Report of the Workgroup on Noninfectious Diseases.

Introduction The Workgroup on Noninfectious Diseases recognized that the strategies for eradication and elimination of infectious diseases would need to be revised when applied to noninfectious diseases. The group divided itself into four subgroups to discuss the following: 1) a conceptual framework for eradication/ elimination strategies as applied to noninfectious diseases, 2) toxic exposures, 3) protein-energy malnutrition, and 4) micronutrient malnutrition. The group noted that the definition for "eradication" from the Dahlem Workshop -- "zero cases, zero risk, cessation of intervention" -- would not apply to noninfectious diseases. The conditions considered for eradication so far have been diseases or "portions of diseases" that have a single cause (e.g. cases of acute flaccid paralysis caused by poliovirus). Some noninfectious diseases (e.g. certain toxic exposures) may qualify for eradication because they have a single cause which could be removed completely (e.g. 2-naphthylamine-induced cancer). However, most noninfectious diseases (e.g. resulting from nutritional deficiency) cannot be "eradicated" because the intervention measures must be continued to ensure that the deficiencies do not recur. The group recognized that there would be difficulty in the strict application to noninfectious diseases of the term "elimination", defined as "zero cases, continuing risk, continuing intervention". For example, micronutrient supplementation, when given to a population with different levels of nutritional adequacy, may not help those with severe deficiency. Furthermore, fluctuations in the adequacy of the diet and supplementation could lead to a rise in cases periodically. However, the group felt that the use of "elimination", despite the technical definition, in relation to nutritional deficiencies and other noninfectious diseases deserved some consideration because of its value as a communications and political tool for rallying enthusiasm, resources and support. Because noninfectious diseases do not fit the strict definition for candidate diseases to be eradicated or eliminated, the group agreed that other criteria were necessary in setting priorities and in competing for resources. These criteria include burden of disease, cost-effectiveness of interventions, political commitment, and social acceptability which, the group emphasized, had to be considered regardless of whether a disease could be eradicated or eliminated. Facilitating and mitigating factors The Workgroup considered that one important factor affecting the success of disease control efforts is the degree of interdependence among communities in terms of community interventions. This interdependence appeared to be less for noninfectious than for infectious diseases. For example, the failure of one community to control nutritional deficiencies in its population did not necessarily result in a negative impact on the incidence of disease in a neighbouring community. In contrast, failure of poliomyelitis eradication in one country may pose a continuing risk to its neighbours. For occupational and environmental diseases, exposures in one community may affect health in another community (e.g. a worker taking home a toxin on his contaminated clothing, or a toxin from a factory affecting distant, downwind communities). In comparison to infectious diseases, the relative lack of international interdependence concerning noninfectious diseases may provide greater latitude for one country to select its own health priorities unfettered by the health situation of others. However, the lower degree of interdependence among communities might result in weaker external support. Another factor affecting the implementation of programmes for noninfectious diseases, which was emphasized, is that the resources from the health system budget to sustain interventions for some noncommunicable diseases (e.g. micronutrient deficiencies) may be reduced after resources from other sectors are tapped. …