Wildfire smoke exposure during pregnancy and perinatal, obstetric, and early childhood health outcomes: A systematic review and meta-analysis

BACKGROUND

Maternal exposure to air pollution during pregnancy is associated with adverse birth outcomes, although less is known for wildfire smoke. This systematic review evaluated the association between maternal exposure to wildfire smoke during pregnancy and the risk of perinatal, obstetric, and early childhood health outcomes.

METHODS

We searched CINAHL Complete, Ovid/EMBASE, Ovid/MEDLINE, ProQuest, PubMed, Scopus, Web of Science, and Google Scholar to identify relevant epidemiological observational studies indexed through September 2023. The screening of titles, abstracts, and full-texts, data extraction, and risk of bias assessment was performed by pairs of independent reviewers.

RESULTS

Our systematic search yielded 28,549 records. After duplicate removal, we screened 14,009 studies, identifying 31 for inclusion in the present review. Data extraction highlighted high methodological heterogeneity between studies, including a lack of geographic variation. Approximately 56.5% and 16% originated in the United States and Brazil, respectively, and fewer in other countries. Among the studies, wildfire smoke exposure during pregnancy was assessed using distance of residence from wildfire-affected areas (n = 15), measurement of air pollutant concentration during wildfires (n = 11), number of wildfire records (n = 3), aerosol index (n = 1), and geographic hot spots (n = 1). Pooled meta-analysis for birthweight and low birthweight were inconclusive, likely due to low number of methodologically homogenous studies. However, the reviewed studies provided suggestive evidence for an increased risk of birthweight reduction, low birthweight, preterm birth, and other adverse health outcomes.

CONCLUSIONS

This review identified 31 studies evaluating the impacts of maternal wildfire smoke exposure on maternal, infant, and child health. Although we found suggestive evidence of harm from exposure to wildfire smoke during pregnancy, more methodologically homogenous studies are required to enable future meta-analysis with greater statistical power to more accurately evaluate the association between maternal wildfire smoke and adverse birth outcomes and other health outcomes.

Maternal Pertussis Vaccination, Infant Immunization, and Risk of Pertussis

OBJECTIVES

Following the introduction of jurisdictional maternal pertussis vaccination programs in Australia, we estimated maternal vaccine effectiveness (VE) and whether maternal pertussis vaccination modified the effectiveness of the first 3 primary doses of pertussis-containing vaccines.

METHODS

We conducted a population-based cohort study of 279 418 mother-infant pairs using probabilistic linkage of administrative health records in 3 Australian jurisdictions. Infants were maternally vaccinated if their mother had a documented pertussis vaccination ≥14 days before birth. Jurisdictional immunization records were used to identify receipt of the first 3 infant doses of pertussis-containing vaccines. Infant pertussis infections were identified using notifiable disease records. VE was estimated using Cox proportional hazard models.

RESULTS

Pertussis was administered during 51.7% (n = 144 429/279 418) of pregnancies, predominantly at 28-31 weeks' gestation. VE of maternal pertussis vaccination declined from 70.4% (95% confidence interval [CI], 50.5-82.3) among infants <2 months old to 43.3% (95% CI, 6.8-65.6) among infants 7-8 months old and was not significant after 8 months of age. Although we observed slightly lower VE point estimates for the third dose of infant pertussis vaccine among maternally vaccinated compared with unvaccinated infants (76.5% vs 92.9%, P = .002), we did not observe higher rates of pertussis infection (hazard ratio, 0.70; 95% CI, 0.61-3.39).

CONCLUSIONS

Pertussis vaccination near 28 weeks' gestation was associated with lower risk of infection among infants through 8 months of age. Although there was some evidence of lower effectiveness of infant vaccination among maternally vaccinated infants, this did not appear to translate to greater risk of disease.

Association between maternal influenza vaccination and neurodevelopmental disorders in childhood: a longitudinal, population-based linked cohort study

OBJECTIVE

To assess the association between in utero exposure to seasonal inactivated influenza vaccine (IIV) and the risk of a diagnosis of a neurodevelopmental disorder in early childhood.

DESIGN

Retrospective cohort study.

SETTING

Population-based birth registry linked with health administrative databases in Western Australia (WA).

PARTICIPANTS

Singleton, liveborn children born between 1 April 2012 and 1 July 2016 in WA.

EXPOSURE

Receipt of seasonal IIV during pregnancy obtained from a state-wide antenatal vaccination database.

MAIN OUTCOME MEASURES

Clinical diagnosis of a neurodevelopmental disorder was recorded from hospital inpatient and emergency department records. We used Cox proportional hazard regression, weighted by the inverse-probability of treatment (vaccination), to estimate the hazard ratio (HR) of neurodevelopmental disorders associated with in utero exposure to seasonal IIV.

RESULTS

The study included 140 514 children of whom, 15 663 (11.2%) were exposed to seasonal IIV in utero. The prevalence of neurodevelopmental disorders was 5.4%, including mental or behavioural (0.4%), neurological (5.1%), seizure (2.2%) and sleep disorders (2.7%). Maternal IIV was not associated with increased risk of neurodevelopmental disorders (HR 1.00; 95% CI 0.91 to 1.08). Children exposed in the first trimester had a lower risk of seizure disorders (adjusted HR [aHR] 0.73; 95% CI 0.54 to 0.998), and preterm children exposed any time during pregnancy had a lower risk of sleep disorders (aHR 0.63; 95% CI 0.41 to 0.98).

CONCLUSIONS

We did not observe increased risk of neurodevelopmental disorders following in utero exposure to seasonal IIV. Although we observed some evidence for lower risk of seizure and sleep disorders, additional studies are required to confirm.

Timing and temporal trends of influenza and pertussis vaccinations during pregnancy in three Australian jurisdictions: The Links2HealthierBubs population-based linked cohort study, 2012-2017

BACKGROUND

Antenatal inactivated influenza (IIV) and pertussis-containing vaccines (dTpa) offer protection against severe respiratory infections for pregnant women and infants <6 months of age. Both vaccines are recommended in pregnancy; however, little is known about temporal or jurisdictional trends and predictors of uptake.

AIMS

To identify gaps and predictors of IIV and/or dTpa vaccinations in Australian pregnancies from 2012 to 2017.

MATERIALS AND METHODS

We conducted a probabilistically linked, multi-jurisdictional population-based cohort study, drawing from perinatal data collections and immunisation databases. We used a generalised linear mixed model with a random effect term to account for clustering of multiple pregnancies within mothers, to calculate vaccination uptake, and identify predictors of uptake by maternal demographic, pregnancy, and health characteristics.

RESULTS

Of 591 868 unique pregnancies, IIV uptake was 15%, dTpa 27% and 12% received both vaccines. Pertussis vaccinations in First Nations pregnancies were 20% lower than non-Indigenous pregnancies; dTpa was strongly associated with IIV uptake (risk ratio (RR): 8.60, 95% CI 8.48-8.73). This trend was temporally and jurisdictionally consistent. First Nations women were more likely to have had IIV in pregnancy before the introduction of dTpa in the pregnancy program: (RR: 1.48, 95% CI 1.40-1.57), but less likely after dTpa implementation (RR: 0.78, 95% CI 0.76-0.80).

CONCLUSIONS

Inequity in vaccine uptake between First Nations and non-Indigenous pregnancies, and dismal rates of vaccination in pregnancy overall need urgent review, particularly before the next influenza pandemic or pertussis outbreak. If antenatal dTpa is driving IIV uptake, changes in antenatal healthcare practices are needed to ensure vaccines are offered equitably and optimally to protect against infection.

The risk of major structural birth defects associated with seasonal influenza vaccination during pregnancy: A population-based cohort study

INTRODUCTION

Seasonal inactivated influenza vaccine (IIV) is routinely recommended during pregnancy to protect both mothers and infants from complications following influenza infection. While previous studies have evaluated the risk of major structural birth defects in infants associated with prenatal administration of monovalent pandemic IIV, fewer studies have evaluated the risk associated with prenatal seasonal IIV.

METHODS

We conducted a population-based cohort study of 125,866 singleton births between 2012 and 2016 in Western Australia. Birth registrations were linked to the state's registers for congenital anomalies and a state prenatal vaccination database. We estimated prevalence ratios (PR) of any major structural birth defect and defects by organ system. Vaccinated pregnancies were defined as those with a record of IIV in the first trimester. Inverse probability treatment weighting factored for baseline probability for vaccination. A Bonferroni correction was applied to account for multiple comparisons.

RESULTS

About 3.9% of births had a major structural birth defect. Seasonal IIV exposure during the first trimester was not associated with diagnosis of any major structural birth defect diagnosed within 1 month of birth (PR 0.98, 95% CI: 0.77, 1.28) or within 6 years of life (PR 1.02, 95% CI: 0.78, 1.35). We identified no increased risk in specific birth defects associated with seasonal IIV.

CONCLUSION

Based on registry data for up to 6 years of follow-up, results suggest there is no association between maternal influenza vaccination and risk of major structural birth defects. These results support the safety of seasonal IIV administration during pregnancy.

Neuropsychiatric outcomes in offspring after fetal exposure to maternal influenza infection during pregnancy: A systematic review

Increasing evidence suggests that influenza infection in pregnancy may disrupt fetal neurodevelopment. The impact of maternal influenza infection on offspring neuropsychiatric health has not been comprehensively reviewed. We systematically reviewed comparative studies evaluating associations between maternal influenza infection and neuropsychiatric health outcomes in offspring. We searched MEDLINE, EMBASE, CINAHL, and Web of Science for articles published until January 7, 2022. Included were English studies evaluating neuropsychiatric outcomes in offspring aged > 6 months born to women with and without influenza during pregnancy, defined as clinical or laboratory-confirmed influenza illness, or being pregnant during pandemics/epidemics. Of 12,010 records screened, 42 studies were included. Heterogeneity in study design, exposures, and outcome definitions precluded meta-analyses. Four of 14 studies assessing schizophrenia reported adjusted ratio estimates from 0.5 to 8.2; most 95% CIs contained the null value; study quality was high in three of four. Two studies reported an increased risk of schizophrenia with influenza exposure any time during pregnancy (adjusted incidence rate ratio 8.2, 95% CI: 1.4-48.8; adjusted odds ratio 1.3, 95% CI: 1.2-1.5); another reported a reduced risk with first-trimester exposure (adjusted risk ratio 0.5, 95% CI: 0.3-0.9). Seven studies of autism spectrum disorder reported adjusted ratio estimates from 0.9 to 4.0; all 95% CIs included the null value; study quality was high in four. No conclusions could be drawn about the association between exposure to maternal influenza and neuropsychiatric outcomes due to the limited quantity and quality of available research. Large observational studies with long-term follow-up are required to investigate these associations.

Maternal influenza vaccination and child mortality: Longitudinal, population-based linked cohort study

Influenza vaccination is recommended to protect mothers and their infants from influenza. Few studies have evaluated the association between maternal influenza vaccination and child mortality. We aimed to evaluate the association between in utero exposure to seasonal inactivated influenza vaccine (IIV) and mortality among young children. This longitudinal, population-based cohort study included 191,247 maternal-child pairs in Western Australia between April 2012 and December 2017. Maternal vaccine information was obtained from a state-wide antenatal vaccination database. Mortality was defined as a record of a death registration. We used Cox proportional hazard models, weighted by the inverse-probability of treatment (vaccination), to estimate the hazard ratio of child mortality associated with in utero exposure to seasonal IIV. This study found no association between in utero exposure to seasonal IIV and mortality through age five years.

The curious case of missing heartbeats

Paroxysmal atrioventricular block (AVB) is a poorly defined and easily missed bradyarrhythmia, which can potentially lead to sudden cardiac death. It is under-recognised due to its abrupt onset and unpredictability. We describe a case that had paroxysmal AVB post-coronary angioplasty and highlight the mechanism as well as the management of this rare condition.

Prenatal influenza vaccination and allergic and autoimmune diseases in childhood: A longitudinal, population-based linked cohort study

BACKGROUND

Few studies have evaluated the effect of maternal influenza vaccination on the development of allergic and autoimmune diseases in children beyond 6 months of age. We aimed to investigate the association between in utero exposure to seasonal inactivated influenza vaccine (IIV) and subsequent diagnosis of allergic and autoimmune diseases.

METHODS AND FINDINGS

This longitudinal, population-based linked cohort study included 124,760 singleton, live-born children from 106,206 mothers in Western Australia (WA) born between April 2012 and July 2016, with up to 5 years of follow-up from birth. In our study cohort, 64,169 (51.4%) were male, 6,566 (5.3%) were Aboriginal and/or Torres Strait Islander children, and the mean age at the end of follow-up was 3.0 (standard deviation, 1.3) years. The exposure was receipt of seasonal IIV during pregnancy. The outcomes were diagnosis of an allergic or autoimmune disease, including asthma and anaphylaxis, identified from hospital and/or emergency department (ED) records. Inverse probability of treatment weights (IPTWs) accounted for baseline probability of vaccination by maternal age, Aboriginal and/or Torres Strait Islander status, socioeconomic status, body mass index, parity, medical conditions, pregnancy complications, prenatal smoking, and prenatal care. The models additionally adjusted for the Aboriginal and/or Torres Strait Islander status of the child. There were 14,396 (11.5%) maternally vaccinated children; 913 (6.3%) maternally vaccinated and 7,655 (6.9%) maternally unvaccinated children had a diagnosis of allergic or autoimmune disease, respectively. Overall, maternal influenza vaccination was not associated with diagnosis of an allergic or autoimmune disease (adjusted hazard ratio [aHR], 1.02; 95% confidence interval [CI], 0.95 to 1.09). In trimester-specific analyses, we identified a negative association between third trimester influenza vaccination and the diagnosis of asthma (n = 40; aHR, 0.70; 95% CI, 0.50 to 0.97) and anaphylaxis (n = 36; aHR, 0.67; 95% CI, 0.47 to 0.95).We did not capture outcomes diagnosed in a primary care setting; therefore, our findings are only generalizable to more severe events requiring hospitalization or presentation to the ED. Due to small cell sizes (i.e., <5), estimates could not be determined for all outcomes after stratification.

CONCLUSIONS

In this study, we observed no association between in utero exposure to influenza vaccine and diagnosis of allergic or autoimmune diseases. Although we identified a negative association of asthma and anaphylaxis diagnosis when seasonal IIV was administered later in pregnancy, additional studies are needed to confirm this. Overall, our findings support the safety of seasonal inactivated influenza vaccine during pregnancy in relation to allergic and autoimmune diseases in early childhood and support the continuation of current global maternal vaccine programs and policies.

Longitudinal, population-based cohort study of prenatal influenza vaccination and influenza infection in childhood

BACKGROUND

Influenza vaccination is recommended to protect mothers and their infants from influenza infection. Few studies have evaluated the health impacts of in utero exposure to influenza vaccine among children more than six months of age.

METHODS

We used probabilistically linked administrative health records to establish a mother-child cohort to evaluate the risk of influenza and acute respiratory infections associated with maternal influenza vaccination. Outcomes were laboratory-confirmed influenza (LCI) and hospitalization for influenza or acute respiratory infection (ARI). Adjusted hazard ratios (aHRs) accounted for child's Aboriginal status and were weighted by the inverse-probability of treatment.

RESULTS

14,396 (11.5%) children were born to vaccinated mothers. Maternally vaccinated infants aged < 6 months had lower risk of LCI (aHR: 0.33; 95% CI: 0.13, 0.85), influenza-associated hospitalization (aHR: 0.39; 95% CI: 0.16, 0.94) and ARI-associated hospitalization (aHR: 0.85; 95% CI: 0.77, 0.94) compared to maternally unvaccinated infants. With the exception of an increased risk of LCI among children aged 6 months to < 2 years old following first trimester vaccination (aHR: 2.28; 95% CI: 1.41, 3.69), there were no other differences in the risk of LCI, influenza-associated hospitalization or ARI-associated hospitalization among children aged > 6 months.

CONCLUSION

Study results show that maternal influenza vaccination is effective in preventing influenza in the first six months and had no impact on respiratory infections after two years of age.

The effects of birth spacing on early childhood development in high-income nations: A systematic review

OBJECTIVE

This study aimed to systematically review the literature on the associations between birth spacing and developmental outcomes in early childhood (3-10 years of age). Studies examining the associations between interpregnancy intervals and child development outcomes during and beyond the perinatal period have not been systematically reviewed.

METHODS

We searched Ovid/MEDLINE, Global Health, PsycINFO, EMBASE, CINAHL Plus, Educational Source, Research Starters, ERIC, Scopus, PubMed, Social Science Research Network database, and ProQuest's Social Sciences Databases for relevant articles published between 1 January 1989 and 25 June 2021. Studies published in English, conducted in populations residing in high-income countries with any measure of birth spacing, and child development outcomes among children aged <10 years were included. Two authors independently assessed the eligibility of studies and extracted data on the study design, setting and population, birth spacing, outcomes, and results.

RESULTS

The search yielded 1,556 records, of which seven studies met the inclusion criteria. Five of these seven studies used birth intervals as the exposure measure. Definitions of exposure differed between the studies. Three studies reported an association between short birth spacing and poorer child development outcomes, and two studies reported an association between long birth spacing and poorer child development outcomes.

CONCLUSION

Currently, limited evidence suggests that the adverse effects of sub-optimal birth spacing are observable beyond infancy.

Implication of Current ASE/EACVI Left Ventricular Diastolic Function Classification in Predicting 2-Year MACE in Asymptomatic Patients with Diabetes and Hypertension

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes. Substantial number of patients were classified as indeterminate DF based on the current ASE/EACVI guidelines. The implication of current DF classification in predicting MACE among diabetic patients is not well established.

Purpose

To assess prognostic impact of current guidelines-based DF classification, and determine predictors of 2-year MACE based on individual LVDD parameters.

Methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients had no prior cardiovascular events, had preserved left ventricular (LV) ejection fraction on echocardiography and sinus rhythm on ECG at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LVDD. The 2016 ASE/EACVI guidelines were applied to classify DF. All patients were followed up until 2 years to assess MACE.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 (7.45); mean duration of DM was 10.5 (5.41). 80 (72.1%) patients were classified as having normal DF (nDF); 24 (21.6%) patients were classified as indeterminate DF (iDF); 7 patients (6.3%) were classified as LVDD. Patients with LVDD had significantly higher LV mass index (LVMI) (mean 121.72±23.28g/m2 vs 116.62±24.66g/m2 in iDF vs 102.50±22.89g/m2 in nDF); higher left atrial volume index (LAVI) (mean 41.24±10.28ml/m2 vs 30.55±10.07ml/m2 in iDF vs 25.75±6.30ml/m2 in nDF); lower lateral e' velocity (mean 6.35±2.05cm/s vs 7.37±1.73cm/s in iDF vs 8.59±2.13cm/s in nDF); higher septal E/e' ratio (mean 14.89±3.29 vs 12.16±3.99 in iDF vs 9.99±2.35 in nDF); higher average septal-lateral E/e' ratio (mean 14.22±3.77 vs 11.34±3.74 in iDF vs 9.04±2.10 in nDF).

Among these 111 patients, 10 patients (9%) reported MACE at 2 years. The risk of 2-year MACE is elevated in both iDF [odds ratio (OR) 3.80, 95% CI 0.87–16.54, p=0.075] and LVDD [OR 7.60, 95% CI 1.11–52.02, p=0.039]. LVMI (OR 1.027, 95% CI 1.004– 1.051, p=0.023), LAVI (OR 1.092, 95% CI 1.017–1.172), and average septal-lateral E/e' ratio (OR 1.276, 95% CI 1.047–1.557, p=0.016) significantly correlated with 2-year MACE.

Conclusions

LVDD is correlated with increased MACE at 2 years. LVMI, LAVI and average septal-lateral E/e' ratio were predictors of increased risk of MACE at 2 years. Further investigation with larger sample size is warranted.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health Malaysia

Interpregnancy interval and hypertensive disorders of pregnancy: A population-based cohort study

BACKGROUND

Despite extensive research on risk factors and mechanisms, the extent to which interpregnancy interval (IPI) affects hypertensive disorders of pregnancy in high-income countries remains unclear.

OBJECTIVES

To examine the association between IPI and hypertensive disorders of pregnancy in a high-income country setting using both within-mother and between-mother comparisons.

METHODS

A retrospective population-based cohort study was conducted among 103 909 women who delivered three or more consecutive singleton births (n = 358 046) between 1980 and 2015 in Western Australia. We used conditional Poisson regression with robust variance, matching intervals of the same mother and adjusted for factors that vary within-mother across pregnancies, to investigate the association between IPI categories (reference 18-23 months), and the risk of hypertensive disorders of pregnancy. For comparison with previous studies, we also applied unmatched Poisson regression (between-mother analysis).

RESULTS

The incidence of preeclampsia and gestational hypertension during the study period was 4%, and 2%, respectively. For the between-mother comparison, mothers with intervals of 6-11 months had lower risk of preeclampsia with adjusted relative risk (RR) 0.92 (95% confidence interval [CI] 0.85, 0.98) compared to reference category of 18-23 months. With the within-mother matched design, we estimated a larger effect of long IPI on risk of preeclampsia (RR 1.29, 95% CI 1.18, 1.42 for 60-119 months; and RR 1.30, 95% CI 1.10, 1.53 for intervals ≥120 months) compared to 18-23 months. Short IPIs were not associated with hypertensive disorders of pregnancy.

CONCLUSIONS

In our cohort, longer IPIs were associated with increased risk of preeclampsia. However, there was insufficient evidence to suggest that short IPIs (<6 months) increase the risks of hypertensive disorders of pregnancy.

Impact of 2016 ASE/EACVI recommendations on evaluation of left ventricular diastolic function and clinical outcomes in patients with diabetes and hypertension without prior adverse cardiac events

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes, compared to those without diabetes. The complexity of previous 2009 ASE/EACVI algorithms makes diastolic function (DF) assessment challenging. Hence, prognostic value of LVDD estimates in clinical setting is not well-established.

Objective

To evaluate the impact of 2016 recommendations in estimates of LVDD and predicting cardiovascular outcomes in patients with diabetes and hypertension.

Materials and methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients were clinically NYHA Class I, had no prior adverse cardiac events, and had preserved left ventricular (LV) ejection fraction on echocardiography at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LVDD. Both 2009 and 2016 algorithms were applied in DF assessment. All patients follow-up at 1 year to assess clinical outcomes.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 (7.45); mean duration of diabetes was 10.5 (5.41). 55 (50.5%) patients had LV hypertrophy on echocardiography.

Prevalence of LVDD (14.4% vs 55.0%) and elevated LV filling pressure (9.0% vs 26.1%) were lower with 2016 compared with 2009 recommendations. Prevalence of indeterminate DF was 18.0% and 12.6% according to 2016 and 2009 recommendations respectively. Concordance between 2016 and 2009 recommendations was fair (k=0.29, p&lt;0.001), with a reclassification rate of 45.9%.

None out of 45 patients who were diagnosed with indeterminate and normal DF according to 2016 and LVDD with 2009 algorithms developed MACE at 1 year. Out of 12 patients diagnosed with LVDD based on both 2016 and 2009 recommendations, 4 patients developed MACE at 1 year. 2016 recommendations showed better accuracy (sensitivity=80.0%; specificity=88.68%) than 2009 recommendations (sensitivity=80.0%; specificity= 45.28%) in predicting MACE at 1 year.

Conclusions

The application of 2016 recommendations results in lower prevalence of LVDD. The 2016 criteria detect more advanced cases and predict 1 year cardiovascular outcomes better. Further studies are warranted to investigate the prognostic impact of this criteria.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institute of Health (NIH), Ministry of Health Malaysia

'Links2HealthierBubs' cohort study: protocol for a record linkage study on the safety, uptake and effectiveness of influenza and pertussis vaccines among pregnant Australian women

INTRODUCTION

Pregnant women and infants are at risk of severe influenza and pertussis infection. Inactivated influenza vaccine (IIV) and diphtheria-tetanus-acellular pertussis vaccine (dTpa) are recommended during pregnancy to protect both mothers and infants. In Australia, uptake is not routinely monitored but coverage appears sub-optimal. Evidence on the safety of combined antenatal IIV and dTpa is fragmented or deficient, and there remain knowledge gaps of population-level vaccine effectiveness. We aim to establish a large, population-based, multi-jurisdictional cohort of mother-infant pairs to measure the uptake, safety and effectiveness of antenatal IIV and dTpa vaccines in three Australian jurisdictions. This is a first step toward assessing the impact of antenatal vaccination programmes in Australia, which can then inform government policy with respect to future strategies in national vaccination programmes. METHODS AND ANALYSIS: 'Links2HealthierBubs' is an observational, population-based, retrospective cohort study established through probabilistic record linkage of administrative health data. The cohort includes births between 2012 and 2017 (~607 605 mother-infant pairs) in jurisdictions with population-level antenatal vaccination and health outcome data (Western Australia, Queensland and the Northern Territory). Perinatal data will be the reference frame to identify the cohort. Jurisdictional vaccination registers will identify antenatal vaccination status and the gestational timing of vaccination. Information on maternal, fetal and child health outcomes will be obtained from hospitalisation and emergency department records, notifiable diseases databases, developmental anomalies databases, birth and mortality registers.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Western Australian Department of Health, Curtin University, the Menzies School of Health Research, the Royal Brisbane and Women's Hospital, and the West Australian Aboriginal Health Ethics Committees. Research findings will be disseminated in peer-reviewed journals, at scientific meetings, and may be incorporated into communication materials for public health agencies and the public.

Effects of interpregnancy interval on pregnancy complications: protocol for systematic review and meta-analysis

INTRODUCTION

Interpregnancy interval (IPI) is the length of time between a birth and conception of the next pregnancy. Evidence suggests that both short and long IPIs are at increased risk of adverse pregnancy and perinatal outcomes. Relatively less attention has been directed towards investigating the effect of IPI on pregnancy complications, and the studies that have been conducted have shown mixed results.This systematic review will aim to provide an update to the most recent available evidence on the effect of IPI on pregnancy complications.

METHOD AND ANALYSIS

We will search electronic databases such as Ovid/MEDLINE, EMBASE, CINAHL, Scopus, Web of Science and PubMed to identify peer-reviewed articles on the effects of IPI on pregnancy complications. We will include articles published from start of indexing until 12 February 2018 without any restriction to geographic setting. We will limit the search to literature published in English language and human subjects. Two independent reviewers will screen titles and abstracts and select full-text articles that meet the eligibility criteria. The Newcastle-Ottawa tool will be used to assess quality of observational studies. Where data permit, meta-analyses will be performed for individual pregnancy complications. A subgroup analyses by country categories (high-income vs low and middle-income countries) based on World Bank income group will be performed. Where meta-analysis is not possible, we will provide a description of data without further attempt to quantitatively pool results.

ETHICS AND DISSEMINATION

Formal ethical approval is not required as primary data will not be collected. The results will be published in peer-reviewed journals and presented at national and international conferences.

PROSPERO REGISTRATION NUMBER

CRD42018088578.

Impact of pharmacist-involved collaborative care on the clinical, humanistic and cost outcomes of high-risk patients with type 2 diabetes (IMPACT): a randomized controlled trial

WHAT IS KNOWN AND OBJECTIVE

With the increasing prevalence of diabetes, the physician-centred model is challenged to deliver holistic care in Asia. Diabetes may be managed effectively within a multidisciplinary collaborative care model; however, evidence on its effectiveness in Asian patients is lacking. Therefore, the primary objective was to evaluate the clinical outcomes of multidisciplinary collaborative care vs physician-centred care in diabetes. The secondary objectives were to evaluate humanistic and economic outcomes among the two types of care.

METHODS

This 6-month prospective, open-label, parallel-arm, randomized, controlled study was conducted at four outpatient healthcare institutions. High-risk patients aged ≥21 years with uncontrolled type 2 diabetes, polypharmacy and comorbidities were included. Patients with type 1 diabetes or those who were unable to communicate independently were excluded. The control arm received usual care with referrals to nurses and dietitians as needed. The intervention arm (multidisciplinary collaborative care) was followed up with pharmacists regularly, in addition to receiving the usual care. The primary outcomes included HbA1c, systolic blood pressure, low-density lipoprotein and triglycerides. The secondary outcomes included scores from the Problem Areas in Diabetes (PAID) and the Diabetes Treatment Satisfaction Questionnaires (DTSQ), and diabetes-related health service utilization rates and costs.

RESULTS AND DISCUSSION

Of 411 eligible patients, 214 and 197 patients were randomized into the intervention and control arms, respectively. At 6 months, 141 patients in the intervention arm (65.9%) and 189 patients in the control arm (95.9%) completed the study. Mean HbA1c reduced from 8.6%±1.5% at baseline to 8.1%±1.3% at 6 months in the intervention arm (P=.04), with up to mean HbA1c improvement of 0.8% in patients with greater levels of uncontrolled glycemia. Whereas the mean HbA1c in the control arm remained unchanged (8.5%±1.4%) throughout the 6-month period. Improvements in PAID and DTSQ scores, reduction in physician workload and an average cost savings of US$91.01 per patient were observed in the intervention arm over 6 months.

WHAT IS NEW AND CONCLUSIONS

The positive clinical, humanistic and economic outcomes highlighted the value of multidisciplinary collaborative care for Asian diabetic patients, thereby supporting the effectiveness of this approach in managing chronic diseases.

Anticoagulation use and predictors of stroke, bleeding and mortality in multi-ethnic Asian patients with atrial fibrillation: A single centre experience

INTRODUCTION

Atrial fibrillation (AF) is the most common cardiac arrhythmia in singapore. We describe a cohort of multi-ethnic Asian patients with AF, with the aim to evaluate anticoagulation use and to identify factors predictive of stroke, bleeding and all-cause mortality.

MATERIALS AND METHODS

this was a single centre, retrospective cohort study. All patients with an admission diagnosis of AF between 1 January 2000 and 31 December 2010 were identified. Of these patients, those who had follow-up data up to 31 December 2012 were included in the study.

RESULTS

there were 1095 eligible patients. the mean age was 67±14 years, mean cHADs2 score was 2±1 and mean HAs-bLED score 2±1. Of the 1095 patients, 657 (62.0%) had a cHADs2 score ≥ 2 but only 215 (32.7%) were eventually prescribed warfarin. Patients not on warfarin were older (p<0.0001) and were more likely females (p<0.0001). Among patients not on warfarin, 52% had HAs-bLED score ≤3. Multivariate analysis revealed that warfarin use and high HAs-bLED score were associated with increased bleeding risk. Age, Indian ethnicity and cHADs2 score were predictive of ischemic stroke. All-cause mortality was significantly related to age, presence of heart failure and HAs-bLED score.

CONCLUSIONS

Anticoagulation management of AF patients remains inadequate. Objective assessment of bleeding risks should be performed before withholding anticoagulation.

Ventricular tachycardia storm: a case series and literature review

INTRODUCTION

Ventricular tachycardia (VT) storm is an uncommon but life-threatening condition. We describe the incidence, causes and management of VT storm among patients admitted to the coronary care unit of a large tertiary hospital.

MATERIALS AND METHODS

Between 1 November 2009 and 30 April 2010, 198 patients were admitted to the coronary care unit and 7 (3.5%) presented with VT storm. A retrospective review of their records was conducted. The mean follow-up period was 268 (196 to 345) days.

RESULTS

The mean age was 67 years and 4 patients were male. One patient had a previous myocardial infarction. All had abnormal left ventricular ejection fraction, median of 30%. Acute myocardial infarction (4 patients) was the most common trigger, followed by decompensated heart failure (1), systemic inflammatory response syndrome on a background of non-ischemic dilated cardiomyopathy (1) and bradycardia-induced polymorphic VT (1). Three patients had polymorphic VT and the rest had monomorphic VT. Intravenous amiodarone, lignocaine, overdrive pacing and intra-aortic balloon pump counterpulsation were useful in arrhythmia control. Three patients underwent coronary revascularization, 3 patients received implantable cardioverter-defibrillators, 1 had a permanent cardiac pacemaker, 1 died during the acute episode. Five out of the 6 survivors were prescribed oral beta-blockers upon discharge. On follow-up, none of the patients had a recurrence of the tachyarrhythmia.

CONCLUSION

Acute myocardial infarction was the main trigger of VT storm in our patients. Intravenous amiodarone, lignocaine, overdrive pacing and intra-aortic balloon pump counterpulsation were useful at suppressing VT storm.

Anatomical changes in the primary visual cortex of the congenitally blind Crx-/- mouse

Mutations in the human cone-rod homeobox (Crx) gene are associated with retinal dystrophies such as Leber Congenital Amaurosis (LCA), characterized by complete or near complete absence of vision from birth. The photoreceptors of Crx-/- mice lack outer segments, and therefore cannot capture light signals through rods and cones, thus resulting in a lack of normal retinal ganglion cell activity from birth. Using specific antibodies to subsets of neurons and markers of activity, we examined the impact of this absence of sensory input on the development of the primary visual cortex (V1) in early postnatal Crx-/- mice, before wiring of the visual system is complete, and in adulthood. We revealed that Crx-/- mice did not exhibit gross anatomical differences in V1; however, they exhibited significantly fewer calcium-binding protein (parvalbumin and calbindin-D28k) expressing interneurons, as well as reduced nonphosphorylated neurofilament expression in V1. These results reveal that the Crx mutation and lack of light stimulation through the photoreceptor pathway regulate the development and phenotype of different neuronal populations in V1 but not its general morphology. We conclude, therefore, that photoreceptor-mediated visual input during development is crucial for the normal postnatal development and maturation of subsets of cortical neurons.

Electrocardiographical case. Narrow complex tachycardia provoked by the Valsalva manoeuvre

A 19-year-old Chinese man presented with tachyarrhythmia during a human centrifuge session while performing a Valsalva manoeuvre at near normal (+1.4 Gz) centripetal forces. It was likely that the hydrostatic effects of sustained centrifugal forces, the distortion of the heart's shape, as well as swings in the autonomic dominance pre- and post-Valsalva manoeuvre, contributed to the tachyarrhythmia. The 12-lead ECG showed a narrow complex tachycardia with visible P-waves after the QRS complexes consistent with a long R-P' tachycardia. The intracardiac electrogram demonstrated a concentric retrograde atrial activation during narrow complex tachycardia. The V-A interval was 150 ms which was much longer than in typical atrioventricular nodal reentry tachycardia, which is usually less than 70 ms. The A-H interval was short and the H-A interval was long, indicating that antegrade activation was over the fast pathway and retrograde activation was over the slow pathway. The diagnosis was atypical atrioventricular nodal reentry tachycardia, and radiofrequency ablation was successfully applied to the slow AV nodal pathway.

Electrocardiographical case. A case of wide complex tachycardia

A 43-year-old Chinese woman complained of a one week history of irregular rapid palpitations associated with chest discomfort and dyspnoea. Her heart rate was more than 160 beats per minute and blood pressure was 154/95 mmHg. 12-lead electrocardiogram (ECG) showed a wide complex tachycardia with a slightly irregular rhythm. Delta waves were also present. She was treated appropriately with intravenous procainamide but developed torsades de pointes secondary to prolonged QT interval. Electrophysiology study revealed atrial tachycardia with a left-sided accessory pathway which was successfully ablated.

Shunting for syringomyelia in patients with spinal cord injuries: self-reported, long-term effects in 8 patients

OBJECTIVE

To investigate the long-term effects of shunting on neurologic outcome of syringomyelia, a complication of spinal cord injury (SCI).

DESIGN

Retrospective data collection using telephonic survey.

SETTING

University based medical center.

PARTICIPANTS

Eight of 15 patients who had shunts placed between 1976 and 1999.

INTERVENTIONS

Review of clinical records and self-reported telephone interview.

MAIN OUTCOMES MEASURES

Initial clinical presentation, recovery after shunt placement, and subsequent neurologic status were recorded. Patients were asked to rate symptomatic improvement after surgery on a 100-point analog scale; they were also asked whether they would have the surgery again.

RESULTS

Presenting symptoms were weakness in all 8 patients, pain in 5 patients, and numbness in 5 patients. After shunting, 6 patients had improved strength, all had less pain, and 2 had less numbness. Six patients experienced neurologic decline an average of 2 years after shunt placement, 3 because of shunt failure, 2 from a new syrinx, and 1 from both shunt failure and new syrinx. Two of the 3 patients who underwent second shunt placements for a new syrinx had full neurologic recovery. Six patients said they would repeat the shunting procedure if necessary, 1 was uncertain, and 1 would not.

CONCLUSION

Initial improvements noted after shunting provide long-lasting effects, even though many patients may need a second procedure. Less pain and improved strength are more significant than decreased numbness.

A case of post-traumatic syringomyelia. Neuropathological findings after 1 year of cystic drainage

A 58-year-old man sustained C4-C5 post-traumatic myelopathy with C3-C4 subluxation, slight compression of C3 vertebral body, C4 spinous process fracture and C6 compression fracture. He subsequently developed syringomyelia from C4 to C6, which was shunted into the subarachnoid space. Postoperatively, there was some but insignificant improvement of his symptoms although a postoperative metrizamide spinal computerised tomography showed complete drainage of the cyst. This patient died 1 year later. Autopsy examination of the spinal cord showed extensive damage of the posterior half of the cord at C3-C4 but the damage was much less extensive from C4 to C6 (where the syrinx was located), affecting mainly the right dorsal column at C4 and the right dorsal column and right anterior horn at C5-C6. In this patient, the syrinx developed in the partially damaged segments of the cord at the level of the spinal fractures and complete drainage of the cyst was not followed by satisfactory relief of his symptoms.

Spinal cord injury in forty-four patients with cervical spondylosis

Within a 12-year period, 44 (9.4%) of 466 patients had spinal cord injury complicating cervical spondylosis. A history of alcoholic use preceding the accident was obtained in 12 (54.5%) of 22 patients whose cord injury was due to a minor fall. The initial myelopathy was complete in 10 patients and incomplete in 34. Although neurological recovery was seen in the majority of the patients with incomplete cord lesion, complete recovery was unusual and most of the patients were partly or completely wheelchair dependent. No patient developed acute neurological deterioration after injury but seven expired. The mortality rate was much higher in the patients whose initial cord lesion was complete (50% or 5/10) than in those with incomplete myelopathy (5.9% or 2/34). There was no delayed neurological deterioration due to progressive spondylosis of the spine but three patients developed post-traumatic syringomyelia several months to several years after the injury.

Cervical spinal cord injury complicating ankylosing spondylitis

Within a period of 12 years 466 patients with acute spinal cord injury were admitted to our Centre, seven of these having ankylosing spondylitis (AS). A history of alcohol consumption preceding the accident was present in five patients, and in four there was a history of neurological deterioration before their admission. An epidural hematoma was found in one patient and four expired within 3 months of their injury. The incidence of ankylosing spondylitis in cervical cord injury was 1.5%, and an associated epidural hematoma was present in some 14% of the patients. The mortality rate was 57%. There was a high incidence of alcoholic use before the accident. Neurological deterioration commonly occurred before admission.

Posttraumatic cervical syringomyelia. Incidence, clinical presentation, electrophysiological studies, syrinx protein and results of conservative and operative treatment

In eleven years, 30 (3.2%) of 951 patients with spinal cord injury developed cervical syringomyelia. This condition was found in 22 (4.5%) of 488 posttraumatic tetraplegic and 8 (1.7%) of 463 posttraumatic paraplegic patients; the incidence was about 8 per cent in patients with complete tetraplegia. This study demonstrated the rarer clinical manifestations of syringomyelia, namely autonomic dysfunction, alterations in the sensory level with postural changes, the early occurrence of tendon areflexia and painless motor deterioration. Prolonged F wave latencies were present in all patients with a demonstrable syrinx and a higher protein content was found in the syrinx than in the cisternal fluid. Some of the symptoms and signs in a proportion of the patients treated conservatively remained stable without operative treatment over a number of years. Most of the patients in whom operation was performed for progressive motor weakness or severe pain had good postoperative results although a few developed late sensory or motor changes. There was no benefit in operating on a patient with a small syrinx.

Colorectal carcinoma and myelopathy

The incidence and pathological features of colorectal carcinoma in a population of veterans disabled by myelopathy were examined by record review. Thirteen cases of colorectal carcinoma were found among the 1023 such individuals (99 percent male) who were hospitalized and subsequently followed between April 1, 1973 and September 22, 1983. The age adjusted incidence rates ranged from 316 per 100,000 person years in the sixth decade to 1886 per 100,000 person years in the ninth decade of age. These rates were two to six times the highest reported rates for general male populations (P less than 0.05). The location of carcinoma was proximal to the rectosigmoid colon in 62 percent of the 13 paralyzed patients, but in only 12 percent of 31 nonparalyzed male patients with colorectal carcinoma diagnosed at the same hospital in 1977-1979 (P less than 0.001). The stage of the tumor at diagnosis was Dukes Kirklin C in 83 percent of paralyzed patients and 48 percent of the nonparalyzed patients (P less than 0.001). We conclude that colorectal carcinoma is more common, more proximal in location, and more advanced at diagnosis in male subjects with myelopathy than in nonparalyzed male subjects.

Complete sensory and motor recovery from anterior spinal artery syndrome after sprain of the cervical spine. A case report

A patient sustained C7-C8 incomplete myelopathy with dissociated sensory loss after a whiplash injury. Cervical radiograms showed no fracture or dislocation but separation of the C4-C5 and C5-C6 spinous processes and anterior tilting on C5 on C6 vertebral body only in the head-neck flexed position. Complete sensory and motor recovery occurred after neck immobilization. The patient's transient neurologic deficits were probably caused by vascular insufficiency of an anterior radicular artery at the C5-C6 intervertebral foramen.

Two spinal cord lesions in a patient with ankylosing spondylitis and cervical spine injury

A patient with ankylosing spondylitis sustained C3-C4 vertebral subluxation and C4-C5 myelopathy after a hyperextension trauma. Autopsy showed that several segments below the main cervical cord lesion at the fractured site, there was a second spinal cord lesion at the T1 vertebral level with no corresponding local bony or ligamentous damage. The thoracic cord lesion was probably secondary to traction of the upper thoracic cord, where the blood supply is poor, in a narrow and rigid spinal canal at the moment of extreme hyperextension.

Anterior spinal artery syndrome and its natural history

The anterior spinal artery syndrome in three patients is described and from the literature 60 additional patients were collected. Motor recovery in the following groups of patients was noted: (1) Partial loss of motor function and pain sensation--70.4 per cent (19/27); (2) Complete motor loss but partial loss of pain--83.3 per cent (5/6); (3) Paresis but pain sensation absent--66.7 per cent (6/9); and (4) Absent motor function and pain--38.9 per cent (7/18). Motor recovery was also found to vary according to aetiology: (A) Unknown cause--92.9 per cent (13/14); (B) Post-infection or vaccination--88.9 per cent (8/9); (C) Anterior spinal artery occlusion--33.3 per cent (3/9); (D) Spinal cord angioma--20 per cent (2/10); and (E) Aortic lesion--20 per cent (1/5). Patients with sparing of motor function or pain sensation below the lesion do better than those without both functions. Neurological return also varies with the aetiology of the syndrome.

Radiography of posttraumatic syringomyelia

Posttraumatic syringomyelia was studied in 15 patients. Gas myelography in 12 patients showed a definite spinal cord swelling in 10 and a probable cord enlargement in two. Plain spinal computed tomography (CT) in four patients demonstrated intramedullary radiolucent zones in three. After intrathecal injection of metrizamide in 10 patients, cysts were opacified in eight. Postoperative CT in two patients demonstrated collapse of the cyst in one. Gas myelography shows the extent and site of maximal dilatation of the cyst where a shunt can be placed. CT is less invasive and provides a definitive diagnosis.

Post-traumatic spinal epidural hematoma

Five patients with vertebral fracture and spinal epidural hematoma (SEH) are described. Another 58-year-old man developed a post-traumatic SEH without bony damage. From the literature, 38 patients (31 male, 4 female, and 3 unknown) were collected. Ankylosing spondylitis or rheumatoid arthritis was noted in 9 of 12 subjects between 50 and 75 years of age. Two groups of patients were identified: Group 1--16 patients with spinal fracture (aged 23 to 63 years), and Group 2--22 patients without spinal fracture (the age was less than 18 years in 12 subjects). In Group 2, a coagulation defect or spinal epidural vascular malformation resulted in a SEH in 6 patients. The preoperative myelopathy was complete in 3 patients each from Group 1 (23.1%) and Group 2 (16.7%). Of the 31 patients operated upon, 9 of the 13 from Group 1 (69.3%) and 6 of the 18 from Group 2 (33.3%) underwent laminectomy within 1 week after the onset of symptoms. Postoperative neurological return was observed in 38.5% (5 of 13) and 88.9% (16 of 18) of these two groups of patients, respectively. Post-traumatic SEHs, predominant in the male population, are often associated with vertebral disease in elderly patients. In the very young patient, there is usually no fracture/dislocation of the spine. A predisposing lesion may be present when spinal fracture is not evident. The prognosis after surgical intervention is better in patients without spinal fracture than in those with vertebral damage, probably because of less contusion to the spinal cord and the presence of very young subjects in the former group of patients.

Posttraumatic anterior spinal cord syndrome: pathological studies of two patients

Two patients sustained acute anterior spinal cord injury associated with a posteriorly displaced bone fragment and herniated cervical disc. Postmortem examination of both spinal cords showed extensive destruction of the cord at the site of injury with sparing of the posterior portion of the dorsal columns; the anterior spinal artery was patent. We conclude that posttraumatic anterior spinal cord syndrome can be caused by damage to the anterior part of the cord without involvement of the anterior spinal artery.

Post-traumatic acute anterior spinal cord syndrome

Thirteen patients with motor complete but sensory incomplete lesions following vertebral and spinal cord injuries are described. Sensory dissociation was present with more impairment of pain than touch or proprioception. The loss of pain sensation was complete in seven patients, but was incomplete in the other six subjects four of whom showed major motor recovery. The major point of interest of this study is to show that patients who retain not only touch but also pain sensation have a definitely better prognosis for neurological recovery.

Preoperative neurological status in predicting surgical outcome of spinal epidural hematomas

The postoperative progress of 3 patients with spinal epidural hemorrhage, but without spinal fracture or dislocation, is presented. From the literature, 158 cases were collected of spontaneous spinal epidural hematoma treated surgically. Postoperative return of motor function was noted in 95.3%, 87%, and 45.3% of the patients with incomplete sensorimotor, incomplete sensory but complete motor, and complete sensorimotor lesions, respectively. Complete sensorimotor recovery occurred in 41.9%, 26.1%, and 11.3% of these 3 groups of patients, respectively. Recovery following surgical treatment depends on the severity of neurological deficits before treatment. However, the absence of motor or sensorimotor functions preoperatively does not necessarily indicate a poor prognosis.

Spontaneous cervical epidural hemorrhage, anterior cord syndrome, and familial vascular malformation: case report

Complete motor tetraplegia with incomplete sensory loss was caused by spontaneous epidural bleeding from an arteriovenous malformation in the cervical region. There was a family and personal history of cutaneous hemangioma.

Radionuclide cerebral blood flow and carotid angiogram. Correlation in internal carotid artery disease

Radionuclide cerebral blood flow (CBF) examinations of 48 patients with atherosclerosis, 18 with occlusion and 30 with stenosis of the internal carotid artery (ICA) were correlated with their respective cerebral angiograms. The following results were obtained. Flow was visually unilaterally diminished in 29 (60%) of 48 patients, including 14 (78%) with occlusion and 15 (50%) with stenosis. Sixty-two percent of the subjects with severe stenoses and 46% of the patients with mild stenoses had a positive flow study. Diminished flow was evident in the neck in 80% of the patients, intracranially in 20%. Positive radionuclide angiograms always pointed to the side with occlusion or the greater degree of stenosis even though bilateral interanl carotid disease was frequently found (54%). The data leading to the differentiation between major and minor ICA stenosis are not sufficient to justify any conclusion.