Cohort study of health outcomes in the electricity supply industry

Introduction

The Data Protection Act (DPA) sets out the rights of data subjects, and the duties of organisations which hold personal data on individuals (data subjects). That includes that the data controller, University of Warwick (UoW) provides information to data subjects.

Who is in the cohort?

The cohort comprises CEGB employees who had a period of at least six months employment between 1973 and 1982. Unless you were employed between these dates you will not be in the cohort. If you were employed during this period, but for less than the whole period, you may not have been included in the data set. Data from different CEGB regions was collected at different times within the nine year period.

What data is held by University of Warwick?

UoW took over the ‘CEGB National Epidemiology File’ data set in 2025 from University of Birmingham (UoB). The data set was pseudonymised in 2012 whilst the study was managed by UoB. A pseudonymised data set contains no names or other personal identifiers. That means that UoW have no means of identifying by name anyone within the data set. This is consistent with best practice, and the requirements of the DPA for data sets where personal identifiers are no longer required to enable analysis of the data. It ensures confidentiality of data for everyone in the cohort.

It also means that it is impossible for UoW to provide information to an individual data subject, or even to know if they are within the data set.

How can University of Warwick analyse data if they have no personal identifiers?

UoW receive periodic updates from NHS England about when they receive a death certificate, or notification of a diagnosis of cancer on the NHS cancer registry, for a person who is included in the cohort.

When the data set was pseudonymised, each data subject was assigned a unique identifier which is held in the CEGB data set and by NHS England. NHS England has the list of all of the names and dates of birth with each unique identifier. This allows NHS England to inform UoW when a death or cancer incidence is registered for the person with the corresponding unique identifier. This allows analysis of cause of death against occupation for the cohort as a whole.

Further information

Dr Linda Nichols at the University of Warwick is the lead researcher for this study. The process of transferring the study from University of Birmingham where the study was previously managed, to University of Warwick is ongoing. Hence some of the documentation and privacy notice still refer to University of Birmingham until all NHS permissions are obtained and the study file can be transferred.

If you have any queries regarding this study please contact . Further information can be found in the privacy noticeLink opens in a new window.

If you think you might be included in this cohort, but do not want your data to be used for research, please contact the NHS England opt-out service at National data opt-out - NHS DigitalLink opens in a new window

Previous publications from this cohort

Harrington JM, McBride DI, Sorahan T, Paddle GM, van Tongeren M. 1997. Occupational exposure to magnetic fields in relation to mortality from brain cancer among electricity and transmission workers. Occup Environ Med. 54: 7-13. https://doi.org/10.1136/oem.54.1.7Link opens in a new window; pdfLink opens in a new window

Harrington JM, Nichols L, Sorahan T, van Tongeren M. 2001. Leukaemia mortality in relation to magnetic field exposure: findings from a study of United Kingdom electricity generation and transmission workers, 1973–97. Occup Environ Med. 58: 307-314. https://doi.org/10.1136/oem.58.5.307Link opens in a new window; pdfLink opens in a new window

Sorahan T, Nichols L, van Tongeren M, Harrington JM. 2001. Occupational exposure to magnetic fields relative to mortality from brain tumours: updated and revised findings from a study of United Kingdom electricity generation and transmission workers, 1973–97. Occup Environ Med. 58: 626-630. https://doi.org/10.1136/oem.58.10.626Link opens in a new window; pdfLink opens in a new window

Sorahan T, Nichols L. 2004. Mortality from cardiovascular disease in relation to magnetic field exposure: Findings from a study of UK electricity generation and transmission workers, 1973–1997. Am J Ind Med. 45: 93-102. https://doi.org/10.1002/ajim.10314Link opens in a new window; pdfLink opens in a new window

Nichols L, Sorahan T. 2005. Mortality of UK electricity generation and transmission workers, 1973-2002. Occup Med. 55: 541-548. https://doi.org/10.1093/occmed/kqi157Link opens in a new window; pdfLink opens in a new window

Sorahan T, Kheifets L. 2007. Mortality from Alzheimer’s, motor neurone and Parkinson’s disease in relation to magnetic field exposure: findings from the study of UK electricity generation and transmission workers, 1973-2004. Occup Environ Med. 64: 820-826. https://doi.org/10.1136/oem.2006.031559Link opens in a new window; pdfLink opens in a new window

Sorahan T. 2012. Cancer incidence in UK electricity generation and transmission workers, 1973-2008. Occup Med. 62: 496-505. https://doi.org/10.1093/occmed/kqs152Link opens in a new window; pdfLink opens in a new window

Sorahan T. 2014. Magnetic fields and leukaemia risks in UK electricity supply workers. Occup Med. 64: 150-156. https://doi.org/10.1093/occmed/kqu002Link opens in a new window; pdfLink opens in a new window

Sorahan T. 2014. Magnetic fields and brain tumour risks in UK electricity supply workers. Occup Med. 64: 157-165. https://doi.org/10.1093/occmed/kqu003Link opens in a new window; pdf Link opens in a new window

Sorahan T, Mohammed N. 2014. Neurodegenerative disease risks and magnetic field exposures in UK electricity supply workers. Occup Med. 64: 454-460. https://doi.org/10.1093/occmed/kqu105Link opens in a new window; pdfLink opens in a new window

Sorahan T. 2019. Cancer incidence in UK electricity generation and transmission workers, 1973-2015. Occup Med. 69: 342-351. https://doi.org/10.1093/occmed/kqz082Link opens in a new window; pdfLink opens in a new window

Sorahan T, Nichols L. 2022. Motor neuron disease risk and magnetic field exposures. Occup Med. 72(3): 184-190. https://doi.org/10.1093/occmed/kqab180Link opens in a new window; pdfLink opens in a new window