Prenatal paracetamol exposure and risk of asthma and elevated immunoglobulin E in childhood

Monitoring of drug intake during pregnancy by questionnaires and LC-MS/MS drug urine screening: evaluation of both monitoring methods

Various studies pointed towards a relationship between chronic diseases such as asthma and allergy and environmental risk factors, which are one aspect of the so-called Exposome. These environmental risk factors include also the intake of drugs. One critical step in human development is the prenatal period, in which exposures might have critical impact on the child's health outcome. Thereby, the health effects of drugs taken during gestation are discussed controversially with regard to newborns' disease risk. Due to this, the drug intake of pregnant women in the third trimester was monitored by questionnaire, in addition to biomonitoring using a local birth cohort study, allowing correlations of drug exposure with disease risk. Therefore, 622 urine samples were analyzed by an untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) urine screening and the results were compared to self-administered questionnaires. In total, 48% (n = 296) reported an intake of pharmaceuticals, with analgesics as the most frequent reported drug class in addition to dietary supplements. 182 times compounds were detected by urine screening, with analgesics (42%; n = 66) as the predominantly drug class. A comparison of reported and detected drug intake was performed for three different time spans between completion of the questionnaires and urine sampling. Even if the level of accordance was low in general, similar percentages (~25%, ~19%, and ~ 20%) were found for all groups. This study illustrates that a comprehensive evaluation of drug intake is neither achieved by questionnaires nor by biomonitoring alone. Instead, a combination of both monitoring methods, providing complementary information, should be considered.

Epigenomics and allergic disease

Allergic disease development is affected by both genes and the environment, and epigenetic mechanisms are hypothesized to mediate these environmental effects. In this article, we discuss the link between the environment, DNA methylation and allergic disease, as well as questions of causality inherent to analyses of DNA methylation. From the practical side, we describe characteristics of allergic phenotypes and contrast different epidemiologic study designs used in epigenetic research. We examine methodological considerations, how best to conduct preprocessing and analysis of DNA methylation data sets, and the latest methods, technologies and discoveries in this rapidly advancing field. DNA methylation and other epigenetic marks are firmly entwined with allergic disease, a link that may hold the basis for future allergic disease diagnosis and treatment.

Prenatal and infant exposure to acetaminophen and ibuprofen and the risk for wheeze and asthma in children

BACKGROUND

Several studies have reported an association between use of over-the-counter antipyretics during pregnancy or infancy and increased asthma risk. An important potential limitation of these observational studies is confounding by indication.

OBJECTIVES

We investigated the association of antipyretic intake during pregnancy and during the first year of life (infancy) with asthma-related outcomes before and after controlling for early-life respiratory tract infections.

METHODS

We included 1490 mother-child pairs in Project Viva, a longitudinal prebirth cohort study. We categorized prenatal acetaminophen exposure as the maximum intake (never, 1-9 times, or ≥10 times) in early pregnancy or midpregnancy and ibuprofen intake as presence or absence in early pregnancy. We expressed intake of antipyretics in infancy as never, 1 to 5 times, 6 to 10 times, or more than 10 times. We examined the associations of acetaminophen and ibuprofen (per unit increase in exposure category) during pregnancy and infancy with wheeze, asthma, and allergen sensitization in early childhood (3-5 years of age, n = 1419) and midchildhood (7-10 years of age, n = 1220).

RESULTS

Unadjusted models showed an increased asthma risk in early childhood for higher infant acetaminophen (odds ratio [OR], 1.21; 95% CI 1.04-1.41) and ibuprofen (OR, 1.35; 95% CI, 1.19-1.52) intake. Controlling for respiratory tract infections attenuated estimates for acetaminophen (OR, 1.03; 95% CI, 0.88-1.22) and ibuprofen (OR, 1.19; 95% CI, 1.05-1.36). Prenatal acetaminophen was associated with increased asthma (OR, 1.26; 95% CI, 1.02-1.58) in early childhood but not midchildhood.

CONCLUSIONS

Adjustment for respiratory tract infections in early life substantially diminished associations between infant antipyretic use and early childhood asthma. Respiratory tract infections should be accounted for in studies of antipyretics and asthma to mitigate bias caused by confounding by indication.

Prenatal exposure to acid-suppressive drugs and the risk of allergic diseases in the offspring: a cohort study

BACKGROUND

Recent studies reported increased risks for the development of asthma in children after prenatal exposure to acid-suppressive drugs. As a result of common pathogenesis, associations could also be present for other allergic diseases.

METHODS

Using the prescription database IADB.nl, we conducted a cohort study amongst 33 536 children in the Netherlands, with a maximum follow-up of 8 years. Maternal exposure was defined as ≥1 dispensed prescription for proton pump inhibitors (PPIs) and/or Histamine 2-antagonists (H2As) during pregnancy. Children were considered to have a drug-treated allergic disease if they received either ≥2 prescriptions for dermal (atopic dermatitis), inhaled (asthma) or nasal (allergic rhinitis) steroids within a 12-month period. Clustered Cox proportional hazard regression was used to estimate crude and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI).

RESULTS

The aHR for the development of any allergic disease was 1.37 (95% CI: 1.14-1.66) for children exposed to PPIs or H2As. Prenatal exposure to PPIs and/or H2As was associated with atopic dermatitis, asthma and allergic rhinitis with aHRs of 1.32 (95% CI 1.06-1.64), 1.57 (95% CI 1.20-2.05) and 2.40 (95% CI 1.42-4.04), respectively. The aHR for the development of two or more (aHR 2.13 95% CI: 1.43-3.19) and three allergic diseases (aHR 5.18 95% CI: 2.16-12.42) were even more elevated after prenatal exposure to PPIs or H2As.

CONCLUSION

Prenatal exposure to PPIs and H2As appeared associated with an increased risk for the development of atopic dermatitis, asthma and allergic rhinitis in the offspring, especially with the development of multiple allergic diseases. Because our study has limitations inherent to observational studies, prospective studies are now warranted to confirm our findings.

Cyclooxygenase inhibition abrogates aeroallergen-induced immune tolerance by suppressing prostaglandin I2 receptor signaling

BACKGROUND

The prevalence of allergic diseases has doubled in developed countries in the past several decades. Cyclooxygenase (COX)-inhibiting drugs augmented allergic diseases in mice by increasing allergic sensitization and memory immune responses. However, whether COX inhibition can promote allergic airway diseases by inhibiting immune tolerance is not known.

OBJECTIVE

To determine the role of the COX pathway and prostaglandin I2 (PGI2) signaling through the PGI2 receptor (IP) in aeroallergen-induced immune tolerance.

METHODS

Wild-type (WT) BALB/c mice and IP knockout mice were aerosolized with ovalbumin (OVA) to induce immune tolerance prior to immune sensitization with an intraperitoneal injection of OVA/alum. The COX inhibitor indomethacin or vehicle was administered in drinking water to inhibit enzyme activity during the sensitization phase. Two weeks after sensitization, the mice were challenged with OVA aerosols. Mouse bronchoalveolar lavage fluid was harvested for cell counts and TH2 cytokine measurements.

RESULTS

WT mice treated with indomethacin had greater numbers of total cells, eosinophils, and lymphocytes, and increased IL-5 and IL-13 protein expression in BAL fluid compared to vehicle-treated mice. Similarly, IP knockout mice had augmented inflammation and TH2 cytokine responses compared to WT mice. In contrast, the PGI2 analog cicaprost attenuated the anti-tolerance effect of COX inhibition.

CONCLUSION

COX inhibition abrogated immune tolerance by suppressing PGI2 IP signaling, suggesting that PGI2 signaling promotes immune tolerance and that clinical use of COX-inhibiting drugs may increase the risk of developing allergic diseases.

Maternal 25-hydroxyvitamin D and its association with childhood atopic outcomes and lung function

Background

It has been suggested that maternal vitamin D status in pregnancy influences the risk of asthma and atopy in the offspring. The epidemiological evidence to support these claims is conflicting and may reflect chance findings and differences in how vitamin D was assessed.

Objective

To examine the association between blood total maternal 25-hydroxy vitamin D (25(OH)D) concentrations in pregnancy and offspring asthma, atopy and lung function in the largest birth cohort study to date.

Methods

Participants were largely of white European origin and resident in the South West of England. We examined the associations of maternal 25(OH)D concentrations in pregnancy with the following outcomes in the offspring: wheeze, asthma, atopy, eczema, hayfever, at mean age 7.5 years (n = 3652–4696 depending on outcome), IgE at 7 years (n = 2915) and lung function and bronchial responsiveness at mean age 8.7 years (n = 3728–3784).

Results

Sixty-eight per cent of mothers had sufficient (> 50 nmol/L) concentrations of 25(OH)D, 27% were insufficient (27.5–49.99 nmol/L) and 5% were deficient (< 27.5 nmol/L). There was no evidence to suggest that maternal 25(OH)D concentration in pregnancy was associated with any respiratory or atopic outcome in the offspring. These findings remained after adjustment for season of measurement and for potential confounders. There was also no evidence that these relationships followed a non-linear form and no evidence that either deficient or high concentrations of maternal 25(OH)D were associated with atopic or respiratory outcomes.

Conclusions

We found no evidence that maternal blood 25(OH)D concentration in pregnancy is associated with childhood atopic or respiratory outcomes.

Paracetamol: a focus for the general pediatrician

Paracetamol (acetaminophen) is one of the most popular and widely used drugs for the treatment of pain and fever in children. This drug has multiple mechanisms of action, but its pharmacodynamic is still not well known. The central nervous system is the main site of action and it mirrors the paracetamol effect compartment. The recommended dosages and routes of administration should be different whether paracetamol is used for the treatment of pain or fever. For example, the rectal route, while being efficacious for the treatment of fever, should be avoided in pain management. Paracetamol is a safe drug, but some clinical conditions and concomitant drugs, which are frequent in clinical practice, may increase the risk of paracetamol toxicity. Therefore, it is important to optimize its administration to avoid overdoses and maximize its effect. The principal mediator of the paracetamol toxicity is the N-acetyl-p-benzo-quinone imine (NAPQI), a toxic product of the paracetamol metabolism, which could bind cysteine groups on proteins forming paracetamol-protein adduct in the liver.

CONCLUSION

Although frequently prescribed, the concept of "effect compartment concentration" and the possible co-factors that could cause toxicity at recommended doses are not familiar to all pediatricians and general practitioners. We reviewed the literature concerning paracetamol mechanisms of action, we highlighted some relevant pharmacodynamic concepts for clinical practice, and we summarized the possible risk factors for toxicity at therapeutic dosages.

Febrile and gynecological infections during pregnancy are associated with a greater risk of childhood eczema

BACKGROUND

Mounting evidence suggests that fetal exposures may exert long-term effects on the function of the skin and of the immune system. This study aimed at assessing whether maternal complications during pregnancy are associated with an increased risk of eczema during childhood.

METHODS

The associations between hypertension/preeclampsia, febrile infections, or gynecological infections during pregnancy and the occurrence of childhood eczema were studied in a population (n = 3907) of children, aged 3-14 yrs, living in Italy. Their parents filled in a standardized questionnaire about the presence of children's eczema and the events that occurred during pregnancy, birth, and the first year of the child's life.

RESULTS

7.7%, 3.8%, and 6.1% of the pregnancies were complicated by hypertension/preeclampsia, febrile infections, and gynecological infections, respectively. The prevalence of eczema was significantly higher in children born to mothers who had experienced febrile (35.5% vs. 22.0%; p < 0.001) or gynecological infections (35.3% vs. 21.6%; p < 0.001) compared with those born to mothers who had not suffered from that specific pregnancy complication, while hypertension/preeclampsia was not significantly associated with childhood eczema. After adjusting for potential confounders, the risk of eczema was significantly higher in children born to mothers who reported febrile infections during the 1st trimester (OR: 2.32; 95% CI: 1.11-4.82) and gynecological infections during the 3rd trimester of pregnancy (OR: 2.73; 95% CI:1.73-4.31).

CONCLUSIONS

Fetal exposure to febrile and gynecological infections might enhance the risk of eczema in the offspring, especially when occurring in specific trimesters of pregnancy. These findings suggest that febrile and gynecological infections might interfere with fetal and perinatal programming of the immune function and skin through different mechanisms.

Epidemiology of Respiratory Allergies and Asthma

Asthma has puzzled and confused physicians from the time of Hippocrates to the present day. The word “asthma” comes from a Greek word meaning “panting” (Keeney 1964), but reference to asthma can also be found in ancient Egyptian, Hebrew, and Indian medical writings (Ellul-Micallef 1976; Unger and Harris 1974). There were clear observations of patients experiencing attacks of asthma in the second century and evidence of disordered anatomy in the lung as far back as the seventeenth century (Dring et al. 1689).

Effects of maternal exposure to di(2-ethylhexyl)phthalate (DEHP) during pregnancy on susceptibility to neonatal asthma

Di(2-ethylhexyl) phthalate (DEHP) is used as a plasticizer and is widely dispersed in the environment. In this study, we investigated the effects of maternal exposure to DEHP during pregnancy on neonatal asthma susceptibility using a murine model of asthma induced by ovalbumin (OVA). Pregnant BALB/c mice received DEHP from gestation day 13 to lactation day 21. Their offspring were sensitized on postnatal days (PNDs) 9 and 15 by intraperitoneal injection of 0.5μg OVA with 200μg aluminum hydroxide. On PNDs 22, 23 and 24, live pups received an airway challenge of OVA for 30min. Offspring from pregnant mice that received DEHP showed reductions in inflammatory cell count, interleukin (IL)-4, IL-13, and eotaxin in their bronchoalveolar lavage fluid and in total immunoglobulin E and OVA-specific IgE in their plasma compared with offspring from pregnant mice that did not receive DEHP treatment. These results were consistent with histological analysis and immunoblotting. Maternal exposure to DEHP reduces airway inflammation and mucus production in offspring, with a decrease in inducible nitric oxide synthase (iNOS) in the lung tissue. This study suggests that maternal exposure to DEHP during pregnancy reduces asthmatic responses induced by OVA challenge in offspring. These effects were considered to be closely related to the suppression of Th2 immune responses and iNOS expression.

The self-prescribed use of aromatherapy oils by pregnant women

BACKGROUND

While some studies have reported effectiveness of aromatherapy oils use during labour there is no reported evidence of efficacy or risks of aromatherapy oils use for pregnancy-related symptoms or conditions. A number of aromatherapy oils are unsafe for use by pregnant women yet there is currently no research examining the prevalence and characteristics of women who use aromatherapy oils during pregnancy.

AIM

To conduct an empirical study of the prevalence and characteristics of women who use aromatherapy oils during pregnancy.

METHODS

The research was conducted as part of the Australian Longitudinal Study on Women's Health (ALSWH), focusing on the nationally representative sample of Australian women aged 31-36 years. Data were collected via a cross-sectional questionnaire (n=8200) conducted in 2009.

RESULTS

Self-prescribed aromatherapy oils were used by 15.2% of pregnant women. Pregnant women were 1.57 (95% CI: 1.01, 2.43) times more likely to self-prescribe use of aromatherapy oils if they have allergies or hayfever, and 2.26 (95% CI: 1.34, 3.79) times more likely to self-prescribe use of aromatherapy oils if they have a urinary tract infection (UTI).

CONCLUSION

Our study highlights a considerable use of aromatherapy oils by pregnant women. There is a clear need for greater communication between practitioners and patients regarding the use of aromatherapy oils during pregnancy, as well a need for health care practitioners to be mindful that pregnant women in their care may be using aromatherapy oils, some of which may be unsafe.

Prenatal paracetamol exposure and child neurodevelopment: a sibling-controlled cohort study

BACKGROUND

Paracetamol is used extensively during pregnancy, but studies regarding the potential neurodevelopmental sequelae of foetal paracetamol exposure are lacking. Method Between 1999 and 2008 all pregnant Norwegian women were eligible for recruitment into the prospective Norwegian Mother and Child Cohort Study. The mothers were asked to report on their use of paracetamol at gestational weeks 17 and 30 and at 6 months postpartum. We used data on 48 631 children whose mothers returned the 3-year follow-up questionnaire by May 2011. Within this sample were 2919 same-sex sibling pairs who were used to adjust for familial and genetic factors. We modelled psychomotor development (communication, fine and gross motor development), externalizing and internalizing behaviour problems, and temperament (emotionality, activity, sociability and shyness) based on prenatal paracetamol exposure using generalized linear regression, adjusting for a number of factors, including febrile illness, infections and co-medication use during pregnancy.

RESULTS

The sibling-control analysis revealed that children exposed to prenatal paracetamol for more than 28 days had poorer gross motor development [β 0.24, 95% confidence interval (CI) 0.12-0.51], communication (β 0.20, 95% CI 0.01-0.39), externalizing behaviour (β 0.28, 95% CI 0.15-0.42), internalizing behaviour (β 0.14, 95% CI 0.01-0.28), and higher activity levels (β 0.24, 95% CI 0.11-0.38). Children exposed prenatally to short-term use of paracetamol (1-27 days) also had poorer gross motor outcomes (β 0.10, 95% CI 0.02-0.19), but the effects were smaller than with long-term use. Ibuprofen exposure was not associated with neurodevelopmental outcomes.

CONCLUSION

Children exposed to long-term use of paracetamol during pregnancy had substantially adverse developmental outcomes at 3 years of age.

Acetaminophen and pregnancy: short- and long-term consequences for mother and child

Counter-intuitively, over-the-counter medication is commonly taken by pregnant women. In this context, acetaminophen (APAP, e.g. Paracetamol, Tylenol) is generally recommended by physicians to treat fever and pain during pregnancy. Thus, APAP ranks at the top of the list of medications taken prenatally. Insights on an increased risk for pregnancy complications such as miscarriage, stillbirth, preterm birth or fetal malformations upon APAP exposure are rather ambiguous. However, emerging evidence arising from human trials clearly reveals a significant correlation between APAP use during pregnancy and an increased risk for the development of asthma in children later in life. Pathways through which APAP increases this risk are still elusive. APAP can be liver toxic and since APAP appears to freely cross the placenta, therapeutic and certainly toxic doses could not only affect maternal, but also fetal hepatocytes. It is noteworthy that during fetal development, the liver transiently functions as the main hematopoietic organ. We here review the effect of APAP on metabolic and immunological parameters in pregnant women and on fetal development and immune ontogeny in order to delineate novel, putative and to date underrated pathways through which APAP use during pregnancy can impair maternal, fetal and long term children's health. We conclude that future studies are urgently needed to reconsider the safety and dosage of APAP during pregnancy and - based on the advances made in the field of reproduction as well as APAP metabolism - we propose pathways, which should be addressed in future research and clinical endeavors.

Effect of paracetamol use on the modification of the development of asthma by reactive oxygen species genes

BACKGROUND

Recent studies have identified an increase in the prevalence of asthma associated with paracetamol use.

OBJECTIVE

To identify the relationship among asthma, biomarkers, genes, and paracetamol use in preschool children.

METHODS

We undertook a population-based, cross-sectional survey of 933 preschool children. Asthma status was classified according to medical history and asthmatic symptoms. History of paracetamol use in infancy was recorded. Impulse oscillometry, blood tests for eosinophils and total IgE, and genotyping of NAT2, Nrf2, and GSTP1 polymorphisms by TaqMan assay were conducted.

RESULT

Paracetamol use in infancy was associated with an increased risk of treatment for asthma within the previous 12 months. Paracetamol use together with a family history of asthma increased the risk of asthma diagnosis ever, current asthma, and treatment for asthma within the previous 12 months. Gene polymorphisms in NAT2 (rs4271002), Nrf2 (rd6726395), and GSTP1 (rd1695) increased the risk of treatment for asthma within the last 12 months. Eosinophils were significantly elevated in the group with paracetamol use and a family history of asthma; however, the serum total IgE level and IOS did not show any significant difference.

CONCLUSION

Paracetamol use in infancy was significantly associated with increased risk of asthma. The association is more significant in genetically susceptible children, related to antioxidant genes, and the effect may be mediated by eosinophilic inflammation.

Prenatal and perinatal analgesic exposure and autism: an ecological link

BACKGROUND

Autism and Autism Spectrum Disorder (ASD) are complex neurodevelopmental disorders. Susceptibility is believed to be the interaction of genetic heritability and environmental factors. The synchronous rises in autism/ASD prevalence and paracetamol (acetaminophen) use, as well as biologic plausibility have led to the hypothesis that paracetamol exposure may increase autism/ASD risk.

METHODS

To explore the relationship of antenatal paracetamol exposure to ASD, population weighted average autism prevalence rates and paracetamol usage rates were compared. To explore the relationship of early neonatal paracetamol exposure to autism/ASD, population weighted average male autism prevalence rates for all available countries and U.S. states were compared to male circumcision rates - a procedure for which paracetamol has been widely prescribed since the mid-1990s. Prevalence studies were extracted from the U.S. Centers for Disease Control and Prevention Summary of Autism/ASD Prevalence Studies database. Maternal paracetamol usage and circumcision rates were identified by searches on Pub Med.

RESULTS

Using all available country-level data (n = 8) for the period 1984 to 2005, prenatal use of paracetamol was correlated with autism/ASD prevalence (r = 0.80). For studies including boys born after 1995, there was a strong correlation between country-level (n = 9) autism/ASD prevalence in males and a country's circumcision rate (r = 0.98). A very similar pattern was seen among U.S. states and when comparing the 3 main racial/ethnic groups in the U.S. The country-level correlation between autism/ASD prevalence in males and paracetamol was considerably weaker before 1995 when the drug became widely used during circumcision.

CONCLUSIONS

This ecological analysis identified country-level correlations between indicators of prenatal and perinatal paracetamol exposure and autism/ASD. State level correlation was also identified for the indicator of perinatal paracetamol exposure and autism/ASD. Like all ecological analyses, these data cannot provide strong evidence of causality. However, biologic plausibility is provided by a growing body of experimental and clinical evidence linking paracetamol metabolism to pathways shown to be important in autism and related developmental abnormalities. Taken together, these ecological findings and mechanistic evidence suggest the need for formal study of the role of paracetamol in autism.

Effects of ibuprofen, diclofenac, naproxen, and piroxicam on the course of pregnancy and pregnancy outcome: a prospective cohort study

OBJECTIVE

To investigate the individual effects of ibuprofen, diclofenac, naproxen, and piroxicam on pregnancy outcome.

DESIGN

Cohort study.

SETTING

Norwegian population.

POPULATION

A total of 90 417 women and singleton child pairs.

METHODS

The Norwegian Mother and Child Cohort Study and Medical Birth Registry of Norway data sets were used.

MAIN OUTCOME MEASURES

Infant survival, congenital malformations, structural heart defects, neonatal complications, haemorrhage during pregnancy and postpartum, asthma at age of 18 months.

RESULTS

One or more of the four nonsteroidal anti-inflammatory drugs (NSAIDs) were used by 6511 pregnant women (7.2%). No effect on rates of infant survival, congenital malformation, or structural heart defects was found. The use of ibuprofen in the second trimester was significantly associated with low birthweight (adjusted OR 1.7, 95% CI 1.3-2.3), and ibuprofen use in the second and third trimesters was significantly associated with asthma in 18-month-old children (adjusted OR 1.5, 95% CI 1.2-1.9; adjusted OR 1.5, 95% CI 1.1-2.1). The use of diclofenac in the second trimester was significantly associated with low birthweight (adjusted OR 3.1, 95% CI 1.1-9.0), whereas diclofenac use in the third trimester was significantly associated with maternal vaginal bleeding (adjusted OR 1.8, 95% CI 1.1-3.0). No associations with other neonatal complications were found.

CONCLUSIONS

The lack of associations with congenital malformations is reassuring. The significant association between diclofenac and ibuprofen use late in pregnancy, and maternal bleeding and asthma in the child, respectively, is consistent with their pharmacological effects. The increased risk of low birthweight may partly have been caused by underlying inflammatory conditions, and was reassuringly similar to the expected baseline risk of low birthweight.

Acetaminophen and asthma

Acetaminophen is a widely used medication for the treatment of pain and fever in children and pregnant women. There is substantial epidemiological evidence in adults and children that acetaminophen use is associated with asthma symptoms. There is also a considerable body of evidence that supports a modest but consistent association of acetaminophen use in pregnancy and early infancy with asthma in later childhood. This relationship is robust to adjustment for a large range of potential confounding factors and, in some studies, shows clear evidence of a dose-dependent association but the possibility of confounding by indication has remained a concern. However, the epidemiological evidence is now compelling and there is a clear need to establish causation so that appropriate advice and interventions can be developed for children at risk of asthma. This requires randomised trials of analgesics and antipyretics, including acetaminophen, in a variety of clinical settings.

The effect of a single dose of acetaminophen on airways response in children with asthma

Accumulating evidence suggests that the use of acetaminophen increases the risk of developing asthma and that its widespread use has contributed to the increasing prevalence of asthma.

STUDY DESIGN

To investigate the immediate effect of a single dose of acetaminophen on airways reactivity and inflammation in asthmatic and controls. A double blind placebo-controlled study was conducted on 42 asthmatic children and 21 healthy age-matched controls. Each participant received one oral dose of acetaminophen (15 mg/kg [160 mg/mL]) and one dose of a volume-matched placebo. Physical examination, spirometry results, and fractional exhaled nitric oxide levels were assessed before and 60 minutes following acetaminophen or placebo ingestion.

RESULTS

None of the studied variables showed any significant change after acetaminophen or placebo ingestion in either the asthmatic or the control groups.

CONCLUSIONS

One single dose of acetaminophen neither evokes a bronchoconstriction response nor an increase in airway inflammation in children with asthma.

Maternal occupational exposure to asthmogens during pregnancy and risk of asthma in 7-year-old children: a cohort study

OBJECTIVES

The objective of this study was to examine whether maternal exposure to asthmogens during pregnancy is associated with the development of asthma in 7-year-old Danish children, taking atopic status and sex into consideration.

DESIGN

The study is a prospective follow-up of a birth cohort.

SETTING AND PARTICIPANTS

A total of 41 724 women and their children from The Danish National Birth Cohort were categorised according to maternal occupational exposure. Exposure information was obtained by combining job title in pregnancy and 18 months after pregnancy with a commonly used asthma Job Exposure Matrix.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was parent-reported asthma among their 7-year-old children in an internet-based questionnaire. Secondary outcome was asthma among the same children with or without atopic dermatitis and among boys and girls, respectively.

RESULTS

Prenatal exposure to low molecular weight (LMW) agents was borderline associated with asthma in children with OR 1.17 (0.95 to 1.44) for children with atopic dermatitis and 1.10 (0.98 to 1.22) for children without. Maternal postnatal exposure was associated with asthma (OR 1.15 (1.04 to 1.28). After mutual adjustment,postnatal exposure (OR 1.13 (0.99 to 1.29) and the combined effects of prenatal and postnatal exposure (OR 1.34 (1.19 to 1.51)) seem to increase the risk of asthma in children. No significant associations were observed for other prenatal or postnatal exposures. The gender of the child did not modify the aforementioned associations.

CONCLUSIONS

Maternal occupational exposures during pregnancy do not seem to be a substantial risk factor for the development of asthma in 7-year-old children. Maternal prenatal and postnatal exposures to LMW agents may predispose the propensity of the children to develop asthma. Future studies should prioritise the characterisation of the timing of exposure in relation to the birth.

The relationship between antibiotic therapy in early childhood and the symptoms of allergy in children aged 6-8 years - the questionnaire study results

INTRODUCTION

Studies based on the ISAAC questionnaire suggest a correlation between the use of antibiotics and the prevalence of asthma and allergy in children aged 6-7 years. The number of courses of antibiotic therapy is an important factor.

OBJECTIVES

To investigate the relationship between the use of antibiotics during the first years of life and the prevalence of allergy and asthma among children (aged 6-8 years) in the urban population of Poland.

MATERIALS AND METHODS

A survey-based study with a self-completed questionnaire. The respondents were parents of children aged 6-8 years living in Warszawa, Poland. 1461 completed questionnaires were collected.

RESULTS

Asthma was declared in 4.3% of the children. Wheezing and/or sibilant rhonchi within 12 months before the study was observed in 13.5% of the cases. Asthma medication was taken by 21.8% of the children. Allergic rhinitis was declared in 18.7% of the children. Problems with sneezing, rhinorrhea, and nasal congestion not associated with cold or fever were observed in 40.7% of the children. The analysis of the odds ratios between the use of antibiotics and the symptoms of allergic diseases revealed a clear correlation. The highest odds ratio was observed between the completion of over three courses of antibiotic therapy prior to the age of 12 months and the declaration of one of the following: asthma (OR = 5.59, 95% CI: 2.6-12.01), wheezing and/or sibilant rhonchi (OR = 4.68, 95% CI: 3.01-7.27) and taking medicines for breathlessness (OR = 5.12, 95% CI: 3.42-7.68).

CONCLUSIONS

There is a direct relationship between antibiotic use in the first 3 years of life and asthma and allergy symptoms in children aged 6-8 years old.

Confounding and effect modification in studies of diet and childhood asthma and allergies

OBJECTIVE

To propose a comprehensive set of confounders and effect modifiers that should be considered in epidemiologic investigations.

METHODS

Two reviewers independently critiqued studies included in a recent systematic review and extracted data on the confounders and effect modifiers that were considered and the approaches used to justify inclusion.

RESULTS

Of the 62 studies reviewed, 20 were cohort, 16 case-control, 25 cross-sectional studies, and one ecologic study. All cohort, cross-sectional, and ecologic studies had some adjustment for confounding or consideration of effect modification, but this was only the case for 7/16 (44%) case-control studies. Of the 53 studies that considered confounding or effect modification, 39/53 (74%) gave no justification for the inclusion of the variables considered. Studies that justified the inclusion of the variables did so based on empirical evidence (n = 10), conceptual justification (n = 7), or a combination of the two (n = 3). Confounding was handled mainly by using regression modeling, but some case-control studies utilized matching and anova. Ten studies handled effect modification by stratification, eight tested for interaction, and five used both strategies.

CONCLUSIONS

We have found substantial shortcomings in the handling of confounding and effect modification in studies of diet and development of childhood asthma/allergies. Selection of variables should be based on conceptual considerations and empirical evidence. Using this approach, we have proposed a comprehensive set of confounders and effect modifiers that need to be considered in future studies.

Cohort Profile: the 'children of the 90s'--the index offspring of the Avon Longitudinal Study of Parents and Children

The Avon Longitudinal Study of Parents and Children (ALSPAC) is a transgenerational prospective observational study investigating influences on health and development across the life course. It considers multiple genetic, epigenetic, biological, psychological, social and other environmental exposures in relation to a similarly diverse range of health, social and developmental outcomes. Recruitment sought to enrol pregnant women in the Bristol area of the UK during 1990–92; this was extended to include additional children eligible using the original enrolment definition up to the age of 18 years. The children from 14 541 pregnancies were recruited in 1990–92, increasing to 15 247 pregnancies by the age of 18 years. This cohort profile describes the index children of these pregnancies. Follow-up includes 59 questionnaires (4 weeks–18 years of age) and 9 clinical assessment visits (7–17 years of age). The resource comprises a wide range of phenotypic and environmental measures in addition to biological samples, genetic (DNA on 11 343 children, genome-wide data on 8365 children, complete genome sequencing on 2000 children) and epigenetic (methylation sampling on 1000 children) information and linkage to health and administrative records. Data access is described in this article and is currently set up as a supported access resource. To date, over 700 peer-reviewed articles have been published using ALSPAC data.

Early origins of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and a significant challenge for adult physicians. However, there is a misconception that COPD is a disease of only adult smokers. There is a growing body of evidence to support the hypothesis that chronic respiratory diseases such as COPD have their origins in early life. In particular, adverse maternal factors will interact with the environment in a susceptible host promoting altered lung growth and development antenatally and in early childhood. Subsequent lung injury and further gene-environment interactions may result in permanent lung injury manifest by airway obstruction predisposing to COPD. This review will discuss the currently available data regarding risk factors in early life and their role in determining the COPD phenotype.

Fetal origins of asthma

There is convincing evidence that asthma has its origins in early life. We review the epidemiological and biological evidence for fetal exposures that may have a causal role in asthma development. However, those factors that provoke asthma exacerbations are not necessarily the same as those associated with disease induction. Epidemiological studies have identified many potential exposures linked to asthma but these do not confirm causality and have not been replicated by experiment. Asthma is a heterogeneous disease and there are developmental influences on at least two pathways, airway structure and airway inflammation. The fetus is not immunologically naive and intrauterine exposures can act directly to invoke immunological sensitisation leading postnatally to airway inflammation. Other potential mechanisms include indirect effects on airway and lung growth through fetal nutrition and epigenetic modifications of DNA expression by environmental exposures. Identifying the causal factors will provide the targets for interventions to prevent disease.

Acetaminophen enhances pruritus in a mouse model of contact dermatitis induced by suboptimal concentration of hapten

Acetaminophen (APAP) is one of the most commonly used drugs worldwide to reduce fever, particularly in children. It is generally considered to be a safe drug. However, a number of studies have shown that regular use of APAP increases the risk of developing allergic diseases. Nonetheless, no animal models have been used to investigate these findings. Therefore, we aimed to create an animal model of APAP-induced pruritus in mice. APAP (0.25% and 0.5%) was administered via drinking water daily from infancy, and a suboptimal concentration of 2,4,6-trinitrochlorobenzene (TNCB) was applied repeatedly to each ear three times a week for 7 weeks to evoke chronic allergic contact dermatitis. Neither 0.25% nor 0.5% APAP was overtly hepatotoxic after 73 days of daily administration. Repeated challenge with TNCB evoked increase in the number of scratching bouts compared to day 1. This increase in the number of scratching bouts was significant in 0.25% and 0.5% APAP groups but not in the group treated with TNCB alone. Daily administration of 0.5% APAP significantly increased in the number of scratching bouts compared to TNCB alone on day 29. This animal model will be useful for investigating the mechanism underlying the increased risk of development of eczema caused by regular APAP use and for examining safer and more effective therapy with APAP.

Fetal and infant origins of asthma

Previous studies have suggested that asthma, like other common diseases, has at least part of its origin early in life. Low birth weight has been shown to be associated with increased risks of asthma, chronic obstructive airway disease, and impaired lung function in adults, and increased risks of respiratory symptoms in early childhood. The developmental plasticity hypothesis suggests that the associations between low birth weight and diseases in later life are explained by adaptation mechanisms in fetal life and infancy in response to various adverse exposures. Various pathways leading from adverse fetal and infant exposures to growth adaptations and respiratory health outcomes have been studied, including fetal and early infant growth patterns, maternal smoking and diet, children's diet, respiratory tract infections and acetaminophen use, and genetic susceptibility. Still, the specific adverse exposures in fetal and early postnatal life leading to respiratory disease in adult life are not yet fully understood. Current studies suggest that both environmental and genetic factors in various periods of life, and their epigenetic mechanisms may underlie the complex associations of low birth weight with respiratory disease in later life. New well-designed epidemiological studies are needed to identify the specific underlying mechanisms. This review is focused on specific adverse fetal and infant growth patterns and exposures, genetic susceptibility, possible respiratory adaptations and perspectives for new studies.

Viewpoint: the future of research in pediatric allergy: what should the focus be?

Allergic diseases have been increasing during the last three decades, and exact reasons for this are still debated. Despite intense ongoing research, a lot of aspects of allergic diseases are still poorly understood, resulting in limitations in current therapeutic approach to allergies. In this viewpoint, important unanswered research questions are raised mainly on novel therapeutic approaches to allergic children, and suggestions for future research are raised. Three aspects of pediatric allergy are distinguished: the prevention, control, and cure.

Use of prescription paracetamol during pregnancy and risk of asthma in children: a population-based Danish cohort study

PURPOSE

Use of paracetamol during pregnancy may increase the risk of asthma in offspring. The association between prenatal exposure to maternal use of paracetamol and risk of asthma was investigated.

METHODS

A cohort study of 197,060 singletons born in northern Denmark in 1996-2008 was conducted, with follow-up until the end of 2009. Maternal paracetamol use during pregnancy was defined as a redeemed prescription. Asthma in offspring was defined as at least two prescriptions of both a β-agonist and an inhaled glucocorticoid and/or a hospital diagnosis of asthma during follow-up. Absolute risk of asthma in offspring was estimated using the Kaplan-Meier method and incidence rate ratios adjusted for known risk factors were estimated using Cox proportional-hazards regression.

RESULTS

Overall, 976 (0.5%) children were exposed prenatally to maternal use of prescription paracetamol. During follow-up, 24,506 (12.4%) children developed asthma. Absolute risk of asthma was 7.5% after 2 years and 14.4% after 10 years among the unexposed children. Corresponding risks were 12.7% and 21.6% among the exposed children. The adjusted incidence rate ratio was 1.35 (95% confidence interval: 1.17-1.57) for exposure in any trimester of pregnancy. A similar association was present for paracetamol exposure in each of the trimesters and for maternal use of prescription nonsteroidal anti-inflammatory drugs. Furthermore, maternal prescription use in the year following the relevant delivery also showed similar associations.

CONCLUSION

A robust association was found between prenatal exposure to maternal use of prescription paracetamol and the risk of asthma; however, noncausal explanations could not be ruled out for such association.

Prenatal paracetamol exposure and risk of wheeze at preschool age

AIM

To analyse the association between prenatal paracetamol exposure and preschool wheeze.

METHODS

Data were obtained from a prospective, longitudinal study of a cohort of children born in the region of western Sweden in 2003; 8176 families were randomly selected. The parents answered questionnaires at 6 and 12 months and at 4.5 years of age. The response rate was 55%, i.e. 4496 of the 5398 questionnaires distributed at 4.5 years (83%). Inhaled corticosteroid (ICS) treated wheeze during the last year was regarded as a proxy for doctor-diagnosed asthma. Episodic viral wheeze was defined as wheezing only with viral infections and multiple-trigger wheeze as wheezing also in between infections.

RESULTS

In the multivariate analysis, the risk of ICS-treated wheeze was increased by paracetamol (OR 1.6; 95% CI 1.01-2.6). Within the ICS-treated group, the effect was significant for multiple-trigger wheeze (OR 2.4; 1.2-4.8) but not for episodic viral wheeze (OR 1.1; 0.5-2.3).

CONCLUSION

Prenatal paracetamol exposure was an independent risk factor for ICS-treated wheeze at preschool age, especially among children with ICS-treated multiple-trigger wheeze. Although the analysis adjusted for e.g. maternal asthma and antibiotic use, the possibility of residual confounding by maternal indication (respiratory illness) should be acknowledged.

The association of acetaminophen and asthma prevalence and severity

The epidemiologic association between acetaminophen use and asthma prevalence and severity in children and adults is well established. A variety of observations suggest that acetaminophen use has contributed to the recent increase in asthma prevalence in children: (1) the strength of the association; (2) the consistency of the association across age, geography, and culture; (3) the dose-response relationship; (4) the timing of increased acetaminophen use and the asthma epidemic; (5) the relationship between per-capita sales of acetaminophen and asthma prevalence across countries; (6) the results of a double-blind trial of ibuprofen and acetaminophen for treatment of fever in asthmatic children; and (7) the biologically plausible mechanism of glutathione depletion in airway mucosa. Until future studies document the safety of this drug, children with asthma or at risk for asthma should avoid the use of acetaminophen.

Effect of prenatal exposure to fine particulate matter and intake of Paracetamol (Acetaminophen) in pregnancy on eczema occurrence in early childhood

The goal of the study was to test the hypothesis that prenatal Paracetamol exposure increases the risk of developing eczema in early childhood and that this association may be stronger in children who are exposed in fetal period to higher concentrations of fine particulate matter (PM2.5). The study sample consisted of 322 women recruited from January 2001 to February 2004 in the Krakow inner city area who gave birth to term babies and completed 5-year follow-up. Paracetamol use in pregnancy was collected by interviews and prenatal personal exposure to PM2.5 over 48 h was measured in recruited women in the second trimester of pregnancy. After delivery, every three months in the first 24 months of the newborn's life and every 6 months later, a detailed standardized face-to-face interview on the infant's health was administered to each mother by trained interviewers. During the interviews at each of the study periods after birth, a history of eczema was recorded. The incident rate ratio (IRR) for frequency of eczema events over the follow-up was estimated from the Poisson regression model and the overall effect of main exposure variables on eczema was assessed by odds ratios (ORs) by the logistic model. The estimated relative risk of eczema occurring whenever in the follow-up was related significantly neither with prenatal Paracetamol nor higher PM2.5 exposure, however, their joint effect was significant (OR interaction term=6.04; 95%CI: 1.04-35.16). Of potential confounders considered in the analysis only damp/moldy home significantly increased the risk of eczema (OR=1.53; 95%CI: 1.14-2.05). In contrast, there was an inverse significant association between the presence of older siblings and eczema (OR=0.55; 95%CI: 0.35-0.84). The joint effect of the main exposure variables significantly increased frequency of eczema events (IRR=1.78, 95%CI: 1.22-2.61). In conclusion, the findings of the study suggest that Paracetamol use by mothers in pregnancy is not an independent risk factor for eczema in children, however, even very small doses of Paracetamol taken in pregnancy may contribute to the occurrence of allergic symptoms in early childhood if there is prenatal co-exposure to higher airborne fine particulate matter.

Early exposure to acetaminophen and allergic disorders

PURPOSE OF REVIEW

To summarize the data related to the association between acetaminophen and allergic diseases, and to try to establish a conclusion regarding the extent to which the association is unbiased and what its strength might be.

RECENT FINDINGS

Several studies have shown an association between acetaminophen use during pregnancy and allergic diseases in the offspring. Furthermore, this association has also been found between early exposure and recent exposure to the drug and several allergic conditions. However, other studies did not confirm those associations. Taken together, the available data suggest an unbiased but weak association between acetaminophen consumption and asthma/wheezing. Additional studies are needed to definitely confirm the association with rhinitis, eczema and sensitization.

SUMMARY

Although the use of acetaminophen is weakly associated with asthma/wheezing, the widespread use of the drug might have important public health implications. Thus, controlled studies to definitely establish not only causality but also the magnitude in which acetaminophen might increase allergic disorders are needed.

Frequent use of paracetamol and risk of allergic disease among women in an Ethiopian population

Introduction

The hypothesis that paracetamol might increase the risk of asthma and other allergic diseases have gained support from a range of independent studies. However, in studies based in developed countries, the possibility that paracetamol and asthma are associated through aspirin avoidance is difficult to exclude.

Objectives

To explore this hypothesis among women in a developing country, where we have previously reported aspirin avoidance to be rare.

Methods

In 2005/6 a population based cohort of 1065 pregnant women was established in Butajira, Ethiopia and baseline demographic data collected. At 3 years post birth, an interview-based questionnaire administered to 945 (94%) of these women collected data on asthma, eczema, and hay fever in the past 12 month, frequency of paracetamol use and potential confounders. Allergen skin tests to Dermatophagoides pteronyssinus and cockroach were also performed. The independent effects of paracetamol use on allergic outcomes were determined using multiple logistic regression analysis.

Findings

The prevalence of asthma, eczema and hay fever was 1.7%, 0.9% and 3.8% respectively; of any one of these conditions 5.5%, and of allergen sensitization 7.8%. Paracetamol use in the past month was reported by 29%, and associations of borderline significance were seen for eczema (adjusted OR (95% CI) = 8.51 (1.68 to 43.19) for 1–3 tablets and 2.19 (0.36 to 13.38) for ≥4 tablets, compared to no tablets in the past month; overall p = 0.055) and for ‘any allergic condition’ (adjusted OR (95% CI) = 2.73 (1.22 to 6.11) for 1–3 tablets and 1.35 (0.67 to 2.70) for ≥4 tablets compared to 0 in the past month; overall p = 0.071).

Conclusions

This study provides further cross-sectional evidence that paracetamol use increases the risk of allergic disease.

Many putative endocrine disruptors inhibit prostaglandin synthesis

BACKGROUND

Prostaglandins (PGs) play key roles in development and maintenance of homeostasis of the adult body. Despite these important roles, it remains unclear whether the PG pathway is a target for endocrine disruption. However, several known endocrine-disrupting compounds (EDCs) share a high degree of structural similarity with mild analgesics.

OBJECTIVES AND METHODS

Using cell-based transfection and transduction experiments, mass spectrometry, and organotypic assays together with molecular modeling, we investigated whether inhibition of the PG pathway by known EDCs could be a novel point of endocrine disruption.

RESULTS

We found that many known EDCs inhibit the PG pathway in a mouse Sertoli cell line and in human primary mast cells. The EDCs also reduced PG synthesis in ex vivo rat testis, and this reduction was correlated with a reduced testosterone production. The inhibition of PG synthesis occurred without involvement of canonical PG receptors or the peroxisome proliferator-activated receptors (PPARs), which have previously been described as targets of EDCs. Instead, our results suggest that the compounds may bind directly into the active site of the cyclooxygenase (COX) enzymes, thereby obstructing the conversion of arachidonic acid to PG precursors without interfering with the expression of the COX enzymes. A common feature of the PG inhibitory EDCs is the presence of aromatic groups that may stabilize binding in the hydrophobic active site of the COX enzymes.

CONCLUSION

Our findings suggest a hitherto unknown mode of action by EDCs through inhibition of the PG pathway and suggest new avenues to investigate effects of EDCs on reproductive and immunological disorders that have become increasingly common in recent decades.

Responsible self-medication: perceived risks and benefits of over-the-counter analgesic use

OBJECTIVES

This study examines awareness of the potential risks associated with over-the-counter (OTC) use of paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) among Australian consumers to better understand patterns of usage of these products.

METHODS

We employed two self-reported cross-sectional surveys (conducted in 2001 and 2009) using computer-aided telephone interviewing. Both survey samples were weighted to match national population proportions; data were collected for 3702 respondents (study 1, 2001, n=1901; study 2, 2009, n=1801). The inclusion criteria were age over 18 years and willingness to participate in the survey.

KEY FINDINGS

Self-reported regular use (once or more per month) of OTC analgesics declined between 2001 (67.5%) and 2009 (55.0%; P<0.05). In 2009 42.0% of regular OTC analgesic users were purchasing NSAIDs outside the pharmacy setting (compared with none in 2001). Stated awareness of potential risks has increased slightly among regular paracetamol users (from 49.0% in 2001 to 52.0% in 2009) and regular NSAID users (from 25.0% in 2001 to 41.0% in 2009). Regular OTC analgesic users were considered to be using the product appropriately if there were no contraindications, warnings, precautions or potential drug interactions to the analgesic that they had used. In 2001, significantly more people were using paracetamol appropriately than were using NSAIDs appropriately (98.3 compared with 79.3%; P<0.05). Corresponding figures for 2009 were 96.4 and 69.1% (P<0.5).

CONCLUSIONS

Increasing consumer awareness of the need to consider potential risks prior to taking OTC analgesics is a positive sign. However, this has not translated to an increase in appropriate use of OTC NSAIDs; since ibuprofen has become available outside the pharmacy setting in Australia fewer people are using NSAIDs appropriately according to the label. The quality use of medicines, in particular OTC NSAIDs, is becoming increasingly reliant on product labelling and the ability of consumers to understand and self-assess risk.

Paracetamol in pregnancy and the risk of wheezing in offspring: a systematic review and meta-analysis

BACKGROUND

There is evidence to suggest that the risk of asthma might be increased with exposure to paracetamol in the intrauterine environment, infancy, later childhood and adult life.

OBJECTIVE

To review the evidence from studies investigating the association between paracetamol use in pregnancy and childhood asthma.

METHODS

A systematic review and meta-analysis was undertaken of studies reporting the association between paracetamol use in pregnancy and subsequent asthma in childhood. The primary outcome variable was wheeze in the last 12 months. For tabulated raw data, not adjusted for confounders, random effects odds ratios (OR) were pooled by the inverse variance weighted method.

RESULTS

There were six studies identified that were included in the meta-analysis. The age of children studied ranged from 30 to 84 months. The pooled random effects OR for the risk of current wheeze in the children of women who were exposed to any paracetamol during any stage of pregnancy was 1.21 (95% confidence interval 1.02-1.44). Features of the studies variably included an association with paracetamol use during all trimesters of pregnancy and an association with persistent asthma, severe asthma, and with atopy.

CONCLUSION AND CLINICAL RELEVANCE

The use of paracetamol during pregnancy is associated with an increased risk of childhood asthma. More research is urgently required to determine the impact of paracetamol during pregnancy on the risk of wheezing in offspring so that appropriate public health recommendations can be made.

Animal products, diseases and drugs: a plea for better integration between agricultural sciences, human nutrition and human pharmacology

Eicosanoids are major players in the pathogenesis of several common diseases, with either overproduction or imbalance (e.g. between thromboxanes and prostacyclins) often leading to worsening of disease symptoms. Both the total rate of eicosanoid production and the balance between eicosanoids with opposite effects are strongly dependent on dietary factors, such as the daily intakes of various eicosanoid precursor fatty acids, and also on the intakes of several antioxidant nutrients including selenium and sulphur amino acids. Even though the underlying biochemical mechanisms have been thoroughly studied for more than 30 years, neither the agricultural sector nor medical practitioners have shown much interest in making practical use of the abundant high-quality research data now available. In this article, we discuss some specific examples of the interactions between diet and drugs in the pathogenesis and therapy of various common diseases. We also discuss, using common pain conditions and cancer as specific examples, how a better integration between agricultural science, nutrition and pharmacology could lead to improved treatment for important diseases (with improved overall therapeutic effect at the same time as negative side effects and therapy costs can be strongly reduced). It is shown how an unnaturally high omega-6/omega-3 fatty acid concentration ratio in meat, offal and eggs (because the omega-6/omega-3 ratio of the animal diet is unnaturally high) directly leads to exacerbation of pain conditions, cardiovascular disease and probably most cancers. It should be technologically easy and fairly inexpensive to produce poultry and pork meat with much more long-chain omega-3 fatty acids and less arachidonic acid than now, at the same time as they could also have a similar selenium concentration as is common in marine fish. The health economic benefits of such products for society as a whole must be expected vastly to outweigh the direct costs for the farming sector.

The role of acetaminophen and geohelminth infection on the incidence of wheeze and eczema: a longitudinal birth-cohort study

RATIONALE

Acetaminophen has been hypothesized to increase the risk of asthma and allergic disease, and geohelminth infection to reduce the risk, but evidence from longitudinal cohort studies is lacking.

OBJECTIVES

To investigate the independent effects of these exposures on the incidence of wheeze and eczema in a birth cohort.

METHODS

In 2005-2006 a population-based cohort of 1,065 pregnant women from Butajira, Ethiopia, was established, to whom 1,006 live singleton babies were born. At ages 1 and 3, questionnaire data were collected on wheeze, eczema, child's use of acetaminophen, and various potential confounders, along with a stool sample for geohelminth analysis. Those without wheeze (n = 756) or eczema (n = 780) at age 1 were analyzed to determine the independent effects of geohelminth infection and acetaminophen use in the first year of life on the incidence of wheeze and eczema by age 3.

MEASUREMENTS AND MAIN RESULTS

Wheeze and eczema incidence between the ages of 1 and 3 were reported in 7.7% (58 of 756) and 7.3% (57 of 780) of children, respectively. Acetaminophen use was significantly associated with a dose-dependent increased risk of incident wheeze (adjusted odds ratio = 1.88 and 95% confidence interval 1.03-3.44 for one to three tablets and 7.25 and 2.02-25.95 for ≥ 4 tablets in the past month at age 1 vs. never), but not eczema. Geohelminth infection was insufficiently prevalent (<4%) to compute estimates of effect.

CONCLUSIONS

These findings suggest frequent acetaminophen use early in life increases the risk of new-onset wheeze, whereas the role of geohelminth infection on allergic disease incidence remains to be seen as the cohort matures.

Paracetamol in early infancy: the risk of childhood allergy and asthma

AIM

We investigated whether paracetamol exposure in pregnancy and until 6 months of age was associated with allergic disease in school children.

METHODS

In a prospective birth cohort study in Oslo, 1016 children included at birth were re-investigated at 10 years. Paracetamol exposure in pregnancy and until 6 months of age was registered. Outcomes at 10 years included current asthma, a history of asthma, allergic sensitization and allergic rhinitis.

RESULTS

Maternal paracetamol use in the first trimester increased the risk for allergic rhinitis at 10 years OR (odds ratio) (95%CI) 2.30 (1.06, 4.97) in boys and girls. Paracetamol use until 6 months in girls increased the risk for allergic sensitization OR 2.20 (1.15, 4.22) and a history of asthma OR 2.20 (1.13, 4.30). The ORs for allergic sensitization and history of asthma in girls remained unchanged adjusting for upper or lower airway infections during the first 6 months of life.

CONCLUSION

Paracetamol exposure in pregnancy was associated with allergic rhinitis, but not with asthma or allergic sensitization at 10 years of age. Paracetamol used until 6 months of age was associated with allergic sensitization and having a history of asthma in girls at 10 years of age, even considering concomitant airway infections.

Prenatal and infant acetaminophen exposure, antioxidant gene polymorphisms, and childhood asthma

BACKGROUND

Prenatal and infant acetaminophen exposure has been associated with an increased risk of childhood asthma phenotypes. Demonstration of biologically plausible interactions between these exposures and maternal and child antioxidant gene polymorphisms would strengthen causal inference.

OBJECTIVE

To explore potential interactions between prenatal and infant acetaminophen exposure and antioxidant genotypes on childhood asthma.

METHODS

In the Avon Longitudinal Study of Parents and Children, we typed a functional nuclear erythroid 2 p45-related factor 2 (Nrf2) polymorphism and glutathione S-transferase (GST) M1, T1, and P1 polymorphisms. Effects of prenatal and infant acetaminophen exposure on asthma phenotypes at 7 years were stratified by genotype in >4000 mothers and >5000 children.

RESULTS

Risk of asthma and wheezing associated with early gestation acetaminophen exposure was increased when maternal copies of the minor T allele of Nrf2 were present (P interactions, .02 and .04, respectively). Risk of asthma associated with late gestation exposure was higher when maternal GSTT1 genotype was present rather than absent (P interaction, .006), and risk of wheezing was increased when maternal GSTM1 was present (P interaction, .04). Although acetaminophen use in infancy was associated with an increased risk of atopy, child antioxidant genotype did not modify associations between infant acetaminophen use and asthma phenotypes. However, the increased risk of asthma and wheezing associated with late gestation acetaminophen exposure in the presence of maternal GSTM1 was further enhanced when GSTM1 was also present in the child.

CONCLUSION

Maternal antioxidant gene polymorphisms may modify the relation between prenatal acetaminophen exposure and childhood asthma, strengthening evidence for a causal association. In contrast, relations between infant acetaminophen use and asthma and atopy were not modified by child genotype and may be confounded by pre-existing wheeze or allergy.

Early exposure to paracetamol or to antibiotics and eczema at school age: modification by asthma and rhinoconjunctivitis

The association between early exposure to paracetamol or to antibiotics and eczema is conflicting. This study aims to know whether the early exposure to those drugs is associated with eczema at school age, and whether the strength of the association is modified by the presence of asthma or rhinoconjunctivitis. Children aged 6-7 (n = 13908) from the International Study of Asthma and Allergies in Childhood in Spain provided data about current asthma, rhinoconjunctivitis and eczema. Parent-reported information was also obtained on paracetamol and antibiotic consumption during the first year of life. Logistic regression analysis with eczema as outcome and including exposure to paracetamol or to antibiotics, together with possible confounders, was carried out in the whole sample of children and in five different strata: no respiratory symptom and any respiratory symptom further subdivided into: asthma with rhinoconjunctivitis, asthma without rhinoconjunctivitis and rhinoconjunctivitis without asthma. In the whole sample, exposure to paracetamol was associated with eczema (aOR 1.56 [1.36-1.80]) as was antibiotic consumption (aOR 1.66 [1.43-1.92]). These associations did not substantially change after additionally adjusting for the other drug. A similar pattern was found among children without respiratory symptoms. In children with symptoms, adjusting for the other drug modified the association with paracetamol (aOR from 1.32 [1.03-1.71] to 1.09 [0.83-1.43]) but did not change that with antibiotics (aOR from 1.80 [1.38-2.35] to 1.81 [1.37-2.39]). Early exposure to paracetamol or to antibiotics is associated with an increased prevalence of eczema at school age. Asthma and/or rhinoconjunctivitis substantially modifies this association.

The effects of early and late paracetamol exposure on asthma and atopy: a birth cohort

BACKGROUND

Despite reports of positive associations between paracetamol and asthma, the nature of these associations is unclear.

OBJECTIVE

We aimed to investigate the associations between infant and childhood paracetamol use and atopy and allergic disease at 5-6 years.

METHODS

In a birth cohort study, we collected reported paracetamol exposure between birth and 15 months in Christchurch (n=505) and between 5 and 6 years for all participants (Christchurch and Wellington) (n=914). Outcome data for reported current asthma, reported wheeze and atopy (measured using skin prick tests) were collected at 6 years for all participants. Logistic regression models were adjusted for potential confounders, including the number of chest infections and antibiotic use.

RESULTS

Paracetamol exposure before the age of 15 months was associated with atopy at 6 years [adjusted odds ratio (OR)=3.61, 95% confidence interval (CI) 1.33-9.77]. Paracetamol exposure between 5 and 6 years showed dose-dependent associations with reported wheeze and current asthma but there was no association with atopy. Compared with use 0-2 times, the adjusted OR (95% CI) were wheeze 1.83 (1.04-3.23) for use 3-10 times, and 2.30 (1.28-4.16) for use >10 times: current asthma 1.63 (0.92-2.89) for use 3-10 times and 2.16 (1.19-3.92) for use >10 times: atopy 0.96 (0.59-1.56) for use 3-10 times, and 1.05 (0.62-1.77) for use >10 times.

CONCLUSION AND CLINICAL RELEVANCE

Our findings suggest that paracetamol has a role in the development of atopy, and the maintenance of asthma symptoms. Before recommendations for clinical practice can be made, randomized-controlled trials are needed to determine whether these associations are causal.

Acetaminophen use and risk of asthma, rhinoconjunctivitis, and eczema in adolescents: International Study of Asthma and Allergies in Childhood Phase Three

RATIONALE

There is epidemiological evidence that the use of acetaminophen may increase the risk of developing asthma.

OBJECTIVES

To investigate the risk of asthma and other allergic disorders associated with the current use of acetaminophen in 13- to 14-year-old children in different populations worldwide.

METHODS

As part of the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three, 13- to 14-year-old children completed written and video questionnaires obtaining data on current symptoms of asthma, rhinoconjunctivitis, and eczema, and a written environmental questionnaire obtaining data on putative risk factors, including acetaminophen use in the past 12 months.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure was the odds ratio (OR) of current asthma symptoms associated with acetaminophen use calculated by logistic regression. A total of 322,959 adolescent children from 113 centers in 50 countries participated. In the multivariate analyses the recent use of acetaminophen was associated with an exposure-dependent increased risk of current asthma symptoms (OR, 1.43 [95% confidence interval, 1.33-1.53] and 2.51 [95% confidence interval, 2.33-2.70] for medium and high versus no use, respectively). Acetaminophen use was also associated with an exposure-dependent increased risk of current symptoms of rhinoconjunctivitis and eczema.

CONCLUSIONS

Acetaminophen use may represent an important risk factor for the development and/or maintenance of asthma, rhinoconjunctivitis, and eczema in adolescent children.

Metabolic imprinting, programming and epigenetics – a review of present priorities and future opportunities

Metabolic programming and metabolic imprinting describe early life events, which impact upon on later physiological outcomes. Despite the increasing numbers of papers and studies, the distinction between metabolic programming and metabolic imprinting remains confusing. The former can be defined as a dynamic process whose effects are dependent upon a critical window(s) while the latter can be more strictly associated with imprinting at the genomic level. The clinical end points associated with these phenomena can sometimes be mechanistically explicable in terms of gene expression mediated by epigenetics. The predictivity of outcomes depends on determining if there is causality or association in the context of both early dietary exposure and future health parameters. The use of biomarkers is a key aspect of determining the predictability of later outcome, and the strengths of particular types of biomarkers need to be determined. It has become clear that several important health endpoints are impacted upon by metabolic programming/imprinting. These include the link between perinatal nutrition, nutritional epigenetics and programming at an early developmental stage and its link to a range of future health risks such as CVD and diabetes. In some cases, the evidence base remains patchy and associative, while in others, a more direct causality between early nutrition and later health is clear. In addition, it is also essential to acknowledge the communication to consumers, industry, health care providers, policy-making bodies as well as to the scientific community. In this way, both programming and, eventually, reprogramming can become effective tools to improve health through dietary intervention at specific developmental points.

The role of paracetamol in the pathogenesis of asthma

Paracetamol use represents a putative risk factor for the development of asthma. There is convincing epidemiological evidence that the risk of asthma may be increased with exposure to paracetamol in the intrauterine environment, infancy, later childhood and adult life. A dose-dependent association has also been observed in these different age groups in different populations world-wide. An association has also been shown between paracetamol use in both rhinoconjunctivitis and eczema. There is biological plausibility with paracetamol use leading to decreased glutathione levels resulting in increased oxidant-induced inflammation and potentially enhanced T-helper type 2 responses. At the population level, patterns of paracetamol use might explain, to some extent, the world-wide variation in the prevalence of asthma and related disorders, particularly the high rates in English-speaking countries, which have high per capita prescription and over-the-counter use of paracetamol. A temporal association also exists between the international trends of increasing paracetamol use and increasing prevalence of asthma over recent decades. Further research is urgently required, in particular randomized-controlled trials (RCTs) into the long-term effects of frequent paracetamol use in childhood, to determine the magnitude and characteristics of any such risk. Importantly, RCTs will also enable evidence-based guidelines for the recommended use of paracetamol to be developed.