Healthy worker effect phenomenon: Revisited with emphasis on statistical methods – A review

Abstract

Known since 1885 but studied systematically only in the past four decades, the healthy worker effect (HWE) is a special form of selection bias common to occupational cohort studies. The phenomenon has been under debate for many years with respect to its impact, conceptual approach (confounding, selection bias, or both), and ways to resolve or account for its effect. The effect is not uniform across age groups, gender, race, and types of occupations and nor is it constant over time. Hence, assessing HWE and accounting for it in statistical analyses is complicated and requires sophisticated methods. Here, we review the HWE, factors affecting it, and methods developed so far to deal with it.

Work ability of military police officers

“…Moreover, one cannot dismiss the importance of the “healthy worker effect” 26 , which may have acted in a more relevant way in the composition of this group of military police officers in at least two ways: a) by entering the corporation and selecting individuals with different characteristics to make up the exposure subgroups of and outcome and b) over time in the corporation, excluding those police officers who were presenting poor work ability for different reasons (survival effect of the healthy worker). An important limitation of this investigation was the lack of assessment of work organization, workload and psychosocial workload.…”

“…Além disso, não pode-se afastar a importância do “efeito do trabalhador sadio” 26 , que pode ter agido de forma mais relevante na composição deste grupo de policiais militares, pelo menos de duas formas: a) à entrada na corporação, ao selecionar indivíduos com características diferenciadas para compor os subgrupos de exposição e desfecho e b) ao longo do tempo na corporação, ao excluir aqueles policiais que vinham apresentando baixa capacidade para o trabalho, por motivos diversos (efeito sobrevivência do trabalhador sadio). Uma importante limitação desta pesquisa foi a ausência de algum tipo de avaliação da organização do trabalho, carga de trabalho e cargas psicossociais do trabalho.…”

Self-reported health problems in a health risk appraisal predict permanent work disability: a prospective cohort study of 22,023 employees from different sectors in Finland with up to 6-year follow-up

“…Another limitation of study is the potential selection bias due to differences between respondents and non-respondents. "Healthy worker effect" might be present if employees with worse health level had not responded or they are less likely to hire (Chowdhury et al 2017). Similar bias would potentially result from a "healthy worker survival effect", which means that only healthiest and strongest will remain in the working life (Nordström et al 2016).…”

Night work and postpartum depression: a national register-based cohort study

“…Further investigation of the healthy worker survivor effect among night workers requires specific epidemiological and statistical methods (14,(52)(53)(54)(55). This would require information on the time of onset of depressive symptoms along with information on the reason for changing work schedules.…”

“…These reviews did not inform whether PPD was included in any of the studies. As pointed out by Angerer and colleagues (11), prior studies on depression in relation to night work are challenged by cross-sectional design, self-reported exposure and outcome, and the possibility of the healthy worker survivor effect, ie, the selection of individuals with poorer health status out of night work (13,14).…”