epidemiology

Microbiologist Stanley Falkow is credited with saying, "The goal of every bacterium is to become bacteria." Similarly, the goal of every pathogen is to infect a new host.

Pathogenic microbes face an evolutionary trade-off: On the one hand, they want to be as nasty as possible, because the nastier they are, often the easier it is to spread from one host to the next. Think of Vibrio cholerae, the causative agent of cholera, which upon infection can result in a person producing gallons of diarrhea. Death is due to dehydration, but not before the patient served as an incubator and excreted billions of more bacteria into the environment.

On the other hand, a microbe does not want to be too nasty. If it incapacitates or kills its host quickly, it will be difficult for...

When Erin Brockovich, an environmental activist, shook down Pacific Gas & Electric for $333 million for allegedly poisoning a community with hexavalent chromium and causing cancer and all sorts of other health problems, Julia Roberts portrayed the protagonist in a sensationalized blockbuster movie. It is unlikely, however, that Hollywood will be filming a sequel.

Why? Because not only was Ms. Brockovich wrong, but the State of California has now partially repudiated what she fought for.

Erin Brockovich, Junk Scientist

We've known for a long time that Ms. Brockovich used junk science to score a jackpot settlement. She used a common rhetorical trick, known as the Texas...

A new study in the Journal of the American Medical Association found that 99% of donated brains from people who played in the NFL showed signs of chronic traumatic encephalopathy (CTE), a type of neurodegenerative disease that is thought to result from persistent brain injury from knocks to the head. Signs of CTE were also noted in the brains of 91% of people who played the sport in college and 21% who played in high school.

Predictably, headline writers went crazy:

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Nutrition science is notoriously unreliable. The reason is because a substantial proportion of research in the field is conducted using surveys, and people just aren't very good at remembering what and how much they ate. 

The field is further damaged by a sensationalist press, which breathlessly reports every study and converts minor findings into flashy, eye-catching headlines. The latest example of this is a study that linked increased coffee consumption to reduced mortality. In general, media outlets wrote headlines like, "Drinking coffee may reduce the risk of death."

Well, not exactly. A plethora of data shows that coffee probably has some health benefits. However, after reading the original paper, carefully examining the data, and applying a dose of common sense (...

The media is alive with a new report sure to satisfy the confirmation bias of a billion people; drinking coffee is good for you!! And evidently, the more, the better.

At least that is what the media has chosen to tell us in their interpretation of an article in the journal Annals of Internal Medicine entitled Association of Coffee Consumption With Total and Cause-Specific Mortality Among Nonwhite Populations.

Aren't these the same media groups that decades ago lifted Center for Science...

When I was learning how to do word problems in elementary school, we were taught to ask ourselves a few questions after arriving at an answer. One of them was, "Does my answer make sense?" For example, if a problem asked how many apples a person can buy if he has $5 and each apple costs 50 cents and your answer is negative 17 million, something has gone horribly wrong.

Does my answer make sense? is such a great question, that every published scientific paper henceforth should be required to answer it explicitly. Perhaps we would avoid seeing papers with titles like this:

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Every student in America should be required to take a class called, "What Do We Know, and How Do We Know It?" Perhaps if we learned from an early age how we know the things we claim to know, fewer Americans would fall for ridiculous conspiracy theories.

Public health is a field that is widely misunderstood, even by science journalists. That is because epidemiology is an inexact science that is complicated by a large variability in the quality of the data it produces, as well as by its reliance on advanced statistical methods. Let's leave the latter aside and focus on the former. Which epidemiological studies are most reliable and why?

From weakest to strongest, here are the most common epidemiological study designs:

Case report. A case report is...

Mammographer at WorkA large, long-term study of the value of screening mammography for saving lives of women from breast cancer supports previous studies: there was no detectable benefit in terms of lives saved thanks to routine use of the technology. The study appeared in BMJ.

The study authors led by Dr. Anthony B. Miller of the Dalla Lana School of Public Health, University of Toronto, Canada, followed almost 90,,000 women participants in the Canadian National Breast Screening Study, aged 40 to 59,...

Diet Soda

Dr. Susan E. Swithers from the Purdue Department of Psychological Sciences and Ingestive Behavior Research Center authored a commentary entitled Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements. Her opinion piece was most often mistaken for a scientific study by sensation-seeking media. It appeared in the journal, Trends in Endocrinology and Metabolism.

Much of the media take on this...