After adjusting for age, sex, race, marital status, education, income, health insurance, body mass index, duration of diabetes, glycemic control, use of oral hypoglycemic agents, number of visits to the PCP and consultation with an endocrinologist, the OR for using insulin associated with each kilometer of driving distance was 0.97 (CI 0.95, 0.99; P = 0.013). The gene discussed is INS; the disease is diabetes mellitus.