, May 8, 2018

Coffee, Acrylamide, and Proposition 65 - Part 1

"California Judge Rules Coffee Must Carry Cancer Warning"

That was the headline in the Wall Street Journal on March 29, 2018.
LOS ANGELES—Coffee in the state of California must carry a cancer warning, a judge here ruled, in a blow to Starbucks and other retailers which had argued that a state law meant to protect consumers shouldn’t apply to them. [Source]
And with that decision, we get this:



Why? Because coffee contains a chemical called acrylamide and that chemical appears of the Proposition 65 list of chemicals "known to the state to cause cancer..."

California, way back in the mid-80s, passed a "peoples proposition...:
Proposition 65 became law in November 1986, when California voters approved it by a 63-37 percent margin.  The official name of Proposition 65 is the Safe Drinking Water and Toxic Enforcement Act of 1986.
...requiring business to:
...provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects or other reproductive harm.  These chemicals can be in the products that Californians purchase, in their homes or workplaces, or that are released into the environment. By requiring that this information be provided, Proposition 65 enables Californians to make informed decisions about their exposures to these chemicals.
The idea behind this proposition was that Californian's were being exposed to chemicals because they lived in proximity to, or worked at, businesses that released these carcinogenic chemicals.

Knowing this, a Californian could make the decision to move away, work elsewhere, or not consume/use a product in order to avoid exposure.

Sounds reasonable in principle, but in practice its a pain in the butt and, in my opinion, does little to zip to protect public health. It's a feel good regulation whereby knowing is considered powerful. However in reality, everywhere you go in California you see the warning so avoiding a carcinogen is dang near impossible, unless you want to live in a bubble, but then your own testosterone or estrogen will do you in - they are on the list too!

What we (I was there when this passed) ended up with soon became an OMG! There's a carcinogen in my purse, notify the people, alert!, alert!

We environmental people like to joke that everything in California causes cancer. We are not far off when you look at the list:
This list, which must be updated at least once a year, has grown to include approximately 900 chemicals since it was first published in 1987.
The reason there are 900 chemicals on this list is that there are a bunch of groups that look at chemicals and make a determination of carcinogenicity. There is a lot of differences of opinion when looking at chemicals. Some groups agree and others say not enough evidence.  California looks at this data, errs on the side of caution, and if they agree, put the chemical on the list.

Now the chemical in question here, acrylamide, has been on the list for ever.

It was not until 2002 that we quantified the amount of acrylamide that a person theoretically can consume in a cup of coffee.

With that information, the environmental groups that work tirelessly to save us for chemical harm, went after Starbucks and told them, "y'all need to put a Proposition 65 warning sign up."
The highest profile acrylamide cases have been filed against Starbucks and nearly 100 other coffee manufacturer and retailer defendants. After eight years of litigation, a ruling is expected within days to months. [and Starbucks lost...]
 Starbucks et. al. contends:
Defendants argue there is no increased risk of any chronic diseases, including cancer, associated with coffee consumption.  In fact, defendants contend there is strong evidence that drinking coffee is associated with a decreased risk of several major chronic diseases, such as cardiovascular disease, Type 2 diabetes, liver disease, liver cancer and endometrial cancer. [Source]
The judge in the case did not agree:
On March 28, 2018, Judge Elihu Berle issued a preliminary decision in favor of the plaintiffs in Council for Education and Research on Toxics v. Starbucks Corp. et al., BC435759 (California Superior Court, County of Los Angeles). In that case, the plaintiffs alleged that the defendants, sellers of ready-to-drink coffee, failed to warn consumers that the coffee exposed them to a known carcinogen – acrylamide – in violation of California's Proposition 65. [Source]
 dlapiper.com has a pretty good write up on the back and forth that went on. You can read it here.

What it comes down to is this:
  • Acrylamide is found in coffee. 
  • Acrylamide appears on the Proposition 65 list
  • Acrylamide in a cup of coffee is greater than the No Significant Risk Level (NSRL) of 0.2 mg per day
So...should a coffee drinker be concerned?
.

Next post: Coffee, Acrylamide, and Proposition 65 - Part 2

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Saturday, May 21, 2016

Part 4: Preventing 7,000 deaths from heart disease alone among nonwhites each year

Clark et al at the University of Minnesota produced a research paper titled:
National Patterns in Environmental Injustice and Inequality: Outdoor NO2 Air Pollution in the United States
 They tell us in the abstract:
"For example, we estimate that reducing nonwhites’ NO2 concentrations to levels experienced by whites would reduce Ischemic Heart Disease (IHD) mortality by ,7,000 deaths per year..."
I have been looking at their data, and their claim of a 7,000 reduction in IHD deaths, in the last three posts.  In Part 3 I wrote this:
To me, this calculation of 7,000, or 6,579, or 5,638 is not within the realm of reality. Could NO2 contribute to 5,000 plus IHD deaths per year? Yeah...that's possible if Jerrett's RR of 1,06 is a direct result of an increase in NO2. [Bowman]
Here is what I come up with when I looked at their data.

Let's assume some things first.
  1. The relative risk for IHD with 4,1 ppb NO2 is 1.06.
  2. The incidence of IHD mortality is 109 per 100,000
  3. The population and concentrations for NO2 for 448 urban areas in the US as found in the Excel spreadsheet file "journal.pone.0094431.s001.XLSX" are valid.
  4. The column in that Excel file called "Difference Between LIN and HIW (ppb)" is a valid number.
I am writing this in "real" time, so from this point on, I have no idea what my way of calculating this is going to show.

To start, I needed to know what percent of nonwhites fall below the poverty line. That line seems to be consistent with what the Clark et al authors use for their "Low-Income Nonwhite (LIN) Population-weighted Concentration (ppb)"

I asked Google to get me this information and I found a reputable site with this information.

Next, I went looking in the Excel spreadsheet for the urban areas where the authors calculated a difference between the Low-Income Nonwhite (LIN) Population-weighted Concentration (ppb) and the High-Income White (HIW) Population-weighted Concentration (ppb) of greater than 4.0 ppb.

I chose 4.0 ppb to be consistent with the author's claim that "average NO2 concentrations are 4.6 ppb (38%, p,0.01) higher for nonwhites than for whites" and to be close to the relative risk of 1.06 reported by Jerrett et al for 4.1 ppb NO2.

Okay...I think I am being reasonable and fair here. Let's start.

Assuming that a 4.1 ppb difference in NO2 is associated with a 6% increase in risk for IHD mortality, what was the population of the 448 urban areas where the difference between the low income folks and the high income folks was greater than 4 ppb?

Time for another assumption. I am going to assume that the IHD morality is 109 per 100,000 for the white population in the HIW area.


This group of 12 urban areas represents a total population of 45.2 million people.

Let's do another assumption. Let's assume that within these 12 urban areas the percentage of nonwhites is 40%.

That would mean that the nonwhite population in these 12 urban areas where there is a difference of  at least 4.0 ppb NO2 between low income nonwhites and high income whites, is 18.1 million nonwhites.

Looking at the low income percentages provided by the Kaiser Family Foundation,
  1. 26% of Blacks are low income (26% of 18.1 = 4.7 million)
  2. 24% of Hispanics are low income (24% of 18.1 = 4.3 million)
  3. 15% of Other nonwhites are low income (15% of 18.1 = 2.7 million)
This equals a total of 11.7 million nonwhites living in areas where the difference between NO2 population-weighted concentrations for high-income whites and low-income nonwhites is greater than 4.0 ppb.

Assuming that there is a 6% increase in IHD mortality risk for 4.1 ppb NO2, a risk of 109 per 100,000 for high-income whites would rise to 116 per 100.000 for low-income nonwhites. There would be an additional 7 deaths per 100,000 for a total added deaths from IHD for these 12 urban areas of 823.

Using the same language as in the abstract:
Reducing low-income nonwhites’ NO2 concentrations to levels experienced by high-income whites in 12 urban areas would reduce Ischemic Heart Disease (IHD) mortality by 823 deaths per year. [Bowman]
For that number - 823 - to be correct, the relative risk for NO2 must be 1.06 for 4.1 ppb NO2 and the concentration of NO2 for 11.7 million nonwhites must be 4 ppb higher than for their white neighbors living in the same urban area.

Well that was a fun way to spend my vacation on Friday and this rainy Saturday.

To conclude...there will not be a savings of 7000 nonwhite lives if we lower the concentration of NO2 to that which whites experience. At best I calculate 823 and that number is based on a lot of assumptions all being correct.

Thanks for reading

Jeff


Part 3: Preventing 7,000 deaths from heart disease alone among nonwhites each year

Let's get into the press release statement once more:
Gap results in an estimated 7,000 deaths each year among people of color from heart disease alone
...is that number calculated correctly?

According to their paper, the relative risks in Ischemic Heart Disease mortality from increasing NO2 concentrations by 4.1 ppb is 1.066. This came from the 2003 paper by Jerrett et al.

Reading the Jerrett paper we are told:
All RR estimates are given over the interquartile range of each pollutant.
This value of 1.066 was calculated for the NO2 concentration values between Q1 and Q3


If you look at the Table in the Jarrett paper we see this:


Q1 therefore is the value for NO2 at 25% and Q3 is the value for NO2 at 75%.
Q1 = 10.21
Q3 = 14.33
The difference between Q1 and Q3 is 4.1 ppb.

The RR they calculated for 4.1 ppb is 1.066.

This would lead us to conclude that those who had NO2 exposure between 10.21 and 14.33  had a 6% increase in risk of ischemic heart disease IHD mortality.

Now for me, when I look at stuff like this, I try to look at it collectively. The mean - average - from the Excel file is at the Q1 value in the Jarrett paper.

What I see when I look at this data, is if the IHD is "109 deaths per 100,000 people," that rate takes into account this exposure range. And that value includes the deaths of whites and nonwhites.

The claim of Clark et al, is that "gap results in an estimated 7,000 deaths each year among people of color from heart disease alone."

That value of 7,000 deaths is based on the author's assumption that every nonwhite in the US lives in areas where the N02 concentration is at 14.5 ppb. This assumption - using the Jarrett data for California, places every nonwhite in the US in the forth quartile for distribution.

In other words, based on the Jarrett Table 2 data, 25% of the distribution of NO2 by population contains 100% of the nonwhite population.

That...that cannot be what the Clark et al folks are saying...or is it?

Follow me on my analysis here, just to make sure I am seeing this correctly...

Source
Now they (Clark et al) calculated the Relative Risk (RR) in a weird way (in my opinion):
Relative risks (RR) for NO2 concentrations experienced by nonwhites and whites calculated using: RR = exp(βc), where c is the NO2 concentration (units: ppb), and β = ln(1.066)/(4.1 ppb) = 0.0156 ppb-1.
They then show these calculations:


I think there is an error in this calculation. The second calculation is for the amount of IHD deaths anticipated for whites which should be divided by 1.167 and not 1.254. If I understand their thinking on this, they are comparing one population at an RR of 1.254 (nonwhites) to one at 1.167 (whites).

If I am correct, then the white IHD deaths would be 13,570 for a difference of 5,638 IHD deaths per year.

That amount, however, assumes that the entire US population of nonwhites is exposed to 14.5 ppb of NO2 while the entire population of whites is exposed to 9.9 ppb NO2.

To me, this calculation of 7,000, or 6,579, or 5,638 is not within the realm of reality. Could NO2 contribute to 5,000 plus IHD deaths per year? Yeah...that's possible if Jerrett's RR of 1,06 is a direct result of an increase in NO2.

That's not what Clark et al are wanting to convey:
Gap results in an estimated 7,000 deaths each year among people of color from heart disease alone
They assert that compared to whites, 7,000 more deaths from IHD happen because of NO2 concentrations for this group being 4.6 ppb higher than what whites are exposed to.

That high of a "gap result" is not supported by their data.

So what does the data they present actually tell us?


Next post: Part 4: Preventing 7,000 deaths from heart disease alone among nonwhites each year