Health, as defined by the World Health Organization, is a condition “of complete physical, mental and emotional well being and not simply the absence of illness and disease.” A variety of definitions are used for these purposes over the years. One of those definitions is that health is the sum total of the vital internal and external properties of an individual at the moment of his birth. This definition recognizes that, unlike physical attributes, internal properties are not affected by extrinsic influences. Thus, health can be achieved through a combination of good health maintenance practices and appropriate health interventions.

There are many causes of death around the world, making the search for the definition of “age-related” particularly challenging. The International Statistical Classification of Diseases and Health Problems (IDSHD) has been the source of the World Health Organization’s (WHO’s) definition of age-related illnesses for more than twenty years. The disease/disease paradigm is the most widely accepted means of defining conditions and mortality rates. According to this paradigm, age-related diseases are those that progressively increase in severity with age, whereas age-related deaths are those deaths that are caused by age-related diseases. The third definition of age-related disease is that which is caused by medical or non-medical interventions to an individual, rather than by pathogens.

The availability of adequate health services is considered to be a universal feature of modern society. However, despite this, there are still pockets of communities that suffer from poor health, despite advances in medical care. Similarly, the availability of adequate education and health care, including the prevention of diseases, remains uneven around the globe. In order to understand the root cause of such disparity in health levels across regions and communities, it is necessary to examine the definitions of disease. As a general principle, the disease is defined as any condition that affects the body as a whole, causing damage to organs or leading to disease, death or impairment of function. The absence of a disease is considered to indicate that the disorder or condition has not yet reached the point of being categorized as having a disease.

Most regions have evolved a national standard to determine the presence of a disease or illness, as well as its severity, in populations. Generally accepted definitions of disease to allow for the presence of certain indicators, such as pain, fatigue, and malaise, that indicate the presence of a disease or illness. However, there is a great deal of room for disagreement regarding the presence and severity of these indicators. For instance, some regions define malaise as a symptom of digestive tract disorder, while others insist that it is a sign of heart disease. Likewise, some medical definitions of good health require a person to be free of communicable diseases, while others consider even the absence of such diseases to be an indicator of good health.

The third defining characteristic is mortality, which refers to the age-specific death rate for a particular disease. This definition of public health has been widely used to monitor the demographic distribution of morbidity and mortality, as well as to track the trends in health across generations. This also allows researchers to monitor the evolution of the population and to gain insight into the potential impact of interventions on health. The mortality rate is therefore used as an indicator of morbidity and is therefore connected with other kinds of statistical analysis. A key feature of this definition of public health is the fact that it incorporates all the existing mortality rates for diseases, which allows researchers to distinguish between age-specific deaths, such as those caused by cancers and cardiovascular diseases, and age-specific deaths caused by non-diseases, such as those resulting from accidents.

These three general characteristics are the basis for the current definition of health policy and its various applications. Technically, however, many variations have been introduced over the years to accommodate the constantly changing practice and circumstance of health. Nevertheless, they are essential to the formulation of any definition of health policy and are used universally to classify diseases and to monitor their incidence and mortality. By using a common definition, population monitoring can thus be made much easier in dealing with different health issues.