Type 1 diabetes (T1D) results from an autoimmune destruction of the insulin-producing beta cells. Administration of mucosal insulin in islet autoantibody-negative children who are genetically predisposed for T1D offers the potential for inducing immunological tolerance to beta cells and thereby protect against the development of islet autoimmunity and T1D. Intranasal insulin has the advantage that whole protein will be exposed at the mucosa. Therefore, the available dose of insulin when administered intranasally is likely to be consistent between individuals. On this basis, the investigators aim to conduct a placebo-controlled, double-blind/double-masked primary intervention pilot trial (PINIT Study) of intranasal insulin treatment in islet autoantibody negative children to test immune efficacy and safety in the primary prevention setting. This pilot will help to develop and design a Phase III study aiming to test efficacy of preventing islet autoimmunity and T1D.