Immunotoxic, genotoxic, and endocrine disrupting impacts of polyamide microplastic particles and chemicals.

Due to their exceptional properties and cost effectiveness, polyamides or nylons have emerged as widely used materials, revolutionizing diverse industries, including industrial 3D printing or additive manufacturing (AM). Powder-based AM technologies employ tonnes of polyamide microplastics to produce complex components every year. However, the lack of comprehensive toxicity assessment of particulate polyamides and polyamide-associated chemicals, especially in the light of the global microplastics crisis, calls for urgent action. This study investigated the physicochemical properties of polyamide-12 microplastics used in AM, and assessed a number of toxicity endpoints focusing on inflammation, immunometabolism, genotoxicity, aryl hydrocarbon receptor (AhR) activation, endocrine disruption, and cell morphology. Specifically, microplastics examination by means of field emission scanning electron microscopy revealed that work flow reuse of material created a fraction of smaller particles with an average size of 1-5 µm, a size range readily available for uptake by human cells. Moreover, chemical analysis by means of gas chromatography high-resolution mass spectrometry detected several polyamide-associated chemicals including starting material, plasticizer, thermal stabilizer/antioxidant, and migrating slip additive. Even if polyamide particles and chemicals did not induce an acute inflammatory response, repeated and prolonged exposure of human primary macrophages disclosed a steady increase in the levels of proinflammatory chemokine Interleukin-8 (IL-8/CXCL-8). Moreover, targeted metabolomics disclosed that polyamide particles modulated the kynurenine pathway and some of its key metabolites. The p53-responsive luciferase reporter gene assay showed that particles per se were able to activate p53, being indicative of a genotoxic stress. Polyamide-associated chemicals triggered moderate activation of AhR and elicited anti-androgenic activity. Finally, a high-throughput and non-targeted morphological profiling by Cell Painting assay outlined major sites of bioactivity of polyamide-associated chemicals and indicated putative mechanisms of toxicity in the cells. These findings reveal that the increasing use of polyamide microplastics may pose a potential health risk for the exposed individuals, and it merits more attention.

Is the mental health of older adults receiving care from their children related to their children's dual burden of caregiving and work stress? A linked lives perspective.

OBJECTIVES: Mental health problems are a major concern in the older population in Sweden, as is the growing number of older adults aging alone in their homes and in need of informal care. Using a linked lives perspective, this study explored if older parents' mental health is related to their children's dual burden of informal caregiving and job strain. METHODS: Data from a nationally representative Swedish survey, SWEOLD, were used. Mental health problems in older age (mean age 88) were measured with self-reported 'mild' or 'severe' anxiety and depressive symptoms. A primary caregiving adult child was linked to each older parent, and this child's occupation was matched with a job exposure matrix to assess job strain. Logistic regression analyses were conducted with an analytic sample of 334. RESULTS: After adjusting for covariates, caregiving children's lower job control and greater job strain were each associated with mental health problems in their older parents (OR 2.52, p = 0.008 and OR 2.56, p = 0.044, respectively). No association was found between caregiving children's job demands and their older parents' mental health (OR 1.08, p = 0.799). CONCLUSION: In line with the linked lives perspective, results highlight that the work-life balance of informal caregiving adult children may play a role in their older parent's mental health.

Per- and polyfluoroalkyl substances (PFAS) in sludge from wastewater treatment plants in Sweden - First findings of novel fluorinated copolymers in Europe including temporal analysis.

Thousands of per- and polyfluoroalkyl substances (PFAS) are on the global market, while only a minor proportion is monitored regularly in the environment. Wastewater treatment plants (WWTPs) have been suggested to be a point source for PFAS to the environment due to emission of effluent and sludge. In this study, 81 PFAS including two rarely studied perfluoroalkyl sulfonamide-based (FASA) copolymers were analyzed in sludge samples to understand the usage of PFAS in the society. Sludge samples (n = 28) were collected at four WWTPs in Sweden between 2004 and 2017. The total levels of 79 measured PFAS were between 50 and 1124 ng/g d.w. All sludge samples showed detectable levels of both C8- and C4-FASA-based copolymers. The concentrations of the FASA-based copolymers were proposed to be reported in fluorinated side-chain equivalents (FSC eq.), in order to compare the levels of the copolymers with the other neutral and anionic PFAS, as no authentic standards were available. The concentrations of the FASA-based copolymers in sludge were between 1.4 and 22 ng FSC eq./g d.w. A general predomination of precursor and intermediate compounds was observed. A lower contribution of perfluoroalkyl carboxylic acids was noted for the WWTPs more influenced by domestic emission when compared with more influenced by industrial emission. An overall declining trend in the total PFAS concentration was seen between the years 2004 and 2017. The present study observed a shift from the C8-based chemistry toward shorter chain lengths, included a declining trend for C8-FASA-based copolymer over the entire study period. These findings further demonstrate the occurrence of side-chain fluorinated copolymers in Sweden and that sludge is a useful matrix to reflect the usage of PFAS in society and the potential for environmental exposure.

Analysis and characterization of novel fluorinated compounds used in surface treatments products.

Side-chain fluorinated polymers are speculated to be potential precursors to other non-polymeric aliphatic per- and polyfluoroalkyl acids (PFAAs). Limited knowledge of environmental occurrence of this compound class is partly due to lack of structural information and authentic standards. In this study, two novel fluorinated compounds, suspected to be side-chain fluorinated copolymers used in two commercial technical mixtures (Scotchgard™ Pre-2002 formulation and Scotchgard™ Post-2002 formulation) were analyzed and characterized in order to provide information to facilitate detection and quantification. The commercial mixtures were analyzed using tandem mass spectrometry and high-resolution mass spectrometry; besides already reported C4- and C8-fluoroalkylsulfonamido (FASA) side-chains, a proposed structure was determined for the perfluorooctane (C8) sulfonamide-urethane copolymer in the Pre-2002 formulation. Structural isomers were also observed for C4- and C8-FASA-based copolymers. Total fluorine analysis revealed that the Scotchgard™ Pre-2002 Formulation contained a fluorine content of 0.5% and 1.8% for the Scotchgard™ Post-2002 Formulation. The equivalent FASA side-chain content was determined to be 0.8% for Pre-2002 and 3.1% for Post-2002. Both C4- and C8-FASA-based copolymers underwent hydrolysis and oxidation and were transformed to their respective perfluoroalkyl side chain, which suggest that transformation products can be analyzed for example after total oxidizable precursor (TOP) assay. Both compounds were shown to strongly sorb to sediment particles, which also gives indications about their environmental fate and transport pathways.

Examination of aryl hydrocarbon receptor (AhR), estrogenic and anti-androgenic activities, and levels of polyaromatic compounds (PACs) in tire granulates using in vitro bioassays and chemical analysis.

Tire granulates recovered from end-of-life tires contain a complex mixture of chemicals, amongst them polyaromatic compounds (PACs), of which many are recognized to be toxic and persistent in the environment. Only a few of these PACs are regularly monitored. In this study a combined approach of chemical analysis and a battery of CALUX® in vitro bioassays was used to determine PAC concentrations and estrogenic, (anti)-androgenic and aryl hydrocarbon receptor (AhR) activities in tire granulates. Tire granulates from a recycling company was analyzed for PAHs, alkyl-PAHs, oxy-PAHs and heterocyclic PACs (NSO-PACs), in total 85 PACs. The concentrations of PACs were between 42 and 144 mg/kg, with major contribution from PAHs (74-88%) followed by alkyl-PAHs (6.6-20%) and NSO-PACs (1.8-7.0%). The sum of eight priority PAHs were between 2.3 and 8.6 mg/kg, contributing with 4.7-8.2% of ∑PACs. Bioassay analysis showed presence of AhR agonists, estrogen receptor (ERα) agonists, and androgen receptor (AR) antagonists in the tire granulate samples. Only 0.8-2.4% of AhR-mediated activities could be explained by the chemical analysis. Benzo[k+j]fluoranthenes, benzo[b]fluoranthene, indeno[1,2,3-cd]pyrene, 2-methylchrysene, and 3-methylchrysene were the major contributors to the AhR-mediated activities. The high contribution (98-99%) of unknown bioactive compounds to the bioassay effects in this study raises concerns and urges for further investigations of toxicants identification and source apportionment.

Extractable organofluorine analysis: A way to screen for elevated per- and polyfluoroalkyl substance contamination in humans?

The ubiquitous occurrence of a few per- and polyfluoroalkyl substances (PFAS) in humans and the environment has been previously reported. However, the number of PFAS humans and the environment are potentially exposed to is much higher, making it difficult to investigate every sample in detail. More importantly, recent studies have shown an increasing fraction of potentially unknown PFAS in human samples. A screening tool for identifying samples of concern that may contain high PFAS levels, to be studied more thoroughly, is needed. This study presents a simplified workflow to detect elevated PFAS levels using extractable organofluorine (EOF) analysis. A fluorine mass balance analysis on samples with high EOF, targeting 63 PFAS, can then confirm the PFAS contamination. Whole blood samples from a cohort of individuals with historical drinking water contamination from firefighting foams (n = 20) in Ronneby (Sweden) and a control group (n = 9) with background exposure were used as a case study. The average EOF concentration in the Ronneby group was 234 ng/mLF (<107-592 ng/mLF) vs 24.8 ng/mLF (17.6-37.8 ng/mL F) in the control group. The large difference (statistically significant, p < 0.05) in the EOF levels between the exposed and control groups would have made it possible to identify samples with high PFAS exposure only using EOF data. This was confirmed by target analysis, which found an average ∑PFAS concentration of 346 ng/mL in the exposed group and 7.9 ng/mL in the control group. The limit of quantification for EOF analysis (up to 107 ng/mLF using 0.5 mL whole blood) did not allow for the detection of PFAS levels in low or sub parts per billion (ng/mL) concentrations, but the results indicate that EOF analysis is a suitable screening method sensitive enough to detect elevated/significant/exposure above background levels by known or unknown PFAS.

Organofluorine Mass Balance Analysis of Whole Blood Samples in Relation to Gender and Age.

Studies have highlighted the increasing fraction of unidentified organofluorine (UOF) compounds in human blood, whose health effects are not known. In this study, 130 whole blood samples from the Swedish general population were analyzed for extractable organofluorine (EOF) and selected per- and polyfluoroalkyl substances (PFAS). Organofluorine mass balance analysis revealed that 60% (0-99%) of the EOF in female samples could not be explained by the 63 monitored PFAS; in males, 41% (0-93%) of the EOF was of unidentified origin. Significant differences between both age groups and gender were seen, with the highest fraction of UOF in young females (70% UOF, aged 18-44), which is contrary to what has been reported in the literature for commonly monitored compounds (e.g., perfluorooctane sulfonic acid, PFOS). Increasing the number of monitored PFAS did not lead to a large decrease of the UOF fraction; the seven highest PFAS (C8-C11 PFCAs, C6-C8 PFSAs) accounted for 98% of sum 63 PFAS. The high fraction of UOF in human samples is of concern, as the chemical species of these organofluorine compounds remain unknown and thus their potential health risks cannot be assessed.

Combustion ion chromatography for extractable organofluorine analysis.

Combustion ion chromatography (CIC) has found a role in environmental analytical chemistry for fluorine content analysis. It is used for extractable organofluorine (EOF) analysis to evaluate perfluoroalkyl and polyfluoroalkyl substances (PFASs) and other organofluorine burden. The prevailing assumption has been that all PFASs are incinerated in CIC and matrix components have no impact on this process, but this has not been experimentally evaluated. In this work, the combustion efficiencies of 13 different PFASs were determined (66-110%). A notable difference was observed between calibrating the CIC with inorganic fluorine or organofluorine. Potential interferences from cations and coextracted matrix components from whole blood and surface water samples were evaluated. These observations should be acknowledged when performing EOF analysis using CIC, overlooking either non-100% combustion efficiencies or the differences in calibrating the CIC with inorganic fluorine or organofluorine could lead to underestimating EOF content and through that to misguide policy decisions.

Short intense psychological stress induced by skydiving does not impair intestinal barrier function.

BACKGROUND AND AIM: Psychological stress has been shown to increase intestinal permeability and is associated with the development of gastrointestinal disorders. This study aimed to investigate skydiving as an alternative model to analyse the effect of acute psychological stress on intestinal barrier function. MATERIALS AND METHODS: Twenty healthy subjects participated in a tandem skydive followed by a negative control visit, of which 19 (9 females and 10 males, 25.9 ± 3.7 years) were included in the study. Intestinal permeability was assessed by a multi-sugar urinary recovery test. Sucrose recovery and lactulose/rhamnose ratio in 0-5h urine indicated gastroduodenal and small intestinal permeability, respectively, and sucralose/erythritol ratio in 5-24h urine indicated colonic permeability. Blood samples were taken to assess markers associated with barrier function. This study has been registered at ClinicalTrials.gov (NCT03644979) on August 23, 2018. RESULTS: Skydiving resulted in a significant increase in salivary cortisol levels directly after skydiving compared to the control visit. Cortisol levels were still increased two hours after landing, while cortisol levels before skydiving were not significantly different from the baseline at the control visit. Skydiving did not induce a significant increase in gastroduodenal, small intestinal or colonic permeability. There was also no significant increase in plasma intestinal and liver fatty acid-binding proteins, suggesting no damage to the enterocytes. DISCUSSION: These results show that the acute intense psychological stress induced by skydiving does not affect intestinal permeability in healthy subjects. Future models aiming to investigate the effect of stress on human intestinal barrier function should consider a more sustained exposure to the psychological stressor.

Sauna dehydration as a new physiological challenge model for intestinal barrier function.

The intestinal barrier plays a crucial role in maintaining gut health, and an increased permeability has been linked to several intestinal and extra-intestinal disorders. There is an increasing demand for interventions aimed at strengthening this barrier and for in vivo challenge models to assess their efficiency. This study investigated the effect of sauna-induced dehydration on intestinal barrier function (clinicaltrials.gov: NCT03620825). Twenty healthy subjects underwent three conditions in random order: (1) Sauna dehydration (loss of 3% body weight), (2) non-steroidal anti-inflammatory drug (NSAID) intake, (3) negative control. Intestinal permeability was assessed by a multi-sugar urinary recovery test, while intestinal damage, bacterial translocation and cytokines were assessed by plasma markers. The sauna dehydration protocol resulted in an increase in gastroduodenal and small intestinal permeability. Presumably, this increase occurred without substantial damage to the enterocytes as plasma intestinal fatty acid-binding protein (I-FABP) and liver fatty acid-binding protein (L-FABP) were not affected. In addition, we observed significant increases in levels of lipopolysaccharide-binding protein (LBP), IL-6 and IL-8, while sCD14, IL-10, IFN-É£ and TNF-α were not affected. These results suggest that sauna dehydration increased intestinal permeability and could be applied as a new physiological in vivo challenge model for intestinal barrier function.

Rapid extraction method of polycyclic aromatic compounds in soil using basic silica selective pressurized liquid extraction.

Complex chemical mixtures found in soils at contaminated sites typically includes polycyclic aromatic compounds (PACs), thus posing potential environmental and human health risks. Pressurized liquid extraction (PLE) followed by silica clean-up is one of the most often used extraction methods for PACs in soil. While silica clean-up provide satisfactory recovery of oxygenated polycyclic aromatic hydrocarbons (OPAHs), this technique provides limited recovery of azaarenes. In this work, we used PLE and in-cell clean up with basic silica to increase the recovery of OPAHs and azaarenes. The optimized selective pressurized liquid extraction (SPLE) method used 4 g basic silica, dichloromethane, 100% flush volume, 100 and 120 °C extraction temperatures, with two static cycles for each temperature, no rinse in between the two extractions, and 20 and 120 s purge for the first and second extraction temperature, respectively. The method was validated for a wide range of PAC groups, including OPAHs, azaarenes, alkylated PAHs, and sulfur heterocycles (SPACs), in total 87 PACs, using certified reference material and in comparison to the results from previous inter-laboratory data. Our SPLE method yielded results that are in agreement with certified values and inter-laboratory data from prior analysis. The SPLE method also yielded lower variation than the results from the inter-laboratory data for analysis of OPAH and azaarenes, suggesting better precision than previous methods. More importantly, the SPLE method increases sample analysis throughput as extra clean-up step is not necessary anymore. The SPLE method was then successfully applied to rapidly screen PACs in three soil samples.

Contribution of precursor compounds to the release of per- and polyfluoroalkyl substances (PFASs) from waste water treatment plants (WWTPs).

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous in sludge and water from waste water treatment plants, as a result of their incorporation in everyday products and industrial processes. In this study, we measured several classes of persistent PFASs, precursors, transformation intermediates, and newly identified PFASs in influent and effluent sewage water and sludge from three municipal waste water treatment plants in Sweden, sampled in 2015. For sludge, samples from 2012 and 2014 were analyzed as well. Levels of precursors in sludge exceeded those of perfluoroalkyl acids and sulfonic acids (PFCAs and PFSAs), in 2015 the sum of polyfluoroalkyl phosphoric acid esters (PAPs) were 15-20ng/g dry weight, the sum of fluorotelomer sulfonic acids (FTSAs) was 0.8-1.3ng/g, and the sum of perfluorooctane sulfonamides and ethanols ranged from non-detected to 3.2ng/g. Persistent PFSAs and PFCAs were detected at 1.9-3.9ng/g and 2.4-7.3ng/g dry weight, respectively. The influence of precursor compounds was further demonstrated by an observed substantial increase for a majority of the persistent PFCAs and PFSAs in water after waste water treatment. Perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS) had a net mass increase in all WWTPs, with mean values of 83%, 28%, 37% and 58%, respectively. The load of precursors and intermediates in influent water and sludge combined with net mass increase support the hypothesis that degradation of precursor compounds is a significant contributor to PFAS contamination in the environment.

Temporal trends of PFSAs, PFCAs and selected precursors in Australian serum from 2002 to 2013.

Per- and polyfluoroalkyl substances (PFASs) are a family of compounds that includes numerous compound classes. To date, only a subset of these PFASs have been studied thoroughly in the general population. In this study, pooled serum samples from Australia collected in 2002-2013 were analyzed for PFASs according to gender and age (age categories of 0-4 years, 5-15 years, 16-30 years, 31-45 years, 46-60 years, and >60 years), in total 54 pooled samples and 4920 individuals. Compound classes included were perfluorocarboxylic acids (PFCAs), perfluorosulfonic acids (PFSAs), and two groups of PFCA precursor compounds; polyfluoroalkyl phosphate diesters (diPAPs), and fluorotelomer sulfonic acids (FTSAs). Several PFASs that were not reported in previous studies of Australian serum samples were found in this sample set including; diPAPs, FTSAs, perfluoropentane sulfonic acid (PFPeS), perfluoroheptane sulfonic acid (PFHpS), perfluoroheptane carboxylic acid (PFHpA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and perfluorotridecanoic acid (PFTrDA). Various temporal trends were observed with a significant reduction (p < 0.05) between 2002 and 2013 for 8:2 FTSA, perflurohexane sulfonic acid (PFHxS), PFHpS, PFOS, and perflurooctanoic acid (PFOA). Levels of longer-chained PFDA and PFUnDA started to decrease more recently, between 2006 and 2013, while PFDoDA increased during the same time period. Higher levels in younger age groups (0-4 and 5-15 years) compared to adults (>15 years) were found for 8:2 FTSA and PFHpA, while levels of PFHpS, PFOS, PFUnDA, PFDoDA and PFTrDA were higher in adult age groups compared to younger age groups. Gender-specific patterns were seen for PFOA, PFHxS, PFHpS and PFOS, where levels were lower in women. Changes in manufacturing processes were reflected in the temporal time trends, and differences in bioaccumulation potential between homologues could be associated with age trends. Our results emphasize the importance of including emerging classes of PFASs in biomonitoring studies.

Genetic variants determining survival and fertility in an adverse African environment: a population-based large-scale candidate gene association study.

Human survival probability and fertility decline strongly with age. These life history traits have been shaped by evolution. However, research has failed to uncover a consistent genetic determination of variation in survival and fertility. As an explanation, such genetic determinants have been selected in adverse environments, in which humans have lived during most of their history, but are almost exclusively studied in populations in modern affluent environments. Here, we present a large-scale candidate gene association study in a rural African population living in an adverse environment. In 4387 individuals, we studied 4052 SNPs in 148 genes that have previously been identified as possible determinants of survival or fertility in animals or humans. We studied their associations with survival comparing newborns, middle-age adults, and old individuals. In women, we assessed their associations with reported and observed numbers of children. We found no statistically significant associations of these SNPs with survival between the three age groups nor with women's reported and observed fertility. Population stratification was unlikely to explain these results. Apart from a lack of power, we hypothesise that genetic heterogeneity of complex phenotypes and gene-environment interactions prevent the identification of genetic variants explaining variation in survival and fertility in humans.

Comparison of PFASs contamination in the freshwater and terrestrial environments by analysis of eggs from osprey (Pandion haliaetus), tawny owl (Strix aluco), and common kestrel (Falco tinnunculus).

The level of PFAS (per- and polyfluorinated alkyl substances) contamination in freshwater and terrestrial Swedish environments in 2013/2014 was assessed by analyzing a range of perfluorinated alkyl acids, fluorotelomer acids, sulfonamides, sulfonamidoethanols and polyfluoralkyl phosphate diesters (diPAPs) in predator bird eggs. Stable isotopes ((13)C and (15)N) were analyzed to elucidate the dietary source. The tawny owl (Strix aluco, n=10) and common kestrel (Falco tinnunculus, n=40), two terrestrial species, and the osprey (Pandion haliaetus, n=30), a freshwater specie were included. In addition, a temporal trend (1997-2001, 2008-2009, 2013) in osprey was studied as well. The PFAS profile was dominated by perfluorooctane sulfonic acid (PFOS) in eggs from osprey and tawny owl, while for common kestrel perfluorinated carboxylic acids (∑PFCA) exceeded the level of PFOS. PFOS concentration in osprey eggs remained at the same level between 1997 and 2001 and 2013. For the long-chained PFCAs, there were a significant increase in concentrations in osprey eggs between 1997 and 2001 and 2008-2009. The levels of PFOS and PFCAs were about 10 and five times higher, respectively, in osprey compared to tawny owl and common kestrel. Evidence of direct exposure from PFCA precursor compounds to birds in both freshwater and terrestrial environment was observed. Low levels of diPAPs were detected in a few samples of osprey (<0.02-2.4ng/g) and common kestrel (<0.02-0.16ng/g) eggs, and 6:2 FTSA was detected in a majority of the osprey eggs (<6.3-52ng/g). One saturated telomer acid (7:3 FTCA), which is a transformation marker from precursor exposure, was detected in all species (<0.24-2.7ng/g). The (15)N data showed higher levels in osprey eggs compared to tawny owl and common kestrel, indicating that they feed on a 2-3 times higher trophic level. We conclude that ospreys are continuously exposed to PFAS at levels where adverse toxic effects have been observed in birds.

Production and turnover of ectomycorrhizal extramatrical mycelial biomass and necromass under elevated CO2 and nitrogen fertilization.

Extramatrical mycelia (EMM) of ectomycorrhizal fungi are important in carbon (C) and nitrogen (N) cycling in forests, but poor knowledge about EMM biomass and necromass turnovers makes the quantification of their role problematic. We studied the impacts of elevated CO2 and N fertilization on EMM production and turnover in a Pinus taeda forest. EMM C was determined by the analysis of ergosterol (biomass), chitin (total bio- and necromass) and total organic C (TOC) of sand-filled mycelium in-growth bags. The production and turnover of EMM bio- and necromass and total C were estimated by modelling. N fertilization reduced the standing EMM biomass C to 57% and its production to 51% of the control (from 238 to 122 kg C ha(-1)  yr(-1) ), whereas elevated CO2 had no detectable effects. Biomass turnover was high (˜13 yr(-1) ) and unchanged by the treatments. Necromass turnover was slow and was reduced from 1.5 yr(-1) in the control to 0.65 yr(-1) in the N-fertilized treatment. However, TOC data did not support an N effect on necromass turnover. An estimated EMM production ranging from 2.5 to 6% of net primary production stresses the importance of its inclusion in C models. A slow EMM necromass turnover indicates an importance in building up forest humus.

World-Wide Indoor Exposure to Polyfluoroalkyl Phosphate Esters (PAPs) and other PFASs in Household Dust.

Human exposure to perfluorooctanoic acid (PFOA) and other per- and polyfluoroalkyl substances (PFASs) is ongoing and in some cases increasing, despite efforts made to reduce emissions. The role of precursor compounds such as polyfluorinated phosphate esters (PAPs) has received increasing attention, but there are knowledge gaps regarding their occurrence and impact on human exposure. In this study, mono-, di-, and triPAPs, perfluorinated alkyl acids (PFAAs), saturated, and unsaturated fluorotelomer carboxylic acids (FTCA/FTUCAs), perfluoroalkane sulfonamides, and sulfonamidethanols (FOSA/FOSEs), and one fluorotelomer sulfonic acid (FTSA)) were compared in household dust samples from Canada, the Faroe Islands, Sweden, Greece, Spain, Nepal, Japan, and Australia. Mono-, di-, and triPAPs, including several diPAP homologues, were frequently detected in dust from all countries, revealing an ubiquitous spread in private households from diverse geographic areas, with significant differences between countries. The median levels of monoPAPs and diPAPs ranged from 3.7 ng/g to 1 023 ng/g and 3.6 ng/g to 692 ng/g, respectively, with the lowest levels found in Nepal and the highest in Japan. The levels of PAPs exceeded those of the other PFAS classes. These findings reveal the importance of PAPs as a source of PFAS exposure worldwide.

Determinants of epidemiologic transition in rural Africa: the role of socioeconomic status and drinking water source.

BACKGROUND: Many African countries experience a protracted epidemiologic transition, different from the classical transition in western societies. The factors driving this protracted transition are largely unknown. In northeast Ghana, we studied an ongoing epidemiologic transition and investigated the effects of socioeconomic status and drinking water source on the transition. METHODS: During a 9-year period, we followed a cohort of almost 30 000 individuals and collected information on mortality and fertility rates. In addition, using the standards set out by the WHO, we obtained the causes of death by verbal autopsy. Individuals were stratified according to their socioeconomic status and the households' use of an improved or unimproved drinking water source. RESULTS: Mortality rates decreased by -5.0% annually (p<0.001) and the main cause of death shifted from infectious to non-infectious diseases (p=0.014). General fertility rates and child-women ratios decreased annually by -12.7% (p<0.001) and -11.9% (p<0.001), respectively. There was no difference in the decline of mortality and fertility depending on socioeconomic status or drinking water source. CONCLUSIONS: Factors other than socioeconomic status and drinking water source are responsible for the observed declines in mortality and fertility observed during the protracted epidemiologic transition. Identifying the specific determinants of the ongoing transition is of importance, as they could be targeted in order to further improve public health in rural African countries.

Reflections of older people living in nursing homes.

AIM: To explore experiences of ageing in older people living in nursing homes, based on the gerotranscendence theory. METHOD: Interviews were held with 14 people aged between 80 and 96 years. The results were analysed using content analysis. FINDINGS: The findings were divided into three categories: the self, the cosmic dimension, and social and personal relationships. These three categories were underpinned by eight subcategories. Most participants described improved knowledge about themselves, decreased concern about body and appearance, acceptance and appreciation of life, and less regard for social norms. A fewer participants described a greater affinity with past generations, or thought that the borders between past and present had become blurred. CONCLUSION: This study provides a better understanding of how people experience old age. It also indicates how healthcare professionals could apply the gerotranscendence theory of ageing as a conversation model to enable care to be adjusted according to older people's wishes.

Seasonal variation in child and old-age mortality in rural Ghana.

BACKGROUND: Mortality in tropical countries varies considerably from season to season. As many of these countries have seen mortality moving from child to old-age mortality, we have studied seasonal variation in child and old-age mortality in a rural area in Ghana that currently undergoes an epidemiologic transition. METHODS: In an annual survey from 2002 through to 2011, we followed 29 642 individuals and obtained the cause and month of death from 1406 deceased individuals by making use of verbal autopsies. RESULTS: When comparing the seasons, we observed a trend for higher mortality during the wet season. When comparing separate months, we observed 34% more deaths than expected in September (95% CI 1.04-1.69; p = 0.024) at the end of the wet season and 43% more deaths in April (95% CI 1.13-1.80; p = 0.004) at the end of the dry season, while there were 42% less deaths than expected in December (95% CI 0.52-0.70; p = 0.003), shortly after the wet season. Cause-specific analysis indicated that the peak at the end of the wet season was due to excess mortality from infectious diseases in children and older people alike, whereas the peak in old-age mortality at the end of the dry season was due to non-infectious causes in older people only. CONCLUSIONS: Taken together, our data suggest that during the epidemiologic transition, mortality not only shifts from child to old-age and from infectious to non-infectious, but also from the wet to the dry season.