GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.

Factors affecting the dormancy and germination of bleeding heart [Lamprocapnos spectabilis (L.) Fukuhara] seeds

Information on the optimal conditions to promote the germination of Lamprocapnos spectabilis (L.) Fukuhara seeds is limited; consequently, this study was conducted to establish the requirements to break seed dormancy and promote germination. The selected seeds had morphophysiological dormancy and had not begun embryo development. To study the dormancy breaking and embryo development processes, seeds were subjected to constant or changing temperature treatments during moist stratification. High temperature and humidity resulted in vigorous embryo growth, with the longest embryos occurring after 1 month of incubation at 20 °C. At 4 °C, the seeds required incubation period of at least 3 months to germinate. Embryo growth and germination were higher with changing high and low temperatures than under a constant temperature, and changing temperatures also considerably changed the endogenous hormone levels, embryo development and germination. Bioactive gibberellin (GA) content was higher in seeds incubated at 20 °C for 1 month, then at 4 °C for 2 months. The content of endogenous abscisic acid in seeds subjected to the same treatment decreased by 97.6% compared with that of the untreated seeds. Embryo growth and seed germination require changing high and low temperatures; however, exogenous GA₃ could substitute for high temperatures, as it also causes accelerated germination. In this study, the seeds of L. spectabilis were identified as an intermediate simple type, a sub-level of morphophysiologically dormant seeds.

Randomly Hopping Majorana Fermions in the Diluted Kitaev System α-Ru_{0.8}Ir_{0.2}Cl_{3}

dc and ac magnetic susceptibility, magnetization, specific heat, and Raman scattering measurements are combined to probe low-lying spin excitations in α-Ru_{1-x}Ir_{x}Cl_{3} (x≈0.2), which realizes a disordered spin liquid. At intermediate energies (ℏω>3  meV), Raman spectroscopy evidences linearly ω-dependent Majorana-like excitations, obeying Fermi statistics. This points to robustness of a Kitaev paramagnetic state under spin vacancies. At low energies below 3 meV, we observe power-law dependences and quantum-critical-like scalings of the thermodynamic quantities, implying the presence of a weakly divergent low-energy density of states. This scaling phenomenology is interpreted in terms of the random hoppings of Majorana fermions. Our results demonstrate an emergent hierarchy of spin excitations in a diluted Kitaev honeycomb system subject to spin vacancies and bond randomness.

Statins reduce new-onset atrial fibrillation after acute myocardial infarction: A nationwide study

Atrial fibrillation (AF) is an important complication of acute myocardial infarction (AMI). The association between AF and serum lipid profile is unclear and statin use for lowering the incidence of new-onset AF remains controversial. The objective of this study was to investigate whether statins confer a beneficial effect on AF after AMI.Data available in the Taiwan National Health Insurance Research Database on 32886 AMI patients between 2008 and 2011 were retrospectively analyzed. Total 27553 (83.8%) had complete 1-yr follow-up data. Cardiovascular outcomes were analyzed based on the baseline characteristics and AF type (existing, new-onset, or non-AF). AF groups had significantly higher incidence of heart failure (HF), stroke, all-cause death, and major adverse cardiac and cerebrovascular event (MACCE) after index AMI (all P < .05). In contrast, myocardial re-infarction (re-MI) was not significantly different among the three groups (P = .95). Statin use tended to be associated with lower risk of new-onset AF after AMI (HR: 0.935; 95% confidence interval (CI): 0.877-0.998; P = .0427).Existing AF and new-onset AF subgroups had similar cardiovascular outcomes after AMI and were both inferior to the non-AF group. Statin tended to reduce new-onset AF after AMI.

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

Impact of Pharmacist Interventions on the Long-Term Clinical Outcomes in Patients with Myocardial Infarction

Background

Controlling modifiable risk factors (MRFs) in patients with cardiovascular diseases has been shown to be effective in reducing re-hospitalization rates. The aim of this study was to investigate the rates of controlled MRFs and clinical outcomes after pharmacist interventions in patients with myocardial infarction (MI) after hospital discharge.

Methods

This prospective randomized clinical study was conducted at one medical center in Taiwan, and enrolled patients with MI from January 1, 2012 to December 31, 2014. Patients received medication reconciliation and education from a pharmacist before hospital discharge. The intervention group (IG) received continuous consultations from the pharmacist after discharge, whereas the control group (CG) did not. Primary outcomes included achieving blood pressure < 140/70 mmHg, low-density lipoprotein-cholesterol (LDL-C) < 70 mg/dL, and hemoglobin A1c (HbA1c) < 7% targets. The secondary outcome was major adverse cardiac events (MACEs), defined as re-hospitalization due to MI, unstable angina and stroke.

Results

Two hundred and eight patients completed the study protocol (106 in the IG and 102 in the CG). The rate of achieving blood pressure goal was similar between the two groups. More patients in the IG achieved LDL-C and HbA1c goals than those in the CG at 1 year and 2 years post discharge. However, there was no significant difference in the cumulative incidence of MACEs between the two groups (5.7% vs. 9.8%) (p = 0.262). Diabetes was the only independent predictor of re-hospitalization due to a MACE.

Conclusions

Pharmacist interventions led to a higher rate of optimal controlled MRFs but did not significantly reduce the MACE rate in the patients with MI.

Liraglutide Inhibits Endothelial-to-Mesenchymal Transition and Attenuates Neointima Formation after Endovascular Injury in Streptozotocin-Induced Diabetic Mice

Hyperglycaemia causes endothelial dysfunction, which is the initial process in the development of diabetic vascular complications. Upon injury, endothelial cells undergo an endothelial-to-mesenchymal transition (EndMT), lose their specific marker, and gain mesenchymal phenotypes. This study investigated the effect of liraglutide, a glucagon-like peptide 1 (GLP-1) receptor agonist, on EndMT inhibition and neointima formation in diabetic mice induced by streptozotocin. The diabetic mice with a wire-induced vascular injury in the right carotid artery were treated with or without liraglutide for four weeks. The degree of neointima formation and re-endothelialisation was evaluated by histological assessments. Endothelial fate tracing revealed that endothelium-derived cells contribute to neointima formation through EndMT in vivo. In the diabetic mouse model, liraglutide attenuated wire injury-induced neointima formation and accelerated re-endothelialisation. In vitro, a high glucose condition (30 mmol/L) triggered morphological changes and mesenchymal marker expression in human umbilical vein endothelial cells (HUVECs), which were attenuated by liraglutide or Activin receptor-like 5 (ALK5) inhibitor SB431542. The inhibition of AMP-activated protein kinase (AMPK) signaling by Compound C diminished the liraglutide-mediated inhibitory effect on EndMT. Collectively, liraglutide was found to attenuate neointima formation in diabetic mice partially through EndMT inhibition, extending the potential therapeutic role of liraglutide.

Evaluation of Bleeding Risk in Patients with Acute Myocardial Infarction Undergoing Transradial Percutaneous Coronary Intervention

We investigated the accuracy of various bleeding risk scores to estimate the bleeding risk in patients with acute myocardial infarction (AMI) managed with percutaneous coronary intervention (PCI) access via the radial artery.We retrospectively enrolled 1,651 patients who were definitively diagnosed with ST-elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI). We assessed the predictive validities of 30-day bleeding events in various scoring systems using receiver operating characteristic curves.Overall, ACUITY-HORIZONS exhibited the highest area under the curve to predict 30-day bleeding, followed by ACTION and CRUSADE; HAS-BLED displayed the lowest score. With a cut-off of 17, ACUITY-HORIZONS demonstrated the best discrimination for the Thrombolysis in Myocardial Infarction (TIMI) 30-day serious bleeding rate. We observed significant differences among all-cause death, cardiovascular death, and major adverse cardiac events between the ACUITY-HORIZONS groups with a score of ≤ 17 and > 17. ACUITY-HORIZONS score > 17, initial systolic blood pressure (SBP) < 90 mmHg, and Killip III and IV upon admission positively predicted the 30-day bleeding risk, whereas myocardial infarction (MI) and TIMI major bleeding within 30 days, heart failure at admission, and initial SBP < 90 mmHg positively predicted the 30-day mortality.Comparatively, ACUITY-HORIZON is the most reliable system in predicting 30-day bleeding for patients with AMI via transradial PCI. In the transradial scenario, bleeding and MI within 30 days are substantially related to 30-day mortality.

Exotic Low-Energy Excitations Emergent in the Random Kitaev Magnet Cu_{2}IrO_{3}

We report on magnetization M(H), dc and ac magnetic susceptibility χ(T), specific heat C_{m}(T) and muon spin relaxation (μSR) measurements of the Kitaev honeycomb iridate Cu_{2}IrO_{3} with quenched disorder. In spite of the chemical disorders, we find no indication of spin glass down to 260 mK from the C_{m}(T) and μSR data. Furthermore, a persistent spin dynamics observed by the zero-field muon spin relaxation evidences an absence of static magnetism. The remarkable observation is a scaling relation of χ[H,T] and M[H,T] in H/T with the scaling exponent α=0.26-0.28, expected from bond randomness. However, C_{m}[H,T]/T disobeys the predicted universal scaling law, pointing towards the presence of additional low-lying excitations on the background of bond-disordered spin liquid. Our results signify a many-faceted impact of quenched disorder in a Kitaev spin system due to its peculiar bond character.

Effect of probiotics on fecal excretion, colonization in internal organs and immune gene expression in the ileum of laying hens challenged with Salmonella Enteritidis

A study was conducted to evaluate the supplementation of probiotics on Salmonella colonization in the ceca and various internal organs as well as immune response in laying hens challenged with Salmonella enterica serovar Enteritidis (SE). Thirty-two 46-wk-old White Leghorns (W-36) were housed individually in wired laying cages under 16L:8D lighting schedule. Hens were challenged individually with nalidixic acid resistant Salmonella Enteritidis (SENAR) after which time they were grouped into four treatments: T1 = SENAR unchallenged control, T2 = SENAR challenged control, T3 = SENAR challenged + 0.05% probiotics (Lactobacillus plantarum), and T4 = SENAR challenged + 0.1% probiotics. All hens, including T1, were euthanized and sampled for the liver with gall bladder (L/GB), ileum, ovary, spleen, and ceca on 7-days post-infection (dpi). Fecal screening was performed on individual hens at both 3 and 6 dpi. No difference was detected between the treatments in cecal SENAR enumeration, and the mean log 10 cfu/gm of SENAR in the ceca was 3.7 for all three treatments. The prevalence of SENAR was lowest for ovary in all treatments and was highest in the spleen. However, there were no significant differences among the treatments in the internal organs. There was no significant difference in the fecal shedding among the treatments on either 3 or 6 dpi, with incidence of positive feces higher at 3 dpi compared to 6 dpi (100 vs. 70% to 80%). SENAR challenge resulted in significant upregulation (P < 0.05) of interleukin (IL)-1β, 6, 10, interferon gamma (IFN-γ), and toll-like receptor (TLR)-4 mRNA expression. Highest level of probiotics resulted in a significant decrease in IFN-γ and elevation of IL-6 and IL-10 gene expression in the ileum. However, IL-1B and TLR-4 gene expression were not different from the SENAR challenge control. This study reveals that there was important regulation of immune genes by probiotics supplementation.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

P77 Type II PEG fractures: collar or no collar

Objectives

Type 2 peg fractures are known to have low fusion rates but most are elderly with comorbidities and not fit for surgery. Increasingly, clinicians want to stop using hard collars due to its complications, but with little supporting evidence. We aim to provide data to add to this debate.

Design

Single centre cohort study.

Subjects

145 consecutive patients referred to a Major Trauma Centre as type 2 peg fracture.

Methods

All patients referred with a suspected peg fracture between March 2015 and December 2017 were included. All imaging were assessed and case notes reviewed for patient demographics, fracture management, complications and outcomes.

Results

102 cases were peg fractures (mean age=80 years). 92 (90.2%) were managed conservatively with a hard collar (mean of 87 days). 37% developed symptoms from the collar, namely pain, stiffness and non-tolerance. Bony union was achieved in only 39.1% of patients with increasing age being an independent risk factor (p<0.001). Of the 56 patients who did not have bony union, there were no reported symptoms and 90% were discharged without a collar. 2 patients were offered but declined fixation and neither reported any on-going symptoms.

Conclusions

This study adds to the body of evidence that fusion rates are low, and collar complications are not insignificant when type 2 peg fractures are treated in a hard collar. However, outcomes are good regardless of union, potentially rendering the collar unnecessary. We aim to conduct a randomised prospective study to further investigate.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

Effects of Fabric Counts and Weave Designs on the Properties of Laminated Woven Kenaf/Carbon Fibre Reinforced Epoxy Hybrid Composites

The effects of different fabric materials namely weave designs (plain and satin) and fabric counts (5 × 5 and 6 × 6) on the properties of laminated woven kenaf/carbon fibre reinforced epoxy hybrid composites were evaluated. The hybrid composites were fabricated from two types of fabric, i.e., woven kenaf that was made from a yarn of 500tex and carbon fibre, by using vacuum infusion technique and epoxy resin as matrix. The panels were tested for tensile, flexural, and impact strengths. The results have revealed that plain fabric is more suitable than satin fabric for obtaining high tensile and impact strengths. Using a fabric count of 5 × 5 has generated composites that are significantly higher in flexural modulus as compared to 6 × 6 which may be attributed to their structure and design. The scanned electron micrographs of the fractured surfaces of the composites demonstrated that plain woven fabric composites had better adhesion properties than satin woven fabric composites, as indicated by the presence of notably lower amount of fibre pull out.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Deletion of RasGRF1 Attenuated Interstitial Fibrosis in Streptozotocin-Induced Diabetic Cardiomyopathy in Mice through Affecting Inflammation and Oxidative Stress

Background: Diabetic cardiomyopathy (DCM) is characterized by cardiac fibrosis and stiffness, which often develops into heart failure. This study investigated the role of Ras protein-specific guanine nucleotide releasing factor 1 (RasGRF1) in the development of DCM. Methods: Forty-eight mice were divided into four groups (n = 12 per group): Group 1: Wild-type (WT) mice, Group 2: RasGRF1 deficiency (RasGRF1^−/−) mice. Group 3: Streptozotocin (STZ)-induced diabetic WT mice, Group 4: STZ-induced diabetic RasGRF1^−/− mice. Myocardial functions were assessed by cardiac echography. Heart tissues from all of the mice were investigated for cardiac fibrosis, inflammation, and oxidative stress markers. Results: Worse impaired diastolic function with elevation serum interleukin (IL)-6 was found in the diabetic group compared with the non-diabetic groups. Serum IL-6 levels were found to be elevated in the diabetic compared with the non-diabetic groups. However, the diabetic RasGRF1^−/− mice exhibited lower serum IL-6 levels and better diastolic function than the diabetic WT mice. The diabetic RasGRF1^−/− mice were associated with reduced cardiac inflammation, which was shown by lower invading inflammation cells, lower expression of matrix metalloproteinase 9, and less chemokines compared to the diabetic WT mice. Furthermore, less oxidative stress as well as extracellular matrix deposition leading to a reduction in cardiac fibrosis was also found in the diabetic RasGRF1^−/− mice compared with the diabetic WT mice. Conclusion: The deletion of RasGRF1 attenuated myocardial fibrosis and improved cardiac function in diabetic mice through inhibiting inflammation and oxidative stress.

Assessment of CHA2DS2-VASc score for predicting cardiovascular and cerebrovascular outcomes in acute myocardial infarction patients

Although established guidelines currently recommend the use of the CHA2DS2-VASc score for evaluating embolic risk in AF patients, few studies have evaluated the use of the CHA2DS2-VASc score for predicting cardiovascular outcomes in patients with acute myocardial infarction (AMI). The aim of this study was to determine whether CHA2DS2-VASc score is a predictor of a major adverse cardiocerebral vascular event (MACCE) in AMI patients.This study analyzed data in the Taiwan National Health Insurance Research Database from January 2008 to December 2012. Cardiovascular outcomes were analyzed according to the baseline characteristics, presence of AF, and CHA2DS2-VASc score.Twenty nine thousand four hundred fifty-two patients with non-fatal AMI, 1171 patients (8.3%) were with AF. The Cox regress model showed with the exception of women sex and peripheral artery disease, all the baseline characteristics considered risks in CHA2DS2-VASc scores were independently associated with the increased incidence of MACCE within 1 year after AMI. A CHA2DS2-VASc score of <5 had negative predictive values of 93.37% for recurrent MI, 98.45% for stroke, 94.86% for HF admission, 98.83% for mortality, and 87.80% for MACCE. Regardless of the presence of AF, the CHA2DS2-VASc score was correlated with 1-year MACCE.The CHA2DS2-VASc score was correlated with 1-year MACCE in AMI patients who were discharge alive. The CHA2DS2-VASc score is useful predictor for 1 year MACCE in patients with AMI.

Increased prevalence of vitamin D deficiency in patients with alopecia areata: a systematic review and meta-analysis

BACKGROUND

Alopecia areata (AA) is a hair follicle-specific autoimmune disorder. Vitamin D deficiency has been associated with various autoimmune disorders for its immunomodulatory effects. However, in previous studies, there had been inconsistent association found between AA and vitamin D deficiency.

OBJECTIVE

To demonstrate the differences of the mean serum 25-hydroxyvitamin D level and prevalence of vitamin D deficiency between AA patients and non-AA population.

METHODS

A systematic review and meta-analysis of observational studies on AA and serum vitamin D levels and/or prevalence of vitamin D deficiency was performed searching MEDLINE, Cochrane, Web of Science and Google Scholar databases.

RESULTS

In all, 14 studies including a total of 1255 AA subjects and 784 non-AA control were analysed. The mean serum 25-hydroxyvitamin D level was significantly lower in AA subjects (-8.52 ng/dL; 95% confidential interval; -5.50 to -11.53). The AA subjects had higher odds of vitamin D deficiency (odds ratio of 3.89; 2.02 to 7.49, mean prevalence of 73.8%; 59.1 to 84.6%). However, it was difficult to find clear correlation between serum 25-hydroxyvitamin D level and extent of hair loss in AA subjects.

CONCLUSION

The AA subjects had lower serum 25-hydroxyvitamin D level, and vitamin D deficiency was highly prevalent compared to non-AA controls. Hence, vitamin D deficiency should be assessed in AA patients. Furthermore, nutritional supplementation of vitamin D or topical vitamin D analogues can be considered for AA patients with vitamin D deficiency. The limitation of this study is the highly heterogeneity of the included studies.