School of Public Health

UK Small Area Health Statistics Unit (SAHSU)


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 the Department of Epidemiology and Biostatistics at Imperial College London. The Unit successfully went to competitive tender in 1996 and again in 2000. Since 2007 it has been funded by the Department of Health and Defra.  In 2009 SAHSU became part of the MRC-HPA Centre for Environment and Health which is held jointly between Imperial College London and Kings College London. 

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.

Objective:  To investigate possible health effects associated with sources of environmental pollution.

Expertise:  The Unit has internationally recognised expertise in spatial epidemiology, spatial statistics, and Geographical Information Systems (GIS). Recent work includes the largest studies to date on risk of low birth weight, stillbirth and congenital anomalies near landfill sites, and on chlorination by-products in the water supply and reproductive effects.

Work programme: The Unit is current working on several studies including an environmental health atlas, geographical mapping of childhood diabetes, the health effects of multiple deprivation, and noise pollution in the vicinity of airports. There is a large methodological programme in spatial epidemiology and spatial statistics. SAHSU runs a Rapid Inquiry Facility (RIF) to provide funding departments and health agencies with rapid analyses of available health statistics around sources of environmental pollution within a few working days.

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