Substantial decrease of PFAS with anion exchange resin treatment - A clinical cross-over trial.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) are heat and stain resisting chemicals. They are persistent, bioaccumulating and spread ubiquitously. Many hotspots where humans are exposed to high levels of PFAS have been reported. A few small observational studies in humans suggest that treatment with an Anion Exchange Resin (AER) decreases serum PFAS. This first clinical controlled crossover study aimed to assess whether AER decreases perfluorooctanesulfonic acid (PFOS) in highly exposed adults. METHODS: An open label 1:1 randomized treatment sequence crossover study with allocation to oral AER (cholestyramine 4 g three times daily) or observation for 12 weeks was conducted among citizens from a PFAS hotspot. Main inclusion criteria was serum PFOS > 21 ng/mL. Primary endpoint was change in serum PFOS levels between treatment and observational period. RESULTS: In total, 45 participants were included with a mean age of 50 years (SD 13). Serum PFOS baseline median was 191 ng/mL (IQR: 129-229) and decreased with a mean of 115 ng/mL (95 % CI: 89-140) on treatment, and 4.3 ng/mL in observation period corresponding to a decrease of 60 % (95 % CI: 53-67; p < 0.0001). PFHxS, PFOA, PFNA and PFDA decreased during treatment between 15 and 44 %. No serious adverse events were reported. CONCLUSIONS: Oral treatment with AER significantly lowered serum PFOS concentrations suggesting a possible treatment for enhancing elimination of PFOS in highly exposed adults.

Night work during pregnancy and small for gestational age: a Danish nationwide register-based cohort study.

OBJECTIVE: The aim was to investigate the association between night work during pregnancy and risk of having a small for gestational age (SGA) child. METHODS: This cohort study had payroll data with detailed information on working hours for employees in all Danish administrative regions (primarily hospital employees) between 2007 and 2015, retrieved from the Danish Working Hour Database. Pregnancies, covariates and outcome were identified from the national birth registry. We used logistic regression to investigate the association between intensity and duration of night work during the first 32 pregnancy weeks and SGA. The adjusted model included age, body mass index, socioeconomic status and smoking. Using quantitative bias analysis and G-estimation, we explored potential healthy worker survivor bias (HWSB). RESULTS: The final cohort comprised 24 548 singleton pregnancies in 19 107 women, primarily nurses and medical doctors. None of the dimensions of night work were associated with an increased risk of SGA. We found a tendency towards higher risk of SGA in pregnancies where the women stopped having night shifts during pregnancy. Using G-estimation we found an OR<1 for the association between night work and SGA if all workers continued having night work during pregnancy compared with daywork only. CONCLUSION: We found no increased risk of SGA in association with night work during pregnancy among healthcare workers. G-estimation was not precise enough to estimate the observed indication of HWSB. We need better data on pregnancy discomforts and complications to be able to safely rule out HWSB.

Time trends in per- and polyfluoroalkyl substances (PFAS) concentrations in the Danish population: A review based on published and newly analyzed data.

INTRODUCTION: Per- and polyfluoroalkyl substances (PFAS) are persistent chemicals used in many industries and everyday consumer products and exposure has been linked to several adverse health outcomes. Currently, no systematic monitoring of PFAS levels in the general Danish population has been conducted. OBJECTIVE: To study temporal trends of PFAS concentrations in the Danish population. MATERIALS AND METHODS: In August 2023, we performed a search for original peer-reviewed reports in PubMed using combinations of search terms for PFAS and Denmark. Reports were included if they comprised a Danish study population and direct measurements of PFAS in serum or plasma samples. Scatter plots of medians presented in the reports were used to visualize time-trends of PFAS concentrations among Danish individuals. RESULTS: We included 29 reports based on a total of 18,231 individuals from 19 Danish study populations. A total of 24 PFAS measured in serum or plasma were presented in the reports, the most frequent being PFOS, PFOA, PFDA, PFNA, PFHpA, PFHpS, and PFHxS. Median concentrations of PFOS ranged from 4.0 ng/mL to 44.5 ng/mL, PFOA ranged from 0.8 ng/mL to 9.7 ng/mL, while lower concentrations were presented for the other PFAS. Median concentrations of PFOS and PFOA increased from 1988 until the late 1990s followed by a decrease until 2021. A less clear time-trend were observed for the other PFAS. CONCLUSION: Blood concentrations of PFOS and PFOA in the Danish population have declined substantially from the late 1990s until 2021 reflecting a phase-out of the production and regulation of the use of these PFAS. Time-trends for PFDA, PFNA, PFHpA, PFHpS, and PFHxS were less evident, yet a tendency toward a decline was observed. As only some of the compounds are measured, it is not possible to determine if the decrease in some PFAS is outweighed by an increase in others.

Health perspectives and handling of PFAS contamination in Denmark.

Per- and polyfluorinated alkyl substances (PFAS) are a group of man-made extremely persistent chemicals that have been spread worldwide since the 1950s due to their properties as effective water- and grease-repellent and heat- and temperature-resistant. They are associated with an increasing number of health effects including immune and hormonal disturbances and some types of cancer. We present a review of PFAS pollution in Denmark, the current human exposure, suspected health effects, and patient management in environmental medicine.

Impact of a manager-oriented intervention on occupational exposures and well-being among pregnant hospital and day-care employees: A cluster randomised trial.

BACKGROUND: Pregnancy can make it difficult to cope with demands at work and may affect women's well-being. We investigated if a manager-targeted educational intervention reduced demanding occupational exposures and improved the psychosocial work environment and well-being among pregnant employees. METHODS: Data came from a cluster randomised trial in Danish hospitals and day-care institutions. Work units were assigned randomly and were non-blinded to the intervention, where managers were either invited to participate in a three-hour seminar addressing job adjustment in pregnancy or assigned to a control group undertaking their usual practice. Self-reported outcomes by pregnant employees at the work units were the proportion of pregnant employees with demanding occupational exposures, good psychosocial work environment and good well-being. Mixed logistic regression was applied in the population of responders and in intention-to-treat analyses using multiple imputations. RESULTS: We included 915 pregnant employees: 451 in the intervention group and 464 in the control group. Of 216 invited managers, 103 (48%) participated in the seminar. A total of 339 (37%) pregnant employees answered the questionnaire. The proportion of pregnant employees who had demanding occupational exposures, good psychosocial work environment and good well-being in the intervention versus the control group were 36% versus 39% (odds ratio (OR)=0.90, 95% confidence interval (CI) 0.57-1.44), 56% versus 59% (OR=1.01, 95% CI 0.60-1.71) and 77% versus 73% (OR=1.13, 95% CI 0.68-1.87), respectively. CONCLUSIONS: This manager-targeted educational intervention did not reduce demanding occupational exposures and did not improve the psychosocial work environment or the well-being among pregnant employees in hospital and day-care settings. Comprehensive and participatory interventions may be considered in future studies.

Manager-oriented intervention to reduce absence among pregnant employees in the healthcare and daycare sector: a cluster randomised trial.

OBJECTIVE: The aim was to test if targeting managers with an educational intervention reduces absence among pregnant employees. METHODS: The study was a non-blinded cluster randomised trial conducted in hospitals and daycare institutions from two administrative Danish Regions and two Danish municipalities. Clusters (work units) were assigned randomly and non-blinded to either (1) intervention, where all managers were invited to participate in a 3-hour seminar addressing needs and options for adjustment of work in pregnancy, or (2) control, with practice as usual. The primary outcome based on payroll data was long-term pregnancy-related absence, defined as ≥12.5% cumulated absence during pregnancy weeks 1-32. Intention-to-treat analysis was applied using mixed logistic regression. RESULTS: Ninety work units were included (56 hospital departments and 34 daycare units) with 451 pregnant employees in the intervention group and 464 in the control group. Work units had on average 11 pregnant employees with no difference between the groups. 103 of the 216 invited managers (48%) participated in a the 3-hour seminar. In the intervention group, 154 (34%) had long-term pregnancy-related absence during pregnancy weeks 1-32 vs 166 (36%) in the control group. Relative odds of having long-term pregnancy-related absence, when being in the intervention group, was 1.06 (95% CI 0.71 to 1.58), with an interclass correlation coefficient of 0.07. CONCLUSION: An educational intervention targeting managers did not reduce pregnancy-related absence among pregnant employees. TRIAL REGISTRATION NUMBER: NCT03002987.

[Night work and pregnancy-related complications].

Night work has been associated with sleep disorders as well as cardiovascular, endocrinologic, metabolic and immunological disturbances as shown in this review. Several night shifts in a row and more than one night shift per week is associated with increased risk of pregnancy-related complications. A dose-response pattern has been shown between the number of night shifts during pregnancy and the risk of miscarriage, hypertensive disorders and sick leave. Individual risk assessment of pregnant night workers should focus on their general health, the intensity of night shifts and other adverse working conditions.

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

Objective We aimed to investigate the association of night work during pregnancy with the risk of severe postpartum depression (PPD). Methods We performed a nationwide register-based cohort study of workers in all Danish public hospitals. Daily information on working hours was retrieved from the Danish Working Hour Database from January 2007 to December 2015. Pregnancies, covariates and outcome were identified from national registries for births and hospital contacts. We performed logistic regression of the risk of severe PPD in relation to the number and duration of night shifts, spells of consecutive night shifts, and short shift intervals during the first 32 pregnancy weeks. Analyses were adjusted for age, body mass index, socioeconomic status, parity, sickness absence three months prior to pregnancy, and prior diagnosis of severe depression. Results The study cohort comprised 25 009 singleton pregnancies from 19 382 workers. The majority were nurses or physicians. Overall, we did not observe an increased risk of PPD for any of the dimensions of night work analyzed. We found, however, an increased risk of PPD (adjusted odds ratio 2.08, 95% confidence interval 1.09-4.00) among women who stopped working night shifts after the first pregnancy trimester (N=3094). Conclusion Overall, our results do not support night work during pregnancy as a risk factor for severe PPD among hospital employees. However, we observed a 2-fold increased risk of PPD among women who stopped working night shifts after the first pregnancy trimester. This may reflect the influence of the healthy worker survivor effect and warrants further attention.

Night work during pregnancy and preterm birth-A large register-based cohort study.

BACKGROUND: Melatonin stimulates the production of progesterone, which is essential for the maintenance of pregnancy. Since melatonin in blood is reduced due to work under illuminated conditions during night work, it has been hypothesized that night work may increase the risk of preterm birth. Previous meta-analyses have not revealed increased risk of preterm birth in women working night shifts during pregnancy. Still, these studies might have been limited by inaccurate self-reports of timing, intensity and duration of night work most likely causing bias towards the null. The aim of this is study was to investigate if the frequency and duration of night work during the first (week 1-12) and second (week 13-22) trimester of pregnancy were associated with risk of preterm birth when objective and prospective data on night work are used. METHOD: In a register-based prospective cohort study, we obtained individual day-to-day information on working hours from The Danish Working Hour Database (DWHD, a payroll database including all public service employees in administrative Danish Regions from 2007-2013) and information on preterm birth from the Danish Medical Birth Registry. Night-shift was defined as at least three working hours between 23:00 and 06:00. Preterm birth was defined as giving birth during gestational weeks 23-37. Odds of preterm birth according to working night shifts were analysed by logistic regression. RESULTS: We identified 16,501 pregnant women eligible for the study, of which 10,202 women (61.8%) had at least one night-shift during the first 22 gestational weeks. The risk of preterm birth was not elevated among women working night shifts compared to women working only day shifts during either the first or second trimester. Within night-shift workers, the risk was not related to the number of night shifts, the duration of night shifts, consecutive night shifts or quick returns defined as short intervals between shifts. Odds of preterm birth was not related to change of working schedule from the first to second trimester, although women changing from night shifts in the first trimester to day work only in the second trimester displayed a weak increased odds of preterm birth (OR 1.21, 95%CI 0.98-1.49) compared to women working night shifts in both trimesters. CONCLUSION: Our results, which are without bias from self-report of either exposure or outcome, are in line with the results of previous meta-analyses. Due to the detailed information on hours worked during pregnancy, we were able to investigate several dimensions of night work not previously investigated, of which none were associated with elevated risk of preterm birth.

Night work and miscarriage: a Danish nationwide register-based cohort study.

OBJECTIVE: Observational studies indicate an association between working nights and miscarriage, but inaccurate exposure assessment precludes causal inference. Using payroll data with exact and prospective measurement of night work, the objective was to investigate whether working night shifts during pregnancy increases the risk of miscarriage. METHODS: A cohort of 22 744 pregnant women was identified by linking the Danish Working Hour Database (DWHD), which holds payroll data on all Danish public hospital employees, with Danish national registers on births and admissions to hospitals (miscarriage). The risk of miscarriage during pregnancy weeks 4-22 according to measures of night work was analysed using Cox regression with time-varying exposure adjusted for a fixed set of potential confounders. RESULTS: In total 377 896 pregnancy weeks (average 19.7) were available for follow-up. Women who had two or more night shifts the previous week had an increased risk of miscarriage after pregnancy week 8 (HR 1.32 (95% CI 1.07 to 1.62) compared with women, who did not work night shifts. The cumulated number of night shifts during pregnancy weeks 3-21 increased the risk of miscarriages in a dose-dependent pattern. CONCLUSIONS: The study corroborates earlier findings that night work during pregnancy may confer an increased risk of miscarriage and indicates a lowest observed threshold level of two night shifts per week.

Night work and sick leave during pregnancy: a national register-based within-worker cohort study.

OBJECTIVE: The aim of our study was to investigate the acute effect of night work during pregnancy on the risk of calling in sick the following day using register-based information and the workers as their own controls. METHODS: Using the payroll-based national Danish Working Hour Database, including all public hospital employees in Denmark, we identified 9799 pregnant women with ≥1 day shift and ≥1 night shift and ≥1 day of sick leave during the first 32 pregnancy weeks from January 2007 to December 2013. We performed fixed effects logistic regression, that is, within-worker comparisons, of the risk of sick leave of any duration starting within 24 hours after night shifts of different length versus day shifts. RESULTS: Most of the participants were nurses (64%) or physicians (16%). We found an increased relative risk of sick leave following night shifts compared with day shifts during all pregnancy trimesters. The risk was highest for night shifts lasting >12 hours (OR 1.37, 95% CI 1.15 to 1.63 for nurses; OR 1.87, 95% CI 1.69 to 2.08 for physicians) and among women aged >35 years (OR 1.42, 95% CI 1.24 to 1.63). CONCLUSION: Among Danish public hospital employees night shifts during pregnancy, especially shifts longer than 12 hours, increased the risk of calling in sick the following day independent of personal factors and time-invariant confounders in all pregnancy trimesters.

Night work and hypertensive disorders of pregnancy: a national register-based cohort study.

Objective The aim of this study was to investigate whether night work expressed by number and duration of night shifts, number of consecutive night shifts, and number of quick returns during the first 20 weeks of pregnancy is a risk factor for hypertensive disorders of pregnancy (HDP). Methods The study population comprised Danish workers in public administration and hospitals who gave birth between 2007 and 2013. Exposure was assessed objectively through payroll data. Information on the outcome was retrieved from the National Patient Register. We performed logistic regression on the risk for HDP according to night work adjusted for age, body mass index (BMI), parity, socioeconomic status, and sickness absence prior to pregnancy. Results Among 18 724 workers, 60% had at least one night shift during the first 20 weeks of pregnancy. The prevalence of HDP was 3.7%. Among night workers, the risk of HDP grew with increasing number of consecutive night shifts [odds ratio (OR) 1.41, 95% confidence interval (CI) 1.01-1.98) and of quick returns after night shifts (OR 1.28, 95% CI 0.87-1.95). Among obese women (body mass index ≥30 kg/m 2), those who worked long night shifts and longer spells of consecutive night shifts, and had the highest number of quick returns after night shifts, had a 4-5 fold increased risk of HDP compared to day workers. Conclusion Working consecutive night shifts and quick returns after night shifts during the first 20 pregnancy weeks was associated with an increased risk of HDP, particularly among obese women.

Associations of work activities requiring pinch or hand grip or exposure to hand-arm vibration with finger and wrist osteoarthritis: a meta-analysis.

OBJECTIVE: We systematically reviewed the epidemiologic evidence linking finger and wrist osteoarthritis (OA) with work activities requiring pinch or hand grip or exposure to hand-arm vibration (HAV). METHODS: PubMed and Embase databases were searched up to June 2013. We selected studies assessing the associations of radiographic diagnosed finger and/or wrist joint OA with work activities involving pinch or hand grip or exposure to HAV. We used specific criteria to evaluate completeness of reporting, potential confounding, and bias. Pooled odds ratios (OR) were computed using random-effects meta-analyses. RESULTS: Of the 19 studies included, 17 were cross-sectional, 1 was a prospective cohort, and 1 a case-control study. The meta-analyses of studies that controlled their estimates for at least age and gender showed the associations of pinch grip work with proximal interphalangeal joint [OR 1.56, 95% confidence interval (95% CI) 1.09-2.23] and the first carpometacarpal joint OA (OR 2.10, 95% CI 1.06-4.17), but not with distal interphalangeal, metacarpalphalangeal, or wrist joints OA. Hand grip work and exposure to HAV were not associated with any finger or wrist OA. CONCLUSION: Epidemiological studies provide limited evidence that pinch grip may increase the risk of wrist or finger OA, but causal relation cannot be resolved because of cross-sectional designs and inadequate characterization of biomechanical strain to the hand and wrist.