Indmedica - India's Premier Medical Portal - Cyber Lectures


Epidemiology for Occupational Health Services

Arin Basu

Page 4


Epidemiology, occupational health services, and risk assessment

Occupational Health Services (OHS) are a set of preventive and promotive healthcare services for the employees in an organization. Organized as an interdisciplinary team approach, the occupational health service teams consist of several professionals including occupational physicians, industrial hygienists, occupational health nurses, safety engineers, ergonomists, data analysts, and epidemiologists. The core activities of OHS include pre-employment health checkups to ensure that the job is appropriate for the candidate, periodic health examinations to provide early diagnosis and treatment for selected health risks for a given work unit, and regular employee training programs to identify and prevent adverse health events secondary to occupational exposures to risk factors. These activities need to be evidence driven with respect to risk factor-health outcome linkages. Consequently, several data analytical processes are involved at various stages, including hazard identification at the workplace, characterization of employee health risks involved in the production process, and estimation of the time interval for periodic health examinations. In all these processes, epidemiology as a quantitative qualitative study of health effects can play a pivotal role, more so when integrated with available risk assessment techniques. Epidemiology can be combined with either top down risk analytic techniques such as HazOp studies (Hazard and Operability studies), or risk analytical techniques that build scenarios bottoms-up like Fault Tree or Event Tree Analysis. Hazop studies take into consideration flow charts of industrial processes and use of specific guide words. These are consensus driven diagnostic techniques for fault detection and management at the plant operational level and aim to develop a repository of faults and their management plans based on guide word driven scenarios. Guide words in the context of HazOp studies are a set of operational keywords that are used to describe the flow diagram of the production process under different scenarios. Fault tree or event tree analysis is a technique of fault diagnosis where a “bottoms-up” approach is taken to detect system faults, including logic diagrams and flow of information.

Epidemiological data can be integrated in both HazOp studies and Tree based risk analysis studies. Epidemiological information could be used to evaluate processes that pose significant risk to human health. In event tree analysis or fault tree analysis, where specific discrete events are investigated using specific guide symbols and logic gates, specific health outcomes or diseases can be included in places of words describing plant operations, or illness descriptors can be used as separate nodes, and epidemiological data can be used to arrive at possible sources and management plans for the control of health hazards.

Epidemiology has emerged as the basic science for public health, prevention and health promotion. With respect to occupational health, it may play a crucial role in linking the human health aspects in the existing risk analysis paradigms.


  1. Hennekens, CH, Buring JE, Mayrent SL. Epidemiology in Medicine. 1st Edition. Little Brown and Company, Boston, USA. 1987
  2. Last J. A Dictionary of Epidemiology. 3rd Edition. Oxford University Press. Oxford, UK, 1995
  3. Pearce, N. A Short Introduction to Epidemiology. Centre for Public Health Research, Wellington, NZ, 2003
  4. Kelsey, JL, Whittemore, AS, Evans, AS, Thompson, WD. Methods in Observational Epidemiology, 2nd Edition, Oxford University Press, New York, 1996.
  5. Hill AB. The environment and disease: Association or causation. Proc Royal Soc Med 1965
  6. Baker, D, Kjellstorm, T, Calderon, R, Pastides, H. Environmental Epidemiology: A Textbook on Study Methods and Public Health Applications, World Health Organization, Geneva, 1999.

1 2 3 4 Previous page Back