  We propose a series of methods and models in order to explore the Global
Burden of Disease Study and the provided healthy life expectancy HALE estimates
from the World Health Organization WHO based on the mortality mx of a
population provided in a classical life table and a mortality diagram. Our
estimates are compared with the HALE estimates for the World territories and
the WHO regions along with providing comparative results with to findings of
Chang, Molla, Truman et al. (2015) on the Differences in healthy life
expectancy for the US population by sex, race or ethnicity and geographic
region in 2008 and from Yong and Saito (2009) regarding Trends in healthy life
expectancy in Japan. From the mortality point of view we have developed a
simple model for the estimation of a characteristic parameter b related to the
healthy life years lost to disability and providing full application details
along with characteristic parameter selection and stability of the
coefficients. We also provide a direct estimation method of the parameter b
from the life tables. We straighten the importance of our methodology by
proposing and applying estimates of the parameter b by using the Gompertz and
the Weibull models. From the Health State point of view we summarize the main
points of the first exit time theory to life table data and present the basic
models starting from the first related model published by Janssen and Skiadas
(1995). Even more we develop the simpler 2-parameter health state model and an
extension of a model expressing the infant mortality to a 4-parameter model
which is the simpler model providing very good fitting on the logarithm of the
force of mortality. More important is the use of the Health State Function and
the relative impact on mortality to find an estimate for the healthy life years
lost to disability.
