Latest entry in the “do what I say, not what I do sweepstakes”: although 92 percent of Americans surveyed by phone say they wash their hands after using public restrooms, only 77 percent actually do, according to a study sponsored by the American Society for Microbiology and (self interest alert!) the Soap and Detergent Association. That’s off six percentage points since the last time a study like this was conducted, in 2005.

The real fun is in the details. The researchers observed the behavior of 6,076 adults (3,065 men and 3,011 women) at six sites in four cities: Atlanta’s Turner Field, Chicago’ Museum of Science and Industry and its Shedd Aquarium, New York’s Grand Central Station and Penn Station, and San Francisco’s Ferry Terminal Farmers Market, the same sites as in the 2005 study. The findings that leaped out at me:

• 88 percent of women lathered up, compared to 66 percent of the men. Insert your own joke here.
• In Chicago, they listen to their mothers: 81 percent washed up. New York came in second, with 79 percent washing up, followed by Atlanta (75 percent) and San Francisco (73 percent). I wish to state for the record that if the restrooms at Grand Central did not scream “flee immediately or risk contracting a communicable disease,” New Yorkers would have been number one.
• At Turner Field, only 57 percent of men washed their hands, a national low, but 95 percent of women there did, a national high. Apparently Georgians figure that if one half of a couple is germ free, the others’ microbes give up voluntarily or something.
• The cleanest men were at Chicago’s Shedd Aquarium (81 percent washing), which is also where the fewest women washed up. See explanation above.

My Australian editor says that one of the things that has most struck her in her eight months in the U.S. is Americans’ hygiene obsession, with people treating Purell and hand wipes as extensions of their bodies. I don't plan to tell her that 27 percent of Americans surveyed say they do not always wash their hands after changing a diaper and 22 percent say they do not always hand wash before handling or eating food. And here’s why we need to start a campaign against shaking hands: only 34 percent say they always wash their hands after coughing or sneezing.