Observation of Seven Astrophysical Tau Neutrino Candidates with IceCube.

We report on a measurement of astrophysical tau neutrinos with 9.7 yr of IceCube data. Using convolutional neural networks trained on images derived from simulated events, seven candidate ν_{τ} events were found with visible energies ranging from roughly 20 TeV to 1 PeV and a median expected parent ν_{τ} energy of about 200 TeV. Considering backgrounds from astrophysical and atmospheric neutrinos, and muons from π^{±}/K^{±} decays in atmospheric air showers, we obtain a total estimated background of about 0.5 events, dominated by non-ν_{τ} astrophysical neutrinos. Thus, we rule out the absence of astrophysical ν_{τ} at the 5σ level. The measured astrophysical ν_{τ} flux is consistent with expectations based on previously published IceCube astrophysical neutrino flux measurements and neutrino oscillations.

Creatine and low-dose lithium supplementation separately alter energy expenditure, body mass, and adipose metabolism for the promotion of thermogenesis.

Nutraceutical approaches to promote adipose tissue thermogenesis may help to prevent obesity onset. Creatine is a critical regulator of adipose metabolic function and low-dose lithium supplementation has been shown to promote adipose thermogenesis. In the present study, we sought to directly compare the two supplements for their effects on adipose metabolism and thermogenesis. We show that both supplements increase daily energy expenditure (EE) and reduce body mass in male Sprague-Dawley rats. Lithium increased brown adipose tissue (BAT) mitochondrial and lipolytic proteins that are associated with thermogenesis, while creatine increased BAT UCP1 and mitochondrial respiration. The BAT thermogenic findings were not observed in females. White adipose tissue and skeletal muscle markers of thermogenesis were unaltered with the supplements. Together, the data show that low-dose lithium and creatine have diverging effects on markers of BAT thermogenesis and that each increase daily EE and lower body mass in a sex-dependent manner.

Adverse birth outcomes related to concentrations of per- and polyfluoroalkyl substances (PFAS) in maternal blood collected from pregnant women in 1960-1966.

BACKGROUND: Prior animal and epidemiological studies suggest that per- and polyfluoroalkyl substances (PFAS) exposure may be associated with reduced birth weight. However, results from prior studies evaluated a relatively small set of PFAS. OBJECTIVES: Determine associations of gestational PFAS concentrations in maternal serum samples banked for 60 years with birth outcomes. METHODS: We used data from 97 pregnant women from Boston and Providence that enrolled in the Collaborative Perinatal Project (CPP) study (1960-1966). We quantified concentrations of 27 PFAS in maternal serum in pregnancy and measured infant weight, height and ponderal index at birth. Covariate-adjusted associations between 11 PFAS concentrations (>75% detection limits) and birth outcomes were estimated using linear regression methods. RESULTS: Median concentrations of PFOA, PFNA, PFHxS, and PFOS were 6.189, 0.330, 14.432, and 38.170 ng/mL, respectively. We found that elevated PFAS concentrations during pregnancy were significantly associated with lower birth weight and ponderal index at birth, but no significant associations were found with birth length. Specifically, infants born to women with PFAS concentrations ≥ median levels had significantly lower birth weight (PFOS: ß = -0.323, P = 0.006; PFHxS: ß = -0.292, P = 0.015; PFOA: ß = -0.233, P = 0.03; PFHpS: ß = -0.239, P = 0.023; PFNA: ß = -0.239, P = 0.017). Similarly, women with PFAS concentrations ≥ median levels had significantly lower ponderal index (PFHxS: ß = -0.168, P = 0.020; PFHxA: ß = -0.148, P = 0.018). CONCLUSIONS: Using data from this US-based cohort study, we found that 1) maternal PFAS levels from the 1960s exceeded values in contemporaneous populations and 2) that gestational concentrations of certain PFAS were associated with lower birth weight and infant ponderal index. Additional studies with larger sample size are needed to further examine the associations of gestational exposure to individual PFAS and their mixtures with adverse birth outcomes.

Burnout and its determinants among anaesthesia care providers in Switzerland: a multicentre cross-sectional study.

The escalating epidemic of burnout in healthcare professionals affects provider well-being, patient care and sustainability of healthcare systems. The objective of this study was to determine the prevalence of burnout among anaesthesia care providers (consultants, trainees or nurse anaesthetists) in Switzerland and identify risk factors to develop strategies for prevention. This multicentre cross-sectional study was conducted at 22 anaesthesia departments in the German-speaking part of Switzerland, using an online questionnaire. Burnout assessment was performed using the Maslach Burnout Inventory. Additionally, the questionnaire included questions on workplace and personal risk factors. Of 1630 anaesthesia care providers contacted, 688 (42%) completed the survey. Among respondents who specified their work positions (n = 676), 52% (149/287) of nurses and 59% (229/389) of physicians were at high risk of burnout; and 9% (26/287) of nurses and 18% (70/389) of physicians met the criteria for burnout syndrome. Logistic regression analysis found significant associations between burnout and perceived lack of support at work among physicians (odds ratio (95%CI) 2.66 (1.40-5.24), p = 0.004); being a trainee in the 1st and 2nd year of training (2.91 (1.14-7.41), p = 0.024); being a trainee with > 5 years of experience (2.78 (1.08-6.98), p = 0.031); and male gender among nurses (4.13 (1.62-11.2), p = 0.004) and physicians (2.32 (1.22-4.47), p = 0.011). Work-related errors due to high workload or fatigue were reported by 65% (444/688) and consideration of leaving the profession due to working conditions was expressed by 46% (319/688) of respondents. Anaesthetic care providers in German-speaking Switzerland experience a considerable prevalence of burnout, influenced mainly by workplace factors.

Feasibility of salvage resection following locoregional failure after chemoradiotherapy and consolidation durvalumab for unresectable stage III non-small cell lung cancer.

INTRODUCTION: In patients with unresectable stage III non-small cell lung cancer, high-dose chemoradiotherapy (CRT) followed by consolidation durvalumab improves the 5-year overall survival compared to CRT alone. The feasibility and safety of salvage surgery for such patients who subsequently develop locoregional failure (LRF) is unclear. We evaluated our institutional experience with radical-intent salvage surgery in this patient population. MATERIALS AND METHODS: Details of patients undergoing salvage surgery for locoregional failure after CRT and durvalumab were identified from an institutional surgical database. Each patient's case underwent multidisciplinary discussion at initial disease presentation, and again at time of progression. RESULTS: Ten patients underwent salvage surgery for LRF after prior concurrent (n = 9) or sequential (n = 1) platinum-based high-dose chemo-radiotherapy followed by durvalumab. Consolidation durvalumab was completed in 4 patients, and discontinued in 6, due to either toxicity or disease progression. Median time between end of radiotherapy to detection of LRF was 19 months (range 6-75). Seven patients underwent a lobectomy, 1 a bilobectomy and 2 patients a pneumonectomy. Postoperative morbidity (Clavien-Dindo grade III-V) and 90-day mortality were 10% and 0%, respectively. Median follow-up after surgery was 7 months (range 1-25) during which 2 patients died (both 9 months post-operatively), one due to distant progression, and one of sepsis/bleeding. Eight patients are alive at 1-23 months post-surgery, with 6 showing no evidence of disease. CONCLUSIONS: Our results suggest that salvage pulmonary resection can be performed safely in selected patients with LRF following chemoradiotherapy and durvalumab. This radical-intent treatment option merits consideration by multidisciplinary lung tumor boards.

Observation of high-energy neutrinos from the Galactic plane.

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.

[Frequency and severity of sarcopenia in patients with inflammatory and noninflammatory musculoskeletal diseases : Results of a monocentric study in a tertiary care center]. / Häufigkeit und Schweregrad von Sarkopenie bei Patient*innen mit entzündlichen und nichtentzündlichen muskuloskeletalen Erkrankungen : Ergebnisse einer monozentrischen Studie in einem tertiären Zentrum.

INTRODUCTION: Sarcopenia (SP) is defined as the pathological loss of muscle mass and function. This is a clinically relevant problem, especially in geriatric patients, because SP is associated with falls, frailty, loss of function, and increased mortality. People with inflammatory and degenerative rheumatic musculoskeletal disorders (RMD) are also at risk for developing SP; however, there is little research on the prevalence of this health disorder in this patient group using currently available SP criteria. OBJECTIVE: To investigate the prevalence and severity of SP in patients with RMD. METHODS: A total of 141 consecutive patients over 65 years of age with rheumatoid arthritis (RA), spondylarthritis (SpA), vasculitis, and noninflammatory musculoskeletal diseases were recruited in a cross-sectional study at a tertiary care center. The European Working Group on Sarcopenia in Older People (EWGSOP 1 and 2) definitions of presarcopenia, SP, and severe SP were used to determine the prevalence. Lean mass as a parameter of muscle mass and bone density were measured by dual X­ray absorptiometry (DXA). Handgrip strength and the short physical performance battery (SPPB) were performed in a standardized manner. Furthermore, the frequency of falls and the presence of frailty were determined. Student's T-test and the χ2-test were used for statistics. RESULTS: Of the patients included 73% were female, the mean age was 73 years and 80% had an inflammatory RMD. According to EWGSOP 2, 58.9% of participants probable had SP due to low muscle function. When muscle mass was added for confirmation, the prevalence of SP was 10.6%, 5.6% of whom had severe SP. The prevalence was numerically but not statistically different between inflammatory (11.5%) and noninflammatory RMD (7.1%). The prevalence of SP was highest in patients with RA (9.5%) and vasculitis (24%), and lowest in SpA (4%). Both osteoporosis (40% vs. 18.5%) and falls (15% vs. 8.6%) occurred more frequently in patients with SP than those without SP. DISCUSSION: This study showed a relatively high prevalence of SP, especially in patients with RA and vasculitis. In patients at risk, measures to detect SP should routinely be performed in a standardized manner in the clinical practice. The high frequency of muscle function deficits in this study population supports the importance of measuring muscle mass in addition to bone density with DXA to confirm SP.

Long-Term Outcomes After Chemoradiotherapy and Surgery for Superior Sulcus Tumors.

Introduction: Superior sulcus tumors (SSTs) are uncommon, and their anatomical location can make treatment challenging. We analyzed late outcomes of patients with SST treated with concurrent chemoradiotherapy followed by surgical resection (trimodality) in a single tertiary institution. Methods: Patients with non-small cell SSTs, who underwent trimodality therapy between 2002 and 2017, were selected from a prospective institutional surgical database. Patients were uniformly staged with 18F-fluorodeoxyglucose-positron emission tomography, computed tomography scan of the chest and upper abdomen, and brain imaging. Patients undergoing resection of the lung plus chest wall were grouped as limited SST and those needing extensive resections (e.g., including the vertebral body) as extended SST. Kaplan-Meier survival analysis was performed to determine difference in survival. Multivariate Cox regression was used to identify prognostic factors. Results: A total of 123 patients were identified with a median follow-up of 4.9 years (interquartile range: 1.6-8.9 y). The 90-day postoperative mortality and morbidity (Clavien-Dindo grades III-V) were 6.5% and 21.1%, respectively. Patients with a radical resection (R0: 92.7%) had better survival (p = 0.002), as did those who had major pathologic response (73%) (p = 0.001). Ten-year overall survival (OS) and disease-free survival were 48.1% and 42.6%, respectively. There were no differences in 90-day mortality (p = 0.31) and OS (p = 0.79) between extended SST and limited SST patients. Conclusions: In patients with SST, trimodality resulted in a 10-year estimated OS and disease-free survival of 48.1% and 42.6%, respectively, which were improved after radical resection (R0) and major pathologic response. Survival for limited and extended resections was comparable, and distant relapse was the main pattern of failure. Better systemic treatments are therefore needed.

[Lay version of the 2018 EULAR recommendations for physical activity in people with inflammatory arthritis and osteoarthritis : Translation into German and linguistic validation in German-speaking countries with people affected]. / Die laienverständliche Version der 2018 EULAR Empfehlungen zu körperlicher Aktivität von Menschen mit entzündlich-rheumatischen und degenerativen Erkrankungen : Übersetzung ins Deutsche und sprachliche Validierung im deutschsprachigen Raum mit Betroffenen.

BACKGROUND: Physical activity and exercise are beneficial for people with rheumatic diseases; however, recommendations for the management of rheumatoid arthritis (RA), spondyloarthritis (SpA) and hip- and knee osteoarthritis (HOA/KOA) are usually unspecific with respect to mode and dose of exercise. This is why the 2018 EULAR recommendations for physical activity in people with inflammatory arthritis and osteoarthritis were formulated. The recommendations consist of 4 overarching principles and 10 recommendations. These were also published as a lay version in the English language. AIM: Translation of the lay version into German and its linguistic validation in Austria, Germany and Switzerland. METHODS: A professional translation was reviewed by the authors, including people with, RA, SpA, HOA/KOA from the three German-speaking countries, which provided a prefinal lay version. Subsequently, eight interviews with people with RA, SpA, HOA/KOA were conducted in each country to evaluate understandability, wording, completeness and feasibility of the prefinal lay version. Finally, the authors, i.e. those with RA, SpA, and osteoarthritis, anonymously rated their agreement to the final lay version on a 0-10 scale. RESULTS: The professional translation was substantially revised by the authors and based on the interviews. Formulations were adapted to increase readability and understandability and specify statements. Comments that would have changed content or structure were not considered. Average agreement with the particular recommendations was between 10 (SD 0) and 7.6 (SD 1.67). DISCUSSION: For people with RA/SpA/HOA/KOA the EULAR physical activity recommendations should be available in their mother language. The final German lay version is valid and accepted across all three German-speaking countries. Thus, the physical activity recommendations can be provided to people with rheumatic diseases in an understandable and feasible way.

[How many patients with inflammatory rheumatic diseases have the technical prerequisites for video consultations and are also willing to use this to carry out visits by medical specialist visits?] / Wie viele Patienten mit entzündlich rheumatischen Erkrankungen haben die technischen Voraussetzungen für Videosprechstunden und sind bereit, fachärztliche Visiten so durchzuführen?

BACKGROUND: The currently disseminating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and limited capacities in outpatient rheumatological care, pose questions about possible alternatives to clinical visits, also in view of the digital revolution. It is unclear whether and to what extent patients with inflammatory rheumatic diseases are willing and in a position to deal with the new media, such as video consultation. METHODS: In the middle of the pandemic in May 2020 outpatients were surveyed using a standardized questionnaire in order to document their possibilities and willingness to participate in a video consultation. The treating physicians were asked whether carrying out a video consultation was considered to be a possible and meaningful option. RESULTS: Overall, 232 patients with inflammatory rheumatic diseases were surveyed (64.7% female, average age 54.0 ± 15.2 years), seropositive (n = 58) and seronegative (n = 51) rheumatoid arthritis (RA), spondyloarthritis (SpA, n = 77) including axial SpA (axSpA) and psoriatic arthropathy (PsA) as well as collagenosis and vasculitis (CoV, n = 46). The mean duration of disease was 5.5 ± 8.2 years, whereby in 75 patients (32.3%) it was the first diagnosis. The mean disease activity (0-10, subjective patient self-estimation) was 4.7 ± 2.5. Overall, 176 patients were basically aware of the possibility to carry out video consultations (75.9%) and 166 considered that they were technically capable to participate (71.6%) but only 131 were principally willing to participate (56.5%). Logistic regression analyses showed that the willingness to participate in video consultations decreased with increasing age (ß = 0.28, p = 0.01). According to the medical estimation video consultations were thought to be principally possible for 161 patients for technical reasons (69.4%) and for 127 for medical reasons (54.7%); however, a video consultation within the framework of treatment was only considered to be meaningful by the physician for 76 patients (32.8%). CONCLUSION: Not all patients can or want to participate in video consultations and the willingness declines with increasing age. The estimation of the meaningfulness of video consultations by physicians was also limited to approximately one third of the patients surveyed. This must be taken into consideration for the future planning of video consultations.

Evidence for neutrino emission from the nearby active galaxy NGC 1068.

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy's active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of [Formula: see text] neutrinos at tera-electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera-electron volt gamma rays from this source.

Search for Unstable Sterile Neutrinos with the IceCube Neutrino Observatory.

We present a search for an unstable sterile neutrino by looking for a resonant signal in eight years of atmospheric ν_{µ} data collected from 2011 to 2019 at the IceCube Neutrino Observatory. Both the (stable) three-neutrino and the 3+1 sterile neutrino models are disfavored relative to the unstable sterile neutrino model, though with p values of 2.8% and 0.81%, respectively, we do not observe evidence for 3+1 neutrinos with neutrino decay. The best-fit parameters for the sterile neutrino with decay model from this study are Δm_{41}^{2}=6.7_{-2.5}^{+3.9} eV^{2}, sin^{2}2θ_{24}=0.33_{-0.17}^{+0.20}, and g^{2}=2.5π±1.5π, where g is the decay-mediating coupling. The preferred regions of the 3+1+decay model from short-baseline oscillation searches are excluded at 90% C.L.

[Effect of multimodal rheumatologic complex treatment in patients with axial spondylarthritis : A systematic evaluation with standardized outcome parameters, such as the ASAS Health Index]. / Wirkung der multimodalen rheumatologischen Komplexbehandlung bei Patienten mit axialer Spondyloarthritis : Eine systematische Erhebung mit standardisierten Outcomeparametern wie dem ASAS-Gesundheitsindex.

BACKGROUND: Multimodal rheumatologic complex treatment (MRCT) is based on an acute inpatient treatment concept for patients with clinically relevant functional impairments and exacerbation of pain, which are caused by rheumatic and musculoskeletal diseases. Patients with axial spondylarthritis (axSpA) including ankylosing spondylarthritis (AS) often suffer from such health problems. Regular movement exercises and physical therapy measures are an important pillar of treatment management. The ASAS Health Index (ASAS-HI) can be used to document the global functional ability and health of axSpA patients. The selectivity of the ASAS HI for nonpharmacological treatment changes has so far not yet been proven. OBJECTIVE: Evaluation of the MRCT and ASAS HI for nonpharmacological treatment measures of patients with axSpA carried out in the Ruhr Area Rheumatism Center. The primary endpoint was an improvement of the ASDAS≥ 1.1. It was assumed that > 25% of the patients would achieve this threshold. METHODS: Consecutively included patients with active axSpA and relevant functional impairments received inpatient treatment for 14 days during MRCT. On days 1 (V1) and 14 (V2) all patients completed questionnaires on pain (NRS), disease activity (BASDAI, ASDAS) and function (BASFI, ASAS HI). The clinical examination was carried out using BASMI and measurement of C­reactive protein (CRP) at both times. RESULTS: The 66 prospectively included patients had an average age of 47.2 years (SD 14.2 years), a duration of symptoms of ca. 20 years, 65.3% were male, 75% were positive for HLA B27 and CRP was elevated in 41.3%. The disease activity at V1 was elevated: BASDAI 5.6 (1.8), ASDAS 3.1 (0.9), whereas functional ability and mobility were reduced: BASFI 3.5 (1.8), BASMI 5.6 (2.1), ASAS-HI 8.4 (3.4). During the course the global patient verdict improved (NRS 0-10) from 6.9 (1.7) at V1 to 4.8 (1.8) at V2 and the pain from 6.9 (1.9) to 4.7 (2.0) (all p < 0.001). The disease activity also decreased at V2: BASDAI 4.1 (1.9), ASDAS 2.4 (1.0), function and mobility were also improved: BASFI 4.3 (2.4), BASMI 2.7 (1.6), ASAS HI 6.5 (3.8) (all p < 0.001). CONCLUSION: In this study the effectiveness of a 2­week MRCT according to OPS 8-983.1 with respect to important patient-centered outcomes (PCO) could be proven and the results of previous studies could be confirmed. In this context ASAS-HI was also sensitive to change.

Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{µ} Disappearance at IceCube.

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{µτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of -0.0041≤ε_{µτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

Effects of patient and disease characteristics on global functioning in patients with axial spondyloarthritis in routine care.

BACKGROUND: The ASAS Health Index (ASAS HI) was developed to assess global functioning in patients with axial spondyloarthritis (axSpA). Influencing factors have not been studied to date, especially the influence of inflammation and structural changes in the spine has remained unclear to date. OBJECTIVE: To find out whether and to what degree do axial inflammation, radiographic damage and other clinical features influence global functioning of patients with axSpA. METHODS: Patient reported outcomes (ASAS HI, pain, BASDAI, BASFI, EQ-5D and SF-36) were assessed, spinal mobility by BASMI and depression by SF-36 scores. Axial inflammation was quantified using the MRI Berlin score and structural damage as detected by conventional radiographs by the modified Stokes AS Spinal Score (mSASSS). Correlation and regression analyses were performed to analyze the association between global functioning and other variables. RESULTS: A total of 191 axSpA patients with different degrees of global functioning and disease activity was included, 60.2% had r-axSpA. Syndesmophytes were found in 38.5% of patients - with a median mSASSS score of 3.8 (IQR 1.0-18.7) in r-axSpA and 0.0 (IQR 0.0-1.2) in nr-axSpA patients. The mean MRI score was 2.3 (IQR 0.5-7.6). ASAS HI values correlated significantly with BASMI, BASDAI, BASFI, BMI and MRI scores. However, no significant correlation was found for mSASSS and CRP. Regression analyses revealed that global functioning was significantly influenced by disease activity, physical function, obesity and depression but not by structural damage or spinal inflammation as detected MRI. CONCLUSIONS: Our study shows that global functioning is strongly associated with physical function, body weight and depression in patients with axSpA but not with spinal inflammation and structural damage. This may be explained by the relatively low mSASSS of these well treated patients.

Search for Relativistic Magnetic Monopoles with Eight Years of IceCube Data.

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.995c, without any explicit restriction on the monopole mass. We constrain the flux of relativistic cosmic magnetic monopoles to a level below 2.0×10^{-19} cm^{-2} s^{-1} sr^{-1} over the majority of the targeted speed range. This result constitutes the most strict upper limit to date for magnetic monopoles with ß≳0.8 and up to ß∼0.995 and fills the gap between existing limits on the cosmic flux of nonrelativistic and ultrarelativistic magnetic monopoles.

[Axial spondyloarthritis : Update on management based on the interdisciplinary S3 guidelines on axial spondyloarthritis including early forms and ankylosing spondylitis]. / Axiale Spondyloarthritis : Update zum Management basierend auf der interdisziplinären S3-Leitlinie "Axiale Spondyloarthritis inklusive Frühformen und Morbus Bechterew".

This review article presents the innovations in the update of the S3 guidelines on axial spondylarthritis. The total of eight new recommendations address the areas of the consideration of differential diagnoses, coordination of comorbidity management, including a vaccination strategy, treatment targets, safety of nonsteroidal anti-inflammatory drugs (NSAID), treatment response to biological disease-modifying antirheumatic drugs (bDMARD) and discontinuation strategies when remission has been achieved. In this article the authors deal particularly with the areas of early diagnosis and referral as well as exercise therapy and drug treatment.

Striking sex differences in magnetic resonance imaging findings in the sacroiliac joints in the population.

BACKGROUND: In patients with axial spondyloarthritis (axSpA), magnetic resonance imaging (MRI) is used to detect bone marrow edema (BME) in sacroiliac joints (SIJ) but SIJ BME are also detected in the population. Not much is known about sex differences in that regard. OBJECTIVE: To explore sex-specific differences associated with the extent of BME in the SIJ suggestive of axSpA in a general population cohort study. METHODS: Taking advantage of 793 recently evaluated MRIs of subjects < 45 years taking part in the SHIP cohort, we used negative-binomial (NB) count data regression to analyze factors associated with the extent of SIJ BME. Predictors were explored by model-based boosting (MBB), a machine learning approach. RESULTS: Estimates of NB regression showed strong effects of sex in interaction with age, BMI, back pain, and particularly HLA-B27. The NB regression model showed incidence rate ratios (IRR) for the main effect of sex (females vs. males): 0.94 [95% CI: 0.63; 1.41], HLA-B27: 4.32 [2.09; 9.8], and for the interaction of sex to HLA-B27: 0.22 [0.06; 0.75]. According to MBB, HLA-B27 positivity, BMI, current smoking, back pain in the last 3 months, the interaction of sex and HLA-B27, and delivery in the last 12 months were of highest importance to explain the extent of SIJ BME. CONCLUSIONS: Different factors were associated with the extent of SIJ BME in females and males. Most importantly, HLA-B27 was relevant only in males but not in females in whom a postpartal state was important. This finding may be relevant for the pathogenesis of axSpA.