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Background: Night shift work has been associated with an increased risk for breast and prostate cancer. The effect of circadian disruption on sex steroid production is a possible underlying mechanism, underinvestigated in humans. We have assessed daily rhythms of sex hormones and melatonin in night and day shift workers of both sexes.Methods: We recruited 75 night and 42 day workers, ages 22 to 64 years, in different working settings. Participants collected urine samples from all voids over 24 hours on a working day. Urinary concentrations of 16 sex steroid hormones and metabolites (estrogens, progestagens, and androgens) and 6-sulfatoxymelatonin were measured in all samples. Mean levels and peak time of total and individual metabolite production were compared between night and day workers.Results: Night workers had higher levels of total progestagens [geometric mean ratio (GMR) 1.65; 95% confidence intervals (CI), 1.17–2.32] and androgens (GMR: 1.44; 95% CI, 1.03–2.00), compared with day workers, after adjusting for potential confounders. The increased sex hormone levels among night shift workers were not related to the observed suppression of 6-sulfatoxymelatonin. Peak time of androgens was significantly later among night workers, compared with day workers (testosterone: 12:14 hours; 10:06-14:48 vs. 08:35 hours; 06:52-10:46).Conclusions: We found increased levels of progestagens and androgens as well as delayed peak androgen production in night shift workers compared with day workers.Impact: The increase and mistiming of sex hormone production may explain part of the increased risk for hormone-related cancers observed in night shift workers. Cancer Epidemiol Biomarkers Prev; 24(5); 854–63. ©2015 AACR.

Supplemental Tables 1-5 and Figures 1-2. Supplemental Table 1. Inter-assay precision of the GC-MS method for each sex hormone calculated as the coefficient of variation (CV) after analyzing 15 replicates (3 replicates in 5 different days). Supplemental Table 2. Estimated geometric mean (GM), geometric mean ratio ratio (GMR) and 95% confidence interval (CI) of 24-h mean metabolite levels (mesor) and peak time (acrophase) in night workers compared to day workers in premenopausal women (n=32) by menstrual cycle. Supplemental Table 3. Peak time (acrophase) of metabolite production (hh:mm) in day and night workers among men and women (geometric mean (GM) and 95% confidence intervals (CI)) Supplemental Table 4. Correlations between 6-sulfatoxymelatonin (aMT6s) and sex hormone 24-h mean levels (mesor) and peak time (acrophase) in all subjects, men and women (Pearson correlation coefficients). Supplemental Table 5. Correlations between 6-sulfatoxymelatonin (aMT6s) and sex hormones 24-h mean levels (mesor) and peak time (acrophase) in all, day and night workers (Pearson correlation coefficients). Supplemental Figure 1. Directed acyclic graph (DAG) used for the selections of confounders for the association between night shift work and urinary sex steroid metabolites. Supplemental Figure 2. Scatterplots and correlation coefficients (r) between log-tranformed 24-h mean levels (mesor) and peak time (acrophase) of 6-sulfatoxymelatonin and estradiol, estrone, pregnanediol and testosterone in men and women.

Mechanistic studies are needed to understand how rotating shift work perturbs metabolic processing. We collected plasma samples (n = 196) from 49 males, rotating car factory shift workers at the beginning and end of a night-shift (22:00-06:00 h) and day-shift (06:00 h-14:00 h). Samples underwent targeted LC-MS/MS metabolomics and concentrations of 130 metabolites were log2-transformed and pareto-scaled. An elastic net selected the most influential metabolites for linear mixed models examining within-person variation in metabolite levels at night-shift end (06:00 h) compared to day-shift start (06:00 h). Quantitative enrichment analysis explored differentially enriched biological pathways between sample time points. We included 20 metabolites (amino acids, biogenic amines, acylcarnitines, glycerophospholipids) in mixed models. Night-shift was associated with changes in concentrations of arginine (geometric mean ratio [GMR] 2.30, 95%CI 1.25, 4.23), glutamine (GMR 2.22, 95%CI 1.53, 3.24), kynurenine (GMR 3.22, 95%CI 1.05, 9.87), lysoPC18:2 (GMR 1.86, 95%CI 1.11, 3.11), lysoPC20:3 (GMR 2.48, 95%CI 1.05, 5.83), PCaa34:2 (GMR 2.27, 95%CI 1.16, 4.44), and PCae38:5 (GMR 1.66, 95%CI 1.02, 2.68). Tryptophan metabolism, glutathione metabolism, alanine metabolism, glycine and serine metabolism, and urea cycle were pathways differing between shifts. Night shift work was associated with changes in metabolites and the perturbation of metabolic and biochemical pathways related to a variety of health outcomes.

Background: The epidemiological situation generated by COVID-19 has cast into sharp relief the delicate balance between public health priorities and the economy, with businesses obliged to toe the line between employee health and continued production. In an effort to detect as many cases as possible, isolate contacts, cut transmission chains, and limit the spread of the virus in the workplace, mass testing strategies have been implemented in both public health and industrial contexts to minimize the risk of disruption in activity. Objective: To evaluate the economic impact of the mass workplace testing strategy as carried out by a large automotive company in Catalonia in terms of health and healthcare resource savings. Methodology: Analysis of health costs and impacts based on the estimation of the mortality and morbidity avoided because of screening, and the resulting savings in healthcare costs. Results: The economic impact of the mass workplace testing strategies (using both PCR and RAT tests) was approximately €10.44 per test performed or €5575.49 per positive detected, 38% of this figure corresponds to savings derived from better use of health resources (hospital beds, ICU beds, and follow-up of infected cases), while the remaining 62% corresponds to improved health rates due to the avoided morbidity and mortality. In scenarios with higher positivity rates and a greater impact of the infection on health and the use of health resources, these results could be up to ten times higher (€130.24 per test performed or €69,565.59 per positive detected). Conclusion: In the context of COVID-19, preventive actions carried out by the private sector to safeguard industrial production also have concomitant public benefits in the form of savings in healthcare costs. Thus, governmental bodies need to recognize the value of implementing such strategies in private settings and facilitate them through, for example, subsidies.

Background: Night shift work has been associated with an increased risk for breast and prostate cancer. The effect of circadian disruption on sex steroid production is a possible underlying mechanism, underinvestigated in humans. We have assessed daily rhythms of sex hormones and melatonin in night and day shift workers of both sexes. Methods: We recruited 75 night and 42 day workers, ages 22 to 64 years, in different working settings. Participants collected urine samples from all voids over 24 hours on a working day. Urinary concentrations of 16 sex steroid hormones and metabolites (estrogens, progestagens, and androgens) and 6-sulfatoxymelatonin were measured in all samples. Mean levels and peak time of total and individual metabolite production were compared between night and day workers. Results: Night workers had higher levels of total progestagens [geometric mean ratio (GMR) 1.65; 95% confidence intervals (CI), 1.17–2.32] and androgens (GMR: 1.44; 95% CI, 1.03–2.00), compared with day workers, after adjusting for potential confounders. The increased sex hormone levels among night shift workers were not related to the observed suppression of 6-sulfatoxymelatonin. Peak time of androgens was significantly later among night workers, compared with day workers (testosterone: 12:14 hours; 10:06-14:48 vs. 08:35 hours; 06:52-10:46). Conclusions: We found increased levels of progestagens and androgens as well as delayed peak androgen production in night shift workers compared with day workers. Impact: The increase and mistiming of sex hormone production may explain part of the increased risk for hormone-related cancers observed in night shift workers. Cancer Epidemiol Biomarkers Prev; 24(5); 854–63. ©2015 AACR.