Health, Demography, and Mortality Analysis Fundamentals

Defining Health and Disease

Health is a state of complete physical, mental, and social well-being and not merely the absence of infection or disease.

Disease is a process and the consequent status of a living condition.

Fundamentals of Demography

Demography is the science that has as its objective the study of human populations, specifically their size, structure, evolution, and general characteristics from a quantitative point of view.

• Dimension: The number of persons normally resident in a geographically well-defined territory.
• Territory: The place of residence of persons, which can be globalized or disaggregated (e.g., a nation, a region, a province, a city, or a municipality).
• Total Population: The total population of a geographic area.
• Relative Population: The number of inhabitants per square kilometer (population density).

Key Demographic Variables

A cohort study involves tracking groups of people to monitor their health over time.

Fertility is one of the most important demographic variables used to assess trends in population growth in a country.

Birth represents the natural flow of population growth.

Marriage is a social institution that creates a marriage bond between its members. This tie is socially recognized, either by legal means or by way of customs.

The Lexis Diagram in Demography

The Lexis diagram is used to represent the three time dimensions used in demography:

• Chronological or calendar time: i.e., when the observation occurs.
• Age: The years elapsed since the birth of an individual.
• Generation or cohort: All individuals who share a birth date in the same year.

Axes of the Lexis Diagram

On the abscissa (horizontal axis), we represent the chronological or calendar time, i.e., the time or period in which the population observation is made.

On the ordinate (vertical axis), we represent the age or years elapsed since the birth of an individual.

Disease Classification and Mortality

The International Classification of Diseases (ICD) classifies diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances, and external causes of injury and/or disease.

Life tables (or mortality tables) are theoretical models that describe the extinction of a cohort. They are considered the most comprehensive tools for the analysis of mortality in a population at a given time.

These tables help describe the behavior of mortality through age and sex comparisons.

Survival Analysis Techniques

Survival analysis refers to all techniques that enable the study of the variable "time until an event occurs" and its dependence on other possible explanatory variables.

Survival time is defined as the time interval between the onset of an event and the date of the latest news or follow-up.