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What is public health?

What do we mean by "health"?

Health is a complex phenomenon that can be defined as follows: "Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." (World Health Organization - WHO, 1946).

Far from being static, health varies in space and time, from one individual to another and from one community to another. This phenomenon involves multi-dimensional aspects (physiological, organic, mental and social), which are influenced by a set of individual and collective factors called "determinants".

What is public health?

In 1952, the WHO defined public health as "the art and science of preventing disease, prolonging life, and promoting mental and physical health and efficiency through organized community efforts for 

  • the sanitation of the environment;
  • the control of communicable infections;
  • the education of the individual in personal hygiene;
  • the organization of medical and nursing services for the early diagnosis and preventive treatment of disease; and
  • the development of social machinery to ensure to every individual a standard of living adequate for the maintenance of health, so organizing these benefits as to enable every citizen to realize his birthright of health and longevity."

In Montréal, the public health department (DSP) works day in and day out to protect and improve the health of the population by means of promotion, prevention and protection.

At what level do we intervene?

Health status, that is, the nature of health problems, their distribution, their significance (extent) and their evolution. We can distinguish three levels of health status :

  • overall health status
  • physical health status
  • psychosocial and mental health status

Health determinants, that is, the individual and collective factors that influence the health and well being of the population, including the following:

  • global context (e.g. demographic, economic, social and cultural)
  • social environment (e.g. family environment, school and daycare environment, work environment, local community and neighbourhood)
  • systems (e.g. urban planning, health and social services system)
  • individual characteristics (e.g. lifestyle habits and behaviours, socioeconomic characteristics)