About Us

The Small Area Health Statistics Unit (SAHSU) was established in 1987 following a recommendation from the Black Enquiry into the incidence of leukaemia in children and young adults near the Sellafield nuclear power plant for an organisation to coordinate centrally the monitoring of small area statistics around major installations producing discharges that might present a carcinogenic or mutagenic hazard to the public. In this way early warning of any untoward health effect could be obtained.

The Unit was initially established at the London School of Hygiene and Tropical Medicine but in 1996 transferred to Imperial College London. The Unit now forms a core part of the MRC-PHE Centre for Environment and Health held jointly between Imperial College London and King's College London set up in 2010. 

The main role of SAHSU is to assess the risk to the health of the population from environmental factors by using routinely collected health and population data at a small area scale. To this end, SAHSU holds comprehensive computerised sets of health and demographic data and a range of environmental datasets at high spatial resolution.



The work of the UK Small Area Health Statistics Unit is funded by Public Health England as part of the MRC-PHE Centre for Environment and Health, funded also by the UK Medical Research Council


SAHSU Terms of Reference

  • To develop and maintain databases of health data, environmental exposures as required to meet a specific need, and social confounding factors at the small-area level;
  • To carry out substantive research studies on environment and health issues including studies of the relationship between socio-economic factors and health, in collaboration with other scientific groups as necessary; 
  • To respond rapidly, with expert advice, to ad hoc queries from the funding departments about unusual clusters of disease, particularly in the neighbourhood of industrial installations; 
  • In collaboration with other scientific groups, to build up reliable background information on the distribution of environmental exposure, socio-economic data and disease amongst small areas; 
  • To develop the methodology for analysing and interpreting statistics relating to small areas; 
  • To act as a centre of expertise, disseminating information on developments in spatial epidemiological methods to national and regional groups.