Critical Science

Lots to say here. In today's episode I'm going to talk about something that bothers me -- science by press release. Not all science press releases are bad. Some are fine. But some are just downright awful. When a press release trumpets some alarming and scary number (like a chemical causes a 500% increase in Parkinson's Disease) when the evidence doesn't support it -- that's wrong. And that's what we call Science By Press Release. Scaring people to get your science out there is simply irresponsible in my opinion. But when we see things like this, we need to start our critical thinking processes. We need to look at the evidence. We need to ask questions. And we need to dig. Hopefully, responsible reporters are out there and they'll get ahead of this and they'll ask questions of independent experts (like myself), and bring the topline messages back down to Earth, and make them more nuanced, and ultimately, more scientific, honest, and informative.

Oh yeah, I'm also renumbering my episodes. The season thing was a great idea when I was starting out, but it's kinda artificial, and I'm doing away with it, and just numbering episodes.

Thanks for listening!

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Ever heard of noise? I'm certain you have. In science, when we talk about noise, we're normally talking about the variance or the variability when trying to measure something. In toxicology, that noise is usually the variability associated with a control or unexposed group. If you were to look at heights across a large number of people, you'll no doubt see a distribution that looks kinda like a bell-shaped or "normal" curve. Most people are huddled together near the middle, and then we have some shorter and some taller people -- the tails. Now, consider that distribution, that bell shaped curve, to represent the unexposed population -- our controls.

In toxicology we're also going to have some exposed group. And again, for the sake of argument, that group will also have a distribution of responses, and let's say it's also a bell shaped curve distribution. Now then, in simplistic terms, if those two distributions overlap completely, so that they're identical, we'd say there is no treatment effect. What needs to happen is for the response in the treated group to be so different from control that we can't conclude that the treated group's response came from the control distribution.

Said another way: if I randomly sample from the control distribution and get the same response as I'm seeing in the treated, then there's no treatment effect. That's the simplistic way of explaining this (there are some nuances I'm not bringing up).

Well, in today's episode, we're going to talk about a case where the "signal" (that is the treatment response that NIEHS' scientists say is a real treatment effect) is actually just noise from the control group.

Here's my analysis report on how I came to this judgement, and you can see the analysis code here.

But there are other issues with this particular NIEHS study that says hair relaxers, straighteners, and pressing products are linked to uterine cancer. For starters, NIH's press release made a causal statement that, "women who used chemical hair straightening products were at higher risk for uterine cancer compared to women who did not report using these products" -- that's simply not true at all because this study didn't find causality.

But the other big issue -- the study isn't even representative of the US population of women. 85.6% of the women in the study were white only, and not hispanic or LatinX -- just white. That's way more than we have in the US population. The number of Black or African American women is well below the US population. Same goes for other non-white groups. Which means, these results are not even relevant to the US population of women. We can't translate these results to the US population.

Listen to today's episode to find out more!

Help us continue Critical Science. Every dollar helps us focus on developing new content. It takes a lot of time to do the research that goes in to Critical Science, and subscriptions and other support are the only way we can continue to create this content. Please help us out: https://plus.acast.com/s/critical-science.

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In 1948, a year after a trio of judges wrote the Nuremberg Code in response to Nazi experiments on human subjects kidnapped and imprisoned in concentration camps, Olive Watkins Smith published, "Diethylstilbestrol in the prevention and treatment of complications of pregnancy." In this paper, Smith describes how she and her husband convinced obstetricians across the US to treat pregnant women with an experimental drug -- diethylstilbestrol, or DES. Smith convinced these doctors to treat the pregnant women in their care with a drug where no one understood the potential toxicity, long-term harm, or damage this drug would do to them or their children. Olive Smith and her husband George Smith caused hundreds of women to be exposed to DES, in order to support their ultimately flawed hypothesis that estrogen was the key driver to maintaining a healthy pregnancy.

This is the story of how a pair of scientists, through flawed scientific studies, kicked off a campaign that grew widespread support throughout the scientific community. It's a story of how confirmation bias blinds scientists, and leads to faulty hypotheses and perpetuates flawed understanding of the science. And how confirmation bias, poor study designs, and a lack of scientific integrity ultimately harms millions of people -- in this case millions of pregnant women and their children.

This is the sad, unfortunate story of diethylstilbestrol.

Help us continue Critical Science. Every dollar helps us focus on developing new content. It takes a lot of time to do the research that goes in to Critical Science, and subscriptions and other support are the only way we can continue to create this content. Please help us out: https://plus.acast.com/s/critical-science.

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This is the last episode of Critical Science.

It's not goodbye. It's more like, "until we meet again."

Thank you for listening! Thank you for watching! It's been a lot of fun. I learned a lot, and I hope you have, too. I also hope you had some fun along the way. This actually ran a LOT longer than I ever expected.

I appreciate everyone's support!

I fully anticipate creating a new podcast series at some point. I've got some ideas, some things are more concrete than others.

Be excellent to each other, and I'll see you all again real soon.

Help us continue Critical Science. Every dollar helps us focus on developing new content. It takes a lot of time to do the research that goes in to Critical Science, and subscriptions and other support are the only way we can continue to create this content. Please help us out: https://plus.acast.com/s/critical-science.

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Summary

In this episode, Dr. Lyle Burgoon discusses a study published in JAMA Network Open that claims a link between prenatal exposure to certain chemicals and metabolic syndrome risk in children. He analyzes the study using the seven tips he discussed in a previous episode and highlights several flaws and limitations in the study design. Dr. Burgoon emphasizes the importance of being skeptical and checking biases when evaluating scientific studies. He criticizes the media, particularly CNN, for sensationalizing and misrepresenting the study's findings, causing unnecessary fear and confusion among the public.

Takeaways

Be skeptical and evaluate scientific studies based on their scientific merits, regardless of who funded them.

Consider the study design and sample size when assessing the reliability and generalizability of the findings.

Recognize the limitations and uncertainties in observational studies and the inability to establish causation.

Check biases and avoid confirmation bias when interpreting scientific studies.

Be critical of media reporting on scientific studies and consider waiting for scientific consensus before drawing conclusions.

Help us continue Critical Science. Every dollar helps us focus on developing new content. It takes a lot of time to do the research that goes in to Critical Science, and subscriptions and other support are the only way we can continue to create this content. Please help us out: https://plus.acast.com/s/critical-science.

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