Tattoos as a risk factor for malignant lymphoma: a population-based case-control study.

Background: The popularity of tattoos has increased dramatically over the last few decades. Tattoo ink often contains carcinogenic chemicals, e.g., primary aromatic amines, polycyclic aromatic hydrocarbons, and metals. The tattooing process invokes an immunologic response that causes translocation of tattoo ink from the injection site. Deposition of tattoo pigment in lymph nodes has been confirmed but the long-term health effects remain unexplored. We used Swedish National Authority Registers with full population coverage to investigate the association between tattoo exposure and overall malignant lymphoma as well as lymphoma subtypes. Methods: We performed a case-control study where we identified all incident cases of malignant lymphoma diagnosed between 2007 and 2017 in individuals aged 20-60 years in the Swedish National Cancer Register. Three random age- and sex-matched controls per case were sampled from the Total Population Register using incidence density sampling. We assessed exposure through a questionnaire in 2021, and data on potential confounders were retrieved from registers. We used multivariable logistic regression to estimate the incidence rate ratio (IRR) of malignant lymphoma in tattooed individuals. Findings: The study population consisted of 11,905 individuals, and the response rate was 54% among cases (n = 1398) and 47% among controls (n = 4193). The tattoo prevalence was 21% among cases and 18% among controls. Tattooed individuals had a higher adjusted risk of overall lymphoma (IRR = 1.21; 95% CI 0.99-1.48). The risk of lymphoma was highest in individuals with less than two years between their first tattoo and the index year (IRR = 1.81; 95% CI 1.03-3.20). The risk decreased with intermediate exposure duration (three to ten years) but increased again in individuals who received their first tattoo ≥11 years before the index year (IRR = 1.19; 95% CI 0.94-1.50). We found no evidence of increasing risk with a larger area of total tattooed body surface. The risk associated with tattoo exposure seemed to be highest for diffuse large B-cell lymphoma (IRR 1.30; 95% CI 0.99-1.71) and follicular lymphoma (IRR 1.29; 95% CI 0.92-1.82). Interpretation: Our findings suggested that tattoo exposure was associated with an increased risk of malignant lymphoma. More epidemiologic research is urgently needed to establish causality. Funding: The Swedish Research Council for Health, Working Life and Welfare.

Early-life exposure to perfluoroalkyl substances and serum antibody concentrations towards common childhood vaccines in 18-month-old children in the Odense Child Cohort.

Exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with reduced antibody response to childhood vaccinations. Previous studies have mostly focused on antibodies against diphtheria or tetanus, while fewer studies have assessed antibodies toward attenuated viruses, such as measles, mumps or rubella (MMR). Therefore, we set out to determine associations between prenatal and early postnatal PFAS exposure and vaccine-specific Immunoglobulin G (IgG) in the background-exposed Odense Child Cohort. Blood samples were drawn in pregnancy at gestation weeks 8-16 and from the offspring at age 18 months. In the maternal serum samples we quantified perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA). In the offspring serum samples we quantified the same five PFAS compounds and IgG towards diphtheria, tetanus and MMR. A total of 880 and 841 children were included in the analyses of diphtheria and tetanus or MMR, respectively. Multiple linear regression models were used for estimation of difference in virus-specific IgG per doubling of PFAS concentrations. Maternal PFAS concentrations were non-significantly inversely associated with most vaccine-specific antibody concentrations. Likewise, child PFAS concentrations were associated with non-significant reductions of antibodies towards tetanus and MMR. A significant reduction in the percent difference in mumps antibody concentration per doubling of child PFNA (-9.2% (95% confidence interval: -17.4;-0.2)), PFHxS (-8.3% (-15.0;-1.0) and PFOS (-7.9% (-14.8;-0.4) was found. These findings are of public health concern, as inadequate response towards childhood vaccines may represent a more general immune dysfunction.

Early-Life Exposure to Perfluoroalkyl Substances (PFAS) and Child Language and Communication Development: A Systematic Review.

Language development starts during the fetal period when the brain is sensitive to endocrine disruptions from environmental contaminants. This systematic review aims to systematically summarize the existing literature on early-life exposure to PFAS and children's language and communication development, which is an indicator of neurocognitive development. A structured literature search was conducted using three databases, PubMed, Scopus, and CINAHL, last updated in April 2023. The population was defined as children and young adults. PFAS exposure was assessed pre- or postnatally. The outcome was defined as a language and communication ability assessed with validated instruments, parental self-reports, or clinical language disorder diagnoses. In total, 15 studies were identified for subsequent analyses. Thirteen were performed in background-exposed populations and two in highly exposed populations. There were some indications of potential adverse effects; however, these were not consistent across child sex, age of assessment, or PFAS exposure levels. No systematic effect of early-life PFAS exposure on language and communication development was found. These inconclusive findings may partly be explained by the use of general test instruments with limited validity as to children's language and communication development. Further studies over a wider exposure range using specific language test instruments are needed.

Gestational hypertension, preeclampsia, and gestational diabetes mellitus after high exposure to perfluoroalkyl substances from drinking water in Ronneby, Sweden.

BACKGROUND: Leakage of fire-fighting foam from an airfield caused contamination of the drinking water supplied to a third of the population in Ronneby, resulting in very high serum levels of predominantly perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS). The results of studies investigating the association between exposure to perfluorinated alkyl substances (PFAS) and pregnancy complications are inconsistent, and studies at high exposures of PFOS and PFHxS are lacking. OBJECTIVES: To investigate the association between exposure to high levels of PFAS and gestational hypertension and preeclampsia, and gestational diabetes mellitus. METHODS: We retrieved data on 27 292 childbirths between 1995 and 2013 from the National Medical Birth Register for women that had a residential address in Blekinge county for at least one year before delivery. Residential history was used as a proxy for exposure by categorizing women into high-, intermediate-, or background exposed based on their residential address during the five-year period before childbirth. Data on confounders were retrieved from administrative registers. The outcomes were defined based on International Classification of Diseases codes. We used logistic regression to estimate odds ratios (OR) for gestational hypertension and preeclampsia, and gestational diabetes mellitus. We also investigated effect modification by fetal sex. RESULTS: We found no evidence of increased risk of gestational hypertension and preeclampsia (OR 0.80; CI 0.63-1.03), nor gestational diabetes (OR 1.03; CI 0.67-1.58) after high PFAS exposure. There was no effect modification by fetal sex. DISCUSSION: This was the first study to investigate the association between high exposure to PFOS and PFHxS and pregnancy complications. The results from this study add important knowledge to public health management as new hotspots with high levels of PFAS are continuously discovered.

High Exposure to Perfluoroalkyl Substances and Antibody Responses to SARS-CoV-2 mRNA Vaccine-an Observational Study in Adults from Ronneby, Sweden.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) are widely used, environmentally ubiquitous, and stable chemicals that have been associated with lower vaccine-induced antibody responses in children; however, data on adults are limited. The drinking water from one of the two waterworks in Ronneby, Sweden, was heavily contaminated for decades with PFAS from firefighting foams, primarily perfluorohexane sulfonic acid and perfluorooctanesulfonic acid (PFOS). Vaccination against SARS-CoV-2 offered a unique opportunity to investigate antibody responses to primary vaccination in adults who had been exposed to PFAS. OBJECTIVES: Our objective was to evaluate associations between PFAS, across a wide range of exposure levels, and antibody responses in adults 5 wk and 6 months after a two-dose vaccination regime against SARS-CoV-2. METHODS: Adults age 20-60 y from Ronneby (n=309, median PFOS serum level 47 ng/mL, fifth to 95th percentile 4-213 ng/mL) and a group with background exposure (n=47, median PFOS serum level 4 ng/mL) received two doses of the Spikevax (Moderna) mRNA vaccine. The levels of seven PFAS were measured in serum before vaccination. Serum immunoglobulin G antibodies against the SARS-CoV-2 spike antigen (S-Abs) were measured before vaccination and at 5 wk (n=350) and 6 months (n=329) after the second vaccine dose. Linear regression analyses were fitted against current, historical, and prenatal exposure to PFAS, adjusting for sex, age, and smoking, excluding individuals with previous SARS-CoV-2-infection. RESULTS: PFAS exposure, regardless of how it was estimated, was not negatively associated with antibody levels 5 wk [current PFOS: -0.5% S-Abs/PFOS interquartile range (IQR); 95% confidence interval (CI): -8, 7] or 6 months (current PFOS: 3% S-Abs/PFOS IQR; 95% CI: -6, 12) after COVID-19 vaccination. DISCUSSION: Following a strict study protocol, rigorous study design, and few dropouts, we found no indication that PFAS exposure negatively affected antibody responses to COVID-19 mRNA vaccination for up to 6 months after vaccination. https://doi.org/10.1289/EHP11847.

Detection of the fungicide transformation product 4-hydroxychlorothalonil in serum of pregnant women from Sweden and Costa Rica.

BACKGROUND: 4-hydroxychlorothalonil (HCT, R182281), a transformation product of the fungicide chlorothalonil, was recently identified in human serum and breast milk. There are indications that HCT may be more toxic and environmentally persistent than chlorothalonil. OBJECTIVE: Our aim was to investigate serum concentrations of HCT in pregnant women in Sweden and Costa Rica. METHODS: We developed a quantitative analytical method for HCT using liquid chromatography tandem mass spectrometry. We measured HCT in 1808 serum samples from pregnant women from the general population in Sweden (1997-2015) and in 632 samples from 393 pregnant women from an agricultural population in Costa Rica (2010-2011). In Swedish samples, we assessed time trends and investigated seasonality. In the Costa Rican samples, we evaluated variability between and within women and explanatory variables of HCT concentrations. RESULTS: HCT was detected in all serum samples, and the limit of detection was 0.1 µg/L. The median HCT concentration in the Swedish samples was 4.1 µg/L (interquartile range [IQR] of 2.9 - 5.8 µg/L), and 3.9 times higher in the Costa Rican samples (median: 16.1 µg/L; IQR: 10.6 - 25.0 µg/L). We found clear seasonal variation with higher concentrations in the first half of each year among Swedish women. In the Costa Rican study, women working in agriculture and living near banana plantations had higher HCT concentrations, whilst higher parity and having a partner working in agriculture were associated with decreased HCT, and no clear seasonal pattern was observed. IMPACT STATEMENT: For the first time, this study quantifies human exposure to the fungicide chlorothalonil and/or its transformation product 4-hydroxychlorothalonil (HCT, R182281) and finds higher serum concentrations in women from a tropical agricultural setting as compared with women from the general population in Sweden.

Cohort profile: The Swedish Tattoo and Body Modifications Cohort (TABOO).

PURPOSE: The Swedish Tattoo and Body Modifications Cohort (TABOO) cohort was established to provide an infrastructure for epidemiological studies researching the role of tattoos and other body modifications as risk factors for adverse health outcomes. It is the first population-based cohort with detailed exposure assessment of decorative, cosmetic, and medical tattoos, piercing, scarification, henna tattoos, cosmetic laser treatments, hair dyeing, and sun habits. The level of detail in the exposure assessment of tattoos allows for investigation of crude dose-response relationships. PARTICIPANTS: The TABOO cohort includes 13 049 individuals that participated in a questionnaire survey conducted in 2021 (response rate 49%). Outcome data are retrieved from the National Patient Register, the National Prescribed Drug Register and the National Cause of Death Register. Participation in the registers is regulated by Swedish law, which eliminates the risk of loss to follow-up and associated selection bias. FINDINGS TO DATE: The tattoo prevalence in TABOO is 21%. The cohort is currently used to clarify the incidence of acute and long-lasting health complaints after tattooing based on self-reported data. Using register-based outcome data, we are investigating the role of tattoos as a risk factor for immune-mediated disease, including hypersensitisation, foreign body reactions and autoimmune conditions. FUTURE PLANS: The register linkage will be renewed every third year to update the outcome data, and we have ethical approval to reapproach the responders with additional questionnaires.

Association Between Prenatal and Early Postnatal Exposure to Perfluoroalkyl Substances and IQ Score in 7-Year-Old Children From the Odense Child Cohort.

Perfluoroalkyl substances (PFAS) are persistent chemicals capable of crossing the placenta and passing into breast milk. Evidence suggests that PFAS exposure may affect brain development. We investigated whether prenatal or early postnatal PFAS exposure was associated with intelligence quotient (IQ) scores in schoolchildren from the Odense Child Cohort (Denmark, 2010-2020). We assessed concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) in maternal serum collected during the first trimester of pregnancy and in child serum at age 18 months. At 7 years of age, children completed an abbreviated version of the Wechsler Intelligence Scale for Children, Fifth Edition, from which Full Scale Intelligence Quotient (FSIQ) and Verbal Comprehension Index scores were estimated. In multiple linear regression analyses conducted among 967 mother-child pairs, a doubling in maternal PFOS and PFNA concentrations was associated with a lower FSIQ score, while no significant associations were observed for PFOA, PFHxS, or PFDA. PFAS concentrations at age 18 months and duration of breastfeeding were strongly correlated, and even in structural equation models it was not possible to differentiate between the opposite effects of PFAS exposure and duration of breastfeeding on FSIQ. PFAS exposure is ubiquitous; therefore, an association with even a small reduction in IQ is of public health concern.

Developmental language disorders in preschool children after high exposure to perfluoroalkyl substances from contaminated drinking water in Ronneby, Sweden.

There are indications that early-life exposure to perfluoroalkyl substances (PFAS) can impact neurodevelopment, but results are inconclusive. The objective was to investigate if high early-life exposure to primarily perfluorohexanesulfonic acid (PFHxS) and perfluorooctanesulfonic acid (PFOS) increases the risk of developmental language disorder in children up to seven years of age. Methods: A register-based cohort of all children born 1998-2013 in Blekinge county, Sweden, was studied. Maternal residential history, that is, with or without highly PFAS-contaminated drinking water, during the 5-year period before childbirth was used as a proxy for early-life exposure. Exposure was categorized as high (n = 646), intermediate (n = 1,650), or background (n = 9,599). We used Cox proportional hazards regression to estimate hazard ratios (HR) for (1) referral to a speech- and language pathologist after routine screening at Child Health Services, and (2) subsequent language disorder diagnosis after clinical assessment. Models were adjusted for parity, maternal age, education level, and smoking, and explored effect modification by sex. Results: In children from the high-exposed area, the adjusted HR for referral was 1.23 (95% CI = 1.03, 1.47) and 1.13 (95% CI = 0.97, 1.56) for subsequent diagnosis. There was no increased risk in the intermediate exposure category. Conclusion: Children, particularly girls, with high exposure had an increased risk of both referral and confirmed developmental language disorder. Further research is needed on PFAS in the context of general neurodevelopment, for which language development is a proxy.

Occupational risk of SARS-CoV-2 infection: a nationwide register-based study of the Danish workforce during the COVID-19 pandemic, 2020-2021.

OBJECTIVE: Most earlier studies on occupational risk of COVID-19 covering the entire workforce are based on relatively rare outcomes such as hospital admission and mortality. This study examines the incidence of SARS-CoV-2 infection by occupational group based on real-time PCR (RT-PCR) tests. METHODS: The cohort includes 2.4 million Danish employees, 20-69 years of age. All data were retrieved from public registries. The incidence rate ratios (IRRs) of first-occurring positive RT-PCR test from week 8 of 2020 to week 50 of 2021 were computed by Poisson regression for each four-digit Danish Version of the International Standard Classification of Occupations job code with more than 100 male and 100 female employees (n=205). Occupational groups with low risk of workplace infection according to a job exposure matrix constituted the reference group. Risk estimates were adjusted by demographic, social and health characteristics including household size, completed COVID-19 vaccination, pandemic wave and occupation-specific frequency of testing. RESULTS: IRRs of SARS-CoV-2 infection were elevated in seven healthcare occupations and 42 occupations in other sectors, mainly social work activities, residential care, education, defence and security, accommodation and transportation. No IRRs exceeded 2.0. The relative risk in healthcare, residential care and defence/security declined across pandemic waves. Decreased IRRs were observed in 12 occupations. DISCUSSION: We observed a modestly increased risk of SARS-CoV-2 infection among employees in numerous occupations, indicating a large potential for preventive actions. Cautious interpretation of observed risk in specific occupations is needed because of methodological issues inherent in analyses of RT-PCR test results and because of multiple statistical tests.

COVID-19-related hospital admission in spouses of partners in at-risk occupations.

OBJECTIVE: This study aimed to quantify the risk of COVID-19-related hospital admission in spouses living with partners in at-risk occupations in Denmark during 2020-21. METHODS: Within a registry-based cohort of all Danish employees (N=2 451 542), we identified cohabiting couples, in which at least one member (spouse) held a job that according to a job exposure matrix entailed low risk of occupational exposure to SARS-CoV-2 (N=192 807 employees, 316 COVID-19 hospital admissions). Risk of COVID-19-related hospital admission in such spouses was assessed according to whether their partners were in jobs with low, intermediate or high risk for infection. Overall and sex-specific incidence rate ratios (IRR) of COVID-19-related hospital admission were computed by Poisson regression with adjustment for relevant covariates. RESULTS: The risk of COVID-19-related hospital admission was increased among spouses with partners in high-risk occupations [adjusted IRR (IRRadj)1.59, 95% confidence interval (CI) 1.1-2.2], but not intermediate-risk occupations (IRRadj 0.97 95% 0.8-1.3). IRR for having a partner in a high-risk job was elevated during the first three pandemic waves but not in the fourth (IRRadj 0.48 95% CI 0.2-1.5). Sex did not modify the risk of hospital admission. CONCLUSIONS: SARS-CoV-2 transmission at the workplace may pose an increased risk of severe COVID-19 among spouses in low-risk jobs living with partners in high-risk jobs, which emphasizes the need for preventive measures at the workplace in future outbreaks of epidemic contagious disease. When available, effective vaccines seem essential.

Estimated Transfer of Perfluoroalkyl Substances (PFAS) from Maternal Serum to Breast Milk in Women Highly Exposed from Contaminated Drinking Water: A Study in the Ronneby Mother-Child Cohort.

BACKGROUND: Infancy perfluoroalkyl substances (PFAS) exposure from breastfeeding is partially determined by the transfer efficiencies (TEs) of PFAS from maternal serum into breast milk. However, to our knowledge there are no studies of such TEs in highly exposed populations. OBJECTIVES: We estimated the TEs of PFAS from maternal serum into colostrum and breast milk in a cohort of women with a wide range of PFAS exposures. METHODS: The Ronneby Mother-Child Cohort was established in 2015 after PFAS contamination was discovered in the public drinking water of Ronneby, Sweden. We measured seven PFAS in matched samples of maternal serum at delivery and colostrum and breast milk. We calculated the TE (in percentage) as the ratio of PFAS in colostrum or breast milk to serum multiplied by 100 and evaluated whether TEs varied by PFAS, lactation stage, or exposure level using a series of linear mixed-effects models with a random intercept for each woman. RESULTS: This study included 126 mothers. PFAS associated with firefighting foams [i.e., perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS)] were substantially elevated in the serum, colostrum, and breast milk samples of highly exposed women in the cohort and showed strong correlation. PFHxS and PFOS also contributed the largest fraction of total PFAS on average in colostrum and breast milk. Median TEs varied from 0.9% to 4.3% and were higher for perfluoroalkyl carboxylic acids, including perfluorooctanoic acid, than perfluoroalkane sulfonic acids, including PFHxS and PFOS. TEs varied by exposure level, but there was not a consistent pattern in this variation. DISCUSSION: PFAS concentrations in the colostrum and breast milk of highly exposed women were higher than the concentrations in low-exposed women, and TEs were of a similar magnitude across exposure categories. This implies that breastfeeding may be an important route of PFAS exposure for breastfeeding infants with highly exposed mothers, although the relative contribution of breastfeeding vs. prenatal transplacental transfer remains to be clarified. https://doi.org/10.1289/EHP11292.

Changes in perfluoroalkyl substances (PFAS) concentrations in human milk over the course of lactation: A study in Ronneby mother-child cohort.

BACKGROUND: Little is known about how PFAS concentrations in human milk change over the course of lactation, although this is an important determinant of cumulative infant exposure from breastfeeding. OBJECTIVE: To estimate changes in PFAS concentrations in human milk over the course of lactation in a population with a wide range of exposure from background-to high-exposed. METHODS: We measured PFAS concentrations in colostrum and mature milk samples from women in the Ronneby Mother-Child Cohort. For each PFAS, we estimated the change in concentration from colostrum collected 3-4 days postpartum to mature milk collected 4-12 weeks postpartum using linear mixed-effects models. We evaluated whether this estimated change varied by quartiles of colostrum concentrations. In a subset of mothers with at least three mature milk samples, we estimated the change in concentration per month over the first eight months of lactation. RESULTS: Our study included 77 mother-child pairs, of whom 74 had colostrum and initial mature milk samples and 11 had three or more repeated samples. The concentration change from colostrum to mature milk varied by PFAS. While PFOS increased by 21% (95% CI: 8.9, 35), PFOA decreased by 17% (95% CI: -28, -3.5) and PFHxS decreased by 12% (95% CI: -24, 3.3). In addition, PFAS concentrations tended to increase in women with lower colostrum levels, but decreased or remained the same in women with high colostrum concentrations. When we estimated changes over the course of lactation, we found that PFOA concentrations decreased the most (-12% per month; 95% CI: -22, -1.5), whereas PFHxS and PFOS showed small nonsignificant decreases. CONCLUSIONS: Models for cumulative infancy exposure from breastfeeding need to account for differences in concentration trajectories by PFAS and possibly by maternal exposure level. Additional research is needed to evaluate the relative exposure from breastfeeding vs prenatal exposure, especially in highly exposed communities where breastfeeding guidance is urgently needed.

Occupational risk of COVID-19 related hospital admission in Denmark 2020-2021: a follow-up study.

OBJECTIVE: Mounting evidence indicates increased risk of COVID-19 among healthcare personnel, but the evidence on risks in other occupations is limited. In this study, we quantify the occupational risk of COVID-19-related hospital admission in Denmark during 2020-2021. METHODS: The source population included 2.4 million employees age 20-69 years. All information was retrieved from public registers. The risk of COVID-19 related hospital admission was examined in 155 occupations with at least 2000 employees (at-risk, N=1 620 231) referenced to a group of mainly office workers defined by a COVID-19 job exposure matrix (N=369 341). Incidence rate ratios (IRR) were computed by Poisson regression. RESULTS: During 186 million person-weeks of follow-up, we observed 2944 COVID-19 related hospital admissions in at-risk occupations and 559 in referents. Adjusted risk of such admission was elevated in several occupations within healthcare (including health care assistants, nurses, medical practitioners and laboratory technicians but not physiotherapists or midwives), social care (daycare assistants for children aged 4-7, and nursing aides in institutions and private homes, but not family daycare workers) and transportation (bus drivers, but not lorry drivers). Most IRR in these at-risk occupations were in the range of 1.5-3. Employees in education, retail sales and various service occupations seemed not to be at risk. CONCLUSION: Employees in several occupations within and outside healthcare are at substantially increased risk of COVID-19. There is a need to revisit safety measures and precautions to mitigate viral transmission in the workplace during the current and forthcoming pandemics.

Occupational risk of COVID-19 across pandemic waves: a two-year national follow-up study of hospital admissions.

OBJECTIVE: Assuming that preventive measures to mitigate viral transmission of SARS-CoV-2 at the workplace may have been improved in the course of the COVID-19 pandemic, we examined the occupational risk of COVID-19 related hospital admission across the four pandemic waves in Denmark between week 8, 2020, and week 50, 2021. METHODS: The study included 4416 cases of COVID-19 related hospital admissions among 2.4 million Danish employees aged 20-69 with follow-up in 2020 through 2021. At-risk industrial sectors and a reference population were defined a priory by a job-exposure matrix on occupational risk for COVID-19. Incidence rate ratios (IRR) and potential effect modification by pandemic wave were computed with Poisson regression adjusted for demographic, social and health factors including completed COVID-19 vaccination. RESULTS: We observed an overall elevated relative risk in four of six at-risk industrial sectors, but the pandemic wave only modified the risk among healthcare employees, where the excess risk from a high initial level declined to background levels during the latest waves in models not adjusting for COVID-19 vaccination. In social care, education and transport, the elevated risk was not modified by pandemic wave. CONCLUSION: Danish healthcare employees were to some extent protected against occupational transmission of SARS-CoV-2 during the two last pandemic waves even though the absolute risk conferred by occupation may not have been eliminated. Early vaccination of this group seems not to be the only explanation. The risk in other sectors remained elevated indicating a need to revisit preventive measures.

High in Utero Exposure to Perfluoroalkyl Substances from Drinking Water and Birth Weight: A Cohort Study among Infants in Ronneby, Sweden.

In 2013, the drinking water for one-third of the households in Ronneby, Sweden, was found to be contaminated by perfluorinated alkyl substances (PFAS, >10,000 ng/L) from Aqueous Film Forming Foam (AFFF). In utero PFAS exposure can influence birth weight, but little is known about the effects at very high levels. This study aimed to examine the association between in utero PFAS exposure and birth weight. Infants with mothers from Ronneby exposed to contaminated water at home (high exposure) and infants with mothers from Ronneby not exposed to contaminated water at home (low exposure) were compared to infants with mothers from Blekinge county excluding Ronneby (referents). All infants born in Blekinge county 1995-2013 were included (n = 30,360). Differences in birth weight were only seen among infants born after 2005. For boys, Ronneby high exposure had a lower mean birth weight than referents (-54 g, 95% CI -97; -11). For girls, Ronneby high exposure had a higher mean birth weight than referents (47 g, 95% CI 4; 90). There were no differences in birth weight between referents and Ronneby low exposure. In conclusion, high exposure to PFAS may influence birth weight in a sex-specific way, although the effect estimates were relatively small.

Breastfeeding initiation and duration after high exposure to perfluoroalkyl substances through contaminated drinking water: A cohort study from Ronneby, Sweden.

BACKGROUND: The drinking water in parts of Ronneby was heavily contaminated with perfluoroalkyl substances (PFAS) for decades. Although PFAS has endocrine-disrupting properties and may interfere with breastfeeding, the effects in populations with a point source of high exposure are unknown. OBJECTIVES: To investigate associations between high PFAS exposure and 1) initiation and 2) duration of breastfeeding. METHODS: We retrieved data on infant feeding practices for 2374 children born between 1999 and 2009 from Child Health Care centers in Ronneby and a reference municipality. Residential address before delivery was used as a proxy for exposure, and confounders were obtained from charts and registers. We used modified Poisson regressions to estimate the relative risks (RR) of not initiating breastfeeding, not breastfeeding exclusively after 3 months, and not breastfeeding at all at 6 months. We also estimated hazard ratios (HR) of cessation of exclusive breastfeeding before 6 months and any breastfeeding before 12 months. RESULTS: Mothers who had received contaminated water seemed to have a higher risk of not initiating breastfeeding (RR = 2.4; 95% CI: 0.8, 6.7). Primiparous mothers from the exposed area were at a 1.2 times increased risk (95% CI: 0.9, 1.6) of not exclusively breastfeeding at 3 months and a 1.6 times increased risk (95% CI: 1.2, 2.1) of not breastfeeding at 6 months. The results were confirmed by the Cox regressions, which further showed that the HR for cessation of any breastfeeding was time dependent and higher in early lactation, thereafter decreasing as lactation progressed. We observed no overall associations in multiparous mothers. DISCUSSION: Exposure to high levels of PFAS seemed to be associated with increased risks of not initiating breastfeeding and shorter breastfeeding duration in primiparous mothers. The findings imply that the ability of first-time mothers to establish breastfeeding is a sensitive outcome after high exposure to PFAS.

Susceptibility to COVID-19 after High Exposure to Perfluoroalkyl Substances from Contaminated Drinking Water: An Ecological Study from Ronneby, Sweden.

There is concern that immunotoxic environmental contaminants, particularly perfluoroalkyl substances (PFAS), may play a role in the clinical course of COVID-19 and epidemiologic studies are needed to answer if high-exposed populations are especially vulnerable in light of the ongoing pandemic. The objective was, therefore, to determine if exposure to highly PFAS-contaminated drinking water was associated with an increased incidence of COVID-19 in Ronneby, Sweden, during the first year of the pandemic. We conducted an ecological study determining the sex- and age-standardized incidence ratio (SIR) in the adult population relative to a neighboring reference town with similar demographic characteristics but with only background levels of exposure. In Sweden, COVID-19 is subject to mandatory reporting, and we retrieved aggregated data on all verified cases until 3 March 2021 from the Public Health Agency of Sweden. The SIR in Ronneby was estimated at 1.19 (95% CI: 1.12; 1.27). The results suggest a potential link between high PFAS exposure and susceptibility to COVID-19 that warrants further research to clarify causality.

Detection of bacterial DNA in synovial fluid in dogs with arthritis: a comparison between bacterial culture and 16S rRNA polymerase chain reaction.

BACKGROUND: Septic arthritis (SA) is a serious condition in dogs that requires a prompt diagnosis and treatment to minimize long-term joint pathology. Although bacterial detection in synovial fluid (SF) through culture or cytology is often performed to confirm diagnosis, the sensitivity of these tests is low. The need for a reliable diagnostic tool to confirm the presence of bacteria in SF in humans has led to the increased use of 16S rRNA (i.e., ribosomal RNA) gene sequencing by polymerase chain reaction (16S rRNA PCR). The aim of this prospective clinical study was to compare the sensitivity and specificity of 16S rRNA PCR with bacterial culture on blood agar plates after pre-incubation of SF in paediatric blood bacterial culture bottles to identify bacteria in dogs with clinical signs of SA and to investigate the usefulness of these methods as diagnostic tools. RESULTS: Ten dogs with clinical signs of SA, nine with osteoarthritis (OA, control group) and nine with clinical signs of immune-mediated polyarthritis (IMPA, second control group) were examined. Bacterial culture was positive in seven of 10 dogs with clinical SA, of which only two were positive by 16S rRNA PCR. The sensitivity of 16S rRNA PCR and bacterial culture analysis for dogs with clinical SA were 20% and 70%, respectively. All SF samples collected from control group (n = 9) and second control group (n = 14) animals were negative on culture, and 16S rRNA PCR rendered a specificity of 100%. CONCLUSIONS: Our study showed a lower sensitivity of 16S rRNA PCR than bacterial culture for dogs with clinical SA. Our findings suggest that there is currently no advantage in using 16S rRNA PCR as a diagnostic tool for dogs with clinical SA. Furthermore, our study indicates that pre-incubation in paediatric blood bacterial culture bottles before bacterial cultivation on blood agar plates might enhance bacterial culture sensitivity compared to other culture methods.