Development of a quantitative North and Central European job exposure matrix for wood dust.

Wood dust is an established carcinogen also linked to several non malignant respiratory disorders. A major limitation in research on wood dust and its health effects is the lack of (historical) quantitative estimates of occupational exposure for use in general population-based case-control or cohort studies. The present study aimed to develop a multinational quantitative Job Exposure Matrix (JEM) for wood dust exposure using exposure data from several Northern and Central European countries. For this, an occupational exposure database containing 12653 personal wood dust measurements collected between 1978 and 2007 in Denmark, Finland, France, The Netherlands, Norway, and the United Kingdom (UK) was established. Measurement data were adjusted for differences in inhalable dust sampling efficiency resulting from the use of different dust samplers and analysed using linear mixed effect regression with job codes (ISCO-88) and country treated as random effects. Fixed effects were the year of measurement, the expert assessment of exposure intensity (no, low, and high exposure) for every ISCO-88 job code from an existing wood dust JEM and sampling duration. The results of the models suggest that wood dust exposure has declined annually by approximately 8%. Substantial differences in exposure levels between countries were observed with the highest levels in the United Kingdom and the lowest in Denmark and Norway, albeit with similar job rankings across countries. The jobs with the highest predicted exposure are floor layers and tile setters, wood-products machine operators, and building construction labourers with geometric mean levels for the year 1997 between 1.7 and 1.9 mg/m3. The predicted exposure estimates by the model are compared with the results of wood dust measurement data reported in the literature. The model predicted estimates for full-shift exposures were used to develop a time-dependent quantitative JEM for exposure to wood dust that can be used to estimate exposure for participants of general population studies in Northern European countries on the health effects from occupational exposure to wood dust.

Middle Pleistocene re-organization of Australian Monsoon.

The sensitivity of the Australian Monsoon to changing climate boundary conditions remains controversial due to limited understanding of forcing processes and past variability. Here, we reconstruct austral summer monsoonal discharge and wind-driven winter productivity across the Middle Pleistocene Transition (MPT) in a sediment sequence drilled off NW Australia. We show that monsoonal precipitation and runoff primarily responded to precessional insolation forcing until ~0.95 Ma, but exhibited heightened sensitivity to ice volume and pCO2 related feedbacks following intensification of glacial-interglacial cycles. Our records further suggest that summer monsoon variability at the precessional band was closely tied to the thermal evolution of the Indo-Pacific Warm Pool and strength of the Walker circulation over the past ~1.6 Myr. By contrast, productivity proxy records consistently tracked glacial-interglacial variability, reflecting changing rhythms in polar ice fluctuations and Hadley circulation strength. We conclude that the Australian Monsoon underwent a major re-organization across the MPT and that extratropical feedbacks were instrumental in driving short- and long-term variability.

The usefulness of the STarT back screening tool and single-item general health measures when predicting future disability in patients with low back pain treated in Danish primary care physiotherapy.

INTRODUCTION: The extent to which disease specific screening tools or other health measures add to the predictive value of common clinical factors (pain, disability and socio-demographics) has been sparsely investigated. The aim of this study was to investigate whether a disease specific screening tool and a single-item general health measure adds predictive value to basic information collected in primary physiotherapy care when predicting future disability in patients with low back pain. MATERIAL AND METHODS: This longitudinal cohort study included 354 patients with low back pain from Danish primary care physiotherapy. Information was collected on socio-demographics, common clinical factors, The STarT Back Screening Tool (SBT) and general health perceptions measured as a single item from the SF-36 (GH-1). Disability at 6-month follow-up, measured by the Roland-Morris Disability Questionnaire, was predicted using multiple linear regression models. RESULTS: Clinical factors and baseline disability level explained 28.3% of the variance in 6-month disability scores. With SBT and GH-1 added separately to the baseline model, the explained variance increased by 2.1% (p = 0.01) and 3.6% (p < 0.001), respectively. CONCLUSION: The added value of the disease specific screening tools or the single-item general measure when predicting disability in patients with low back pain was generally small. Moreover, the predictive value of the single-item general measure seems comparable to and slightly better than the disease specific screening tool. Overall these findings may question the clinical utility of such measures.

Disability and physical activity in people with chronic disease receiving physiotherapy. A prospective cohort study.

Chronic disease affects patients' disability and participation in activities of daily living. Longitudinal information on disability and physical activity is generally scarce in patients with chronic disease. The current study aimed to investigate if self-reported disability and physical activity changed in patients with chronic disease receiving physiotherapy. Furthermore, the aim was to assess if an improvement in self-reported disability was related to an increase in objectively measured physical activity and if an aggravation in self-reported disability was related to a decrease in physical activity. Seventy patients with either multiple sclerosis, Parkinson's disease, rheumatoid arthritis or stroke receiving free of charge physiotherapy were tested at baseline and 1 year later. Disability was measured with the self-reported modified Ranking Scale-9 Questionnaire and physical activity was objectively measured using tri-axial accelerometry. Neither self-reported disability nor physical activity changed among patients receiving 1 year of free of charge physiotherapy at group level. Furthermore, self-reported change of disability was not expressed with changes in objectively measured physical activity, indicating that the two measures represent two different constructs.

Higher sea surface temperature in the Indian Ocean during the Last Interglacial weakened the South Asian monsoon.

SignificanceUnderstanding the drivers of South Asian monsoon intensity is pivotal for improving climate forecasting under global warming scenarios. Solar insolation is assumed to be the dominant driver of monsoon variability in warm climate regimes, but this has not been verified by proxy data. We report a South Asian monsoon rainfall record spanning the last ∼130 kyr in the Ganges-Brahmaputra-Meghna river catchment. Our multiproxy data reveal that the South Asian monsoon was weaker during the Last Interglacial (130 to 115 ka)-despite higher insolation-than during the Holocene (11.6 ka to present), thus questioning the widely accepted model assumption. Our work implies that Indian Ocean warming may increase the occurrence of severe monsoon failures in South Asia.

Therapist perceptions of the Danish Physiotherapy Research Database for assessing patients with chronic disease.

BACKGROUND: The Danish Physiotherapy Research Database for chronic patients receiving Free of Charge Physiotherapy (PhysDB-FCP) was piloted over a 1-year period. The purpose of the PhysDB-FCP is to provide a user friendly digital online structured tool that standardizes initial and follow up clinical assessments generating data that can be used for clinical decision making and support future research in physiotherapy for patients with chronic disease. Although initial assessments were completed, the attrition rate was 73% and 90% at 3- and 6- months, respectively, which suggests problems with the current tool. OBJECTIVE: To evaluate the perspectives of the physiotherapists that used the PhysDB-FCP and propose changes to the tool based on this feedback. MATERIALS AND METHODS: Fifty of the 103 physiotherapists introduced to the PhysDB-FCP completed an anonymous online survey. Physiotherapists were asked Likert/categorical and yes/no questions on experiences with the PhysDB-FCP within their practice, perceptions of patient experiences, suitability of the resources and support provided by the PhysDB-FCP working group and the ideal administration frequency of the assessments within the PhysDB-FCP. Open ended feedback on possible improvements to the PhysDB-FCP was also collected. RESULTS: Physiotherapists agreed that the PhysDB-FCP was useful for taking a physiotherapy assessment (74%) and the patient survey was useful for goal setting (72%). Although physiotherapists felt the PhysDB-FCP was well-defined (82%), only 36% would like to use a similar tool again. Generally, the PhysDB-FCP was too time-consuming, administered too frequently and included irrelevant items. For example, 72% of physiotherapists took >45 min to administer the assessment in the first consultation which was performed over multiple sessions. CONCLUSIONS: The perspectives of physiotherapists using The PhysDB-FCP suggest specific changes that will ensure better use of the tool in future practice. Changes will likely involve administering the assessment less frequently (every 6-months to 1-year), shortening the assessment, and using diagnosis-specific assessment items.

Fossil leaf wax hydrogen isotopes reveal variability of Atlantic and Mediterranean climate forcing on the southeast Iberian Peninsula between 6000 to 3000 cal. BP.

Many recently published papers have investigated the spatial and temporal manifestation of the 4.2 ka BP climate event at regional and global scales. However, questions with regard to the potential drivers of the associated climate change remain open. Here, we investigate the interaction between Atlantic and Mediterranean climate forcing on the south-eastern Iberian Peninsula during the mid- to late Holocene using compound-specific hydrogen isotopes from fossil leaf waxes preserved in marine sediments. Variability of hydrogen isotope values in the study area is primarily related to changes in the precipitation source and indicates three phases of increased Mediterranean sourced precipitation from 5450 to 5350 cal. BP, from 5150 to 4300 cal. BP including a short-term interruption around 4800 cal. BP, and from 3400 to 3000 cal. BP interrupted around 3200 cal. BP. These phases are in good agreement with times of prevailing positive modes of the North Atlantic Oscillation (NAO) and reduced storm activity in the Western Mediterranean suggesting that the NAO was the dominant modulator of relative variability in precipitation sources. However, as previously suggested other modes such as the Western Mediterranean Oscillation (WeMO) may have altered this overall relationship. In this regard, a decrease in Mediterranean moisture source coincident with a rapid reduction in warm season precipitation during the 4.2 ka BP event at the south-eastern Iberian Peninsula might have been related to negative WeMO conditions.

Cohort profile: Design and implementation of the Danish Physiotherapy Research Database for patients receiving primary care with chronic disease.

PURPOSE: Free of charge physiotherapy (FCP) is free physiotherapy provided by the Danish government for patients with a range of chronic diseases. To date, the population has not been described in depth making evaluation and decision making difficult. The purpose of this study was to (1) describe the development and the content of a novel clinical physiotherapy database for FCP (PhysDB-FCP) and (2) present the cohort profile based on the data collected. PARTICIPANTS: Ninety-nine clinics (17 460 FCP patients) were invited to participate in the development process from 2018 to 2019. Eleven clinics consented (2780 FCP patients) and 534 patients performed the physiotherapy assessment using the PhysDB-FCP tool, with 393/534 completing the patient survey. FINDINGS TO DATE: The content of the PhysDB-FCP was developed through an iterative process involving consensus between clinical and research workgroups. Prior to using the tool all consenting sites received training to use/administer the tool. All data were collected/stored using the PhysDB-FCP. Items finally chosen for the PhysDB-FCP included demographic information, questions about health status and daily functioning, functional tests, treatment plan and validated questionnaires. The initial patient cohort composed of 63.4% women with main diagnoses of multiple sclerosis (22.7%) and Parkinson's disease (17.0%). The ability to perform personal/instrumental activities of daily living and functional ability varied widely. Other non-physiotherapy related issues were identified in numerous patients (ie, 34.9% of patients were at risk of depression) and multidisciplinary interventional approaches could be considered. FUTURE PLANS: The current study has provided a comprehensive description of patients receiving FCP, using data collected from the novel PhysDB-FCP. Collected information can be used to facilitate microlevel to macrolevel programme evaluation and decisions. Although the PhysDB-FCP is promising, the tool requires optimisation before it is implemented regionally and/or nationally.

Incidence of Free of Charge Physiotherapy in a Danish National Cohort of Stroke, Parkinson's Disease, Multiple Sclerosis and Rheumatoid Arthritis Patients.

BACKGROUND: Denmark is a welfare state with a publically funded healthcare system that includes the right to free of charge physiotherapy (FCP) for patients with chronic or progressive disease who fulfill strict criteria. The aim of this study was to investigate the incidence of referral to FCP in patients with a hospital diagnosis of stroke, multiple sclerosis (MS), Parkinson's disease (PD) and rheumatoid arthritis (RA) between 2007 and 2016. METHODS: The study was register-based and included data from The Danish National Patient Registry and The National Health Service Registry. The study population included the four largest disease groups receiving FCP in Denmark. The incidence of receiving FCP was reported as the cumulated incidence proportion (CIP). RESULTS: The study showed that FCP was mainly initiated within the first 2 years after diagnosis. The 2-year CIP was 8% for stroke patients, 53% for PD patients, 49% for MS patients, and 16% for RA patients. The proportion of patients referred to FCP generally increased over the period of the study due to more patients being referred from medical specialists in primary care. CONCLUSION: This study found substantial differences in the incidence of referral to FCP in a Danish population of stroke, PD, MS and RA patients.

Alterations of the bile microbiome in primary sclerosing cholangitis.

BACKGROUND: Patients with primary sclerosing cholangitis (PSC) display an altered colonic microbiome compared with healthy controls. However, little is known on the bile duct microbiome and its interplay with bile acid metabolism in PSC. METHODS: Patients with PSC (n=43) and controls without sclerosing cholangitis (n=22) requiring endoscopic retrograde cholangiography were included prospectively. Leading indications in controls were sporadic choledocholithiasis and papillary adenoma. A total of 260 biospecimens were collected from the oral cavity, duodenal fluid and mucosa and ductal bile. Microbiomes of the upper alimentary tract and ductal bile were profiled by sequencing the 16S-rRNA-encoding gene (V1-V2). Bile fluid bile acid composition was measured by high-performance liquid chromatography mass spectrometry and validated in an external cohort (n=20). RESULTS: The bile fluid harboured a diverse microbiome that was distinct from the oral cavity, the duodenal fluid and duodenal mucosa communities. The upper alimentary tract microbiome differed between PSC patients and controls. However, the strongest differences between PSC patients and controls were observed in the ductal bile fluid, including reduced biodiversity (Shannon entropy, p=0.0127) and increase of pathogen Enterococcus faecalis (FDR=4.18×10-5) in PSC. Enterococcus abundance in ductal bile was strongly correlated with concentration of the noxious secondary bile acid taurolithocholic acid (r=0.60, p=0.0021). CONCLUSION: PSC is characterised by an altered microbiome of the upper alimentary tract and bile ducts. Biliary dysbiosis is linked with increased concentrations of the proinflammatory and potentially cancerogenic agent taurolithocholic acid.

Labrador Sea freshening at 8.5 ka BP caused by Hudson Bay Ice Saddle collapse.

A significant reduction in the Atlantic Meridional Overturning Circulation and rapid northern Hemisphere cooling 8200 years ago have been linked to the final melting of the Laurentide Ice Sheet. Although many studies associated this cold event with the drainage of Lake Agassiz-Ojibway, recent model simulations have shown that the Hudson Bay Ice Saddle collapse would have had much larger effects on the Atlantic Meridional Overturning Circulation than the lake outburst itself. Based on a combination of Mg/Ca and oxygen isotope ratios of benthic foraminifera, this study presents the first direct evidence of a major Labrador shelfwater freshening at 8.5 ka BP, which we associate with the Hudson Bay Ice Saddle collapse. The freshening is preceded by a subsurface warming of the western Labrador Sea, which we link to the strengthening of the West Greenland Current that could concurrently have accelerated the ice saddle collapse in Hudson Bay.

Responsiveness and minimal important change for the quick-DASH in patients with shoulder disorders.

BACKGROUND: Responsiveness and minimal important change (MIC) are central measurement properties when interpreting scores from health questionnaires. The aim of the study was to evaluate the responsiveness and MIC of the Danish version of the shortened version the Disabilities of the Arm, Shoulder and Hand questionnaire (Quick-DASH) in patients with shoulder disorders referred to primary care physiotherapy treatment. METHODS: The study included 261 patients who completed questionnaires at baseline and 3 and 6 months follow up. Absolute and relative change scores was analysed using receiver-operating-characteristics (ROC) curve analysis with the Patient Global Impression of Change (PGIC) as external anchor. RESULTS: At both 3 and 6 months follow up, the Area under the Curve (ROC AUC) exceeded 0.70 and MIC was 9.1 and 13.6 at 3 and 6 months respectively. CONCLUSION: The Danish version of the Quick-DASH demonstrated adequate ability to measure changes in disability over 3 and 6 months in patients with shoulder disorders undergoing primary care physiotherapy treatment.

The smallest worthwhile effect of primary care physiotherapy did not differ across musculoskeletal pain sites.

OBJECTIVES: To determine and compare estimates of the smallest worthwhile effect (SWE) for physiotherapy in neck, shoulder, and low-back pain patients and to investigate the influence of sociodemographic, clinical, and psychological factors on these estimates. METHODS: A structured telephone interview was conducted before treatment was commenced in 160 patients referred for primary care physiotherapy. The benefit-harm trade-off method was used to estimate the SWE of physiotherapy for the following outcomes; pain, disability, and time to recovery, compared with the improvement achieved without any treatment (natural course). Regression analyses were used to assess the influence of sociodemographics, clinical variables, and intake scores on pain, disability, and psychological scales. RESULTS: The median SWE for improvements on pain and disability was 20% (interquartile range 10%-30%), and the SWE for time to recovery was 10 days (interquartile range 7-14 days) over a period of 6 weeks. These estimates did not differ with respect to pain location (neck, shoulder, or back) and were generally unaffected by sociodemographic, clinical, and psychological factors. CONCLUSION: People with neck, shoulder, and low-back pain need to see at least 20% of additional improvement on pain and disability compared with natural recovery to consider that the effect of physiotherapy is worthwhile, given its costs, potential side effects, and inconveniences.

The effectiveness of a stratified care model for non-specific low back pain in Danish primary care compared to current practice: study protocol of a randomised controlled trial.

BACKGROUND: Prior studies indicate that stratified care for low back pain results in better clinical outcome and reduced costs in healthcare compared to current practice. Stratified care may be associated with clinical benefits for patients with low back pain at a lower cost, but evidence is sparse. Hence this study aims to evaluate the clinical effects and cost-effectiveness of stratified care in patients with non-specific low back pain compared to current practice. METHODS/DESIGN: The study is a two-armed randomised controlled trial in primary care in the Regions of Southern and Central Denmark (2.5 million citizens). Patients with non-specific low back will be recruited by paticpating GPs. Patients are randomised to either (1) stratified care or (2) current practice at participating physiotherapy clinics. In the stratified care arm, the intervention is based on the patient's STarT Back Tool classification and trained accordingly, whereas physiotherapists in the current pratice arm are blinded to the STarT score. Primary outcomes in the trial will be group differences in time off work, improvement in LBP disability measured by the Roland Morris Disability Questionnaire (RMDQ) and patient-reported global change. Secondary measures will be pain intensity, patient satisfaction, data on patient healthcare resource utilisation and quality-adjusted life year based on the EQ-5D-5L. DISCUSSION: Stratified care that effectively targets treatment to relevant sub-groups of patients has potentially great impact on the treatment pathways of low back pain. Thus, if effective, this could result in better patient outcomes and at the same time reduce the costs for treatment of low back pain. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02612467 . Registered on 16 November 2015.

Late Miocene climate cooling and intensification of southeast Asian winter monsoon.

The late Miocene offers the opportunity to assess the sensitivity of the Earth's climate to orbital forcing and to changing boundary conditions, such as ice volume and greenhouse gas concentrations, on a warmer-than-modern Earth. Here we investigate the relationships between low- and high-latitude climate variability in an extended succession from the subtropical northwestern Pacific Ocean. Our high-resolution benthic isotope record in combination with paired mixed layer isotope and Mg/Ca-derived temperature data reveal that a long-term cooling trend was synchronous with intensification of the Asian winter monsoon and strengthening of the biological pump from ~7 Ma until ~5.5 Ma. The climate shift occurred at the end of a global δ13C decrease, suggesting that changes in the carbon cycle involving the terrestrial and deep ocean carbon reservoirs were instrumental in driving late Miocene climate cooling. The inception of cooler climate conditions culminated with ephemeral Northern Hemisphere glaciations between 6.0 and 5.5 Ma.

Know your fish: A novel compound-specific isotope approach for tracing wild and farmed salmon.

The rapid expansion of the aquaculture industry with carnivorous fish such as salmon has been accompanied by an equally rapid development in alternative feed ingredients. This has outpaced the ability of prevailing authentication method to trace the diet and origins of salmon products at the retail end. To close this gap, we developed a new profiling tool based on amino acid δ13C fingerprints. With this tool, we discriminated with high-accuracy among wild-caught, organically, and conventionally farmed salmon groups, as well as salmon fed alternative diets such as insects and macroalgae. Substitution of fishmeal with macroalgae was detected at 5% difference level. The δ13C fingerprints of essential amino acids appear particularly well suited for tracing protein sources, and the non-essentials for tracing lipid origins (terrestrial vs. aquatic). In an industry constantly developing new feed proteins and functional additives, our method is a promising tool for tracing salmon and other seafood products.

Clinical course and prognosis of musculoskeletal pain in patients referred for physiotherapy: does pain site matter?

BACKGROUND: Danish patients with musculoskeletal disorders are commonly referred for primary care physiotherapy treatment but little is known about their general health status, pain diagnoses, clinical course and prognosis. The objectives of this study were to 1) describe the clinical course of patients with musculoskeletal disorders referred to physiotherapy, 2) identify predictors associated with a satisfactory outcome, and 3) determine the influence of the primary pain site diagnosis relative to those predictors. METHODS: This was a prospective cohort study of patients (n = 2,706) newly referred because of musculoskeletal pain to 30 physiotherapy practices from January 2012 to May 2012. Data were collected via a web-based questionnaire 1-2 days prior to the first physiotherapy consultation and at 6 weeks, 3 and 6 months, from clinical records (including primary musculoskeletal symptom diagnosis based on the ICPC-2 classification system), and from national registry data. The main outcome was the Patient Acceptable Symptom State. Potential predictors were analysed using backwards step-wise selection during longitudinal Generalised Estimating Equation regression modelling. To assess the influence of pain site on these associations, primary pain site diagnosis was added to the model. RESULTS: Of the patients included, 66% were female and the mean age was 48 (SD 15). The percentage of patients reporting their symptoms as acceptable was 32% at 6 weeks, 43% at 3 months and 52% at 6 months. A higher probability of satisfactory outcome was associated with place of residence, being retired, no compensation claim, less frequent pain, shorter duration of pain, lower levels of disability and fear avoidance, better mental health and being a non-smoker. Primary pain site diagnosis had little influence on these associations, and was not predictive of a satisfactory outcome. CONCLUSION: Only half of the patients rated their symptoms as acceptable at 6 months. Although satisfactory outcome was difficult to predict at an individual patient level, there were a number of prognostic factors that were associated with this outcome. These factors should be considered when developing generic prediction tools to assess the probability of satisfactory outcome in musculoskeletal physiotherapy patients, because the site of pain did not affect that prognostic association.

Feedback on Measured Dust Concentrations Reduces Exposure Levels Among Farmers.

BACKGROUND: The high burden of exposure to organic dust among livestock farmers warrants the establishment of effective preventive and exposure control strategies for these workers. The number of intervention studies exploring the effectiveness of exposure reduction strategies through the use of objective measurements has been limited. OBJECTIVE: To examine whether dust exposure can be reduced by providing feedback to the farmers concerning measurements of the exposure to dust in their farm. METHODS: The personal dust levels of farmers in 54 pig and 26 dairy cattle farms were evaluated in two measurement series performed approximately 6 months apart. Detailed information on work tasks and farm characteristics during the measurements were registered. Participating farms were randomized a priori to a control (n = 40) and an intervention group (n = 40). Shortly after the first visit, owners of intervention farms only received a letter with information on the measured dust concentrations in the farm together with some general advises on exposure reduction strategies (e.g. use of respirators during certain tasks). Relationships between measured dust concentrations and intervention status were quantified by means of linear mixed effect analysis with farm and worker id as random effects. Season, type of farming, and work tasks were treated as fixed effects. Changes in exposure over time were explored primarily at a farm level in models combined, as well as separate for pig and cattle farmers. RESULTS: After adjustment for fixed effects, an overall reduction of 23% in personal dust exposures was estimated as a result of the intervention (P = 0.02). Exposure reductions attributable to the intervention were similar across pig and cattle farmers, but statistically significant only for pig farmers. Intervention effects among pig farmers did not depend on the individuals' information status; but among cattle farmers a significant 48% reduction in exposure was found only among individuals that reported to have been informed. No systematic differences in changes over time considering the use of respiratory protection between the intervention and control groups were observed. CONCLUSION: The results of the present study suggest reductions between 20 and 30% in personal exposure to inhalable dust to be feasible through simple information provided to the farm owners regarding actual levels of exposure together with instructions on basic measures of prevention. The exact reasons for these effects are unclear, but likely they involve changes in behavior and working practices among intervention farmers.

The dominant detritus-feeding invertebrate in Arctic peat soils derives its essential amino acids from gut symbionts.

Supplementation of nutrients by symbionts enables consumers to thrive on resources that might otherwise be insufficient to meet nutritional demands. Such nutritional subsidies by intracellular symbionts have been well studied; however, supplementation of de novo synthesized nutrients to hosts by extracellular gut symbionts is poorly documented, especially for generalists with relatively undifferentiated intestinal tracts. Although gut symbionts facilitate degradation of resources that would otherwise remain inaccessible to the host, such digestive actions alone cannot make up for dietary insufficiencies of macronutrients such as essential amino acids (EAA). Documenting whether gut symbionts also function as partners for symbiotic EAA supplementation is important because the question of how some detritivores are able to subsist on nutritionally insufficient diets has remained unresolved. To answer this poorly understood nutritional aspect of symbiont-host interactions, we studied the enchytraeid worm, a bulk soil feeder that thrives in Arctic peatlands. In a combined field and laboratory study, we employed stable isotope fingerprinting of amino acids to identify the biosynthetic origins of amino acids to bacteria, fungi and plants in enchytraeids. Enchytraeids collected from Arctic peatlands derived more than 80% of their EAA from bacteria. In a controlled feeding study with the enchytraeid Enchytraeus crypticus, EAA derived almost exclusively from gut bacteria when the worms fed on higher fibre diets, whereas most of the enchytraeids' EAA derived from dietary sources when fed on lower fibre diets. Our gene sequencing results of gut microbiota showed that the worms harbour several taxa in their gut lumen absent from their diets and substrates. Almost all gut taxa are candidates for EAA supplementation because almost all belong to clades capable of biosynthesizing EAA. Our study provides the first evidence of extensive symbiotic supplementation of EAA by microbial gut symbionts and demonstrates that symbiotic bacteria in the gut lumen appear to function as partners both for symbiotic EAA supplementation and for digestion of insoluble plant fibres.