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UKCRC Health Research Classification System

2.2 Factors relating to physical environment

Main inclusion criteria

Environmental or external factors associated with the cause, risk or development of disease, conditions or ill health including:

  • physical agents, occupational hazards, environmental surroundings, radiation and pollution
  • chemicals and nutrients
  • infection by pathogens and studies of infectious agents


Advice on research activities

Involves characterising or identifying environmental or external factors that are determinants in the cause of conditions or disease e.g. studies of infectious agents.

Many studies will involve investigating the impact of environmental factors on biological systems. It may be appropriate to code to both 2.1 Endogenous risks as well as 2.2 Physical risks if the study involves investigating both the external agent and the biological response to that agent.

Excludes studies of infection with prion protein which should be coded as 2.1 Endogenous risks.

Excludes characterisation of antibiotic resistance genes and mechanisms in bacteria which should be coded as 5.1 Pharmaceuticals.

Official terminology

Full name of code

Short name Unique ID
2.2 Factors relating to the physical environment 2.2 Physical risks



Related external links

Common Scientific Outline (CSO) – 2.1 Exogenous Factors in the origin and cause of cancer
Common Scientific Outline (CSO) – 2.3 Interactions of Genes and/or Genetic Polymorphisms with Exogenous and/or Endogenous Factors