Christmas Cheer from BMJ

Fig 1 (Firth et al., 2009). X ray pictures can easily detect an ingested coin. Position of coin on lateral view (left), relative to anterior (right) or posterior picture affects size of image on film.

Every year, BMJ has a special Christmas issue with spoof articles and silly studies. Today's feature examines the relationship between the Dow Jones Industrial Average and the value of coins swallowed by children (Firth et al., 2009):

Main outcome measures Total value of coins ingested and number of incidents of coins versus other objects swallowed, measured before and after the stock market crash of October 2008.

The authors reviewed computerized records from the endoscopy suite at Massachusetts General Hospital:

...we compiled data on all numismatic and sundry detritus acquired (NASDAQ composite index) from children’s gastrointestinal tracts by the paediatric gastroenterology service at our hospital between August 2006 and July 2009. ... We calculated the financial total swallowed and extracted as a fraction of the US$ or 100 cents (FTSE 100 index), and the ratio of patients with coins versus all those with foreign objects removed (pecuniary extraction ratio, PE ratio). We calculated the mean end-of-month closing value of the Dow Jones Industrial Average. We examined whether there was a change in the monthly mean NASDAQ, FTSE, and PE ratio before and after the collapse of the Dow Jones Industrial Average of October 2008.

What did they find? There was no relationship between the value of the stock market and the value of coins swallowed by children, as one might intuitively expect from a population that has no idea that the Dow Jones Industrial Average even exists [except for maybe the 15 (!) year old]:

The patients were aged 1 to 15 years. The NASDAQ composite index was 18. Eleven coins were retrieved from nine patients: three pennies (or cents), five nickels (1 nickel=5 cents), no dimes (1 dime=10 cents), and three quarters (1 quarter=25 cents), giving a total return on ingestment for the period, or FTSE 100 index, of $1.03. Seven other objects in seven children included an unsafe safety pin (open), a battery, a marble, a ballbearing, a magnet, a dentist’s guard, and a rubber doorstopper. The PE ratio was therefore 0.57 (9/16).

...We found no change in the FTSE 100 index (2.3 v 3.1, P=0.77) or PE ratio (0.54 v 0.66, P=0.5) during a period of dramatic Dow Jones (12 537 v 8388, P less than 0.0001), despite the NASDAQ composite index remaining stable (0.4 v 0.5, P=0.75). In other words, despite a massive swing in the stock market there was no concomitant absolute or relative change in paediatric wealth intake against an unaltered background rate of foreign body ingestion.

Nonetheless, the authors bemoan the paucity of gastropecuniary studies and call for further investigations in the numismedical field.

Brain Blogger covers another article from the 2009 issue, Santa Claus: a public health pariah? in their post, Is a Slim Santa Claus Coming to Town? My personal favorite, though, is this announcement from BMJ editor Tony Delamothe: "Anaesthetists’ brains differ markedly from surgeons’. Who would have thought?"

Classics from Christmases past include Are Surgeons Taller And Better Looking Than Other Doctors?, Sword Swallowing And Its Side Effects, Sneezing etiquette and the efficacy of masks, Sex, aggression, and humour: responses to unicycling, and Rage Against the Machine Syncope and the Texting Sign. Happy reading!

Reference

Firth, P., Zheng, H., & Biller, J. (2009). Ingested foreign bodies and societal wealth: three year observational study of swallowed coins. BMJ, 339 (dec04 1). DOI: 10.1136/bmj.b5066