  We propose a method of estimating the Total Loss of Healthy Life Years based
on the first exit time theory for a stochastic process, the resulting Health
State Function and the Deterioration Function estimated as the curvature of the
health state function. We have done many applications in UK and Scotland and
Sweden supporting our theory. Furthermore it was proven that both the WHO and
EU estimates of the healthy life expectancy can result from our method. The WHO
system takes into account the severe and moderate causes in estimating the loss
of healthy life years; instead the EU system calculates the total loss of
healthy life years. For both cases our methodology provides both estimators
from only death and population data. The advantages of our method are
straightforward. We do not need survey data to make the calculations. The
resulting estimates should be used to test and improve the existing survey
based methodologies. While the WHO and EU systems tend to approach each other
differences continue to appear based on the methodology of the related surveys
and the analysis of data. Two main schools are working to these directions one
based on USA the Institute for Health Metrics and Evaluation (IHME) headed by
Christopher J.L. Murray and contributors in all over the world and the European
Health and Life Expectancy Information System (EHLEIS) with Jean-Marie Robine
and a team from the EU member states. Keywords: Deterioration, Loss of healthy
years, HALE, DALE, World Health Organization, WHO, European Union, EU, EHEMU,
IHME, EHLEIS, Healthy life expectancy, Life expectancy.
