Perhaps the biggest remaining question is whether inflammation always precedes insulin resistance. “We don’t truly know which comes first,” says Aruna Pradhan, an epidemiologist at Brigham and Women’s Hospital in Boston. Insulin resistance could develop first and then incite inflammation through its effects on FOXO1. “It’s a chicken-and-egg question,” Dong says. “Nobody knows.”
And inflammation and insulin resistance aren’t the only factors to consider: genetics and environmental influences such as nutrition play a role in diabetes, too. In September 2009 Pradhan and her colleagues published a surprising study in the Journal of the American Medical Association showing that drugs that reduced insulin resistance had little effect on inflammation levels. Bizarrely, the subjects who received placebos had fewer signs of inflammation at the end of the study than those taking the drugs did, suggesting a complex interplay of factors. So even as scientists create a clearer picture of inflammation and diabetes, new puzzle pieces seem to keep adding more complexity to a complex disease.
Note: This article was originally printed with the title, "Inflammatory Clues."