"...a team of scientists at the University of Arizona says the genetic research community must control for the environment when conducting experiments, because it may well affect the results."
Scientists housed pairs of mice in a range of environments: "In some cases, they placed groups of four in small cages containing only bedding; in other cases, they put pairs in sprawling cages that were twice as large and furnished with an exercise wheel, a ladder and a plastic tube that the mice could crawl through. "
"Scientists found that the mice in the luxury accommodations spent an average of 40 percent of their time on their in-home exercise wheel and had significantly less fat tissue around their aortas and weighed up to 40 percent less than their compeers from the cramped quarters. When researchers viewed their aortas under microscopes, they found that they had nearly 80 percent fewer gaps than their packed-in pals. "
Bottom line: they suggest that future studies talk more about the housing conditions of their mice. As for the rest of us, it does make me wonder about the effects of population density, or just the condition/clutter level of one's abode.