Occupational and Environmental Medicine最新文献

Objectives: Despite biological and environmental plausibility, risk factors for infertility have not yet been studied among female firefighters. In this exploratory analysis, we investigated the burden of infertility among a subset of US firefighters enrolled in the Health and Wellness of Women Firefighters Study.

Methods: Women firefighters enrolled in the study responded to surveys administered in 2017 and 2019, reporting on their work environment, reproductive health, infertility history and fertility treatment history among those with infertility. Demographics and reproductive history of firefighters were compared by reported history of infertility. Log binomial regression models were used to estimate the association between occupational factors and risk of infertility.

Results: Of the 562 firefighters in our analysis, 168 of these women (30%) reported a history of infertility. A longer length of employment as a firefighter was associated with a modest, but non-statistically significant, increased relative risk of experiencing infertility (1.39, 95% CI 0.86 to 2.24).

Conclusions: This exploratory analysis highlights an opportunity to further examine infertility and impaired fertility among firefighters. Future studies may focus on comparing the burden of infertility in firefighters to the general population and evaluating the influence of additional occupational factors.

Objectives: Ionising radiation is a human carcinogen; however, there are uncertainties about the shape of the exposure-response function at low doses. We evaluated the relationship between radiation dose and cancer incidence in a cohort of Canadian nuclear power plant workers (NPPWs) with protracted exposures to low-dose ionising radiation.

Methods: The cohort included 75 350 workers employed at one of five Canadian nuclear power plants any time between 1945 and 2010. Exposure to cumulative whole-body effective dose was determined through personal monitoring. A total of 4370 incident cancers were identified through record linkage of these workers to national cancer registries (1969-2010). Vital status was determined through linkages to national mortality and tax databases. Standardised incidence ratios (SIRs) were calculated to compare cancer incidence rates of the cohort with the Canadian general population. Poisson regression was used to characterise dose-response relationships via categorical and linear excess relative risk (ERR) models.

Results: Significantly elevated SIRs were found for solid cancers (combined), melanoma, colon and prostate cancer, while a reduced SIR was found for lung cancer. Positive, but not statistically significant excess risks were found for melanoma (ERR/100 mSv=0.32; 95% CI: -0.23 to 0.87) and prostate cancer (ERR/100 mSv=0.12; 95% CI: -0.05 to 0.29). An inverse association was found for lung cancer (ERR/100 mSv=-0.18; 95% CI: -0.01 to -0.36).

Conclusions: Our findings suggest that Canadian NPPWs have increased risks of prostate cancer and melanoma from low-dose ionising radiation exposure. Estimates should be cautiously interpreted due to the inability to adjust for demographic and lifestyle factors.

Objectives: While injuries/illnesses among emergency responders during extreme bushfires in Victoria, Australia, are well-documented, the impact of bushfire periods on return-to-work (RTW) outcomes is less understood. This study investigates whether workers' compensation claims lodged during extreme bushfire periods are associated with slower RTW, more lost work time and time-off-work relapse.

Methods: Workers' compensation claims made by emergency responders in Victoria (Australia), 2005-2023, were analysed. Claims for injuries/diseases occurring during bushfire periods were compared with those made during non-bushfire periods. Time to first full RTW was determined from income compensation payments as time until first payment cessation of ≥10 days. RTW was analysed using Cox regression models. Compensated workdays and time-off-work relapse occurrences were modelled using generalised linear models and logistic regression, respectively.

Results: Among 11 773 claims, 398 (3.4%) were lodged during extreme bushfires. Extreme bushfire period claims were associated with longer time to RTW (HR of 0.81, 95% CI 0.73 to 0.91). In extreme bushfire periods, median compensated days per claim were 74 (IQR 20, 346) versus 58 (18, 212) in other time periods. In the adjusted modelling, the count ratio for extreme bushfire periods (vs other time periods) was 1.13 (95%CI 1.01 to 1.27): a 13% increase in expected compensated days. Time-off-work relapse occurrence was not significantly affected by extreme bushfire periods.

Conclusion: In emergency responders, bushfire period claims were associated with increased duration of time off work. Tailored RTW programmes that proactively gauge claim complexity associated with exposure to extreme bushfires, as well as provision of targeted services, should be considered.

Objectives: Exposure to bioaerosols from salmon processing is associated with occupational asthma. The prevalence of work-related asthma symptoms in fish processing workers has earlier been reported to be 12%-24%, but small sample sizes and heterogeneity in exposure across studies make generalisability to todays' salmon processing industry questionable. Studies comparing filleting workers and slaughtering workers have shown conflicting results.

Methods: Questionnaire and spirometry data from workers in nine different salmon processing plants were gathered during 2021-2023. Exposure to salmon bioaerosols was defined by work tasks and total time working with salmon. Asthma symptoms and lung function were compared between exposure groups using logistic regression and adjusting for relevant confounding variables.

Results: Of the 867 workers regularly or variably exposed to salmon bioaerosols, 170 (20%) had work-related asthma symptoms. Exposure was associated with symptoms, but not with lung function. Of the 440 exposed workers with spirometry data, 9.8% had expiratory airflow limitation, and all mean lung function measures were below the reference values. The prevalence of work-related asthma symptoms was slightly higher among gutting workers than filleting workers (OR 1.7, 95% CI 1.1 to 2.8).

Conclusions: The prevalence of work-related asthma symptoms is high in salmon processing, probably due to bioaerosol exposure. Salmon processing workers had more expiratory airflow limitation and lower lung function compared with the reference values. Although gutting workers had slightly higher risk for work-related asthma symptoms than filleting workers, all exposed workers seem to be at risk and preventive measures should be taken in all areas where bioaerosols are present.

Cadmium (Cd), a group 1 carcinogen, is linked to the development of pancreatic cancer. Not well-defined is the dose-response relationship between Cd and cancer development.This study investigated the relationship between Cd exposure and the risk of pancreatic cancer through a meta-analysis focusing on pooled relative risk (RR), biomarker comparisons and dose-response relationships.This meta-analysis adhered to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and applied the PECO (population, exposure, comparator and outcomes) framework. Systematic searches of key databases, including PubMed, Cochrane Library, Web of Science, EMBASE, ScienceDirect and ProQuest, were carried out without language restrictions. Studies that met the predefined PECO criteria were chosen, extracting data on effect estimates such as HRs, ORs, RRs and Cd biomarker concentrations. Analyses involved pooled RRs, standardised mean differences for biomarker comparisons and dose-response relationships, using random-effects meta-analysis and meta-regression. Statistical procedures were performed on R V.4.3.0.Cd exposure was significantly associated with an increased risk of pancreatic cancer, with a pooled RR of 1.42 (95% CI=1.16 to 1.73). Subgroup analyses confirmed this association in both occupationally and non-occupationally exposed individuals. Dose-response analyses further revealed that higher Cd biomarker levels correlated with greater pancreatic cancer risk (lnRR coefficient=0.610, p=0.035).Cd exposure is associated with an increased risk of pancreatic cancer, with a dose-response relationship and elevated biomarker levels in cases. Cd exposure is a modifiable risk factor for pancreatic cancer, meriting further investigation.

Objectives: Night shift work has been classified as probably carcinogenic to humans, possibly related to suppression of melatonin secretion. Although experimental studies suggest that melatonin inhibits intestinal tumor proliferation, epidemiological evidence for a relationship between night shift work and colorectal cancer (CRC) risk is lacking.

Methods: We prospectively examined the association between night shift work and CRC in the Nightingale Study. We included 56 477 Dutch female nurses who completed a questionnaire in 2011, including occupational history with detailed (historical) information on night shift work. Until February 2025, 468 incident CRCs were recorded. Age-adjusted HRs and 95% CIs for associations between night shift work variables and CRC risk were estimated using Cox regressions.

Results: CRC risk did not differ between nurses who ever or never worked night shifts (HR=1.13; 95% CI=0.89 to 1.44). A longer duration of working night shifts (≥20 years: HR=1.19; 95%CI=0.89 to 1.60) was neither associated with CRC risk. However, a higher average number of consecutive night shifts per month (continuous per shift; HR=1.04, 95%CI=1.00 to 1.07) and a higher cumulative number of performed night shifts (continuous per 250 shifts: HR=1.02; 95%CI=1.00 to 1.04) were associated with a slightly increased risk. Chronotype did not affect the associations of CRC risk with night shift work.

Conclusions: Although a longer duration of night shift work was not associated with CRC risk, both a higher frequency of and a higher cumulative exposure to night shifts were associated with slightly higher risk, suggesting a potential association between extensive exposure to night shift work and CRC risk.

This systematic review examined the impact of unemployment and re-employment on mental health problems (depression, anxiety and psychological distress) among working-age adults. We searched MEDLINE, Embase, APA PsycINFO and Web of Science (January 2012-March 2024) and included studies from a prior meta-analysis (1990-2012). Risk of bias was assessed using the Newcastle-Ottawa Scale. We conducted random-effects meta-analyses and narrative synthesis and evaluated the certainty of evidence using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Of 9328 search records, 38 prospective longitudinal studies met the inclusion criteria (27 from 2012-2024 and 11 from 1990-2012). A pooled standardised mean difference (SMD, Cohen's d) of 0.19 (95% CI 0.08 to 0.30, I²=88.7%) indicated increased symptom levels among the unemployed compared with those regularly employed. Similarly, pooled effect estimates indicated reduced symptoms after re-employment, with a stronger effect observed in between-group difference-in-difference analyses (SMD=-0.27, 95% CI -0.35 to -0.20, I²=40.1%) than within-group analyses (SMD=-0.19, 95% CI -0.29 to -0.10, I²=84.3%). The certainty of evidence for all outcomes based on our GRADE evaluation was low. Our systematic review and meta-analysis suggest that unemployment increases the risk of mental health problems, while re-employment may reduce this risk. However, due to the lack of high-certainty evidence, further longitudinal studies with multiple follow-ups are needed to strengthen causal inferences and better clarify mental health trajectories before and after re-employment.

Objective: While work provides a crucial source of income and purpose, pain can be a significant limiting factor. Yet robust empirical evidence on the factors underlying the link between pain and being out of work remains scarce. We explore the longitudinal association between pain and being out of work and potential explanatory factors.

Methods: We used nationally representative longitudinal data from the Household, Income and Labour Dynamics of Australia Survey (n=25 973, number of observations=233 989, 2002-2022). We conducted individual fixed effects regressions with a wide range of covariates.

Results: We found that pain in a given year was significantly positively associated with the likelihood of being out of work the year after. Pain interference with work explained this link. This association was moderated by job control: participants who reported very severe pain and low job control were more likely (10.6%) to lose their job next year than those who reported very severe pain and high job control (6.7%).

Conclusions: Pain was associated with being out of work, with job control moderating that link. Having the autonomy to flexibly adapt the nature of work tasks to accommodate pain may protect against being out of work.

Objectives: Shift work disrupts hormonal rhythms, but evidence linking specific shift patterns to cortisol/melatonin variations remains limited. This study evaluated the associations of a rapid-rotating shift pattern (ie, PAN pattern, shift transitions from afternoon to morning to night shifts within approximately 40 hours) and irregular non-PAN pattern shifts with urinary cortisol and melatonin among Hong Kong nurses, while also assessing the role of sleep on rhythmic hormones.

Methods: A 7-day actigraphy-based study recruited 201 shift nurses and 100 daytime workers. First-morning voids on the first non-workday postnight shift or postoffice work measured cortisol and melatonin metabolite (aMT6s) levels. Actigraphy measured sleep parameters. Generalised linear models examined the associations.

Results: PAN pattern nurses slept less than non-PAN nurses (5.8 vs 6.4 hours) and exhibited greater circadian phase delay (16.4 vs 15.9 hours). Non-PAN nurses had the lowest cortisol, cortisone and aMT6s levels, with significantly reduced cortisol levels (β=-0.31, p=0.017) compared with daytime workers. Sleep characteristics strongly influenced hormone levels, with each additional hour of sleep decreasing cortisol levels by 10.3%, while each later hour of wake-up time was associated with 3.9% lower cortisol levels; later sleep midpoints decreased melatonin by 5.1% per hour. A three-way interaction revealed weakened cortisol-sleep duration associations with later wake-up times in PAN nurses (p=0.032).

Conclusions: Irregular shifts, longer sleep duration and delayed wake-up time significantly reduced wakening cortisol levels, while delayed sleep timing suppressed melatonin secretion. These findings highlight how shift arrangements and sleep characteristics disrupt hormonal rhythms in shift workers. Optimising shift patterns and sleep interventions (eg, prioritising duration/consistency) may mitigate circadian disruption and improve shift worker health.

Objectives: To assess absolute levels and longitudinal changes in cardiovascular disease (CVD) risk factors over 6 years among rotating shift workers with night shift work and day workers in industry.

Methods: We studied three groups, 32 night shift workers in Plant A with a high night load, 23 in Plant B with a low night load and 25 day workers during a 6-year follow-up (FU). We collected demographics by questionnaire, measured blood pressure, resting heart rate, carotid intima-media thickness (cIMT), carotid to femoral pulse wave velocity (cfPWV) and maximal oxygen uptake (V̇O_2max). We analysed blood samples including lipids, glycosylated haemoglobin (HbA1c) and C reactive protein (CRP). Mixed models were used to assess changes and differences in changes of these outcomes between shift and day workers.

Results: Over the 6-year FU weight, cfPWV and CRP increased among shift workers with a high night load, and cIMT increased among shift workers with a low night load and among day workers. Over the 6-year FU, a significant decrease in V̇O_2max and an increase in HbA1c were found among all workers. The decrease in V̇O_2max and increase in HbA1c were associated with number of years in shift work.

Conclusions: Rotating shift work with night shift work in industry associates with weight increase, inflammation, arterial stiffness, increase in cIMT and HbA1c but also decreased V̇O_2max. Reducing the number of night shifts and including periods of restitution in the shift plan seem to mitigate some of the CVD risk factors.