DIABETES: WHAT WE KNOW AND WHAT WE DON'TMissing from your otherwise comprehensive article on diabetes ["The Covert Plague," December] was any mention of studies showing that chemicals can produce insulin resistance in animals at levels of exposure lower than found in most people. A recent Centers for Disease Control study found that bisphenol A was present in the urine of 95 percent of people tested. This indicates a continuous and ubiquitous exposure of the population to bisphenol A from the linings of cans, polycarbonate plastic bottles and containers, and possibly dental sealants. Interestingly, bisphenol A also produces insulin resistance in animals. Perhaps we should think beyond diet and exercise.