BackgroundThe status of health of an individual and - more broadly - of a community or population is defined by the status of their determinants of health. A “systemic” approach to define the health determinants is necessary in order to explore the complex relations existing among them. This study is aimed at identifying a ‘composite systemic’ index of health to measure the impact of socioeconomic factors on public health at local level and to analyze possible spatial autocorrelations between neighboring regions.ResultsA Composite Index of Health (CIH) was constructed on the basis of known indicators of socio-economic well-being by using the COMIC (COMposite Indices Creator) Software and was validated on the Italian population and a nationwide comparison has been performed.Analysis of the determinants showed a significant direct correlation between health, environment, work and wealth and inverse correlation between health and social distress. The analysis of data from Italian provinces confirmed the South-North gradient of well-being.ConclusionThe CIH is a reliable and robust index to evaluate the health of a local population. Although it was validated on Italian data, the index can be easily adapted to any Country.