Monday, April 18, 2016

Weinberg's "How One Study Produced a Bunch of Untrue Headlines About Tattoos Strengthening Your Immune System"

In my Honors Statistics course, we have discussion days over the course of a semester. One of the discussion topics involves instances when the media has skewered research results (for another example, see this story about fitness trackers,)

Jezebel writer Caroline Weinberg  describes a modest study that found that people who have at least one previous tattoo experience a boost in their immunity when they get subsequent tattoos, as demonstrated via saliva samples of Immunoglobulin A. This is attributed to the fact that compared to tattoo newbies, tattoo veterans don't experience a cortisol reaction following the tattoo. Small sample size but a pretty big effect.

So, as expected, the media exaggerated these effects...but mostly because the researcher's university's marketing department did so first. Various new outlets stated things like "Sorry, Mom: Getting lots of tattoos could have surprising health benefits" and "Getting multiple tattoos can help prevent colds, study says". Lots of creative extrapolation.

I like this example as it appeals to the Millennials (tattoos!) as well as the psychology/biology/pre-professional science majors (stress/immune responses/cortisol responses) in my classes AND it is a pretty easy study to follow.

One way to use this with your students is to have them identify the questions that need answered before we can make the sort of claims that were made by journalists. How long does the immune boost last (we have no idea)? Is it really an immune boost or just the fact that repeated tattoo-er people don't experience a decrease in immunity? If so, would it be more appropriate to state "Don't get your first tattoo during cold season!"? What are ways to replicate this studying with other painful, repeated experiences (child birth? allergy shots? OT/PT that hurts? distance running? cross-fit class? piercings?)? Does the decrease in immunity, while significant and a large effect size, actually translate into the recently re-tattooed having fewer colds or with the recently first-time-tattooed having more colds?