Prenatal and infant paracetamol exposure and development of asthma: the Norwegian Mother and Child Cohort Study

Asthma Inception: Epidemiologic Risk Factors and Natural History Across the Life Course

Asthma is a descriptive label for an obstructive inflammatory disease in the lower airways manifesting with symptoms including breathlessness, cough, difficulty in breathing, and wheezing. From a clinician's point of view, asthma symptoms can commence at any age, although most patients with asthma-regardless of their age of onset-seem to have had some form of airway problems during childhood. Asthma inception and related pathophysiologic processes are therefore very likely to occur early in life, further evidenced by recent lung physiologic and mechanistic research. Herein, we present state-of-the-art updates on the role of genetics and epigenetics, early viral and bacterial infections, immune response, and pathophysiology, as well as lifestyle and environmental exposures, in asthma across the life course. We conclude that early environmental insults in genetically vulnerable individuals inducing abnormal, pre-asthmatic airway responses are key events in asthma inception, and we highlight disease heterogeneity across ages and the potential shortsightedness of treating all patients with asthma using the same treatments. Although there are no interventions that, at present, can modify long-term outcomes, a precision-medicine approach should be implemented to optimize treatment and tailor follow-up for all patients with asthma.

Acetaminophen for Patent Ductus Arteriosus and Risk of Mortality and Pulmonary Morbidity

OBJECTIVE

Emerging data indicate that acetaminophen may adversely affect lung health. We examined whether acetaminophen compared with cyclooxygenase (COX) inhibitor alone for patent ductus arteriosus (PDA) is associated with mortality or respiratory morbidity in extremely preterm infants.

METHODS

This is a retrospective cohort study using data from the National Institute of Child Health and Human Development Neonatal Research Network. Infants were born at 22 to 28 weeks' gestation or weighing 401 to 1000 g between 2016 and 2020 and received acetaminophen, ibuprofen, and/or indomethacin for PDA closure. The primary outcome was death or grade 2 to 3 bronchopulmonary dysplasia (BPD) at 36 weeks' postmenstrual age. Secondary outcomes included predischarge mortality and respiratory morbidities. Risk ratios were adjusted for baseline and early postnatal factors. Additional exploratory analyses were adjusted for later postnatal covariates.

RESULTS

Of 1921 infants, 627 (32.6%) received acetaminophen and 1294 (67.3%) received COX inhibitor only. Multidrug therapy (42.9% vs 4.7%) and surgical or catheter PDA closure (26.5% vs 19.9%) were more common among acetaminophen-exposed infants. Death or grade 2 to 3 BPD at 36 weeks' postmenstrual age was similar between infants treated with acetaminophen versus COX inhibitor only (57.1% vs 58.3%; adjusted relative risk [aRR] 0.96, 95% confidence interval [CI] 0.87-1.06). Acetaminophen was associated with increased risk of predischarge mortality (13.3% vs 10.0%) when adjusting for perinatal and early postnatal factors (aRR 1.42, 95% CI 1.02-1.93), but not in exploratory analyses that included later postnatal factors (aRR 1.28, 95% CI 0.91-1.82).

CONCLUSIONS

Treatment with acetaminophen versus COX inhibitor alone for PDA was not associated with the composite outcome of death or BPD in extremely preterm infants. Our results support further evaluation of whether acetaminophen for PDA increases mortality.

Early-life risk factors which govern pro-allergic immunity

Allergic diseases affect up to 40% of the global population with a substantial rise in food allergies, in particular, over the past decades. For the majority of individuals with allergy fundamental programming of a pro-allergic immune system largely occurs in early childhood where it is crucially governed by prenatal genetic and environmental factors, including their interactions. These factors include several genetic aberrations, such as filaggrin loss-of-function mutations, early exposure to respiratory syncytial virus, and various chemicals such as plasticizers, as well as the influence of the gut microbiome and numerous lifestyle circumstances. The effects of such a wide range of factors on allergic responses to an array of potential allergens is complex and the severity of these responses in a clinical setting are subsequently not easy to predict at the present time. However, some parameters which condition a pro-allergic immune response, including severe anaphylaxis, are becoming clearer. This review summarises what we currently know, and don't know, about the factors which influence developing pro-allergic immunity particularly during the early-life perinatal period.

Drug-induced fetal and offspring disorders, beyond birth defects

Studies on drug utilization in western countries disclosed that about nine over ten women use at least one or more drugs during pregnancy. Determining whether a drug is safe or not in pregnant women is a challenge of all times. As a developing organism, the fetus is particularly vulnerable to effects of drugs used by the mother. Historically, research has predominantly focused on birth defects, which represent the most studied adverse pregnancy outcomes. However, drugs can also alter the ongoing process of pregnancy and impede the general growth of the fetus. Finally, adverse drug reactions can theoretically damage all developing systems, organs or tissues, such as the central nervous system or the immune system. This extensive review focuses on different aspects of drug-induced damages affecting the fetus or the newborn/infant, beyond birth defects, which are not addressed here.

Prenatal opioid exposure and risk of asthma in childhood: a population-based study from Denmark, Norway, and Sweden

Background: Opioids may modulate the immune function through opioid receptors on immune cells. Long-term consequences of prenatal opioid exposure on the immune system, such as childhood asthma, are unknown. Objectives: To investigate whether prenatal opioid exposure is associated with the risk of childhood asthma. Methods: Cohort study using linked nationwide registers in Denmark (1996-2015), Norway (2005-2015), and Sweden (2006-2013). Children born by mothers who were chronic opioid analgesics users before pregnancy (n = 14,764) or who were receiving opioid maintenance therapy (OMT) before or during pregnancy (n = 1,595) were identified based on information from each of the medical birth registers and prescription registers. Long-term opioid analgesics exposed children were compared to short-term exposed or unexposed, whereas OMT exposed children were compared to OMT unexposed. Asthma among children ≥1 years of age was defined as two or more filled prescriptions of antiasthmatic medication within 365 days, or a diagnosis of asthma. Hazard ratios (HRs) were calculated using Cox proportional hazards regression with attained age as the time scale. Inverse probability of treatment weights based on propensity scores were applied to adjust for measured confounders. Individual level data from Norway and Sweden were pooled, whereas individual level data from Denmark were analyzed separately. For the opioid analgesics comparisons, adjusted HRs (aHR) from the combined Norwegian/Swedish data and the Danish data were pooled in a fixed-effects meta-analysis. Results: For the opioid analgesics cohort, no increased risk of asthma was observed in long-term exposed children neither compared with unexposed [aHR = 0.99 (95% CI 0.87-1.12)], nor compared with short-term exposed [aHR = 0.97 (0.86-1.10)]. No increased risk of asthma was observed in OMT exposed compared with OMT unexposed children [Norway/Sweden: aHR = 1.07 (0.60-1.92), Denmark: aHR = 1.25 (0.87-1.81)]. Results from sensitivity analyses, where potential misclassification of the outcome and misclassification of OMT exposure were assessed, as well as starting follow-up at 6 years of age, showed that the estimates of association were generally robust. Conclusion: We found no association between prenatal exposure to opioids and risk of childhood asthma. Results were consistent across two different opioid exposure groups with different confounder distributions.

Safety of drugs used for the treatment of migraine during pregnancy: a narrative review

INTRODUCTION

Migraine is common in females of childbearing age and negatively impacts quality of life. The majority of those with migraine who become pregnant see an improvement in their condition but not all do. Providing evidence-based recommendations for the pharmacological management of migraine in pregnancy is challenging.

AREAS COVERED

This narrative review provides an update on the safety of drugs used for migraine in pregnancy. National and international guidelines on the management of episodic migraine in adults were used to select the drugs of relevance to pregnant women. The final list of drugs was chosen by a pain specialist who categorized them according to drug class and use in acute management or prevention. PubMed was searched from inception to 31st July 2022 for evidence on drug safety.

EXPERT OPINION

Obtaining high-quality drug safety data in pregnant migraineurs is difficult not least because exposing a fetus to research-related risks is often considered unethical. There is reliance on observational studies which often group drugs together and lack specificities pertinent to drug prescribing like timing, dosing and duration. Improved statistical tools, study designs and the creation of international collaborative frameworks are ways to advance knowledge on drug safety in pregnancy.

Effects of Prenatal Paracetamol Exposure on the Development of Asthma and Wheezing in Childhood: A Systematic Review and Meta-Analysis

The aim of the report was to evaluate whether in utero exposure to paracetamol is associated with risk towards developing respiratory disorders such as asthma and wheeze after birth. MEDLINE (PubMed), EMBASE and Cochrane Library databases were searched for articles published in English to December 2021. The study involved 330,550 women. We then calculated the summary risk estimates and 95% CIs and plotted forest plots using random effect models (DerSimonian-Laird method) and fixed effect models. We also performed a systematic review of the chosen articles and a meta-analysis of studies based on the guidelines outlined in the PRISMA statement. Accordingly, maternal exposure to paracetamol during pregnancy was associated with a significant increased risk of asthma: crude OR = 1.34, 95% CI: 1.22 to 1.48, p < 0.001; and significant increased risk of wheeze: crude OR = 1.31, 95% CI: 1.12 to 1.54, p < 0.002. Results of our study confirmed that maternal paracetamol use in pregnancy is associated with an enhanced risk of asthma and wheezing in their children. We believe paracetamol should be used with caution by pregnant women, and at the lowest effective dose, and for the shortest duration. Long-term use or the use of high doses should be limited to the indications recommended by a physician and with the mother-to-be under constant supervision.

The IL-6/HO-1/STAT3 signaling pathway is implicated in the amelioration of acetaminophen-induced hepatic toxicity: A neonatal rat model

The widespread use of acetaminophen (APAP) in children as an over-the-counter treatment can cause acute liver failure through accidental overdose or ingestion. Therefore, the current research sought to investigate the function of hemin in mitigating the acute hepatotoxic effect of APAP in rat offspring. Thirty-two rats were assigned into four groups: control, hemin, APAP, and hemin/APAP groups. Liver enzymes were measured in serum along with oxidative stress indicators, tumor necrosis factor-α (TNF-α), interleukin-1beta (IL-1β), total nitrites (NOx), and caspase 3 in liver. Immunoblotting of heme oxygenase-1 (HO-1), interleukin-6 (IL-6), Janus kinase 2 (Jak2), and signal transducer and activator of transcription 3 (STAT3) was carried out. The Bax/Bcl2 mRNA expression ratio was determined. A histological study and an immunohistochemical study of phosphorylated STAT3 were also done. Hemin reduced liver enzymes, MDA, TNF-α, NOx, caspase 3, IL-1β, p-STAT3 expression, p-Jak2 expression, IL-6 expression, and Bax/Bcl2 mRNA expression ratio. In contrast, hemin increased GSH, TAC, and the expression of HO-1, improving the histopathological picture of liver tissue. Thus, hemin could ameliorate APAP-induced hepatic toxicity in rat offspring through anti-oxidant, anti-apoptotic, and anti-inflammatory actions with a possible role for the IL-6/HO-1/Jak2/STAT3 pathway.

The use, perceptions and knowledge of safety of over-the-counter medications during pregnancy in a Canadian population

BACKGROUND

The prevalence of prenatal over-the-counter medication use in Canadian women is unknown.

METHODS

A cross-sectional study of prenatal over-the-counter medication use and safety knowledge was conducted among pregnant and post-partum women attending an academic hospital obstetrics clinic.

RESULTS

Seventy-two women participated; 90.3% were Caucasian, 69.4% had a college/university degree, and 61.1% lived in an urban area. Of the 72 women, 87.5% used over-the-counter medications prenatally, first (55.6%), second (65.3%), and third (47.2%) trimesters, with prenatal acetaminophen use most common (72.2%). Women who used over-the-counter medications 1-0onths before conception were more likely to use over-the-counter medications during pregnancy, and 18% of women initiated over-the-counter medications in pregnancy. Women self-reported a medium level of over-the-counter medication safety knowledge (73.6%) and responded that not all over-the-counter medications are safe during pregnancy (95.8%).

CONCLUSION

Despite limited safety profiles of some over-the-counter medications, pre-conception and prenatal over-the-counter medication use was high. Further research on the risk of over-the-counter medications and combinations in pregnancy is needed to help women to make safe choices during pregnancy.

Paracetamol preceding very preterm birth: Is it safe?

INTRODUCTION

The use of paracetamol for pain relief in pregnancy is common. However, the influence of paracetamol on the perinatal adaptation of high-risk infants has not been studied. These data are important for safety, since another inhibitor of prostaglandin synthesis is harmful to infants born very preterm and increases serious morbidity. We studied whether the use of paracetamol had an adverse influence on neonatal adaptation and the outcomes of infants during the first hospitalization.

MATERIAL AND METHODS

We studied the patient records of high-risk mothers and their infants born before 32 weeks of gestation for multiple variables over a period of 84 months in Oulu University Hospital, a regional tertiary care hospital caring for high-risk deliveries and providing neonatal intensive care. In a matched cohort setting, the exposition was defined as paracetamol use <24 h before childbirth. The controls had consumed no paracetamol up to 1 week before delivery. Infants with major anomalies were excluded. The primary outcome was defined as the need for early interventional treatments for the preterm infants. Outcomes during the first hospitalization were also studied.

RESULTS

Altogether, 170 fetuses from 149 mothers were exposed to paracetamol during the study period. The control population, delivering during the same period, consisted of 118 non-exposed fetuses from 104 mothers. Among them, the mothers were pairwise matched according to their medications, amniotic fluid leakage time, clinical infections, and delivery mode. After matching, 72 mothers/group remained, resulting in 88 paracetamol-exposed infants and 85 controls. No perinatal adverse reactions were detected. There were no differences in either circulatory support during the first postnatal day or in the risk for major diseases during the first hospitalization. Paracetamol-exposed infants needed fewer acute delivery room therapies (51.1% vs 65.9%, mean difference -14.89; 95% confidence interval -0.29 to -0.003). Maternal total paracetamol dose in the 1 week before delivery correlated positively with Apgar scores.

CONCLUSIONS

Antenatal paracetamol given within 24 h before birth had no adverse effects on extremely or very preterm infants. The long-term safety of paracetamol and the potential acute benefits for preterm infants during perinatal transition remain to be proven in larger, prospective settings.

Racing against time: leveraging preclinical models to understand pulmonary susceptibility to perinatal acetaminophen exposures

Over the past decade, clinicians have increasingly prescribed acetaminophen (APAP) for patients in the neonatal intensive care unit (NICU). Acetaminophen has been shown to reduce postoperative opiate burden, and may provide similar efficacy for closure of the patent ductus arteriosus (PDA) as nonsteroidal anti-inflammatory drugs (NSAIDs). Despite these potential benefits, APAP exposures have spread to increasingly less mature infants, a highly vulnerable population for whom robust pharmacokinetic and pharmacodynamic data for APAP are lacking. Concerningly, preclinical studies suggest that perinatal APAP exposures may result in unanticipated adverse effects that are unique to the developing lung. In this review, we discuss the clinical observations linking APAP exposures to adverse respiratory outcomes and the preclinical data demonstrating a developmental susceptibility to APAP-induced lung injury. We show how clinical observations linking perinatal APAP exposures to pulmonary injury have been taken to the bench to produce important insights into the potential mechanisms underlying these findings. We argue that the available data support a more cautious approach to APAP use in the NICU until large randomized controlled trials provide appropriate safety and efficacy data.

S3 guideline Allergy Prevention

BACKGROUND

The persistently high prevalence of allergic diseases in Western industrial nations and the limited possibilities of causal therapy make evidence-based recommendations for primary prevention necessary.

METHODS

The recommendations of the S3 guideline Allergy Prevention, published in its last version in 2014, were revised and consulted on the basis of a current systematic literature search. The evidence search was conducted for the period 06/2013 - 11/2020 in the electronic databases Cochrane and MEDLINE, as well as in the reference lists of current reviews and through references from experts. The literature found was screened in two filtering processes, first by title and abstract, and the remaining papers were screened in the full text for relevance. The studies included after this were sorted by level of evidence, and the study quality was indicated in terms of potential bias (low/high). The revised recommendations were formally agreed and consented upon with the participation of representatives of the relevant professional societies and (self-help) organizations (nominal group process). Of 5,681 hits, 286 studies were included and assessed.

RESULTS

Recommendations on maternal nutrition during pregnancy and breastfeeding as well as on infant nutrition in the first months of life again play an important role in the updated guideline: Many of the previous recommendations were confirmed by the current data. It was specified that breastfeeding should be exclusive for the first 4 - 6 months after birth, if possible, and that breastfeeding should continue with the introduction of complementary foods. A new recommendation is that supplementary feeding of cow's milk-based formula should be avoided in the first days of life if the mother wishes to breastfeed. Furthermore, it was determined that the evidence for a clear recommendation for hydrolyzed infant formula in non-breastfed infants at risk is currently no longer sufficient. It is therefore currently recommended to check whether an infant formula with proven efficacy in allergy prevention studies is available until the introduction of complementary feeding. Finally, based on the EAACI guideline, recommendations were made for the prevention of chicken egg allergy by introducing and regularly giving thoroughly heated (e.g., baked or hard-boiled) but not "raw" chicken egg (also no scrambled egg) with the complementary food. The recommendation to introduce peanut in complementary feeding was formulated cautiously for the German-speaking countries: In families who usually consume peanut, the regular administration of peanut-containing foods in age-appropriate form (e.g., peanut butter) with the complementary diet can be considered for the primary prevention of peanut allergy in infants with atopic dermatitis (AD). Before introduction, a clinically relevant peanut allergy must be ruled out, especially in infants with moderate to severe AD. There is still insufficient evidence for an allergy-preventive efficacy of prebiotics or probiotics, vitamin D, or other vitamins in the form of supplements so that recommendations against their supplementation were adopted for the first time in the current guideline. Biodiversity plays an important role in the development of immunological tolerance to environmental and food allergens: there is clear evidence that growing up on a farm is associated with a lower risk of developing asthma and allergic diseases. This is associated with early non-specific immune stimulation due to, among other things, the greater microbial biodiversity of house dust in this habitat. This aspect is also reflected in the recommendations on animal husbandry, on which a differentiated statement was made: In families without a recognizable increased allergy risk, pet keeping with cats or dogs should not generally be restricted. Families with an increased allergy risk or with children with already existing AD should not acquire a new cat - in contrast, however, dog ownership should not be discouraged. Interventions to reduce exposure to dust mite allergens in the home, such as the use of mite allergen-proof mattress covers ("encasings"), should be restricted to patients with already proven specific sensitization against house dust mite allergen. Children born by caesarean section have a slightly increased risk of asthma - this should be taken into account when advising on mode of delivery outside of emergency situations. Recent work also supports the recommendations on air pollutants: Active and passive exposure to tobacco smoke increase the risk of allergies, especially asthma, and should therefore be avoided. Exposure to nitrogen oxides, ozone, and small particles (PM 2.5) is associated with an increased risk, especially for asthma. Therefore, exposure to emissions of nitrogen oxides, ozone, and small particles (PM 2.5) should be kept low. The authors of this guideline are unanimously in favor of enacting appropriate regulations to minimize these air pollutants. There is no evidence that vaccinations increase the risk of allergies, but conversely there is evidence that vaccinations can reduce the risk of allergies. All children, including children at risk, should be vaccinated according to the current recommendations of the national public health institutes, also for reasons of allergy prevention.

CONCLUSION

The consensus of recommendations in this guideline is based on an extensive evidence base. The update of the guideline enables evidence-based and up-to-date recommendations for the prevention of allergic diseases including asthma and atopic dermatitis.

Long-Term Safety of Prenatal and Neonatal Exposure to Paracetamol: A Systematic Review

Introduction: Paracetamol is the most commonly used antipyretic and analgesic in pregnancy. It is also increasingly used off-label in the neonatal intensive care unit. Despite the frequent use of paracetamol, concerns have been raised regarding the high variability in neonatal dosing regimens and the long-term safety of early life exposure. Objective: To investigate the available evidence on the long-term safety of prenatal and neonatal paracetamol exposure. Methods: We conducted a systematic search of the electronic databases Ovid Medline, Ovid Embase and Web of Science from inception to August 2021 for original research studies of any design that described the use of paracetamol in the prenatal or neonatal (within the first four weeks of life) periods and examined the occurrence of neurodevelopmental, atopic or reproductive adverse outcomes at or beyond birth. Results: We identified 1313 unique articles and included 30 studies in the final review. Of all studies, 27 (90%), two (7%) and one (3%) were on the long-term safety of prenatal, neonatal and both prenatal and neonatal exposure, respectively. Thirteen (46%), 11 (39%) and four (15%) studies examined neurodevelopmental, atopic and reproductive outcomes. Eleven (100%), 11 (100%), and three (27%) studies on prenatal exposure reported adverse neurodevelopmental, atopic and reproductive outcomes. Only one study found a possible correlation between neonatal paracetamol exposure and long-term adverse outcomes. Conclusions: The available evidence, although limited, suggests a possible association between prenatal paracetamol exposure and an increased risk of neurodevelopmental, atopic and reproductive adverse outcomes. There is an immediate need for robust data on the long-term safety of paracetamol exposure in the prenatal and neonatal periods.

Environmental exposure during pregnancy and the risk of childhood allergic diseases

BACKGROUND

Allergic diseases are one of the most common and important diseases that can exert hazardous effects on children's health. The prevalence of allergic diseases in childhood is gradually increasing all over the world in recent decades. Known causes of these diseases include anomalous immune responses and allergic inflammatory reactions, but the causes of allergic diseases in childhood are complex.

DATA SOURCES

PubMed, Cochrane Library, Embase and Web of Science were searched for articles focusing on environmental exposure during pregnancy and the risk of childhood allergic diseases, including asthma and atopic dermatitis, and the possible underlying mechanism.

RESULTS

In terms of environmental factors, allergic diseases in childhood are closely related to environmental chemical exposure during pregnancy, including bisphenols, phthalates acid esters, perfluorochemicals, polybrominated diphenyl ethers, and polychlorinated biphenyls. However, allergic diseases in childhood are also closely associated with maternal dietary nutrition, maternal intake of drugs, such as acetylsalicylic acid (aspirin), paracetamol and antibiotics, and maternal lifestyle.

CONCLUSIONS

Several harmful environmental factors during pregnancy can result in the interruption of the function of helper T cells (Th1/Th2), cytokines and immunoglobulins and may activate allergic reactions, which can lead to allergic diseases during childhood.

Paracetamol exposure and asthma: What does the evidence say? An overview of systematic reviews

OBJECTIVE

To conduct an umbrella review collating the existing evidence to determine whether there is an association between exposure of Paracetamol in-utero or in infancy and the development of childhood Asthma.

METHODS

In this review, systematic reviews with or without meta-analysis that reported the association between paracetamol and asthma in children were included. To identify relevant reviews, a search was performed in the electronic databases PubMed, the Cochrane Library, and Ovid MEDLINE. The protocol was registered in PROSPERO CRD42020156023. A separate search was conducted for primary studies from the last 5 years not yet included in systematic reviews reporting the association from January 2016 to March 2021.

RESULTS

The electronic searches identified 1966 review titles. After the removal of 493 duplicates, 1475 titles and abstracts were screened against the eligibility criteria. Full-text screening yielded six systematic reviews to be included in this review. The search for primary studies in the last 5 years yielded 1214 hits, out of which 5 studies were found suitable for inclusion. Three of them, that were not included in the systematic reviews, and have been summarised in this paper. The odds ratios (ORs) for the outcome of asthma in offspring of mothers with prenatal paracetamol consumption in any trimester were 1.28 (1.13-1.39) and 1.21 (1.02-1.44). For first trimester exposures, they were 1.12 (0.99-1.27), 1.39 (1.01-1.91), and 1.21 (1.14-1.28), for the second or third trimester, they were 1.49 (1.37-1.63) and 1.13 (1.04-1.23). For the third trimester only, the figure was 1.17 (1.04-1.31). Of the six reviews included, 1 had a low risk of bias, 2 had an unclear risk while 3 had a high risk of bias assessed using the ROBIS tool. There was no significant increased risk of asthma with early infancy exposure. The inter-study heterogeneity varied from I²  = 41% to I²  = 76% across reviews. In the primary studies, the OR for prenatal exposure ranged from 1.12 (0.25-4.98) to 4.66 (1.92-11.3) and for infancy exposure was 1.56 (1.06-2.30). All three included primary studies were adjudged to be of high quality using the Newcastle Ottawa scale.

CONCLUSIONS

There is a modest association between paracetamol exposure in-utero and the future development of asthma. Exposure in infancy has a less consistant association. All the studies done thus far are observational in nature, with their inherent biases. Further research, preferably randomized controlled trials are recommended to answer this pertinent question.

Prenatal Exposure to Acetaminophen and Childhood Asthmatic Symptoms in a Population-Based Cohort in Los Angeles, California

Acetaminophen is the most common over-the-counter pain and fever medication used by pregnant women. While European studies suggest acetaminophen exposure in pregnancy could affect childhood asthma development, findings are less consistent in other populations. We evaluated whether maternal prenatal acetaminophen use is associated with childhood asthmatic symptoms (asthma diagnosis, wheeze, dry cough) in a Los Angeles cohort of 1201 singleton births. We estimated risk ratio (RR) and 95% confidence interval (CI) for childhood asthmatic outcomes according to prenatal acetaminophen exposure. Effect modification by maternal race/ethnicity and psychosocial stress during pregnancy was evaluated. The risks for asthma diagnosis (RR = 1.39, 95% CI 0.96, 2.00), wheezing (RR = 1.25, 95% CI 1.01, 1.54) and dry cough (RR =1.35, 95% CI 1.06, 1.73) were higher in children born to mothers who ever used acetaminophen during pregnancy compared with non-users. Black/African American and Asian/Pacific Islander children showed a greater than two-fold risk for asthma diagnosis and wheezing associated with the exposure. High maternal psychosocial stress also modified the exposure-outcome relationships. Acetaminophen exposure during pregnancy was associated with childhood asthmatic symptoms among vulnerable subgroups in this cohort. A larger study that assessed prenatal acetaminophen exposure with other social/environmental stressors and clinically confirmed outcomes is needed.

Reflection on modern methods: building causal evidence within high-dimensional molecular epidemiological studies of moderate size

This commentary provides a practical perspective on epidemiological analysis within a single high-dimensional study of moderate size to consider a causal question. In this setting, non-causal confounding is important. This occurs when a factor is a determinant of outcome and the underlying association between exposure and the factor is non-causal. That is, the association arises due to chance, confounding or other bias rather than reflecting that exposure and the factor are causally related. In particular, the influence of technical processing factors must be accounted for by pre-processing measures to remove artefact or to control for these factors such as batch run. Work steps include the evaluation of alternative non-causal explanations for observed exposure-disease associations and strategies to obtain the highest level of causal inference possible within the study. A systematic approach is required to work through a question set and obtain insights on not only the exposure-disease association but also the multifactorial causal structure of the underlying data where possible. The appropriate inclusion of molecular findings will enhance the quest to better understand multifactorial disease causation in modern observational epidemiological studies.

Behavioral Problems at Age 11 Years After Prenatal and Postnatal Exposure to Acetaminophen: Parent-Reported and Self-Reported Outcomes

Several studies have reported associations between prenatal acetaminophen exposure and behavioral outcomes in young children. We aimed to evaluate the associations of prenatal and postnatal exposures to acetaminophen with behavioral problems in children at age 11 years, using behavioral measures reported by parents and children. We studied 40,934 mother-child pairs from the Danish National Birth Cohort enrolled during 1996-2002. Parent-reported and child-reported Strengths and Difficulties Questionnaire (SDQ) responses were collected during the 11-year follow-up. We estimated risk ratios for behavioral problems including total difficulties as well as internalizing or externalizing behaviors following prenatal (during pregnancy) or postnatal (within the first 18 months after birth) acetaminophen exposure. Parent-reported and child-reported SDQ scores were moderately correlated; higher for externalizing (r = 0.59) than internalizing (r = 0.49) behaviors. Prenatal acetaminophen exposure was associated with 10%-40% higher risks for total difficulties and internalizing and externalizing problems based on parent- or child-reported SDQ, with the association being stronger for greater cumulative weeks of acetaminophen use. Postnatal exposure was associated with 16%-19% higher risks for parent-reported internalizing behaviors, but the associations were weak or null for child-reported scores except for prosocial behavior. Our study corroborates published associations between prenatal exposures to acetaminophen and behavioral problems and extends the literature to early adolescence.

A systematic review of asthma case definitions in 67 birth cohort studies

BACKGROUND

Birth cohort studies are a valuable source of information about potential risk factors for childhood asthma. To better understand similarities and variations in findings between birth cohort studies, the methodologies used to measure asthma require consideration.

OBJECTIVE

To review and appraise the definitions of "asthma" used in birth cohort studies.

METHODS

A literature search, conducted in December 2017 in the MEDLINE database and birth cohort repositories, identified 1721 citations published since 1990. Information extracted included: study name, year of publication, sample size, sample age, prevalence of asthma (%), study region, source of information about asthma, measured outcome, and asthma case definition. A meta-analysis evaluated whether asthma prevalence in cohorts from Europe and North America varied by the studies' definition of asthma and by their data sources.

RESULTS

The final review included 67 birth cohorts, of which 48 (72%) were from Europe, 14 (21%) from North America, 3 (5%) from Oceania, 1 (1%) from Asia and 1 (1%) from South America. We identified three measured outcomes: "asthma ever", "current asthma", and "asthma" without further specification. Definitions of "asthma ever" were primarily based upon an affirmative parental response to the question whether the child had ever been diagnosed with asthma by a physician. The most frequently used definition of "current asthma" was "asthma ever" and either asthma symptoms or asthma medications in the last 12 months. This definition of "current asthma" was used in 16 cohorts. There was no statistically significant difference in the pooled asthma prevalence in European and North American cohorts that used questionnaire alone versus other data sources to classify asthma.

CONCLUSION

There is substantial heterogeneity in childhood asthma definitions in birth cohort studies. Standardisation of asthma case definitions will improve the comparability and utility of future cohort studies and enable meta-analyses.

Acetaminophen Attenuates invasion and alters the expression of extracellular matrix enzymes and vascular factors in human first trimester trophoblast cells

Acetaminophen is one of the most common medications taken during pregnancy, considered safe for maternal health and fetal development. However, recent epidemiological studies have associated prenatal acetaminophen use with several developmental disorders in offspring. As acetaminophen can freely cross into and through the placenta, epidemiological associations with prenatal acetaminophen use may reflect direct actions on the fetus and/or the impact of altered placental functions. In the absence of rigorous mechanistic studies, our understanding of how prenatal acetaminophen exposure can cause long-term effects in offspring is limited. The objective of this study was to determine whether acetaminophen can alter key functions of a major placental cell type by utilizing immortalized human first trimester trophoblast cells. This study employed a comparative analysis with the nonsteroidal, anti-inflammatory drug aspirin, which has established effects in first trimester trophoblast cells. We report that immortalized trophoblast cells express the target proteins of acetaminophen and aspirin: cyclooxygenase (COX) -1 and -2. Unlike aspirin, acetaminophen significantly repressed the expression of angiogenesis and vascular remodeling genes in HTR-8/SVneo cells. Moreover, acetaminophen impaired trophoblast invasion by over 80%, while aspirin had no effect on invasion. Acetaminophen exposure reduced the expression of matrix metalloproteinase (MMP)-2 and -9 and increased the expression of tissue inhibitors of matrix metalloproteinases 2, leading to an imbalance in the ratio of proteolytic enzymes. Finally, a bioinformatic approach identified novel acetaminophen-responsive gene networks associated with key trophoblast functions and disease. Together these results suggest that prenatal acetaminophen use may interfere with critical trophoblast functions early in gestation, which may subsequently impact fetal development.

Intrauterine Exposure to Acetaminophen and Adverse Developmental Outcomes: Epidemiological Findings and Methodological Issues

PURPOSE OF REVIEW

Acetaminophen (or paracetamol) is one of the most commonly used medications during pregnancy. We reviewed recent epidemiological evidence regarding intrauterine exposure to acetaminophen and risk for asthma, neurodevelopment disorders, and reproductive health in childhood.

RECENT FINDINGS

An increasing number of cohort studies have suggested that maternal use of acetaminophen during pregnancy was associated with increased risk for asthma; neurodevelopmental disorders, especially ADHD and behavioral problems; and genital malformations in the offspring. Oxidative stress and inflammation or endocrine effects are plausible shared biological mechanisms for the exposure to influence multiple developmental outcomes. We discussed methodological challenges that can threaten the validity of these observational data, including confounding and measurement errors. Novel statistical methods and research designs that can be used to mitigate these issues were introduced. Given the high prevalence of use, findings regarding intrauterine exposure to acetaminophen on multiple child health outcomes raise concerns. Research on causal and non-causal mechanisms that might explain these associations should be a priority.

Randomised controlled trial of paracetamol or ibuprofen, as required for fever and pain in the first year of life, for prevention of asthma at age 6 years: paracetamol or ibuprofen in the primary prevention of asthma in Tamariki (PIPPA Tamariki) protocol

INTRODUCTION

Asthma is one of the most common diseases in the world and is a global public health burden. There is an urgent need for research that leads to evidenced-based primary prevention strategies to reduce the prevalence of asthma. One novel risk factor that might have a role in the pathogenesis of asthma is the use of paracetamol in early life. This trial aims to determine if paracetamol, compared with ibuprofen use, as required for fever and pain in the first year of life, increases the risk of asthma at age 6 years.

METHODS AND ANALYSIS

The Paracetamol and Ibuprofen in Primary Prevention of Asthma in Tamariki trial is a multicentre, open-label, two-arm parallel randomised controlled trial. 3922 infants born at ≥32 weeks' gestation will be randomly allocated to receive only paracetamol or only ibuprofen for treatment of fever and pain, if required in the first year of life. The primary outcome is asthma at 6 years of age, defined as the presence of wheeze in the preceding 12 months. Secondary outcomes include hospital admissions for bronchiolitis, wheeze or asthma in the first year of life, and within the first 6 years of life; wheeze at 3 years of age; eczema within the first year and at 3 and 6 years of age; atopy at 3 and 6 years of age.

ETHICS AND DISSEMINATION

The trial has been approved by the Northern A Health and Disability Ethics Committee of New Zealand (17/NTA/233). Dissemination plans include publication in international peer-reviewed journals, and presentation at national and international scientific meetings, assimilation into national and international guidelines, and presentation of findings to lay audiences through established media links.

TRIAL REGISTRATION NUMBER

ACTRN12618000303246; Pre-results.

Over-the-counter analgesics during pregnancy: a comprehensive review of global prevalence and offspring safety

BACKGROUND

Analgesia during pregnancy is often necessary. Due to their widespread availability, many mothers opt to use over-the-counter (OTC) analgesics. Those analgesic compounds and their metabolites can readily cross the placenta and reach the developing foetus. Evidence for safety or associations with adverse health outcomes is conflicting, limiting definitive decision-making for healthcare professionals.

OBJECTIVE AND RATIONALE

This review provides a detailed and objective overview of research in this field. We consider the global prevalence of OTC analgesia during pregnancy, explain the current mechanistic understanding of how analgesic compounds cross the placenta and reach the foetus, and review current research on exposure associations with offspring health outcomes.

SEARCH METHODS

A comprehensive English language literature search was conducted using PubMed and Scopus databases. Different combinations of key search terms were used including 'over-the-counter/non-prescription analgesics', 'pregnancy', 'self-medication', 'paracetamol', 'acetaminophen', 'diclofenac', 'aspirin', 'ibuprofen', 'in utero exposure', 'placenta drug transport', 'placental transporters', 'placenta drug metabolism' and 'offspring outcomes'.

OUTCOMES

This article examines the evidence of foetal exposure to OTC analgesia, starting from different routes of exposure to evidence, or the lack thereof, linking maternal consumption to offspring ill health. There is a very high prevalence of maternal consumption of OTC analgesics globally, which is increasing sharply. The choice of analgesia selected by pregnant women differs across populations. Location was also observed to have an effect on prevalence of use, with more developed countries reporting the highest consumption rates. Some of the literature focuses on the association of in utero exposure at different pregnancy trimesters and the development of neurodevelopmental, cardiovascular, respiratory and reproductive defects. This is in contrast to other studies which report no associations.

WIDER IMPLICATIONS

The high prevalence and the challenges of reporting exact consumption rates make OTC analgesia during pregnancy a pressing reproductive health issue globally. Even though some healthcare policy-making authorities have declared the consumption of some OTC analgesics for most stages of pregnancy to be safe, such decisions are often based on partial review of literature. Our comprehensive review of current evidence highlights that important knowledge gaps still exist. Those areas require further research in order to provide pregnant mothers with clear guidance with regard to OTC analgesic use during pregnancy.

Prevention of Asthma: Targets for Intervention

Approximately 300 million people worldwide are estimated to be affected by asthma, and the number of patients affected is growing exponentially-with potential for an additional 100 million people affected by the condition by 2025. With this increasing burden of disease, there is high motivation to discover effective prevention strategies. Strategies aimed at stalling the atopic progression, modifying the microbiome, preventing respiratory viral infections, and reducing the impact of toxin/pollutant exposure through dietary supplements have had limited success in the prevention of asthma. This is likely because asthma is heterogenous and is influenced by different genetic and environmental factors. Genes underlie a predisposition to asthma and allergic sensitization, whereas exposure to allergens, respiratory infections, and pollution may modify asthma pathogenesis and the variation in severity seen among individuals. Future advances in asthma prevention may include a more personalized approach: genetic variations among susceptible individuals with distinct asthma phenotypes or different biomarkers of disease may help individualize prevention strategies and render them more . In this article, we summarize interventions that have been studied for the prevention of asthma and identify some of the clinical trials that are actively underway in asthma prevention.

Paternal antidepressant use as a negative control for maternal use: assessing familial confounding on gestational length and anxiety traits in offspring

Background

Maternal antidepressant use in pregnancy has been associated with both shorter gestational length and child anxiety. We employed paternal antidepressant use as a negative-control exposure to indirectly assess whether confounding by genetic or shared familial environmental factors associated with depression may explain these associations.

Methods

The study sample came from the population-based Norwegian Mother and Child Cohort Study (MoBa) that recruited participants from 1999 to 2008. We included 70 959 families where the father completed a questionnaire about medication use in the 6 months prior to pregnancy. In 42 511 infants who completed the 3-year follow-up, we computed Z-scores for the anxiety domain of the Child Behavior Checklist. We used linear and logistic regression to assess the association between paternal antidepressant use, gestational age at birth and child anxiety.

Results

Antidepressants were used by 1.1% (n = 755) of fathers. Paternal antidepressant use was not associated with gestational age at birth [β = 0.63 days, 95% confidence interval (CI) –1.56, 0.31] whereas it was positively associated with a child anxiety symptom Z-score and high anxiety symptoms (odds ratio 1.33, 95% CI 0.90, 1.97) in unadjusted analyses. This association was attenuated when controlling for maternal and paternal history of depression and other measured factors (odds ratio 1.14, 95% CI 0.76, 1.69).

Conclusions

These results support the suggested effect of maternal use of antidepressants in pregnancy on shorter gestation; however, they suggest familial confounding could explain the association between maternal use of antidepressants and anxiety traits in the offspring.

Early life acetaminophen exposure, glutathione S-transferase genes, and development of adolescent asthma in a high-risk birth cohort

BACKGROUND

Although the impact of early life acetaminophen on asthma risk is still not clear, potential interactions with glutathione S-transferase (GST) genes due to reduced antioxidant function in particular polymorphisms, and possible impact on lung function, have never been investigated in adolescents.

OBJECTIVE

We aimed to investigate associations between early life acetaminophen use and adolescent asthma and lung function and to assess potential interactions by GST polymorphisms.

METHODS

Acetaminophen use was recorded 18 times up to age 2 years (n = 575 [92.7%]). Participants were genotyped for GST polymorphisms (GSTM1/T1/P1) (n = 429 [69.2%]). Asthma and lung function were measured at 12 (n = 365 [58.9%]) and 18 years (n = 413 [66.6%]). Regression models assessed associations and interactions.

RESULTS

Doubling of days of acetaminophen use was associated with reduced prebronchodilator FEV₁/forced vital capacity (β coefficient, -0.10; 95% CI, -0.19 to -0.01) and midexpiratory flow (-0.09; 95% CI, -0.18 to 0) at 18 years, but this association was not found when restricted for nonrespiratory reasons, suggesting confounding by indication. However, in children with GSTM1 null and GSTT1 present, increasing acetaminophen use for nonrespiratory reasons was associated with reduced FEV₁ and midexpiratory flow at 18 years (interaction between GSTM1/T1 and acetaminophen P < .05). Increased acetaminophen use was associated with asthma at 18 years for children with GSTP1 Ile/Ile (odds ratio, 1.66; 95% CI, 1.07 to 2.57), but not other GSTP1 genotypes.

CONCLUSIONS

These novel findings need to be investigated for consistency in other studies but suggest that children carrying risk genotypes may be susceptible to respiratory consequences from acetaminophen use.

Medication Use among Pregnant Women from the 2015 Pelotas (Brazil) Birth Cohort Study

Background: Medication use during pregnancy is a common practice that has been increasing in recent years. The aim of this study is to describe medication use among pregnant women from the 2015 Pelotas (Brazil) Birth Cohort Study. Methods: This paper relies on a population-based cohort study including 4270 women. Participants completed a questionnaire about the antenatal period, including information about medication use. We performed descriptive analyses of the sample and the medications used and adjusted analyses for the use of medications and self-medication. Results: The prevalence of medication use was 92.5% (95% CI 91.7-93.3), excluding iron salts, folic acid, vitamins, and other minerals. The prevalence of self-medication was 27.7% (95% CI 26.3-29.1). In the adjusted analysis, women who had three or more health problems during pregnancy demonstrated higher use of medicines. Self-medication was higher in lower income groups and among smokers and multiparous women (three pregnancies or more). Acetaminophen, scopolamine, and dimenhydrinate were the medications most commonly used. Conclusions: This study describes the pattern of drug use among pregnant women in a population-based cohort study, with a high prevalence of self-medication. Greater awareness of the risks of self-medication during pregnancy is required, focusing on groups more prone to this practice, as well as ensuring qualified multidisciplinary prenatal care.

Recurrent wheezing during the first 3 years of life in a birth cohort of moderate-to-late preterm infants

BACKGROUND

Data addressing short- and long-term respiratory morbidity in moderate-late preterm infants are limited. We aim to determine the incidence of recurrent wheezing and associated risk and protective factors in these infants during the first 3 years of life.

METHODS

Prospective, multicenter birth cohort study of infants born at 32⁺⁰ to 35⁺⁰  weeks' gestation and followed for 3 years to assess the incidence of physician-diagnosed recurrent wheezing. Allergen sensitization and pulmonary function were also studied. We used multivariate mixed-effects models to identify risk factors associated with recurrent wheezing.

RESULTS

A total of 977 preterm infants were enrolled. Rates of recurrent wheezing during year (Y)1 and Y2 were similar (19%) but decreased to 13.3% in Y3. Related hospitalizations significantly declined from 6.3% in Y1 to 0.75% in Y3. Independent risk factors for recurrent wheezing during Y2 and Y3 included the following: day care attendance, acetaminophen use during pregnancy, and need for mechanical ventilation. Atopic dermatitis on Y2 and male sex on Y3 were also independently associated with recurrent wheezing. Palivizumab prophylaxis for RSV during the first year of life decreased the risk or recurrent wheezing on Y3. While there were no differences in rates of allergen sensitization, pulmonary function tests (FEV_0.5 ) were significantly lower in children who developed recurrent wheezing.

CONCLUSIONS

In moderate-to-late premature infants, respiratory symptoms were associated with lung morbidity persisted during the first 3 years of life and were associated with abnormal pulmonary function tests. Only anti-RSV prophylaxis exerted a protective effect in the development of recurrent wheezing.

Overdoses of Acetaminophen Disrupt the Thyroid-Liver Axis in Neonatal Rats

OBJECTIVE

The aim of the study was to examine the impact of neonatal acetaminophen (APAP; paracetamol) administrations on the thyroid-liver axis in male Wistar rats.

METHODS

APAP (100 or 350mg/kg) was orally administered to neonates from Postnatal Day (PND) 20 to 40.

RESULTS

Both APAP doses elicited a substantial increase in serum TSH, albumin, AST, ALT, and ALP values, and a profound decrease in serum FT4 and FT3 values at PND 40 relative to those in the control group. Additionally, the hypothyroid state in both APAP-treated groups may increase the histopathological variations in the neonatal liver, such as destructive degeneration, fibrosis, fatty degeneration, fibroblast proliferation, haemorrhage, oedema, and vacuolar degeneration, at PND 40. Moreover, in the APAP groups, a marked depression was recorded in the t-SH and GSH levels and GPx and CAT activities at PND 40 in the neonatal liver compared to those in the control group. However, the levels of hepatic LPO, H2O2, and NO were increased in both APAP-treated groups at PND 40. All previous alterations were dose- dependent.

CONCLUSION

Neonatal APAP caused a hypothyroidism and disturbed hepatic cellular components by increasing prooxidant markers and decreasing antioxidant markers, causing hepatotoxicity. Thus, neonatal administrations of APAP may act as a neonatal thyroid-liver disruptor.

The burden of asthma in an inner-city area: A historical review 10 years after Isaac

Background

According to the International Study of Asthma and Allergies in Childhood (ISAAC) methodology, in 2003, the prevalence of asthma symptoms in children 6-7 years old and adolescents 13-14 years old was 11.6% and 13.7%, respectively. Since then, the number of asthma cases has increased worldwide. The study was conducted in several districts in northern Mexico City to evaluate the prevalence of asthma in these age groups and examine possible risk factors. The data were compared to the 2003 results from the same area.

Methods

This was a comparative cross-sectional study following the official Global Asthma Network (GAN) methodology. The parents or guardians of participants completed a questionnaire that explored demographics, asthma symptoms, diagnoses, and possible risk factors. Central tendency measurements were determined for statistical analysis and chi-squared distribution for possible risk factors.

Results

A total of 2515 children aged 6-7 years and 3375 adolescents aged 13-14 years participated in the study. Compared to the ISAAC results, we found a greater prevalence of wheezing in both children (at some time in life, 19.2% vs. 27.1%; over the last year, 6.8% vs. 10.6%) and adolescents (at some time in life, 16.9% vs. 19.7%), and for children with an asthma diagnosis (4.5% vs. 5.1%). For both groups, the most common risk factor associated with wheezing was the presence of rhinitis symptoms.

Conclusions

Asthma symptoms are highly prevalent in Mexico City, occurring in almost 20% of adolescents. Compared to a decade ago, there was a 7.9% increase in the prevalence of asthma symptoms in children. Almost half of the children and adolescents presenting with symptoms had experienced more than four episodes per year. However, less than 50% of children and adolescents with asthma symptoms had been diagnosed with this disorder, suggesting under-diagnosis.

Analyzing Missing Data in Perinatal Pharmacoepidemiology Research: Methodological Considerations to Limit the Risk of Bias

Pharmacoepidemiological studies on the safety of medication during pregnancy are all susceptible to missing data (ie, data that should have been recorded but for some reason were not). Missing data are ubiquitous, irrespective of the data source used. Bias can arise when incomplete data on confounders, outcome measures, pregnancy duration, or even cohort selection criteria are used to estimate prenatal exposure effects that would be obtained from the fully observed data, if these were available for each mother-child dyad. This commentary describes general missing data mechanisms and methods, and illustrates how missing data were handled in recent medication in pregnancy research, according to the utilized data source. We further present one applied example on missing data analysis within MoBa (the Norwegian Mother, Father and Child Cohort Study), and finally illustrate how the causal diagram framework can be helpful in assessing risk of bias due to missing data in perinatal pharmacoepidemiology research. We recommend that applied researchers limit missing data during data collection, carefully diagnose missingness, apply strategies for missing data mitigation under different assumptions, and finally include evaluations of robustness results under these assumptions. Following this set of recommendations can aid future perinatal pharmacoepidemiology research in avoiding the problems that result from failure to consider this important source of bias.

Safe Expectations: Current State and Future Directions for Medication Safety in Pregnancy Research

Medication use in pregnancy is common, but information about the safety of most medications in pregnant women or their infants is limited. In the absence of data from randomized clinical trials to guide decisions made by regulators, clinicians, and patients, we often have to rely on well-designed observational studies to generate valid evidence about the benefits and risks of medications in pregnancy. Spontaneous reporting, primary case-control and cohort studies, pregnancy exposure registries, and electronic health data have been used extensively for studying medication safety in pregnancy. This article discusses these data sources, their strengths and limitations, and possible strategies and approaches to mitigating limitations when planning studies or interpreting findings from the literature. Strategies discussed include combining data sources across institutional or national borders, developing and using more sophisticated study designs, and taking advantage of existing analytic methods for more complex data structures, such as time-varying exposure or unmeasured confounding. Finally, we make recommendations for study designs that aid in better risk-related communication.

Prenatal oxidative balance and risk of asthma and allergic disease in adolescence

BACKGROUND

Fetal oxidative balance (achieved when protective prenatal factors counteract sources of oxidative stress) might be critical for preventing asthma and allergic disease.

OBJECTIVE

We examined prenatal intakes of hypothesized protective nutrients (including antioxidants) in conjunction with potential sources of oxidative stress in models of adolescent asthma and allergic disease.

METHODS

We used data from 996 mother-child pairs in Project Viva. Exposures of interest were maternal prepregnancy body mass index and prenatal nutrients (energy-adjusted intakes of vitamins D, C, and E; β-carotene; folate; choline; and n-3 and n-6 polyunsaturated fatty acids [PUFAs]), air pollutant exposures (residence-specific third-trimester black carbon or particulate matter with a diameter of less than 2.5 μm [PM2.5]), acetaminophen, and smoking. Outcomes were offspring's current asthma, allergic rhinitis, and allergen sensitization at a median age of 12.9 years. We performed logistic regression. Continuous exposures were log-transformed and modeled as z scores.

RESULTS

We observed protective associations for vitamin D (odds ratio [OR], 0.69 [95% CI, 0.53-0.89] for allergic rhinitis), the sum of the n-3 PUFAs eicosapentaenoic acid and docosahexaenoic acid (OR, 0.81 [95% CI, 0.66-0.99] for current asthma), and the n-3 PUFA α-linolenic acid (OR, 0.78 [95% CI, 0.64-0.95] for allergen sensitization and OR, 0.80 [95% CI 0.65-0.99] for current asthma). Black carbon and PM2.5 were associated with an approximately 30% increased risk for allergen sensitization. No multiplicative interactions were observed for protective nutrient intakes with sources of oxidative stress.

CONCLUSIONS

We identified potential protective prenatal nutrients (vitamin D and n-3 PUFAs), as well as adverse prenatal pro-oxidant exposures that might alter the risk of asthma and allergic disease into adolescence.

Medication Use and Pain Management in Pregnancy: A Critical Review

BACKGROUND

Pain during pregnancy is common, and its management is complex. Certain analgesics may increase the risk for adverse fetal and pregnancy outcomes, while poorly managed pain can result in adverse maternal outcomes such as depression and hypertension. Guidelines to assist clinicians in assessing risks and benefits of exposure to analgesics for the mother and unborn infant are lacking, necessitating evidence-based recommendations for managing pain in pregnancy.

METHODS

A comprehensive literature search was conducted to assess pregnancy safety data for pharmacological and nonpharmacological pain management methods. Relevant clinical trials and observational studies were identified using multiple medical databases, and included studies were evaluated for quality and possible biases.

RESULTS

Paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) are appropriate for mild to moderate pain, but NSAIDs should be avoided in the third trimester due to established risks. Short courses of weaker opioids are generally safe in pregnancy, although neonatal abstinence syndrome must be monitored following third trimester exposure. Limited safety data for pregabalin and gabapentin indicate that these are unlikely to be major teratogens, and tricyclic antidepressants and serotonin-norepinephrine reuptake inhibitors have limited but overall reassuring safety data. Many of the included studies were limited by methodological issues.

CONCLUSIONS

Findings from this review can guide clinicians in their decision to prescribe analgesics for pregnant women. Treatment should be tailored to the lowest therapeutic dose and shortest possible duration, and management should involve a discussion of risks and benefits and monitoring for response. Further research is required to better understand the safety profile of various analgesics in pregnancy.

Transition for Adolescents and Young Adults With Asthma

Asthma is a complex, heterogenous medical condition which is very common in children and adults. The transition process from pediatric to adult health care services can be a challenge for young people with chronic medical conditions. The significant changes in physical and mental health during this time, as well as the many unique developmental and psychosocial challenges that occur during adolescence can complicate and impede transition if not adequately addressed and managed. The transition period can also be a challenging time for health professionals to assess readiness for transition and manage some of the complications which are particularly common during this time, including poor adherence to therapy, smoking, drug use, and emerging mental health conditions. The natural history, presentation, symptoms, and management of asthma is often significantly different when comparing pediatric and adult practice. In addition, management in infants, toddlers, school aged children, and adolescents differs significantly, offering an additional challenge to pediatric physicians managing asthmatic children and young people. Despite these challenges, if the transition process for young people with asthma is planned and performed in a formalized manner, many of these issues can be addressed, allowing the transition to occur smoothly despite changes that may occur in medical and psychosocial domains.

Prescribed analgesics in pregnancy and risk of childhood asthma

Many epidemiological studies have reported a positive association between prenatal exposure to paracetamol and childhood wheezing and asthma. We investigated whether the link between prenatal analgesic exposure and asthma/wheeze is specific to paracetamol, and whether it is causal or confounded.Using linked Swedish health register data we investigated the relation between various prescribed analgesics in pregnancy and the risk of childhood asthma/wheeze in a population of 492 999, and used negative paternal control and sibling comparison approaches to explore unmeasured confounding.After controlling for potential confounders, prescribed opioids, antimigraine drugs and paracetamol were all positively associated with childhood asthma/wheeze risk at all ages (e.g. for asthma/wheeze at age 4 years: adjusted OR 1.39 (95% CI 1.30-1.49), 1.19 (95% CI 1.01-1.40) and 1.47 (95% CI 1.36-1.59) for opioids, antimigraine drugs and paracetamol, respectively). The results of the paternal control analysis did not suggest the presence of unmeasured confounding by genetics or shared environment. However, the sibling control analysis broadly suggested that associations between prenatal exposure to the analgesics and asthma/wheeze were confounded by specific maternal factors (e.g. for asthma/wheeze at age 4 years: adjusted OR 0.91 (95% CI 0.62-1.31), 0.50 (95% CI 0.17-1.45) and 0.80 (95% CI 0.50-1.29) for opioids, antimigraine drugs and paracetamol, respectively).We propose that analgesic use in pregnancy does not cause childhood asthma/wheeze and that the association is confounded by unmeasured factors that are intrinsic to the mother, such as chronic pain or anxiety.

Key paediatric messages from the 2018 European Respiratory Society International Congress

In this article, the Group Chairs and early career members of the European Respiratory Society (ERS) Paediatric Assembly highlight some of the most interesting findings in the field of paediatrics which were presented at the 2018 international ERS Congress.

Follow-up study of the early, randomised paracetamol trial to preterm infants, found no adverse reactions at the two-years corrected age

AIM

We examined the long-term outcomes and safety of early intravenous paracetamol for ductus arteriosus closure at a corrected age of two years.

METHODS

This was a follow-up of the 2013-2014 randomised, double-blind Preterm Infant's Paracetamol Study at Oulu University Hospital, Finland, which recruited 48 very preterm infants within 24 hours of birth. They received intravenous paracetamol or a placebo for four days. In 2015-2017, we followed up 44 infants (92%) at two years of corrected age. This included clinical and neurodevelopmental assessments and a parental medical history questionnaire.

RESULTS

The 44 infants (55% boys) were born at 23⁵ -31⁶ weeks of gestation. No differences in the cardiac parameters, including blood pressures and ultrasound scan results, were found. Neurodevelopmental stages, as quantified by the Griffiths test, were similar. No signs of autism were reported. Asthma medication was more common in the control group, but the difference was not significant. Atopy scores, numbers of infections and the use of public health services were similar between the two groups.

CONCLUSION

No long-term adverse reactions of early intravenous paracetamol were detected two years later. Larger trials are needed on the safety and efficacy of paracetamol prophylaxis for early ductal closure in very preterm infants.

Antibiotics, acetaminophen and infections during prenatal and early life in relation to type 1 diabetes

Background

Infections in early life have been linked to type 1 diabetes (T1D) risk, but no previous study has comprehensively analysed exposure to antibiotics, acetaminophen and infections during pregnancy and early childhood in relation to offspring risk of T1D.

Methods

Participants in the Norwegian Mother and Child Cohort Study (n = 114 215 children, of whom 403 children were diagnosed with T1D) reported infections and medication use through repeated questionnaires from pregnancy until the children were 18 months old. Adjusted hazard ratios (aHR) for offspring T1D were estimated through Cox regression adjusted for child's sex, maternal age and parity, maternal T1D, smoking in pregnancy, education level, pre-pregnancy body mass index (BMI) and birthweight. Antibiotic use was also analysed in a population-based register cohort of 541 036 children of whom 836 developed T1D.

Results

Hospitalization for gastroenteritis during the first 18 months of life was associated with increased risk (aHR 2.27, 95% CI 1.21 - 4.29, P = 0.01) of T1D. Childhood infections not requiring hospitalization, or any kind of maternal infection during pregnancy, did not predict offspring risk of T1D. Antibiotic or acetaminophen use in pregnancy, or child`s use in early childhood, was not associated with risk of T1D.

Conclusions

Our study, which is population-based and the largest of its kind, did not find support for general early life infections, infection frequency or use of antibiotics or acetaminophen to play a major role in childhood T1D. Hospital admission for gastroenteritis was associated with T1D risk, but must be interpreted cautiously due to scarcity of cases.

Long-term adverse effects of paracetamol - a review

Paracetamol (acetaminophen) is the most commonly used drug in the world, with a long record of use in acute and chronic pain. In recent years, the benefits of paracetamol use in chronic conditions has been questioned, notably in the areas of osteoarthritis and lower back pain. Over the same period, concerns over the long-term adverse effects of paracetamol use have increased, initially in the field of hypertension, but more recently in other areas as well. The evidence base for the adverse effects of chronic paracetamol use consists of many cohort and observational studies, with few randomized controlled trials, many of which contradict each other, so these studies must be interpreted with caution. Nevertheless, there are some areas where the evidence for harm is more robust, and if a clinician is starting paracetamol with the expectation of chronic use it might be advisable to discuss these side effects with patients beforehand. In particular, an increased risk of gastrointestinal bleeding and a small (~4 mmHg) increase in systolic blood pressure are adverse effects for which the evidence is particularly strong, and which show a degree of dose dependence. As our estimation of the benefits decreases, an accurate assessment of the harms is ever more important. The present review summarizes the current evidence on the harms associated with chronic paracetamol use, focusing on cardiovascular disease, asthma and renal injury, and the effects of in utero exposure.

Leptin receptor gene polymorphisms and sex modify the association between acetaminophen use and asthma among young adults: results from two observational studies

Background

Epidemiologic studies have demonstrated associations between acetaminophen use and asthma. This investigation sought to determine whether sex modifies the acetaminophen-asthma association and whether leptin (LEP) and leptin receptor (LEPR) gene polymorphisms modulate the sex-specific associations.

Methods

Data from the Isle of Wight birth cohort (IOW; n = 1456, aged 18 years) and Kuwait University Allergy (KUA; n = 1154, aged 18–26 years) studies were analyzed. Acetaminophen use and current asthma were self-reported. Genotype information for eighteen polymorphisms in LEP and LEPR genes were available in the IOW study. Associations between acetaminophen use and asthma were stratified by sex and genotype. Poisson regression models with robust variance estimation were evaluated to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals (CI).

Results

Acetaminophen use was dose-dependently associated with an increased prevalence of current asthma in the IOW and KUA studies. In both studies, sex-stratified analysis showed that acetaminophen use was associated with asthma among males, but not in females (P_interaction <  0.05). Moreover, a sex- and genotype-stratified analysis of the IOW data indicated that acetaminophen was associated with asthma to a similar extent among males and females carrying two common alleles of LEPR polymorphisms. In contrast, among those carrying at least one copy of the minor allele of LEPR polymorphisms, the magnitude of association between acetaminophen use and asthma was pronounced among males (aPR = 6.83, 95% CI: 2.87–16.24), but not among females (aPR = 1.22, 95% CI: 0.61–2.45).

Conclusions

The identified sex-related effect modification of the acetaminophen-asthma association varied across LEPR genotypes, indicating that the sex-specific association was confined to individuals with certain genetic susceptibility. If the acetaminophen-asthma association is causal, then our findings will aid susceptibility-based stratification of at-risk individuals and augment preventive public health efforts.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0892-y) contains supplementary material, which is available to authorized users.

Investigation of possible risk factors in the development of seasonal allergic conjunctivitis

AIM

To analyze the possible risk factors in the development of seasonal allergic conjunctivitis (SAC) through an evaluation of skin allergy tests and data obtained from questionnaires.

METHODS

The study included a total of 75 SAC patients and 71 control subjects without SAC diagnosis who were admitted to the Abant Izzet Baysal University Medical Faculty Ophthalmology Clinic between March 2016 and December 2016. Skin prick tests were performed for all participants. Serum levels of total IgE and 25-OH vitamin D were also measured. In the tear, total IgE levels were measured. Moreover, possible risk factors for the onset of SAC (smoking, paracetamol exposure, vitamin D supplementation and environmental factors etc.) were examined for all patients by both prenatal and postnatal aspects.

RESULTS

The patients with SAC were found to have a history of maternal paracetamol exposure during the prenatal period. Likewise, in the same patient group, the duration of postnatal vitamin D supplementation was shorter (P<0.001). However, no significant correlation was found between SAC and maternal antibiotic exposure, maternal smoking, the mode of delivery and birth weight, as well as presence of pets. Moreover, patients with SAC were more likely to have asthma, allergic rhinitis and oral allergy syndrome. We have also found that SAC patients' mothers and siblings were more likely to have allergic conjunctivitis. Likewise, their fathers were more likely to have allergic rhinitis.

CONCLUSION

Prenatal maternal paracetamol exposure and shorter duration of vitamin D supplementation in the postnatal period may play a role in development of SAC. Therefore prevention of unnecessary gestational paracetamol intake and vitamin D supplementation during infancy could potentially reduce the onset and development of SAC.

Environmental factors and eosinophilic esophagitis

The incidence and prevalence of eosinophilic esophagitis (EoE) have markedly increased over the past 2 decades, outpacing increased detection of the disease. Although genetic susceptibility markers for EoE have begun to be elucidated, the rate at which EoE has increased in incidence suggests environmental factors predominate. Despite many advances in understanding of the pathogenesis of EoE, the cause of EoE is unknown. This article reviews the emerging data related to environmental risk factors for EoE. Many of these environmental factors are rooted in the theoretical framework of the hygiene hypothesis, specifically mediation of disease development through dysbiosis. Other hypotheses are based on associations that have been observed in studies of non-EoE allergic disease. We describe the evidence that early-life exposures, including antibiotic use, acid suppression, and cesarean delivery, can increase the risk of disease. We also describe the evidence that infectious agents, such as Helicobacter pylori, are inversely associated with disease. Current evidence on geographic risk factors, such as population density, climate zone, and seasonality, is reviewed. We also describe behavioral factors that have been evaluated. Limitations of the existing research are discussed, and recommendations for future areas of research, including assessment of gene-environment interaction, are presented.

Role of combined prenatal and postnatal paracetamol exposure on asthma development: the Czech ELSPAC study

BACKGROUND

Prenatal and postnatal paracetamol exposure has been previously associated with asthma development in childhood in Western populations. We explore the association between prenatal and postnatal paracetamol exposure and asthma development in a Central European sample of Czech children, suggesting possible additive effect of the both exposures. Furthermore, since aspirin had been used more widely during study data collection in Central Europe, we also compared asthma development for those exposed to paracetamol and aspirin.

METHODS

We used data from 3329 children born in the 1990s as members of the prospective Czech European Longitudinal Study of Pregnancy and Childhood. Data about prenatal and postnatal paracetamol and aspirin exposure, and potential covariates were obtained from questionnaires completed by mothers. Data about incident asthma were obtained from paediatrician health records.

RESULTS

60.9% of children received paracetamol only postnatally, 1.5% only prenatally and 4.9% of children were exposed both during pregnancy and infancy. Prevalence of asthma in following population was 5% at 11 years. Being exposed to paracetamol both in prenatal and postnatal period was associated with asthma development (unadjusted OR 1.98, 95% CI 1.02 to 3.87). Being exposed only in the postnatal period was also significantly associated with increased risk of asthma. No association between prenatal exposure only and outcome was found. A higher but non-significant risk of asthma was observed for those whose mothers used paracetamol during pregnancy compared with those who used aspirin.

CONCLUSIONS

The main findings of this prospective birth cohort study add to previous observations linking prenatal and early postnatal paracetamol exposure to asthma development. However, the magnitude of effect is relatively modest, and therefore, we recommend paracetamol to remain the analgesic and antipyretic of choice throughout pregnancy and early childhood.

Paracetamol Medication During Pregnancy: Insights on Intake Frequencies, Dosages and Effects on Hematopoietic Stem Cell Populations in Cord Blood From a Longitudinal Prospective Pregnancy Cohort

Background

Paracetamol is the first choice for antipyretic or analgesic treatment throughout pregnancy. Products with Paracetamol are readily available over the counter and therefore easily accessible for self-medication. Epidemiological data on Paracetamol intake pattern during pregnancy and its potential immunological effects are sparse. We aimed to analyze a possible association between Paracetamol medication and numbers of hematopoietic stem cells (HSC) in cord blood.

Methods

The objective was addressed in the PRINCE (PRENATAL DETERMINANTS OF CHILDREN'S HEALTH) study, a population-based prospective pregnancy cohort study initiated in 2011 at the University Medical Center in Hamburg, Germany. 518 healthy pregnant women with singleton pregnancies were recruited during the first trimester. Three examinations were scheduled at the end of the 1st (gestational week 12–14), the 2nd (gestational week 22–24) and the 3rd trimester (gestational week 34–36). For 146 of these women, cord blood flow cytometry data were available. Paracetamol intake was assessed for each trimester of pregnancy.

Findings

Among the 518 enrolled women, 40% took Paracetamol as main analgesic treatment during pregnancy. The intake frequency and dosage of Paracetamol varied between the women and was overall low with a tendency towards higher frequencies and higher dosages in the third trimester. Paracetamol intake, particularly during the third trimester, resulted in decreased relative numbers of HSCs in cord blood, independent of maternal age, first-trimester BMI, parity, gestational age and birth weight (− 0.286 (95% CI − 0.592, 0.021), p = 0.068).

Interpretation

Prenatal Paracetamol intake, especially during the third trimester, may be causally involved in decreasing HSCs in cord blood.

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Paracetamol is the main analgesic agent used during pregnancy.

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Maternal Paracetamol intake was negatively associated with hematopoietic stem cell frequencies in cord blood.

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The third trimester seems to be most susceptible for Paracetamol induced reduction of the immune cell progenitors.

Our study focuses on the impact of Paracetamol intake during pregnancy on the offspring's immune development. We were able to show that maternal Paracetamol intake, particularly in the third trimester of pregnancy, was negatively associated with hematopoietic stem cell frequencies in cord blood. These results provide a potential missing link for an association between prenatal Paracetamol medication and childhood disease, particularly asthma, by adding a possible immunological pathway. While we fully acknowledge the medical need of analgesics in pregnancy to prevent or treat more harmful events, our data are valuable for clinical recommendations on self-medication with the OTC drug Paracetamol.

Prenatal paracetamol use and asthma in childhood: A systematic review and meta-analysis

OBJECTIVES

Some studies have suggested that prenatal paracetamol exposure might associate with the risk of child asthma. However, other studies have not confirmed this result. Therefore, we conducted a meta-analysis to investigate their relationship.

METHODS

Two authors searched Pubmed and Embase databases up to June 2016. The strength of the association was calculated with the OR and respective 95% CIs. The random-effects model was chosen to calculate the pooled OR.

RESULTS

A total of 13 articles of more than 1,043,109 individuals were included in the meta-analysis. A statistically significant association between prenatal paracetamol exposure and child asthma risk was found. The data showed that prenatal paracetamol exposure could increase the risk of child asthma (OR=1.19; 95% CI, 1.12-1.27; P<0.00001) in a random-effect model. Six studies reported paracetamol exposure during the first trimester of pregnancy. We found that paracetamol exposure during the first trimester of pregnancy was associated with increased risk of child asthma (OR=1.21; 95% CI, 1.14-1.28; P<0.00001). Furthermore, we observed that paracetamol exposure during the 2-3 trimesters of pregnancy was also associated with child asthma risk (OR=1.13; 95% CI, 1.04-1.23; P=0.005).

CONCLUSIONS

This study suggested that prenatal paracetamol exposure was significantly associated with the increased risk of child asthma.

Is acetaminophen safe in pregnancy?

Acetaminophen is thought to be the safest analgesic and antipyretic medicine for pregnant women, and it is widely used all over the world. However, prenatal acetaminophen was reported to be associated with asthma, lower performance intelligence quotient (IQ), shorter male infant anogenital distance (predicting poor male reproductive potential), autism spectrum disorder, neurodevelopmental problems (gross motor development, communication), attention-deficit/hyperactivity disorder, poorer attention and executive function, and behavioral problems in childhood. Each article has poor power to show risks of acetaminophen, however, the integration of the articles that showed adverse effects of acetaminophen may have power to show them. Acetaminophen use in childhood was associated with autism spectrum disorder, asthma symptoms, wheezing, and allergic disease. Acetaminophen is the safest medicine as analgesics for nociceptive pain and antipyretics in childhood and pregnancy. There is no alternative medication of acetaminophen. Acetaminophen should not be withheld from children or pregnant women for fears it might develop adverse effects. Acetaminophen should be used at the lowest effective dosage and for the shortest time. When we know the possible, rare but serious complications, we should use acetaminophen in pregnancy only when needed and no safer option for pain or fever relief is available. Health care providers should help inform the general lay public about this difficult dilemma.

Prenatal exposures and the development of childhood wheezing illnesses

PURPOSE OF REVIEW

To critically evaluate and summarize studies published between July 2015 and June 2016 linking prenatal exposures and the onset of childhood wheezing illnesses and to discuss future research directions in this field.

RECENT FINDINGS

The aggregated evidence indicates a consistent detrimental effect of prenatal exposure to parental smoking, outdoor air pollution, and maternal stress on childhood wheezing illnesses. Less consistent evidence suggests an adverse impact of maternal obesity during pregnancy and prenatal exposure to antibiotics on these outcomes. There is insufficient evidence to support an association between in-utero exposure to acetaminophen or prenatal levels of specific nutrients (such as vitamin D, folic acid, or polyunsaturated fatty acids) and childhood wheezing illnesses.

SUMMARY

Several common potentially modifiable prenatal exposures appear to be consistently associated with childhood wheezing illnesses (e.g. parental smoking, outdoor air pollution, and maternal stress). However, the effect of many other prenatal exposures on the onset of childhood wheezing illnesses remains unclear. The existing scientific evidence from the past year does not allow us to make any new recommendations on primary prevention measures. Intervention studies will best demonstrate whether changing the prenatal environment can prevent childhood wheezing illnesses and asthma.