Occupational exposure to whole-body vibrations and pregnancy complications: a nationwide cohort study in Sweden

Integrating a life course perspective in work environment and health research: empirical challenges and interdisciplinary opportunities

A healthy working life is fundamental for individuals and society. To date, increasingly research connects the earlier, pre-working life to later working life experiences and beyond, recognizing that a worker’s health and exposure starts before the working life begins. The research, however, often lacks a fundamental understanding of (i) the underlying mechanisms and pathways accounting for differences in different life stages and (ii) the role of the social environment in shaping working life experiences. By integrating a life course perspective in our research and crossing disciplinary borders in rigorous, collaborative research, we may get a better understanding of the complex and dynamic interplay between work, environment and health.

A life course perspective for work environment and health research A life course perspective in work environment and health research emphasizes the importance of prior life experiences, including the environments in which individuals were raised and exposed, their familial and educational backgrounds, and their physical and mental health status before entering the workforce (1, 2). Life course research in different disciplines has been instrumental in developing more robust causal models (3, 4), particularly for understanding developmental health trajectories and socioeconomic health inequalities (eg, 5–7).

Adopting an interdisciplinary life course perspective in work environment and health research helps researchers answering questions as to whether and how the timing, duration, intensity, and context of past and present exposures (ie, pre-working, working, and non-working exposures) are associated with later life work and health outcomes. For instance, the ‘exposome paradigm’ is a concept used to describe the sum of occupational and environmental exposures an individual encounters throughout life, and how these exposures impact biology and health (8). In exposome research, a broad range of genetic, biological, chemical, physical, social and lifestyle factors is examined throughout the life course to provide a comprehensive picture of potential risk factors impacting working life health (9). In exposome research and beyond, it is important to examine how the exposure-outcome relationships are shaped by specific social, cultural and historical contexts (2). The conceptual framework of the ‘Social Exposome’ may help to integrate the social environment in conjunction with the physical environment into the exposome concept (10). Moreover, focusing on both historical and contemporary contexts is essential not only for advancing research but also for informing policy and practice, for example by identifying entry points for interventions.

Exposures during the life course During the individual’s life course, several vulnerable time windows for the impact of a multitude of exposures that potentially harm, protect or promote health, eg, occupational, environmental and social, can be distinguished. The (combinations of) exposures may operate in different life stages and contexts and – directly or indirectly via intergenerational transmission – contribute to health (figure 1). The individual may be particulary sensitive to harmful exposures or adverse experiences during developmental life stages, ie, pre/perinatal, childhood, adolescence, pregnancy and menopause/andropause. Other life stages may reflect vulnerable time windows due to a clustering of exposures, eg, work and family demands during parenthood, or an accumulation of exposures during the (working) life course at retirement and post-retirement age.

As illustrated in figure 1, occupational exposure(s) can be divided in exposure through the parents’ exposure (early in life) and an individuals’ own exposure (later in life). Already in the pre/perinatal life stage, occupational exposure starts through the intergenerational transmission of the parents’ occupational exposures. Current and bioaccumulated occupational exposure of chemicals and particles in the father at the time of conception can affect sperm quality. Together with the mother’s exposure to occupational exposures of chemicals and particles prior to conception – or chemicals, particles, physical factors, ergonomic load, organizational and (psycho-)social conditions at work during pregnancy – this may affect fetal development and later disease development during the child’s life course (11–15). During childhood, the growing child is exposed to parental occupational exposure(s), directly through chemicals and particles in the work clothes and skin or indirectly through organizational and psychosocial factors in the work environment that may increase the risk for mental and physical health problems in parents, which in turn may affect their parental rearing quality (16, 17).

During adolescence and early adulthood, individuals usually encounter their first direct occupational exposures through their first (student) job or jobs. Already from this life stage, occupational exposures may accumulate during the (working) life course and may affect not only the active working life but also the post working life. Also important to note is that brain plasticity is not limited to childhood, adolescence or young adulthood as it persists throughout life. Some studies indicate that high physical and chemical exposure during this life stage, can increase the risk of disease later in life (18). A poor psychosocial school or work environment in younger years may also increase the risk of adverse labour market outcomes and mental health problems later in life (19, 20). In adulthood, men and women often start with (the planning of) family formation. Some occupational exposures affect fecundability, others can increase the risk of pregnancy-related disease, such as preeclampsia, hypertension or diabetes, or affect the offspring (21, 22). Chemicals, heat and stress-related exposures affect the ability to conceive. During pregnancy, the bodily and mental systems are vulnerable with changes in the endocrine and inflammation response that can dysregulate the HPA-axis, resulting in a prolonged stress response. The placenta can filter out many hazards, but not all toxicants, such as methylmercury and arsenic (23, 24). Physical exposure, such as noise and vibration, but also shift and night work can affect the womb and cause fetal growth restriction, preterm birth, and hearing impairment (eg, 12, 13, 25–27). During parenthood, occupational exposures may affect the parents’ (mental) health and work-family balance (28, 29). Many chemical and physical exposures have now manifested in disease, eg, allergy, asthma and musculoskeletal diseases (28). During menopause in women, with a drastic decrease in oestrogen, and the slow testosterone decline in men (sometimes referred to as andropause), dysregulations of the hormone system may disrupt and affect the individual’s susceptibility for occupational exposures in a way similar to environmental exposures (30). Towards retirement, the total cumulative occupational exposure burden over the working life course and the current exposure will affect the ability to stay at work and in the labor market. Post retirement, most direct occupational exposures have ceased, but others may have (bio-) accumulated over time and may cause health problems that manifest after retirement (31, 32).

Along with occupational exposures, a multitude of other exposures are present during the entire life course that may operate across different contexts to contribute to health (see figure 1). For instance, chemical, physical and social stressors during the life course leave traces (‘memories’) on the molecular and tissue levels that may affect later life health (33). Epigenetic marks act as heritable memories in the cell as they respond to different endogenous and exogenous signals and can be propagated from one generation of cells to the next generation of cells (33). Next to the epigenetic marks, the social environment and social determinants of health during the life course, eg, socio-economic and lifestyle factors, social relationships, social cohesion and support, are known to impact health and add to the multitude of exposures to be examined, among others in conjunction with the environmental exposome (eg, 34). In residential, family and school contexts, exposures such as air pollution, drinking water pollution, noise, artificial light at night, limited access to green space and crowding may play a role, as can adverse childhood experiences (eg, 35, 36). Moreover, on the overarching societal context, legislations, labor market conditions, norms, values and cultural aspects may affect worker health (2, 37).

Main knowledge gaps and challenges Both conceptual and empirical challenges have to be tackled when conducting work environment and health research with an interdisciplinary life course perspective. On the conceptual level, different paradigms and nomenclature still exist in the various disciplines examining the impact of (occupational) exposures on later life health outcomes, which contributes to fragmented research and publication thereof in specialized journals. On the empirical level, questions arise such as: Is it feasible to examine mechanisms and pathways across different exposure levels considering a life course perspective? Is the follow-up duration of existing birth and other cohorts sufficient to address the dynamic interplay between the work environment and health? Are the multifaceted, constantly changing contexts captured? Effect sizes are often small on an individual level and statistical power decreases when several rare assumptions have to be fulfilled to examine clusters or combinations of exposures and contexts in relation to health outcomes.

Big data, interdisciplinary research protocols and innovative, advanced statistical models to capture the life course perspective are needed to proceed beyond the exposome studies that are currently being finalized within the EU Horizon 2020 exposome call (https://www.humanexposome.eu). Moreover, a better understanding is needed of how occupational, environmental and social exposures affect individuals (i) in vulnerable time windows, eg, do exposures contribute to health advantages and/or disadvantages, and (ii) while transitioning between and within different life stages (38). Studies in different disciplines have focused on the childhood and retirement life stages, see eg, the research on the school-to-work transition or the work-to-retirement transition (39–41), but little is known about the menopause or andropause life stage. Last, rigorous examinations of different lifecourse models (eg, sensitive periods) and exposure models (eg, current, first, last, peak, single, chronic or accumulated), and their impact on health are needed within and across the different vulnerable time windows and life stages as exposure-outcome relationships may differ and thus call for targeted (preventive) policies and practices (42–44).

Interdisciplinary research opportunities The challenges towards a better understanding of the complex and dynamic interplay between the work environment and health provide ample opportunities for rigorous, collaborative quantitative and in-depth qualitative life course research across different research strands. Researchers from different disciplines, such as occupational and environmental medicine, epidemiology, toxicology, health science, sociology, psychology, demography, public (mental) health, and genetics to name a few, should not shy away from the complexity, but embrace the opportunity to use their knowledge and skills to collectively address relevant research questions.

Interdisciplinary research opportunities are already present today and will emerge even more in the years to come as more cohorts designed as birth cohorts or multi-generational cohorts mature (eg, LifelinesNext, 45). Researchers have or get access to (national) registers, databases with individual-level internal and external exposure information and neighbourhood-level exposure information or linkages of all these exposure and health data, allowing them to examine the impact of exposures in advanced causal models on later life health. To illustrate the value of and research opportunities with existing data, Ubalde-Lopez and colleagues (46) recently argued that parental work-related data collected in birth cohorts is a valuable yet underutilized resource that could be exploited more fruitfully in the collaboration between birth cohort research, occupational epidemiology and sociology. Having said that, the authors also refer to the possible constraints of eg, cross-national comparative research in terms of technical (ie, harmonization) and ethical challenges (46).

In conclusion, to move research on the work environment and health forward, we call for a more integrated, interdisciplinary approach that considers the timing and accumulation of occupational, environmental and social exposures over the life course.

Occupational exposure to whole-body vibration and neck pain in the Swedish general population

The primary aim of this study was to determine if occupational exposure to whole-body vibration (WBV) was associated with reporting neck pain. A cross-sectional study was conducted on a sample of the general population living in northern Sweden, aged 24-76 years. Data was retrieved through a digital survey that collected subjectively reported information on exposure to WBV and biomechanical exposures as well as neck pain. The study included 5,017 participants (response rate 44%). Neck pain was reported by 269 men (11.8%) and 536 women (20.2%). There was a statistically significant association between reporting occupational exposure to WBV half the time or more (adjusted OR 1.91; 95% CI 1.22-3.00) and reporting neck pain. In gender-stratified analyses, the same pattern was observed in men, while there were too few women to determine any association. We conclude that occupational exposure to whole-body vibration was associated with neck pain in men.Practitioner summary: This cross-sectional, survey-based study investigated associations between self-reported occupational whole-body vibration and neck pain. It showed significant associations between frequent exposure to whole-body vibration and neck pain among men but not women. In occupational health care settings, whole-body vibration could be considered as a possible risk factor for neck pain.

Physical exposures in the work environment during pregnancy - a challenge for risk assessment

Pregnant women have been preforming work-related activities during pregnancy since time immemorial, from the traditional hunter-gatherer or forager society to today’s modern world. But ever since our society has been industrialized, exposure patterns for pregnant women have changed dramatically, and they keep changing. This change is due partly to exposure changes overall in the labor market and partly the changes in the gender balance in different occupations.

To some extent, women have been protected from the most hazardous occupations, since these mainly have been held by men (1). But active strategies within Europe to move towards a gender-balanced work force have increased the number of women seeking employment in hazardous work environments. One example is heavy truck and lorry drivers, who are predicted to be 40% female by 2030 (2). Today, the labor participation rate for women is high, with a total of 67% in Europe and 74–80% in Scandinavian countries (3), leading to a workforce that eventually has as many exposed women as men.

A gender-balanced work force across occupations brings diversity and thus benefits to the work site (4). But it also introduces a challenge, especially in exposed blue-collar occupations. So far, much emphasis has been given to chemical and particles exposure. This is a very important and crucial area for the risk assessment for pregnant workers (5, 6) but not the only hazard present in occupational settings. Too little attention has been paid to physical factors in the work environment during pregnancy in association with health effects, even though physical factors are more prevalent than chemical and particles exposure in occupational settings. The exception is physical load, about which several original articles and reviews have been published (7–9). But physical exposure is a broad concept and also includes exposure to temperature, whole-body vibration, and noise.

Among the physical exposures in occupational settings, physically strenuous work has been the most studied. This area includes work postures, heavy lifting, standing/walking, sedentary work as well as a cardiovascular strain from physical labor. Recent reviews show an overall modest effect for physically strenuous work during pregnancy as well as pregnancy complications and adverse birth outcomes (10). In summary, the evidence so far concludes that pregnant workers should avoid occasional heavy lifting and lifting >10 kg in general (9). Heat in residential settings during pregnancy has been extensively studied (11), and some studies have also focused on occupational settings. An association between heat exposure and heat stress in relation to pregnancy complications as well as birth outcomes has been reported (12). But the evidence is not strong enough to recommend specific temperature levels in occupational settings for pregnant workers.

Only a few studies have investigated noise and whole-body vibration and its effect on pregnant workers. In both areas, reviews have shown inconclusive results (13, 14) and, since then, only a handful studies have been published, including only one large scale cohort study divided into five manuscripts (15–19). The evidence so far suggests that working full-time (8 hours) in weighted average of >80dBA occupational noise and >0.5m/s2 whole-body vibration is associated with an increased risk of pregnancy complications and negative birth outcomes. But since these findings come from one cohort, they need to be confirmed in other high quality cohort studies where levels of exposure can be assessed.

An important review on the evidence so far regarding physical exposures during pregnancy and preterm birth is on the way; the method and protocols have already been published (20), but a review is only as good as its included studies, and we need more high-quality original studies in this research area. Overall, more prospective cohort studies with objectively assessed exposures are needed to be able to identify a safe level for occupational physical exposures during pregnancy. So far, the current evidence on physical load is predominantly based on self-reported physical load, and future studies should focus on high quality objective exposure assessment to increase the level of evidence within this part of the research field.

To be able to progress, future studies also need detailed information on absence from work. In many countries, absence from work due to pregnancy benefit, sick leave and parental leave is common during pregnancy. In Sweden, 7 out of 10 women apply for leave of absence benefits at some point during pregnancy [21). In contrast to chemical exposures, that can bioaccumulate, physical exposures predominately affect the working mother during pregnancy. Hence, to correctly assess occupational exposure to physical factors during pregnancy in relation to health effects in the mother and child, absence from work needs to be addressed properly. Associations can otherwise be missed due to misclassification of exposure. This have been shown in a large-scale cohort study from Sweden, where associations only were found in full time workers with low leave of absence during pregnancy [16-18).

Leave of absence data is also needed to assess the potential beneficial effect that leave of absence can have on the pregnant worker. This was shown in Skröder et al 2021, where pregnant women highly exposed to whole-body vibration only had an increased risk of preterm birth if they had few days of leave of absence during pregnancy. With increased levels of leave of absence from work, women highly exposed to whole-body vibration at work had the same risk of delivering preterm as the general working population. In high levels of leave of absence data, women highly exposed to whole-body vibration had a lower risk of preterm birth then the general population with the same level of absence from work, indicating a healthy worker effect [16). Leave of absence during pregnancy can also be seen as an intermediate measure, since early health effects can lead to an increased level of sick leave, parental leave or pregnancy benefit. An association between exposure at the workplace and level of absence from work have been seen in a recent Danish study and in a recent review [22, 23).

High quality environmental epidemiological studies have been of use when assessing the effect of occupational exposure during pregnancy to chemical and particle exposure on pregnancy complications and birth outcomes. But for physical exposures, the exposures and levels differ substantially between environmental and occupational settings and some of the mechanisms. This is true for the mechanism between noise and health, where occupational and residential exposure to noise both are associated with a stress mechanism, but were only the residential exposure contribute to sleep disturbance and related health effects [13). An exposome approach is needed to identify and assess all the potential risk factors for pregnant women [24). In the exposome concept, multiple exposures in a life course perspective are assessed, with a focus on vulnerable stages, such as pregnancy. It is important to adjust for other co-exposures in the work environment, such as chemical and particle exposure, psychosocial exposures, shift work and other physical exposures when assessing the relationship between occupational exposure to one physical factor and the outcome. These exposures are partly correlated with each other [15-19). Few previous studies have been able to adjust for other occupational exposures at work when investigating individual occupational exposures. Very few studies examined the interaction of occupational exposure and how they jointly contribute to the risk of health effects in the mother and child, even though most of these exposures correlate in the work place [25). Some of the existing birth cohort studies can be regarded as hidden treasures for occupational data, with detailed information on occupational environment of the parents that many times have not been used [26). We need to be able to produce valid exposure-response curves and thereby ensure a safe work environment for the pregnant worker and her child. But also, to avoid excluding women from the labor market during pregnancy unnecessary. An unnecessary exclusion from the labor market can hinder female workers career advancement to the next level of their career and lead to lower salaries, and in the end lower pensions compared to men. So, a well-balance discussion based on high quality evidence can provide a safe and non-discriminatory work environment for pregnant women.

Regarding chemical and particle exposure, an equal low level of exposure for both men and women in reproductive ages can reduce reproductive effects successfully. In physical exposures, there is less need to reduce exposure levels for all, unless these are associated with other health outcomes. It is mainly women of reproductive age who need to be protected, preferably early on since at least whole-body vibration is suspected to be associated with miscarriages. A better system to identify and inform pregnant workers already at the time of their prenatal care registration (usually in gestational week 10) is needed. Overall, there remains a significant knowledge gap regarding the effect of physical occupational exposures during pregnancy and health effects among children. More high-quality cohort studies with objectively assessed exposure that have access to leave-of-absence-during-pregnancy data are needed to increase the level of knowledge in this important area so researchers can generate accurate exposure–response functions and provide correct and well-balanced advice to occupational health services, employers, and pregnant workers.

References 1. Statistikdatabasen - Online database on occupation and demographics.[Internet] Sweden. Statistics Sweden [Cited: 2023 Oct 01 Available from: https://www.statistikdatabasen.scb.se/pxweb/en/ssd/START__AM__AM0208__AM0208E/YREG54/table/tableViewLayout1/ 2. Fler tjejer blir lastbilsförare 40 procent kvinnliga chaufförer om 10 år tror TYA. More girls become truck drivers 40 percent female drivers in 10 years TYA believes [Internet] Landskrona Sveriges trafikbildares riksförbund, [Cited: 2023 Oct 06] Avaliable from: https://www.str.se/mittitrafiken/artikelarkiv/fler-tjejer-blir-lastbilsforare-40-procent-kvinnliga-chaufforer-om-10-ar-tror-tya]. 3. Women’s employment in the EU [Internet]. Brussels. Eurostat.. [Cited: 2023 Sep 18]. Available at: https://ec.europa.eu/eurostat/web/products-eurostat-news/-/EDN-20200306-1 4. Johansson M, Ringblom L. The business case of gender equality in Swedish forestry and mining - restricting or enabling organizational change. Gender Work Org. 2017;24(6):628-642. https://doi.org/10.1111/gwao.12187 5. Rim KT. Reproductive toxic chemicals at work and efforts to protect workers’ health: A literature review. Saf Health Work. 2017;8(2):143-150. https://doi.org/10.1016/j.shaw.2017.04.003 6. Bonde JPE. On endocrine disruption at the workplace - how to get from suggestive to conclusive evidence? Scand J Work Environ Health. 2020;46(4):335-338. https://doi.org/10.5271/sjweh.3897 7. Marbury MC. Relationship of ergonomic stressors to birthweight and gestational age. Scand J Work Environ Health. 1992;18(2):73-83. https://doi.org/10.5271/sjweh.1598 8. Paul JA, van Dijk FJ, Frings-Dresen MH. Work load and musculoskeletal complaints during pregnancy. Scand J Work Environ Health. 1994;20(3):153-9. https://doi.org/10.5271/sjweh.1414 9. Croteau A. Occupational lifting and adverse pregnancy outcome: a systematic review and meta-analysis. Occup Environ Med. 2020;77(7):496-505. https://doi.org/10.1136/oemed-2019-106334 10. Palmer KT, Bonzini M, Bonde JPE. Pregnancy: occupational aspects of management: concise guidance. Clin Med (Lond). 2013;13(1):75-9. https://doi.org/10.7861/clinmedicine.13-1-75 11. Veenema RJ, Hoepner LA, Geer LA. Climate change-related environmental exposures and perinatal and maternal gealth outcomes in the US. Int J Environ Res Public Health, 2023 20(3). https://doi.org/10.3390/ijerph20031662 12. Rekha S, Bhuvana NS, Kanmani S, Vidhya V. A comprehensive review on hot ambient temperature and its impacts on adverse pregnancy outcomes. J Mother Child. 2023;27:10-20. https://doi.org/10.34763/jmotherandchild.20232701.d-22-00051 13. Ristovska G, Laszlo HE, Hansell AL. Reproductive outcomes associated with noise exposure - a systematic review of the literature. Int J Environ Res Pub Health. 2014;11(8):7931-7952. https://doi.org/10.3390/ijerph110807931 14. Seidel H. Selected health risks caused by long-term, whole-body vibration. Am J Ind Med. 1993;23(4):589-604. https://doi.org/10.1002/ajim.4700230407 15. Skröder H, Pettersson H, Albin M, Gustavsson P, Rylander L, Norlén F, et al. Occupational exposure to whole-body vibrations and pregnancy complications: a nationwide cohort study in Sweden. Occup Environ Med. 2020;77(10):691-698. https://doi.org/10.1136/oemed-2020-106519 16. Skröder H, Pettersson H, Norlén F, Gustavsson P, Rylander L, Albin M, et al. Occupational exposure to whole body vibrations and birth outcomes - A nationwide cohort study of Swedish women. Sci Total Environ. 2021;751:141476. https://doi.org/10.1016/j.scitotenv.2020.141476 17. Selander J, Albin M, Rosenhall U, Rylander L, Lewné M, Gustavsson P. Maternal occupational exposure to noise during pregnancy and hearing dysfunction in children: a nationwide prospective cohort study in Sweden. Environ Health Pers. 2016;124(6):855-860. https://doi.org/10.1289/ehp.1509874 18. Selander J, Rylander L, Albin M, Rosenhall U, Lewné M, Gustavsson P. Full-time exposure to occupational noise during pregnancy was associated with reduced birth weight in a nationwide cohort study of Swedish women. Sci Total Environ. 2019;651:1137-1143. https://doi.org/10.1016/j.scitotenv.2018.09.212 19. Lissåker CT, Gustavsson P, Albin M, Ljungman P, Bodin T, Sjöström M. et al. Occupational exposure to noise in relation to pregnancy-related hypertensive disorders and diabetes. Scand J Work Environ Health. 2021;47(1):33-41. https://doi.org/10.5271/sjweh.3913 20. Adane HA, Iles R, Boyle JA, Collie A. Maternal occupational risk factors and preterm birth: Protocol for a systematic review and meta-analysis. PLoS One. 2023;18(7):e0283752. https://doi.org/10.1371/journal.pone.0283752 21. Försäkringskassan. Gravidas socialförsäkringsskydd - Jämlik, ekonomisk trygghet? [Pregnant women`s social security protection - Equal, financial security?] 2022: https://www.forsakringskassan.se/download/18.7fc616c01814e179a9f81c/1662473039324/gravidas-socialforsakringsskydd-socialforsakringsrapport-2022-2.pdf. 22. Hansen ML, Thulstrup AM, Juhl M, Kristensen JK, Ramlau-Hansen CH. Occupational exposures and sick leave during pregnancy: results from a Danish cohort study. Scandinavian Journal of Work Environment & Health. 2015;41(4):397-406. https://doi.org/10.5271/sjweh.3507 23. Henrotin JB, Gulisano F, Sick leave during pregnancy and occupational factors: a systematic review. Occup Med. 2022;72(8):550-558.https://doi.org/10.1093/occmed/kqac090 24. Handakas E, Robinson O, Laine JE. The exposome approach to study children`s health. Curr Op Environ Sci Health. 2023;32. https://doi.org/10.1016/j.coesh.2023.100455 25. Nurminen T, Kurppa K. Occupational noise exposure and course of pregnancy. Scand J Work Environ Health. 1989;15(2):117-124. https://doi.org/10.5271/sjweh.1873 26. Ubalde-Lopez M, Garani-Papadatos T, Scelo G, Casas M, Lissåker C, Peters S, et al. Working life, health and well-being of parents: a joint effort to uncover hidden treasures in European birth cohorts. Scand J Work Environ Health. 2021;47(7):550-560. https://doi.org/10.5271/sjweh.3980

Prevalence of Reproductive Health Issues among US Female Law Enforcement Officers

Reproductive health is a considerable concern among US female law enforcement officers (LEOs). Miscarriage and preterm birth rates are significantly higher in women firefighters than published US averages. Since law enforcement and firefighting share occupational conditions and practices, adverse birth outcomes were hypothesized to be greater in female law enforcement officers (LEOs) than the US averages. Occupational hazards may place pregnant LEOs at a higher risk for complicated pregnancies and adverse birth outcomes. This study quantified pregnancy outcomes in female LEOs using a cross-sectional survey and compared them to US averages and large prospective studies. The participants (N = 162, 72.2% aged 31-49, 85.2% Caucasian) averaged 2.5 ± 1.4 pregnancies. Stress (59.1%) and shiftwork (59.8%) were the most common reported exposures. Miscarriage and preterm birth rates were 19.1% and 16.4%, respectively. Miscarriages were significantly greater among participants compared to prospective studies [χ2 (1, N = 911,971) = 20.51, p < 0.001]. Female LEOs of childbearing age should receive education about potential reproductive health hazards and take precautions against them. Moreover, policymakers, human resources, and healthcare providers should understand how law enforcement work might affect maternal health.

Women's Employment in Industries and Risk of Preeclampsia and Gestational Diabetes: A National Population Study of Republic of Korea

Background

Some working conditions may pose a higher physical or psychological demand to pregnant women leading to increased risks of pregnancy complications.

Objectives

We assessed the association of woman's employment status and the industrial classification with obstetric complications.

Methods

We conducted a national population study using the National Health Information Service database of Republic of Korea. Our analysis encompassed 1,316,310 women who experienced first-order live births in 2010-2019. We collected data on the employment status and the industrial classification of women, as well as their diagnoses of preeclampsia (PE) and gestational diabetes mellitus (GDM) classified as A1 (well controlled by diet) or A2 (requiring medication). We calculated odds ratios (aORs) of complications per employment, and each industrial classification was adjusted for individual risk factors.

Results

Most (64.7%) were in employment during pregnancy. Manufacturing (16.4%) and the health and social (16.2%) work represented the most prevalent industries. The health and social work exhibited a higher risk of PE (aOR = 1.11, 95% confidence interval [CI]: 1.03-1.21), while the manufacturing industry demonstrated a higher risk of class A2 GDM (1.20, 95% CI: 1.03-1.41) than financial intermediation. When analyzing both classes of GDM, women who worked in public administration and defense/social security showed higher risk of class A1 GDM (1.04, 95% CI: 1.01, 1.07). When comparing high-risk industries with nonemployment, the health and social work showed a comparable risk of PE (1.02, 95% CI: 0.97, 1.07).

Conclusion

Employment was associated with overall lower risks of obstetric complications. Health and social service work can counteract the healthy worker effect in relation to PE. This highlights the importance of further elucidating specific occupational risk factors within the high-risk industries.

Effects of whole-body vibration on reproductive physiology in a rat model of whole-body vibration

Findings from epidemiological studies suggest that occupational exposure to whole-body vibration (WBV) may increase the risk of miscarriage and contribute to a reduction in fertility rates in both men and women. However, workers exposed to WBV may also be exposed to other risk factors that contribute to reproductive dysfunction. The goal of this experiment was to examine the effects of WBV on reproductive physiology in a rat model. Male and female rats were exposed to WBV at the resonant frequency of the torso (31.5 Hz, 0.3 g amplitude) for 4 hr/day for 10 days. WBV exposure resulted in a significant reduction in number of developing follicles, and decrease in circulating estradiol concentrations, ovarian luteinizing hormone receptor protein levels, and marked changes in transcript levels for several factors involved in follicular development, cell cycle, and steroidogenesis. In males, WBV resulted in a significant reduction in spermatids and circulating prolactin levels, elevation in number of males having higher circulating testosterone concentrations, and marked alterations in levels of transcripts associated with oxidative stress, inflammation, and factors involved in regulating the cell cycle. Based upon these findings data indicate that occupational exposure to WBV contributes to adverse alterations in reproductive physiology in both genders that may lead to reduction in fertility.

Traditional practices during pregnancy and childbirth among mothers in Shey Bench District, South West Ethiopia

Objective:

Pregnancy and child birth is the most critical period in the health of women and children and the objective of this study was to explore traditional practices among mothers during pregnancy and delivery in Shey Bench District, South West Ethiopia, and we hope the evidence generated could benefit decision-makers and concerned bodies who are interested in this important public health issue.

Methods:

A descriptive qualitative study, which is an ideal approach when an uncomplicated description is desired that focuses on the details of what, where, when, and why of an event or experience, was conducted from March to May 2019 in Shey Bench District and a purposively selected 43 women have participated in the study. In-depth interviews and key informant interviews were conducted and data were analyzed by Open code 4.2 software and summarized following content analysis approach. Findings were narrated based on the major categories and study participants’ words were used as quotes.

Results:

In this study, it was found that mothers have experience of traditional practices mainly of abdominal massage, use of herbs, prohibition of some food types, and strenuous physical exercise during pregnancy and childbirth. As of the reasons; mothers reported as traditional practices help them to make the labor easy and fast, alleviate discomforts, and avoid unwanted big size of the fetus. Experience of health problem following practice of traditional practices like vaginal bleeding and child death were also reported. However, some study participants indicated as community members are changing their mind because of getting advice from health professionals.

Conclusion:

Although traditional practices were found to be exercised by mothers believing to get benefits, there were reports of health side effects on mothers and the fetus from applying abdominal massage, herbal medicine, food prohibition, and strenuous physical exercise during their pregnancy and childbirth. Therefore, concerned working bodies shall design and implement necessary interventions, particularly health education programs to bring a better a change against harmful traditional practices.

Applying the exposome concept to working life health

Exposures at work have a major impact on noncommunicable diseases (NCDs). Current risk reduction policies and strategies are informed by existing scientific evidence, which is limited due to the challenges of studying the complex relationship between exposure at work and outside work and health. We define the working life exposome as all occupational and related nonoccupational exposures. The latter includes nonoccupational exposures that may be directly or indirectly influenced by or interact with the working life of the individual in their relation to health. The Exposome Project for Health and Occupational Research aims to advance knowledge on the complex working life exposures in relation to disease beyond the single high exposure–single health outcome paradigm, mapping and relating interrelated exposures to inherent biological pathways, key body functions, and health. This will be achieved by combining (1) large-scale harmonization and pooling of existing European cohorts systematically looking at multiple exposures and diseases, with (2) the collection of new high-resolution external and internal exposure data. Methods and tools to characterize the working life exposome will be developed and applied, including sensors, wearables, a harmonized job exposure matrix (EuroJEM), noninvasive biomonitoring, omics, data mining, and (bio)statistics. The toolbox of developed methods and knowledge will be made available to policy makers, occupational health practitioners, and scientists. Advanced knowledge on working life exposures in relation to NCDs will serve as a basis for evidence-based and cost-effective preventive policies and actions. The toolbox will also enable future scientists to further expand the working life exposome knowledge base.

Occupational Risk Factors and Hypertensive Disorders in Pregnancy: A Systematic Review

Hypertensive disorders in pregnancy (HDP), including gestational hypertension (GH) and preeclampsia (PE), characterize a major cause of maternal and prenatal morbidity and mortality. In this systematic review, we tested the hypothesis that occupational factors would impact the risk for HDP in pregnant workers. MEDLINE, Scopus, and Web of Knowledge databases were searched for studies published between database inception and 1 April 2021. All observational studies enrolling > 10 pregnant workers and published in English were included. Un-experimental, non-occupational human studies were excluded. Evidence was synthesized according to the risk for HDP development in employed women, eventually exposed to chemical, physical, biological and organizational risk factors. The evidence quality was assessed through the Newcastle–Ottawa scale. Out of 745 records identified, 27 were eligible. No definite conclusions could be extrapolated for the majority of the examined risk factors, while more homogenous data supported positive associations between job-strain and HDP risk. Limitations due to the lack of suitable characterizations of workplace exposure (i.e., doses, length, co-exposures) and possible interplay with personal issues should be deeply addressed. This may be helpful to better assess occupational risks for pregnant women and plan adequate measures of control to protect their health and that of their children.

Occupational exposure to whole body vibrations and birth outcomes - A nationwide cohort study of Swedish women

BACKGROUND

More women in reproductive ages are entering occupations where exposure to whole body vibrations (WBV) is common (e.g. in transportation and construction). Previous studies based on self-assessed exposure suggest increased risks of adverse birth outcomes, but it is unclear at what exposure levels and if the current exposure guidelines are appropriate during pregnancy.

OBJECTIVES

To investigate whether occupational WBV-exposure increases the risk of preterm birth, low birth weight, and/or small-for-gestational age, in a large, nationwide, prospective, cohort study.

DESIGN

The Fetal Air Pollution Exposure cohort (FAIR) was formed by merging data from multiple, national registers, and the present study includes singletons born 1994-2014 to working women in Sweden (n = 1,091,080 births). WBV-exposure was assessed quantitatively using a job-exposure matrix based on measurements, and calculated odds ratios were adjusted for potential confounders such as smoking and BMI, and other occupational exposures like noise, combustion particles, and physically and psychologically strenuous work. Data on absence from work (full-/part time, sick leave, parental leave, etc.) was also used.

RESULTS

Exposure to WBV during pregnancy, among women with low absence from work (n = 476,419), was associated with an increased risk of preterm birth, below the occupational exposure limit (1.15 m/s²). Compared to unexposed mothers, the OR was 1.38 (95% CI: 1.05, 1.83) for exposure ≥0.5 m/s², corresponding to an increase from 47/1000 cases to 65/1000 cases. No increased risk was found for small-for-gestational age.

CONCLUSIONS

Exposure to WBV was associated with an increased risk of preterm birth. The results suggest that the current permissible exposure and action levels for WBV-exposure do not adequately protect pregnant women with continuous exposure.