Book Review: Count Down

Count Down is by Shanna Swan and Stacey Colino. The subtitle is: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race (That's a long subtitle!). Of the books I've read recently, Count Down has probably had the most concrete impact on my life. It details how environmental contaminants (mainly, microplastics and other chemicals) are messing with our reproductive systems (and perhaps other aspects of our health as well).

Although it's always hard to know how much to trust this or that scientific study, I've decided it's worth it to make a few changes to hopefully have a bit lower plastic/chemical load in my system: I've started exclusively using metal cookware and ceramic tableware (no plastic spatulas, no non-stick pans, no plastic plates or bowls); I finally got a metal water bottle; and I'm trying to not touch receipts (yep, really). Chemicals are everywhere so if you believe the arguments in this book it could lead to changes in many different aspects of your life. I continue looking into other changes I may make in the future to avoid these endocrine disrupting chemicals.

Reproductive health is declining

The book begins by citing sources that both men's and women's reproductive health has been declining over the last ~40 years. The "count" of the title refer's to men's sperm count:

Between 1973 and 2011, sperm concentration (the number of sperm per milliliter of semen) dropped more than 52 percent among random men in Western countries; meanwhile, the total sperm count fell by more than 59 percent. We came to these conclusions after examining the findings from 185 studies involving 42,935 men that had been conducted during this thirty-eight-year period.

And there's more to sperm than just how many of them there are:

For fertility, it isn’t just the number of sperm that matters; it’s also about the sperm’s shape and how they move. That is, are they able to swim in a way that suggests they’re likely to be able to reach and penetrate an unfertilized egg? If sperm are swimming in a circle (what’s called nonprogressive motility), that’s not good; it’s the equivalent of revving your car’s engine in neutral—you’re not going to get anywhere.

This motility has been declining, as well:

In a study published in 2016 involving 9,425 semen specimens from nearly five hundred men, researchers found a significant decline between 2003 and 2013 in sperm concentration, motility, and total count among young adult men who were attending or had recently completed college in the Boston area. While 69 percent of the aspiring sperm donors made the cut in 2003, only 44 percent did in 2013. This was true despite that the more recent group of guys had improved lifestyle variables such as a decline in alcohol use, smoking, and body weight and an increase in steady exercise.

This decline may have been partly "hidden" by a changing definition of what healthy sperm levels are:

Meanwhile, the World Health Organization’s reference value for the lowest sperm concentration that’s compatible with fertility...has declined over the last thirty years...our idea of what’s a “good enough” sperm concentration has actually gone down. It used to be 40 million/mL, then it was lowered by the WHO to 20 million/mL in 1980 and to 15 million/mL in 2010. For the sake of comparison, back in the 1940s, 60 million/mL was considered an adequate sperm count.

Other indicators of reproductive health aren't looking great, either:

testosterone levels have been declining—by 1 percent per year since 1982, according to research from the United States and several European countries.

Although the title focuses on men's health, there is evidence women's reproductive health has been declining as well:

On the female side of the equation, miscarriage rates are also increasing by about 1 percent per year.

Swan argues that, overall, the evidence for women's health is less clear. However, there are other clues she points to that suggest this is an issue for women as well: beginning puberty at a younger age ("In Japan, the onset of menstruation shifted from 13.8 years for girls born in the 1930s to 12.8 years for those born in the 1950s to 12.2 years for those born in the 1970s and 1980s."), more diagnosis of endometriosis ("more than a threefold increase between 1996 and 2008 in [women 18-24] who were newly diagnosed with endometriosis."), and a "decline in the ability to conceive a pregnancy and carry it to term" (known as "impaired fecundity").

We can't monitor women's reproductive health quite as easily. For one, it's not possible to do so in an unobtrusive way — it's relatively simple to obtain a sperm sample. And though I mentioned above the rate of miscarriages, the male partner's health can seemingly impact this as well:

In fact, recent research found that in couples who experience recurrent miscarriages, the men have twice the level of DNA fragmentation in their sperm and four times higher levels of reactive oxygen species in their semen, which can cause DNA damage to sperm, than men whose partners didn’t have a history of repeated miscarriages.

Alligators and frogs

Since we can't ethically run a controlled experiment exposing people to contaminants, Count Down draws on studies of wildlife, scientific research in the lab, and natural experiments to draw out the connection between reproductive health and chemical contaminants. Here's a story she relates about Florida alligators:

For many years, Lake Apopka...was among the most contaminated lakes in Florida. This was due to pesticide use in agricultural activities around the lake, a nearby sewage treatment facility, and a 1980 major pesticide spill, of a mixture of dicofol, DDT and its metabolites, and sulfuric acid, from the former Tower Chemical Company, which was adjacent to the lake. These pesticides can act as estrogens, binding to and activating estrogen receptors and inducing cellular growth that’s estrogen-dependent.

In the 1990s, University of Florida wildlife biologist Lou Guillette Jr., PhD, and his colleagues compared the reproductive development in juvenile alligators from Lake Apopka and those from a (clean) control lake, Lake Woodruff, in central Florida. Going out on the lakes at night in teams in airboats, the researchers would catch baby gators and take various body or body-fluid measurements; or they would collect eggs from nests during the day. They found that at six months of age, baby female alligators from Lake Apopka had blood estrogen levels that were nearly twice that of the female alligators from uncontaminated Lake Woodruff...and more abnormalities in their eggs and ovarian follicles...

...The young male alligators from Lake Apopka had their own set of problems, particularly abnormally small penises and poorly organized seminiferous tubules (where sperm cells germinate and mature before being transported) in the testicles. What’s more, the Lake Apopka male alligators had significantly lower testosterone concentrations...Even in the wild on Lake Apopka, the hatching success rate of alligators was only 5 percent, compared to the 85 percent success rate it should be in a less contaminated lake.

Those of you who have unfortunately spent too much time online, like I have, may remember when Alex Jones went on a rant about "chemicals that are "making the friggin' frogs gay."" It turns out that this is...maybe not all that far from the truth. This is something that I remembered hearing about in left-leaning spaces on Reddit, where it was treated like a total joke, but now I think I was wrong to not take it more seriously—I'd found it "too good to check". Count Down says:

In animals, there have been changes in mating behavior, with more reports of male turtles humping other male turtles, and female fish and frogs becoming masculinized after being exposed to certain chemicals.

This feels like an example of "politics as pure affiliation": usually, us crunchy liberals are the ones who worry about environmentalism and being contaminated by industrial chemicals. But when it's Alex Jones, a right-wing personality, going on this rant, it gets treated as a joke.

(In terms of politics and affiliation, there's something to the "gay" part, too. Since the liberal side is generally protecting people's right to be gay, Jones insinuating that frogs being turned gay is a bad thing needs to be countered with the reminder that there's nothing wrong with being gay. That became the sole response instead of digging in to try to understand the larger picture of chemical contamination and reproductive health.)

I'd like to think this is a cause area where right-wing and left-wing people can come together to agree —environmental liberals want to live in a world free of chemical contamination, while conservative folks often stress the importance of masculinity and traditional families, which requires women giving birth to healthy babies (and, Republican or Democrat, I doubt many men are excited about the idea of having "abnormally small penises" like those Florida alligators). I am curious how some of my very liberal friends would respond to some of these issues. Although I haven't focused on it in this review, Swan suggests that these chemicals that are effecting our reproductive health may have a related impact on our gender expression and/or sexuality as well.

The evidence here is more speculative, for a number of reasons, including that we can't ask Florida alligators what their gender identity is. She says very clearly that she respects all people and their right to self-identification. However, she thinks (and I agree) that it's best if our children are born and grow up free of chemical contamination that may affect their development. But I do wonder if there are any people out there who think it's a good thing if environmental contamination makes men and women more similar:

For example, boys tend to acquire spatial ability (the capacity to understand and remember the spatial relations among objects) earlier, while girls’ language skills often develop at a younger age than boys’ do. My research and that of others has shown that higher exposure to some hormone-influencing chemicals can decrease male-female differences in these kinds of abilities.

Are we sure it's the chemicals?

Whenever I read nonfiction, I know I need to keep the reproducibility crisis in mind (funnily enough, that Wikipedia article starts with this note: "This article is about an issue of scientific methodology. For the reproducibility crisis in humans, see Male infertility crisis."! Intertwining crises!). If I read a nonfiction book that references scientific studies, I have to ask myself, can I actually trust this? Do we know male testosterone levels are declining? Do we know that these environmental toxins exist? And are these chemicals causing the reproductive issues? What direct evidence do we have?

So I tried to dig in to the counter-argument, at least a little bit. The Male infertility crisis article linked above says the infertility crisis is well accepted:

Some scientists have called into question the extent of the crisis, pointing out that sperm-count studies are geographically sparse, often fail to account for the subject's age, and use the single metric of sperm count as a predictor of male fertility. However, the scientific community generally accepts that it is a key issue of male health.

On their face, these seem like relatively weak criticisms, since there are multiple quotes I've already included above where the age of the study subjects is accounted for and comparisons are made only across consistent age groups (e.g. "young men who had recently completed college"; "women 18-24"). The book's headline study covered "185 studies involving 42,935 men" in "random Western countries"—so the sample size is pretty large. Regarding the sparseness of results across the globe, she does say:

In our meta-analysis, there were much less data on sperm counts from men from South America, Asia, and Africa; however, more recent research reports declines in those regions as well.

For example, this study based in China caught my eye, as it shows a correlation between BPA levels and sperm count:

When researchers from Kaiser Permanente conducted a study with factory workers in China to evaluate the effects of exposure to BPA, they found that men with detectable levels of BPA in their urine were more than four times as likely to have lower sperm counts, more than three times as likely to have poorer sperm vitality, and more than twice as likely to have lower sperm motility than those with undetectable BPA in their urine.

A final reason to believe in this contamination hypothesis is that we do have an understanding of how these chemicals actually interact with our body:

Some EDCs [endocrine disrupting chemicals] act like impostor hormones and bind to receptor sites where the natural androgen or estrogen is supposed to dock, thereby fooling our bodies into responding to them as if they’re the real deal. Sometimes this results in too much or too little of that natural hormone being produced or released...other EDCs can alter our bodies’ sensitivity to different hormones.

So, on the one hand, we do know that these chemicals disrupt our hormonal systems (that's exactly how they got their name). But on the other hand, there's still something of a missing link in our understanding of how the body works — how does "too little of some hormone being produced" lead to declining fertility?

Tied up with the question of "is this book right?" is the question of "if this book is right, why haven't we done something about it?". The Wikipedia article on Endocrine Disruptors offers this discussion:

There has been controversy over endocrine disruptors, with some groups calling for swift action by regulators to remove them from the market, and regulators and other scientists calling for further study. Some endocrine disruptors have been identified and removed from the market... but it is uncertain whether some endocrine disruptors on the market actually harm humans and wildlife at the doses to which wildlife and humans are exposed. Additionally, a key scientific paper, published in 1996 in the journal Science, which helped launch the movement of those opposed to endocrine disruptors, was retracted and its author found to have committed scientific misconduct.

So there's a few problems. First, are the doses actually high enough to effect us? Second, are the benefits we get from using these chemicals worth the harm that they are causing in other ways? Third, this is a classic example of a problem that requires "collective action", which the USA has clearly not been very good at these last few years.

The government response seems like your typical story of the government not getting anything done, partly due to general incompetence and partly due to the need to consider everyone's various complaints. According to Wikipedia:

In 1998, the EPA announced the Endocrine Disruptor Screening Program by establishment of a framework for priority setting, screening and testing more than 85,000 chemicals in commerce...Based [on] recommendations from an advisory panel, the agency expanded the screening program to include male hormones, the thyroid system, and effects on fish and other wildlife...animal testing is essential for scientific validity, but has been opposed by animal rights groups. Similarly, proof that these effects occur in humans would require human testing, and such testing also has opposition...

The EPA is still finding it difficult to execute a credible and efficient endocrine testing program...As of 2016, the EPA had estrogen screening results for 1,800 chemicals

As mentioned above, another reason for the slow government response is that this issue is quite complex and hard to study. I've already mentioned the difficulty of doing studies on human (and even animal) subjects. The Wikipedia article mentions other issues: it's hard to study across time as exposure in the womb may have effects many years later; the complexity of the way chemicals and hormones interact in the body; uncertainty over what doses are harmful, and more.

Regulating chemicals and medicines

Another complicating factor is just how many chemicals there are, and how we regulate them:

Unlike drugs, which must have a proven record of safety and efficacy before they’re allowed to come to market, chemicals are largely presumed innocent from the start...This means manufacturers can use these chemicals in a wide array of consumer products with little oversight or restriction...

Even decades after the 1976 Toxic Substances Control Act was enacted, few of the approximately eighty-five thousand chemicals that have been produced for use in commercial products, many of which have been identified as potential threats to human health, have even been tested, let alone banned or regulated.

This comparison to medical drugs is interesting. Should any manufactured chemical that ends up in human bodies should be regulated under the same umbrella?

Swan says that there are "approximately eighty-five thousand chemicals" used commercially, and I learned through a search that around ~1,500 drugs have FDA approval (as of 2014). So, there would need to be something like 50x more regulation if commercial chemicals were to be regulated the way FDA-approved drugs are. Given that commercial chemicals need to be tested for just safety and not effectiveness, we could assume safety and effectiveness each require 50% of the manpower and call this roughly 25x "more regulation".

Of course, many people think that the FDA already isn't doing a good job at regulating medical drugs. Scott Alexander has written about this and suggested an alternate approval scheme that could be used for commercial chemicals as well:

...Grant drugs one-star, two-star, etc approvals. Maybe one-star would mean it seems grossly safe, the rats we gave it to didn’t die, but we can’t say anything more than that. Two-star means it’s almost certainly safe, but we have no idea about effectiveness. Three-star means some weak and controversial evidence for effectiveness, this is probably where aducanumab is right now. Four-star means that scientific consensus is lined up behind the idea that this is effective, this is probably where the COVID vaccines are right now...

So how would we determine which chemicals need to be regulated, anyway? You could set a limit on the level of a particular chemical in the human body above which it needs to be confirmed safe, but different chemicals may be toxic at different levels. We could just require every chemical to be proven safe before it's used in industry, but that seems like such a big change it's not almost even worth imagining.

Swan also classifies chemicals by how long they take to break down or remain in our bodies. It might make sense to first focus regulation on the "forever chemicals" that persistently remain in our bodies, as we'd need to ban them ASAP just to be able to have a noticeable effect years from now:

“Legacy chemicals” stick around and can cause problems long after they’re released into our bodies and the environment. These include persistent organic pollutants...such as dioxin, [DDT, and PCBs]. The adage that “nothing lasts forever” isn’t true of these chemicals, which were designed precisely to last; they remain in the environment and our bodies for years...Because they are not water-soluble, they don’t degrade, and they are stored in body fat and other tissues.

By contrast, nonpersistent chemicals such as BPA, phenols, and phthalates are water-soluble, which means they essentially wash out of our bodies and the environment, and they do not accumulate in the body’s fat. These short-lived chemicals have half-lives of four to twenty-four hours. Even so, levels of human exposure to many nonpersistent chemicals—such as phthalates and phenols—tend to be fairly stable because of our continual use of products that contain them.

On the other hand, focusing regulatory efforts on the short-lived chemicals would let us reap immediate positive benefits from getting those permanently out of our systems.

One question I wished she had answered for me: of the plastics/chemicals that have been tested, how often do we find that they're harmful? There are at least some plastics that are safer, for example, Swan offers this advice on plastic containers:

For food storage, your best bet is to use glass, metal, or ceramic containers with tops or aluminum foil. If you do opt for plastic containers, use this rhyme to help you remember which recycling codes are safer and which aren’t: 4, 5, 1, and 2, all the rest are bad for you.

So, are 20% of the chemicals that we've studied potentially harmful? Or is it more like 80%? I didn't have a clear idea of this after finishing the book, and an answer to this question would let us have a feeling for how grave the situation is. Do we need to ban every plastic? Or could we ban 20 compounds and get 80% of the benefit?

The difference between regulatory schemes for commercial chemicals and medicine enables an interesting, likely harmful practice these companies can use: since chemicals are presumed innocent until proven guilty, if one chemical is found to be harmful to wildlife or humans, it can be easily replaced by a new chemical that has the same effect but a different chemical structure. Is this new chemical safe or not? We don't know! But now the package can be labeled (for example) "BPA Free", even though it may contain a chemical just as detrimental to our health as BPA that just hasn't been studied as extensively yet. Swan calls this "regrettable substitution". Imagine if drug companies could do the same thing for medicine!

If this all has been interesting to you, then read Count Down for more (and pray for those alligators!).