It was estimated in 1994 that ∼5% of the U.S. population had diabetes with associated healthcare costs of $40 billion.(103) Insulin injections available at the time were effective when used correctly, but patient compliance was hindered by fear of injections and social stigmas associating needle injections and drug use, as well as the inconvenience of needing to refrigerate injectable insulin products.(104) These shortcomings of insulin injections provided a market opportunity for inhaled insulin. This evidence concerns the gene INS and diabetes mellitus.