Primary and secondary prevention strategies of pre-type 1 diabetes. Potentials and pitfalls.

Over the past decade, a large part of type 1 diabetes research has focused on the possibility of preventing the disease. The objective of this article is to analyze which potential and pitfalls different preventive strategies may involve from the individual, epidemiological, and ethical perspectives. Two potential prevention strategies are considered: l) to try to arrest or delay an already ongoing immune destruction of the beta-cells, and 2) to try to intervene with exposures that may initiate this process. In addition to the potential effects of immune modulation, this prevention strategy depends on screening for risk markers. There are inherent ethical problems with screening because of the introduction of awareness of risk in healthy individuals and also because false positivity, the rate of which differs tremendously in high- and low-risk groups. Because of these latter circumstances, the most promising low-risk preventive treatments presently used in trials, i.e., nicotinamide and insulin, will probably only be feasible in high-risk groups, such as family members, though this group covers only 10-15% of potential cases. The second strategy aiming at eradicating environmental initiators of the beta-cell destruction will avoid the problem of screening and approach a total population at risk. Potential risk factors, such as food components (cow's milk proteins, gliadin or nitroso products) or different viruses, are indicated by animal and epidemiological studies. So far, however, no single environmental risk factor has been proven to be necessary and certainly not sufficient for the disease causation, and the etiological fractions estimated in population-based studies are low. It is concluded that more basic research is warranted before effective and safe prevention can be introduced for type 1 diabetes. Most probably, different preventive strategies must be applied to different groups and populations and in different phases of the beta-cell destruction.