Assessment of exposure to shiftwork mechanisms in the general population: the development of a new job-exposure matrix

Abstract

This JEM provides a set of indicators reflecting biologically plausible mechanisms for the potential impact of shiftwork on health and may provide an alternative method of exposure assessment in the absence of detailed job history and exposure data.

Association between shiftwork and the risk of colorectal cancer in females: a population-based case–control study

“…We used a JEM to assess exposure to two different types of shiftwork (graveyard shiftwork and early-morning shiftwork) and six mechanistic variables (light at night while working night shifts, phase shift while working night shifts, sleep disturbances while working night shifts, poor diet while working night shifts, lack of physical activity while working night shifts and lack of vitamin D while working night shifts) 22. The definitions of probable exposure to each of the eight variables are outlined in online supplementary table 1.…”

“…The definitions of probable exposure to each of the eight variables are outlined in online supplementary table 1. The JEM predicts the probability that a particular job (based on ISCO-68 code) involved exposure to each of the eight shiftwork variables 22. As recommended by the creators of the JEM, we used a 30% probability cut-off to classify exposure to each of the shiftwork variables as this cut-off was found to have the most acceptable level of specificity (>75%) without compromising sensitivity (≥70%) 22.…”

“…The JEM predicts the probability that a particular job (based on ISCO-68 code) involved exposure to each of the eight shiftwork variables 22. As recommended by the creators of the JEM, we used a 30% probability cut-off to classify exposure to each of the shiftwork variables as this cut-off was found to have the most acceptable level of specificity (>75%) without compromising sensitivity (≥70%) 22. We also conducted a sensitivity analysis to assess if using a 50% probability cut-point for all the shiftwork variables resulted in ORs further from the null than those observed when using the 30% cut-off, with the rationale that a stricter definition of shift work would result in fewer false positives when assessing possible exposure to each of the shiftwork variables.…”

Personal light-at-night exposures and components of variability in two common shift work industries: uses and implications for future research

“…There are a number of opportunities for refinement in this area, since to date most shift work job exposure matrices have focused on assessing the probability of exposure to night shift work rather than specific characteristics of shift work (such as LAN exposures) that may affect health (32). Quantitative measurements of LAN exposure could be used to develop exposure estimates that are less prone to exposure misclassification and bias versus subjectively defined measures (32), and to test the validity of subjective proxy measures (eg, self-reported exposures or expert assessment).…”

“…There are a number of opportunities for refinement in this area, since to date most shift work job exposure matrices have focused on assessing the probability of exposure to night shift work rather than specific characteristics of shift work (such as LAN exposures) that may affect health (32). Quantitative measurements of LAN exposure could be used to develop exposure estimates that are less prone to exposure misclassification and bias versus subjectively defined measures (32), and to test the validity of subjective proxy measures (eg, self-reported exposures or expert assessment). Variance components estimated from quantitative measurements could also be applied to optimize the performance of a shift work job exposure matrix by identifying grouping variables (such as industry, job, or worksite) that most effectively Hall et al discriminate homogenous groups to increase exposure contrast (33).…”