Toward measuring the impact of ecological disintegrity on human health

Ecological integrity refers to the ability of environmental life-support sy stems to sustain themselves in the face of human-induced impacts. We used a correlational, aggregate-data study design to explore whether life expecta ncy, as a general measure of population health, is linked to large-scale de clines in ecological integrity. Most of the data were obtained from World R esources Institute publications. Selected surrogate measures of ecological integrity and gross domestic product (GDP) per capita (as a socioeconomic c onfounder) were modeled, for the first time, using linear regression techni ques with life expectancy as the health outcome. We found a modest relation between ecological integrity and life expectancy, but the direction of the association was inconsistent. When GDP per capita was controlled, the rela tion between ecological integrity and life expectancy was lost. GDP per cap ita was the overwhelming predictor of health. Any relation between ecologic al integrity and health may be mediated by socioeconomic factors. The effec t of declines in ecological integrity may be cushioned by the exploitation of ecological capital, preventing a direct association between measures of exposure and outcome. In addition, life expectancy may be too insensitive a measure of health impacts related to ecological decline, and more sensitiv e measures may need to be developed.