"In order to pool data across many studies to obtain large samples, BMI is conveniently available for these studies, " said Barry I.

WSJ: A Good Way to Measure Obesity? Fat Chance

According to NPR, because the researchers only analyzed the samples for genetic signatures of different pathogens, they couldn't determine whether the bugs were alive, and potentially reproducing in the water, but there were no pool-related diseases reported in Atlanta during the summer the samples were gathered.

CNN: Yuck! What's in your pool water