Mortality by occupation: the best basis for actionable results?
Authors: Edmund Jessop
Journal: The Lancet Public Health (2017)

Chimney sweepers' cancer of the scrotum,1Brown JR Thornton JL Percival Pott (1714–1788) and chimney sweepers cancer of the scrotum.Br J Ind Med. 1957; 14: 68-70PubMed Google Scholar wool-sorters' disease,2Bell JH Anthrax and the wool trade.Am J Public Health. 2002; 92: 754-757Crossref PubMed Scopus (11) Google Scholar and lung cancer in uranium miners3Roscoe RJ Deddens JA Salvan A Schnorr TM Mortality among Navajo uranium miners.Am J Public Health. 1995; 85: 535-540Crossref PubMed Scopus (56) Google Scholar have taught us that the workplace can be full of hazards—chemical, biological, and radioactive. More recently, findings from the Whitehall and other studies have shown the huge effects on health of social structures and psychological processes in the workplace.4Bosma H Marmot MG Hemingway H Nicholson AC Brunner E Stansfeld SA Low job control and risk of coronary heart disease in Whitehall II (prospective cohort) study.Br Med J. 1997; 314: 558Crossref PubMed Scopus (717) Google Scholar, 5Kuper H Singh-Manoux A Siegrist J Marmot M When reciprocity fails: effort-reward imbalance in relation to coronary heart disease and health functioning within the Whitehall II study.Occup Environ Med. 2002; 59: 777-784Crossref PubMed Scopus (271) Google Scholar Researchers have subsequently investigated specific workforces to study important questions about occupational epidemiology in relation to particular hazards and diseases.6Floderus B Persson T Stenlund C Wennberg A Ost A Knave B Occupational exposure to electromagnetic fields in relation to leukemia and brain tumours: a case-control study in Sweden.Cancer Causes Control. 1993; 4: 465-476Crossref PubMed Scopus (236) Google Scholar In The Lancet Public Health, Srinivasa Vittal Katikireddi and colleagues7Katikireddi SV Leyland AH McKee M Ralston K Stuckler D Patterns of mortality by occupation in the UK, 1991–2001: a comparative analysis of linked census and mortality records.Lancet Public Health. 2017; (published online Oct 23.)http://dx.doi.org/10.1016/S2468-2667(17)30193-7PubMed Google Scholar do something rather different. By eschewing particular diseases and analysing all-cause mortality, they implicitly draw attention to the sort of person who does a particular job, rather than the type of work they do. All-cause mortality is unlikely to reveal particular hazards; it is a summary measure that sheds light on the overall circumstances (economic, social, and lifestyle) of a particular occupational group. Katikireddi and colleagues used data from census-based longitudinal cohorts to examine all-cause mortality by occupation for the different countries of the UK. The study is not without its problems. Information governance restrictions meant that each cohort—Scotland, Northern Ireland, England and Wales—had to be studied separately. Loss of out-of-area deaths vitiated the Northern Ireland dataset. The ad-hoc groupings of occupations into roughly 60 categories mean that direct comparisons between men and women are not possible. Despite these limitations, the analysis produces many interesting findings—namely, that mortality rates vary substantially by occupation and, although improvements have been shown in most occupational groups, it has increased in others. However, as with all descriptive studies, it raises many questions for further research. In offering an analysis of mortality by occupation, the investigators draw attention to the health status of groups in society defined by the answer to the question “What is the full title of your main job?” A key strength of the study is its distinction of 63 categories; however, in interpretation of the results it can be useful to group them into patterns. When this grouping is done, it seems likely that the patterns we see are due as much to the composition of these occupational groups as to direct workplace hazards; hence, mortality by occupation not occupational mortality. The mortality gradient between health professionals, health associate professionals, and health care and related personal services is intriguing and unlikely to be attributable to major differences in workplace exposure to chemical, biological, or radiation hazards. This gradient might well be due to differences in status, pay, education, lifestyle, and many other factors. Analytical categories are not value-neutral, so why choose occupation as the category for analysis? Why not, for example, analyse according to main hobby, or main place of shopping? The answer is partly because occupational data are available in official statistics in a way that these other categories are not, although this argument is circular: government statisticians ask those questions because we analyse them. Occupation might also be chosen because “main job” implies a substantial proportion of our waking hours. Analytical categories are mostly chosen because they are actionable. Katikireddi and colleagues recognise this factor in their call to policy makers in Scotland to act on the important finding that Scotland's excess mortality is concentrated in occupational groups with high mortality. Scotland, Northern Ireland, England and Wales are not primarily geographies, but jurisdictions—they have governments with powers and responsibilities. Political jurisdictions give a clear frame for action. How to act on occupational categories with a poor mortality record is less clear. Well-defined occupations might have trade associations or similar to work with. But as working patterns change, the question “what is your main job?” becomes increasingly ambiguous, especially in fluid low-wage sectors of society. In future, other classifications and categories might provide a better basis for actionable results. I declare no competing interests. Patterns of mortality by occupation in the UK, 1991–2011: a comparative analysis of linked census and mortality recordsMortality rates differ greatly by occupation. The excess mortality in Scotland is concentrated among low-skilled workers and, although mortality has improved in men and women in most occupational groups, some groups have experienced increased rates. Future research investigating the specific causes of death at the detailed occupational level will be valuable, particularly with a view to understanding the health implications of precarious employment and the need to improve working conditions in very specific occupational groups. Full-Text PDF Open Access