The risk of recurrent small-for-gestational-age infants at term is dependent on the number of previously affected births.

BACKGROUND: Small-for-gestational-age infants are at a substantially increased risk of perinatal complications, but the risk of recurrent small-for-gestational-age is not well known, particularly because there are many demographic and obstetrical factors that interact and modify this risk. We investigated the relationship between previous small-for-gestational-age births and the risk of recurrence at term in a large Australian cohort. OBJECTIVE: We aimed to identify key demographic and obstetrical variables that influence the risk of recurrence of a small-for-gestational-age infant at term. The primary outcome measure was the odds of recurrence of small-for-gestational-age in subsequent pregnancies up to a maximum of 4 consecutive term births. STUDY DESIGN: This was a retrospective analysis of women who had more than 1 consecutive nonanomalous, singleton, term live births between July 1997 and September 2018 at the Mater Mother's Hospital in Brisbane, Australia. Women with multiple pregnancy, preterm birth, or major congenital malformations were excluded. Small-for-gestational-age was defined as birthweight at the <10th centile. We calculated the odds of recurrence depending on the number of previous small-for-gestational-age infants and if only the preceding infant was small-for-gestational-age. The study population was dichotomized into small-for-gestational-age and non-small-for-gestational-age for each consecutive pregnancy. Univariate analyses compared baseline demographic and obstetrical characteristics followed by logistic regression modeling to determine the odds of recurrence in the second, third, and fourth pregnancies. RESULTS: The final study comprised 24,819 women. The proportion of women who had a small-for-gestational-age infant in their first pregnancy was 9.4%, whereas the proportion of women who had a small-for-gestational-age infant in their second, third, and fourth pregnancies after the birth of a previous small-for-gestational-age infant were 20.5% (479 of 2338), 24.6% (63 of 256), and 30.4% (14 of 46), respectively. Regardless of parity, the odds of recurrence increased if the preceding infant was small-for-gestational-age. The odds of recurrence increased markedly if there was more than 1 previous small-for-gestational-age infant. In women with 3 previous small-for-gestational-age infants, the adjusted odds of another small-for-gestational-age infant were 66.00 (95% confidence interval, 11.35-383.76). Maternal age, body mass index, ethnicity, and smoking were significant risk factors for recurrent small-for-gestational-age. However, maternal diabetes mellitus or hypertension, either in a previous or current pregnancy, did not influence the risk of recurrence. CONCLUSION: The risk of recurrence in a subsequent pregnancy increased if there was a previous small-for-gestational-age birth. Women with consecutive small-for-gestational-age infants were at the highest risk of recurrence. Our results highlight that women with a previous small-for-gestational-age infant are at a substantial risk of another small infant and need to be counseled and monitored appropriately.

Identification of bacteria and fungi sampled from the conjunctival surface of normal horses in South-East Queensland, Australia.

OBJECTIVE: To identify bacteria and fungi found on the conjunctival surface of normal horse eyes; to investigate potential risk factors for these microflora; and to determine their susceptibility to common topical ophthalmic antimicrobials. ANIMALS STUDIED: A total of 95 client-owned horses were studied. PROCEDURES: Horses within sub-tropical Australia (South-East Queensland) were sampled once between April 2012 and March 2013. A conjunctival swab was taken from each eye and cultured for aerobic bacteria and fungi. Organisms were identified by colony morphology and phenotype. Antimicrobial disk diffusion susceptibility testing for commonly used antimicrobials was performed. RESULTS: Positive bacterial cultures were returned from 187/190 (98.4%) eyes from 94/95 (98.9%) horses. The most common species included Staphylococcus spp. (25.2% of total bacterial isolates), Bacillus cereus (17.4%), Bacillus spp. (14.1%), and Corynebacterium spp. (8.9%). Most bacterial isolates were susceptible to neomycin and fluoroquinolones. Positive fungal cultures were returned from 111/190 (58.4%) eyes from 73 (76.8%) horses. The most common species identified included: Penicillium spp. (16.7% of fungal isolates), Aspergillus spp. (15.4%), and Scopulariopsis spp. (10.3%). Most (≥90%) molds were susceptible to ketoconazole, voriconazole, itraconazole, and miconazole. Yeasts were most susceptible to ketoconazole. There was no significant effect of breed, age, sex, purpose, or housing of the horse or climatic conditions on bacterial or fungal culture status. CONCLUSIONS: Bacteria and fungi were commonly isolated from the eyes of healthy horses. The antibiotic and antifungal susceptibilities identified can be used as a guide for empirical therapy after cytology in the treatment of corneal ulceration in horses.

Birth-weight centiles and the risk of serious adverse neonatal outcomes at term.

BACKGROUND: Birth-weight is an important determinant of perinatal outcome with low birth-weight being a particular risk factor for adverse consequences. AIM: To investigate the impact of neonatal sex, mode of birth and gestational age at birth according to birth-weight centile on serious adverse neonatal outcomes in singleton term pregnancies. MATERIALS AND METHODS: This was a retrospective cohort study of singleton term births at the Mater Mother's Hospital, Brisbane, Australia. Serious adverse neonatal outcome was defined as a composite of severe acidosis at birth (pH ≤7.0 and/or lactate ≥6 mmol/L and/or base excess ≤-12 mmol/L), Apgar <3 at 5 min, neonatal intensive-care unit admission and antepartum or neonatal death. The main exposure variable was birth-weight centile. RESULTS: Of the 69,210 babies in our study, the overall proportion of serious adverse neonatal outcomes was 9.1% (6327/69,210). Overall, neonates in the <3rd birth-weight centile category had the highest adjusted odds ratio (OR) for serious adverse neonatal outcomes [OR 3.53, 95% confidence interval (CI) 3.06-4.07], whilst those in the ≥97th centile group also had elevated odds (OR 1.51, 95% CI 1.30-1.75). Regardless of birth modality, smaller babies in the <3rd centile group had the highest adjusted OR and predicted probability for serious adverse neonatal outcomes. When stratified by sex, male babies consistently demonstrated a higher predicted probability of serious adverse neonatal outcomes across all birth-weight centiles. The adjusted odds, when stratified by gestational age at birth, were the highest from 37+0 to 38+6 weeks in the <3rd centile group (OR 5.97, 95% CI 4.60-7.75). CONCLUSIONS: Low and high birth-weights are risk factors for serious adverse neonatal outcomes. The adjusted OR appears to be greatest for babies in the <3rd birth-weight centile group, although an elevated risk was also found in babies within the ≥97th centile category.

Diagnostic Performance of Cerebroplacental Ratio Thresholds at Term for Prediction of Low Birthweight and Adverse Intrapartum and Neonatal Outcomes in a Term, Low-Risk Population.

OBJECTIVES: To investigate the screening performance and best threshold centile (5th vs. 10th) of the cerebroplacental ratio (CPR) in low-risk, term pregnancies to predict low birthweight and adverse intrapartum and neonatal outcomes in a term, low-risk population. METHODS: This was a blinded, prospective, cross-sectional study of low-risk singleton pregnancies at term. Women attended fortnightly from 36 weeks for CPR and estimated fetal weight assessment. Intrapartum and neonatal outcomes were recorded. Primary outcomes assessed were low birthweight, cesarean section for intrapartum fetal compromise, and composite adverse neonatal outcome. RESULTS: A total of 483 women participated in the study. The CPR 10th centile (1.48) threshold resulted in the best screening performance. Sensitivities for low birthweight, cesarean section for intrapartum fetal compromise, and composite adverse neonatal outcome of 41.9, 61.1, and 38.3% were achieved for false-positive rates of 17.7, 17.7, and 15.2%, respectively. The corresponding areas under the receiver operating characteristic curves were 0.62, 0.72, and 0.62. CONCLUSION: The CPR 10th centile resulted in the best screening performance, although this would be considered fair at best. The CPR 10th centile may be useful as part of a risk stratification tool for prediction of low birthweight and adverse intrapartum and neonatal outcomes.

Screening Performance of Placental Growth Factor for the Prediction of Low Birth Weight and Adverse Intrapartum and Neonatal Outcomes in a Term Low-Risk Population.

INTRODUCTION: Fetuses who fail to reach their genetic growth potential are thought to have sub-optimal placental function. Low placental growth factor (PlGF) levels have been shown to be predictive of placentally mediated conditions, such as pre-eclampsia or fetal growth restriction. We investigated the screening performance of PlGF for the prediction of low birth weight (<10th centile for gestation) and adverse intrapartum and neonatal outcomes in apparently low-risk term pregnancies. MATERIALS AND METHODS: Maternal PlGF levels were measured fortnightly in a blinded, prospective, observational study from 36 weeks of pregnancy. Women and clinicians were blinded to PlGF results, and pregnancies were managed according to local policies and guidelines. Intrapartum and neonatal outcomes were recorded. PlGF was analysed for association with, and predictive capacity for, low birth weight, caesarean section for intrapartum fetal compromise (CS-IFC) and adverse neonatal outcomes. RESULTS: A total of 438 women were included in the final analysis. Lower PlGF levels were associated with low birth weight, CS-IFC and adverse neonatal outcome. For a false-positive rate of 10 and 20%, respectively, the corresponding sensitivities were 9.7-11.1% and 22.2-26.8%. CONCLUSION: As a sole predictor for low birth weight, CS-IFC and adverse neonatal outcome, PlGF was poor as a test.

Impact of Maternal Body Mass Index on Intrapartum and Neonatal Outcomes in Brisbane, Australia, 2007 to 2013.

BACKGROUND: The aim of this study was to evaluate the influence of maternal body mass index on intrapartum and neonatal outcomes at one of the largest maternity hospitals in Australia. METHODS: A retrospective cross-sectional study of 55,352 term singleton deliveries at the Mater Mothers' Hospital in Brisbane, Australia, was conducted. The study cohort was stratified into six groups based on the World Health Organization's body mass index classification. The normal body mass index category was the reference group for all comparisons. Multivariate logistic regression was used to examine the effect of maternal body mass index, adjusted for maternal age, ethnicity, parity, and preexisting conditions (e.g., diabetes mellitus and hypertension), on selected intrapartum and neonatal outcomes. RESULTS: Women in the overweight and Obese I, II, and III categories were more likely to have chronic or gestational hypertension/preeclampsia, and preexisting or gestational diabetes mellitus. They also had an increased risk for induction of labor, elective and emergency cesarean, and postpartum hemorrhage. Underweight women were less likely to require induction of labor and emergency cesarean. Infants born to women with increased body mass index were more likely to require neonatal resuscitation, neonatal intensive care unit admission, and have lower Apgar scores at 5 minutes. CONCLUSION: There is an increased risk of adverse intrapartum and neonatal outcomes for women who are overweight and obese, with the risks increasing with rising body mass index. Appropriately targeted weight management strategies and health education may yield improved maternal and perinatal outcomes if effectively implemented before pregnancy. These may particularly be of benefit in the teenage cohort that has yet to embark on pregnancy.

Impact of mode of delivery after 32 weeks' gestation on neonatal outcome in dichorionic diamniotic twins.

AIM: The purpose of this study was to investigate neonatal outcome of dichorionic diamniotic twins born beyond 32 weeks' gestation according to mode of delivery at a major tertiary center in Australia. METHODS: This was a retrospective cohort study of women with dichorionic diamniotic twins delivering at ≥32 weeks' gestation at a large tertiary maternity center in Australia using data from a maternity database. Primary and secondary outcomes included mode of delivery, birthweight, stillbirth, Apgar score, neonatal unit admission, neonatal resuscitation, death and respiratory distress. RESULTS: Of 1261 women, 82.9% (1045/1261; 2090 babies) delivered at ≥32 weeks' gestation. The mode of delivery for these babies was as follows: normal vaginal delivery, 419 (20%); instrumental delivery, 179 (8.6%); emergency cesarean section, 658 (31.5%); and elective cesarean section, 834 (39.9%). Babies delivered by emergency cesarean section or instrumental vaginal delivery had worse outcome. In contrast, the lowest complications were seen in the uncomplicated vaginal delivery and elective cesarean section cohorts. CONCLUSIONS: Neonatal outcome was worse for those delivering via emergency cesarean section or instrumental vaginal delivery compared with elective cesarean section or uncomplicated vaginal delivery. The rate of uncomplicated vaginal delivery, however, was low, with only 14.8% of women delivering both babies vaginally without any form of intervention.

Systematic review and metaanalysis of perinatal outcomes after radiofrequency ablation and bipolar cord occlusion in monochorionic pregnancies.

The aim of this study was to analyze perinatal outcomes after selective reduction in monochorionic pregnancies with the use of either radiofrequency ablation (RFA) or bipolar cord occlusion (BCO). This was a systematic review and metaanalysis that included all studies with ≥5 cases that described perinatal outcomes after BCO or RFA that were identified in PubMed, Embase, Web of Science, COCHRANE, CINAHL, Academic Search Premier, Science Direct, and MEDLINE that were published between 1965 and July 2014. For count data, incidence risk ratios (IRR; 95% confidence interval [CI]) were calculated with BCO as the reference standard. The analysis included 481 cases of BCO and 320 cases of RFA from 17 studies. The mean median gestations at procedure were 21.1 ± 1.2 weeks (BCO) and 18.8 ± 2.5 weeks (RFA; P = .03). The rate of cotwin death was higher in the RFA group (14.7%) vs the BCO group (10.6%; IRR, 1.38; 95% CI, 0.93-2.05; P = .11). The live birth rate was 81.3% for the RFA group and 86.7% in the BCO group (IRR, 0.93; 95% CI, 0.80-1.09; P = .41). BCO had higher neonatal death rates (8.1%) vs RFA (4.5%; IRR, 0.56; 95% CI, 0.30-1.04; P = .07). Overall survival was 76.8% for RFA and 79.1% for BCO (IRR, 0.97; 95% CI, 0.82-1.14; P = .72); however, none of these differences were statistically significant. Preterm premature rupture of membranes occurred in 17.7% of RFA cases and 28.2% of the BCO cases (IRR, 0.63; 95% CI, 0.43-0.91; P = .01). The mean median gestational age at delivery was 34.7 ± 1.7 weeks in the RFA group and 35.1 ± 1.6 weeks in the BCO group. Our data do not demonstrate clearly the superiority of 1 procedure over the other. The clinical situation and preference of the operator are important considerations. Rates of preterm delivery and preterm premature rupture of membranes remain substantial for both procedures.

Prenatal extra-abdominal bowel dilatation is a risk factor for intrapartum fetal compromise for fetuses with gastroschisis.

OBJECTIVE: The aim of this study was to investigate the prenatal ultrasound features that were associated with intrapartum fetal distress in fetuses with gastroschisis. METHODS: This was a retrospective observational study of all cases of gastroschisis referred to and delivering at the Mater Mothers' Hospital in Brisbane, Australia. Maternal demographics, prenatal ultrasound features including the presence of bowel dilatation, umbilical artery and middle cerebral artery Doppler indices and amniotic fluid volume as well as intrapartum outcome details were analysed using univariate and multivariate logistic regression to ascertain factors predictive of intrapartum compromise. RESULTS: The study cohort included 155 cases of gastroschisis over a 16-year period. The overall perinatal loss rate was 5.9% (four intrauterine fetal deaths, four neonatal deaths and one termination of pregnancy). The live birth rate was 96.8% (150/155). Fetal heart rate abnormalities occurred in 55.1% of cases. The overall caesarean section rate was 40.9% (63/154), of which 63.5% (40/63) was emergency procedures. Both univariate and multivariate analysis confirmed that only extra-abdominal bowel dilatation was a risk factor for intrapartum fetal compromise necessitating emergency delivery. CONCLUSIONS: Extra-abdominal bowel dilatation is a risk factor for intrapartum fetal compromise (OR 2.2; 95%CI 1.03-4.7) and emergent delivery.

Serum vitamin D levels are lower in Australian children and adolescents with type 1 diabetes than in children without diabetes.

Vitamin D is synthesised in the skin through the action of UVB radiation (sunlight), and 25-hydroxy vitamin D (25OHD) measured in serum as a marker of vitamin D status. Several studies, mostly conducted in high latitudes, have shown an association between type 1 diabetes mellitus (T1DM) and low serum 25OHD. We conducted a case-control study to determine whether, in a sub-tropical environment with abundant sunlight (latitude 27.5°S), children with T1DM have lower serum vitamin D than children without diabetes. Fifty-six children with T1DM (14 newly diagnosed) and 46 unrelated control children participated in the study. Serum 25OHD, 1,25-dihydroxy vitamin D (1,25(OH)(2) D) and selected biochemical indices were measured. Vitamin D receptor (VDR) polymorphisms Taq1, Fok1, and Apa1 were genotyped. Fitzpatrick skin classification, self-reported daily hours of outdoor exposure, and mean UV index over the 35 d prior to blood collection were recorded. Serum 25OHD was lower in children with T1DM (n = 56) than in controls (n = 46) [mean (95%CI) = 78.7 (71.8-85.6) nmol/L vs. 91.4 (83.5-98.7) nmol/L, p = 0.02]. T1DM children had lower self-reported outdoor exposure and mean UV exposure, but no significant difference in distribution of VDR polymorphisms. 25OHD remained lower in children with T1DM after covariate adjustment. Children newly diagnosed with T1DM had lower 1,25(OH)(2) D [median (IQR) = 89 (68-122) pmol/L] than controls [121 (108-159) pmol/L, p = 0.03], or children with established diabetes [137 (113-153) pmol/L, p = 0.01]. Children with T1DM have lower 25OHD than controls, even in an environment of abundant sunlight. Whether low vitamin D is a risk factor or consequence of T1DM is unknown.

Human intravenous immunoglobulin use for hematological immune-mediated disease in dogs.

OBJECTIVE: To report on survival rates and risk factors in dogs with immune-mediated hemolytic anemia (IMHA) and immune-mediated thrombocytopenia (ITP) treated with human IV immunoglobulin (hIVIG; Privigen). We hypothesized that hIVIG could be used as a salvage treatment to improve survival and reduce the requirement for ongoing blood transfusion therapy in IMHA and ITP patients. ANIMALS: 52 client-owned dogs with IMHA or ITP were included, comprising 31 females (28 spayed and 3 entire) and 21 males (19 castrated and 2 entire). Miniature Schnauzers were the most common breed (5), with a further 24 different breeds identified. PROCEDURES: A retrospective cohort study was conducted between January 2006 and January 2022 that assessed the survival rates, risk factors, and need for ongoing transfusion in dogs with IMHA and ITP treated with hIVIG compared with those not receiving hIVIG. RESULTS: Of 36 dogs that did not receive hIVIG, 29 (80%) survived and 7 (24%) died, and of 16 dogs administered hIVIG, 11 (69%) survived and 5 (31%) died (P = .56). No effect of PCV at admission or age on the risk of death was detected (OR, 1.00; 95% CI, 0.94 to 1.08; P = .89; and OR, 1.10; 95% CI, 0.85 to 1.47; P = .47, respectively). CLINICAL RELEVANCE: This was the largest study to date of dogs with hematological immune-mediated disease treated with hIVIG. There was no difference in survival rates for dogs that received hIVIG versus those treated with standard immunosuppression. The benefit of hIVIG as a salvage treatment appears limited.

Importance of hepatic fibrosis in cystic fibrosis and the predictive value of liver biopsy.

UNLABELLED: Cystic fibrosis liver disease (CFLD), which results from progressive hepatobiliary fibrosis, is an important cause of morbidity and mortality, but it is difficult to identify before portal hypertension (PHT) ensues. Clinical signs, serum alanine aminotransferase (ALT) levels, and ultrasound (US) are widely applied, but their value in predicting the presence of cirrhosis, the development of PHT, or adverse outcomes is undetermined. The potential gold standard, liver biopsy, is not standard practice and, notwithstanding sampling error considerations, has not been systematically evaluated. Forty patients with cystic fibrosis (median age = 10.6 years) with abnormal clinical, biochemical, and US findings were subjected to dual-pass percutaneous liver biopsy. Clinical outcomes were recorded over 12 years of follow-up (median = 9.5 years for survivors). Logistic regression and receiver operating characteristic analyses were applied to predict hepatic fibrosis (which was assessed by fibrosis staging and quantitative immunohistochemistry) and the occurrence of PHT. PHT occurred in 17 of 40 patients (42%), including 6 of 7 (17%) who died during follow-up. Clinical examination, serum ALT levels, and US findings failed to predict either the presence of liver fibrosis or the development of PHT. Fibrosis staging on liver biopsy, where the accuracy was improved by dual passes (P = 0.002, nonconcordance = 38%), predicted the development of PHT (P < 0.001), which occurred more frequently and at a younger age in those with severe fibrosis. CONCLUSION: Clinical modalities currently employed to evaluate suspected CFLD help to identify a cohort of children at risk for liver disease and adverse outcomes but do not predict an individual's risk of liver fibrosis or PHT development. Liver fibrosis on biopsy predicts the development of clinically significant liver disease. Dual passes help to address sampling concerns. Liver biopsy has a relevant role in the management of patients with suspected CFLD and deserves more widespread application.

Transcriptional basis for hepatic fibrosis in cystic fibrosis-associated liver disease.

OBJECTIVES: Liver disease contributes to significant morbidity and mortality in cystic fibrosis (CF). Although all patients with CF express the defective CF transmembrane conductance regulator in cholangiocytes, many develop asymptomatic fibrosing liver disease. Only some develop cirrhosis, with pathogenesis remaining enigmatic. Available noninvasive diagnostic tools do not identify patients at risk before development of advanced fibrosis. We conducted a pilot study to identify genes associated with hepatic injury and fibrosis on liver biopsy that may help elucidate determinants of CF-associated liver disease (CFLD). METHODS: Liver tissue from children with CFLD with various stages of hepatic fibrosis was compared with pediatric controls using cDNA array analysis. Differential expression of genes of interest was then assessed relative to pediatric control liver and non-CF cholestatic disease control liver from patients with biliary atresia, using both real-time reverse transcription-polymerase chain reaction and immunohistochemistry. RESULTS: cDNA array demonstrated differential expression of numerous genes associated with hepatic fibrogenesis including collagens, matrix metalloproteinases, and chemokines in CFLD versus normal controls, particularly decreased expression in tissue remodeling genes including plasminogen activator inhibitor-1 (PAI-1, up to 25-fold) and tissue inhibitor of metalloproteinase-1 (TIMP-1); this was validated by real-time reverse transcription-polymerase chain reaction (PAI-1, P = 0.004; TIMP-1, P = 0.019). No significant decrease in PAI-1 or TIMP-1 mRNA was observed in biliary atresia versus normal control. Immunohistochemistry confirmed the decreased expression of hepatic PAI-1 and TIMP-1 protein in CFLD versus both normal and biliary atresia disease controls. CONCLUSIONS: The coordinated differential expression of these genes associated with liver fibrosis provides evidence for a transcriptional basis for the pathogenesis of CFLD and provides avenues for further study. Clarifying the pathogenesis of CFLD will facilitate techniques for early, precirrhotic detection and targeted interventions.

Use of the electroretinogram in a paediatric hospital.

BACKGROUND: To review the use of electroretinography and identify common reasons for referral and diagnoses at a tertiary paediatric hospital. DESIGN: Retrospective cohort study. PARTICIPANTS: Three hundred and eighteen patients (male 195, female 123) aged <18 years with 388 electroretinograms were included. METHODS: All electroretinograms performed at the Royal Children's Hospital, Brisbane from 1998 to 2005 were reviewed. Normative data and electroretinograms from patients aged ≥18 years were excluded. MAIN OUTCOME MEASURES: Reasons for referral and diagnoses were determined from each patient's first electroretinogram. Concordance between the first electroretinogram diagnosis and clinical referral was reviewed to determine whether the electroretinogram was normal, inconclusive, confirmed, excluded, or changed the clinical diagnosis or provided a new diagnosis. RESULTS: The median age at the time of the first investigation was 3.78 years (range 2.6 weeks to 17.5 years). The most common reasons for referral were nystagmus (n = 93), decreased vision (n = 33) and sensorineural deafness (n = 29). After one electroretinogram, 51% were normal (n = 162) and 15% were inconclusive (n = 49). The most common electroretinography diagnosis was cone rod dystrophy. The first electroretinogram for each patient confirmed the clinical suspicion in 17.6% (n = 56) and excluded it in 23% (n = 73) of cases. The electroretinogram resulted in a changed diagnosis in 0.9% (n = 3) and provided a new diagnosis in 15.1% (n = 48). Overall, the first electroretinogram was considered useful in 85% cases (n = 269). CONCLUSIONS: Electroretinography is a valuable investigation for evaluating paediatric eye disease and in this series confirmed, excluded, changed or provided a new diagnosis in 85% of cases.

Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence, Risk Factors and Outcomes for Horses after Retirement from Racing.

There is international public concern regarding retirement of racehorses, including the reason for retirement and the outcome for horses after racing. However, there are currently no prospective studies investigating these factors. A recent independent inquiry in Queensland, Australia, highlighted that the true outcomes for horses after retirement from racing are largely unknown. Furthermore, there are currently no measures to monitor the outcome for racehorses and their welfare once they have left the care of the trainer. This study investigated these gaps in knowledge through a weekly survey conducted over a 13-month period. We aimed to evaluate: (1) the incidence of retirement, (2) the reasons and risk factors for retirement and (3) the medium-term (greater than 6 months) outcomes for horses after retirement. Data were collected through personal structured weekly interviews with participating trainers and analysed using negative binomial and logistic regression. There was a low incidence of retirements, namely 0.4% of horses in training per week. The season and training track did not affect the incidence of retirement. Musculoskeletal injuries were the most common reason for retirement (40/110 horses, 36%). Involuntary retirements accounted for 56/100 (51%) of retirements, whereby musculoskeletal injuries, respiratory or cardiac conditions and behavioural problems prevented the horse from racing The odds of voluntary retirement, whereby the horse was retired due to racing form or impending injury, increased with each additional race start (OR 1.05; p = 0.01) and start/year of racing (OR 1.21; p = 0.03) but decreased with increasing percentage of first, second and third places (OR 0.94; p < 0.001). Medium-term follow-up (median 14 months, IQR 11, 18, range 8-21) revealed that most horses (108/110; 98%) were repurposed after retirement, almost half as performance horses (50/110; 46%). Horses that voluntarily retired had 2.28 times the odds of being repurposed as performance horses than those retired involuntarily (p = 0.03). Whether retirement was voluntary or involuntary did not influence whether horses were used for breeding or pleasure. The primary limitation of this study is that our results reflect retirement in racehorses in South East Queensland, Australia, and may not be globally applicable. Furthermore, we were unable to monitor the long-term outcome and welfare of horses in their new careers. It is vital that the industry is focused on understanding the risks for voluntary rather than involuntary retirement and optimising the long-term repurposing of horses. There is a need for traceability and accountability for these horses to ensure that their welfare is maintained in their new careers.

The Risk Factors for Musculoskeletal Injuries in Thoroughbred Racehorses in Queensland, Australia: How These Vary for Two-Year-Old and Older Horses and with Type of Injury.

Musculoskeletal injuries (MSI) continue to affect Thoroughbred racehorses internationally. There is a strong interest in developing training and management strategies to reduce their impact, however, studies of risk factors report inconsistent findings. Furthermore, many injuries and fatalities occur during training rather than during racing, yet most studies report racing data only. By combining racing and training data a larger exposure to risk factors and a larger number of musculoskeletal injuries are captured and the true effect of risk factors may be more accurately represented. Furthermore, modifications to reduce the impact of MSI are more readily implemented at the training level. Our study aimed to: (1) determine the risk factors for musculoskeletal injuries and whether these are different for two-year-old and older horses and (2) determine whether risk factors vary with type of injury. This was performed by repeating analyses by age category and injury type. Data from 202 cases and 202 matched controls were collected through weekly interviews with trainers and analysed using conditional logistic regression. Increasing dam parity significantly reduced the odds of injury in horses of all age groups because of the effect in two-year-old horses (odds ratio (OR) 0.08; 95% confidence interval (CI) 0.02, 0.36; p < 0.001). Increasing total preparation length is associated with higher odds of injury in horses of all ages (OR 5.56; 95% CI 1.59, 19.46; p = 0.01), but particularly in two-year-old horses (OR 8.05; 95% CI 1.92, 33.76; p = 0.004). Increasing number of days exercised at a slow pace decreased the odds of injury in horses of all ages (OR 0.09; 95% CI 0.03, 0.28; p < 0.001). The distance travelled at three-quarter pace and above (faster than 13 m/s; 15 s/furlong; 800 m/min; 48 km/h) and the total distance travelled at a gallop (faster than 15 m/s; 13 s/furlong; 900 m/min; 55 km/h) in the past four weeks significantly affected the odds of injury. There was a non-linear association between high-speed exercise and injury whereby the odds of injury initially increased and subsequently decreased as accumulated high-speed exercise distance increased. None of the racing career and performance indices affected the odds of injury. We identified horses in this population that have particularly high odds of injury. Two-year-old horses from primiparous mares are at increased odds of injury, particularly dorsal metacarpal disease. Two-year-old horses that have had a total preparation length of between 10 and 14 weeks also have increased odds of injury. Horses of all ages that travelled a total distance of 2.4-3.8 km (12-19 furlongs) at a gallop in the last four weeks and horses three years and older that travelled 3.0-4.8 km (15-24 furlongs) at three-quarter pace and above also have increased odds of injury. We recommend that these horses should be monitored closely for impending signs of injury. Increasing the number of days worked at a slow pace may be more effective for preventing injury, if horses are perceived at a higher risk, than resting the horse altogether. Early identification of horses at increased risk and appropriate intervention could substantially reduce the impact of musculoskeletal injuries in Thoroughbred racehorses.

A Prospective Study of Training Methods for Two-Year-Old Thoroughbred Racehorses in Queensland, Australia, and Analysis of the Differences in Training Methods between Trainers of Varying Stable Sizes.

Worldwide, musculoskeletal injuries remain a major problem for the Thoroughbred racing industry. There is a strong interest in developing training and management strategies to reduce the impact of musculoskeletal injuries, however, progress has been limited by studies reporting conflicting findings, and a limited understanding of the role of different training methods in preventing injury. There is little data on patterns of rest periods and exercise data and how these vary between trainers. This prospective study of two-year-old racehorses was conducted in Queensland, Australia and involved weekly personal structured interviews with 26 trainers over 56 weeks. Detailed daily exercise data for 535 horses providing 1258 training preparations and 7512 weeks at risk were collected. Trainers were categorised into three groups by the mean number of two-year-old horses that they had in work each week over the study duration: (1) Small stables with five or less, (2) Medium stables with 6 to 15 and (3) Large stables with greater than 15 horses in training. Differences between trainers with small, medium and large stable sizes were evaluated using linear regression, Kruskal-Wallis equality-of-populations rank test if linear models were mis-specified or Chi-squared tests for categorical variables. Significant differences were observed between trainers, with horses from larger stables accumulating a greater high-speed exercise volume (p < 0.001), attaining training milestones more frequently (p = 0.01) and taking less time to reach their training milestones (p = 0.001). This study provides detailed data to which training practices from other locations can be compared. Presenting actual training data rather than trainers' estimation of a typical program provides a more accurate assessment of training practices. Understanding how training practices vary between regions improves comparability of studies investigating risk factors and is an important step towards reducing the impact of musculoskeletal injuries.

Survival Analysis of Training Methodologies and Other Risk Factors for Musculoskeletal Injury in 2-Year-Old Thoroughbred Racehorses in Queensland, Australia.

Musculoskeletal injuries remain a global problem for the Thoroughbred racing industry and there is conflicting evidence regarding the effect of age on the incidence of injuries. The ideal time to commence race training is strongly debated, with limited supporting literature. There is also conflicting evidence regarding the effect of high-speed exercise on musculoskeletal injuries. There is a strong interest in developing training and management strategies to reduce the frequency of injuries. The types of musculoskeletal injuries vary between 2-year-old and older horses, with dorsal metacarpal disease the most common injury in 2-year-old horses. It is likely that risk factors for injury in 2-year-old horses are different than those for older horses. It is also likely that the risk factors may vary between types of injury. This study aimed to determine the risk factors for musculoskeletal injuries and dorsal metacarpal disease. We report the findings of a large scale, prospective observational study of 2-year-old horses in Queensland, Australia. Data were collected weekly for 56-weeks, from 26 trainers, involving 535 2-year-old Thoroughbred racehorses, 1, 258 training preparations and 7, 512-weeks of exercise data. A causal approach was used to develop our statistical models, to build on the existing literature surrounding injury risk, by incorporating the previously established causal links into our analyses. Where previous data were not available, industry experts were consulted. Survival analyses were performed using Cox proportional hazards or Weibull regression models. Analysis of musculoskeletal injuries overall revealed the hazard was reduced with increased exposure to high-speed exercise [Hazard ratio (HR) 0.89, 95% Confidence Interval (CI) 0.84, 0.94, p < 0.001], increased number of training preparations (HR 0.58, 95% CI 0.50, 0.67, p < 0.001), increased rest before the training preparation (HR 0.89, 95% CI 0.83, 0.96, p = 0.003) and increased dam parity (HR 0.86, 95% CI 0.77, 0.97, p = 0.01). The hazard of injury was increased with increasing age that training commenced (HR 1.13, 95% CI 1.06, 1.19, p < 0.001). Analyses were then repeated with the outcome of interest dorsal metacarpal disease. Factors that were protective against dorsal metacarpal disease and musculoskeletal injuries overall included: increased total cumulative distance (HR 0.89, 95% CI 0.82, 0.97, p = 0.001) and total cumulative days exercised as a gallop (HR 0.96, 95% CI 0.92, 0.99, p = 0.03), the number of the training preparations (HR 0.43, 95% CI 0.30, 0.61, p < 0.001). The age that training commenced was harmful for both dorsal metacarpal disease (HR 1.17, 95% CI 1.07, 1.28, p < 0.001 and overall musculoskeletal injuries.). The use of non-ridden training modalities was protective for dorsal metacarpal disease (HR 0.89, 95% CI 0.81, 0.97, p = 0.008), but not musculoskeletal injuries overall. The male sex increased the hazard of DMD compared to females (HR 2.58, 95% CI 1.20, 5.56, p = 0.02), but not MSI overall. In summary, the hazard of musculoskeletal injury is greatest for 2-year-old horses that are born from uniparous mares, commence training at a later age, are in their first training preparation, have undertaken little high-speed exercise or had limited rest before their training preparation. The hazard of dorsal metacarpal disease is greatest for 2-year-old horses that are males, commence training at a later age, are in their first training preparation, have undertaken little high-speed exercise or had limited use of non-ridden training modalities. Close monitoring of these high-risk horses during their training program could substantially reduce the impact of MSI. Furthermore, an understanding of how training methodologies affect the hazard of MSI facilitates modification of training programs to mitigate the risk impact of injury. The strengths of this study include a large sample size, a well-defined study protocol and direct trainer interviews. The main limitation is the inherent susceptibility to survival bias.

Genotypic diversity, circulation patterns and co-detections among rhinoviruses in Queensland, 2001.

PURPOSE: Rhinoviruses (RVs) occur more frequently than other viruses and more often in people displaying symptoms than in those without. We sought to estimate the spectrum of RV diversity, RV species seasonality and to analyse RV involvement in respiratory virus co-detections. METHODOLOGY: A convenience collection of 1179 airway sample extracts from patients with suspected respiratory infections, collected during 2001, was subjected to comprehensive molecular testing. RESULTS: RVs were the most common virus detected. We were able to genotype ~90 % of RV detections, identifying 70 distinct RVs, spanning all three species. RV-Bs were under-represented. We found RV species co-circulated at times, although one species usually dominated. Each species displayed a bimodal distribution. CONCLUSION: Notably, RVs and influenza A viruses (IFAV) seldom co-occurred, supporting their roles as primary pathogens of the airway among acutely ill infants. Whether RV circulation has a moderating or controlling effect on the IFAV season or is controlled by it cannot be determined from these data. Despite the frequent perception that RVs commonly co-occur with another virus, our findings indicated this was not always the case. Nearly 80 % of RV detections occurred alone. Understanding more about population-level interference between viruses may allow us to harness aspects of it to generate a non-specific antiviral intervention that mimics a putative protective effect. For routine respiratory virus screening to best serve the patient, RV testing should be a principal component of any acute respiratory illness testing algorithm throughout the year.