Antibiotics and asthma medication in a large register-based cohort study - confounding, cause and effect

No detrimental association between antibiotic use and immune checkpoint inhibitor therapy: an observational cohort study comparing patients with ICI-treated and TKI-treated melanoma and NSCLC

BACKGROUND

The role of antibiotics in malignancies treated with immune checkpoint inhibitors (ICI) remains unclear. Several studies suggested a detrimental impact of antibiotic use on the response to ICI, but were susceptible to confounding by indication. Our objective was therefore to assess whether the relationship between antibiotic use and ICI response is causative or merely associative.

METHODS

A large, single-center observational cohort study was performed with individuals treated for either non-small cell lung carcinoma (NSCLC) or metastatic melanoma. An effect modification approach was used, aiming to estimate the association between antibiotic use and overall survival (OS) and compare these estimates between individuals receiving first-line ICI treatment versus those receiving first-line tyrosine kinase inhibitors (TKIs). Exposure of interest was antibiotic use within 30 days before the start of anticancer treatment. HRs for OS were estimated for antibiotics versus no antibiotics in each cohort using multivariable propensity adjusted analysis. The "true antibiotic effect" within the ICI versus TKI cohort was modeled using an interaction term.

RESULTS

A total of 4534 patients were included, of which 1908 in the ICI cohort and 817 in the TKI cohort. Approximately 10% of patients in each cohort used antibiotics within 30 days before the start of anticancer treatment. Our results demonstrate a lack of synergistic interaction between current antibiotic use and ICI therapy in relation to OS: although antibiotic use was significantly associated with OS decline in the ICI cohort (HR=1.26 (95% CI 1.04 to 1.51)), a similar magnitude in OS decline was found within the TKI cohort (HR=1.24 (95% CI 0.95 to 1.62)). This was reflected by the synergy index (HR=0.96 (95% CI 0.70 to 1.31)), which implied no synergistic interaction between current antibiotic use and ICI.

CONCLUSION

This study strongly suggests that there is no causal detrimental association between antibiotic use and ICI therapy outcome when looking at OS in individuals with malignant melanoma or NSCLC. The frequently observed inverse association between antibiotics and ICI response in previous studies is most likely driven by confounding by indication, which was confirmed by the findings in our reference TKI cohort.

Effectiveness of Influenza Vaccination in Reducing Subsequent Antibiotic Prescribing in Young Children Attending Australian General Practices-A Case-Control Study

BACKGROUND

Vaccination against influenza may reduce antibiotic use, but data are limited and imprecise.

METHODS

We conducted a case-control study using deidentified data from a large national primary care database to evaluate antibiotic prescribing changes following influenza vaccination in children 1-4 years old attending primary care in the Australian 2018 and 2019 influenza seasons. Cases were prescribed β-lactam or macrolide antibiotics during the influenza season and controls were not. Influenza vaccination was documented in the medical records. Adjusted odds ratios for antibiotic prescribing according to influenza vaccination status were estimated using generalized estimating equations, controlling for age, asthma diagnosis, other vaccinations, practice visit frequency, and attendance week.

RESULTS

In 2018, 11 282 cases and 32 020 controls were eligible, and in 2019, 12 705 cases and 36 858 controls. Antibiotic prescriptions were less likely in vaccinated participants in 2018 (aOR, 0.65; 95% CI, 0.62-0.69) and 2019 (aOR, 0.78; 95% CI, 0.73-0.82) and did not vary by age, the number of GP visits, or prior prescribing of antibiotics. In the subgroup of children vaccinated in the preceding season, influenza vaccination was not associated with a reduction in antibiotic use (2018-aOR, 1.12; 95% CI, 0.90-1.39; 2019-aOR, 1.30; 95% CI, 1.16-1.46). From our estimates, potentially 100 000 antibiotic prescriptions could be avoided annually in Australia if all children in this age range were vaccinated.

CONCLUSIONS

Influenza vaccination may substantially reduce antibiotic prescribing among young children. This effect should be considered in the overall assessment of the costs and benefits of childhood influenza vaccination programs.

Influence of the early-life gut microbiota on the immune responses to an inhaled allergen

Antibiotics, among the most used medications in children, affect gut microbiome communities and metabolic functions. These changes in microbiota structure can impact host immunity. We hypothesized that early-life microbiome alterations would lead to increased susceptibility to allergy and asthma. To test this, mouse pups between postnatal days 5-9 were orally exposed to water (control) or to therapeutic doses of azithromycin or amoxicillin. Later in life, these mice were sensitized and challenged with a model allergen, house dust mite (HDM), or saline. Mice with early-life azithromycin exposure that were challenged with HDM had increased IgE and IL-13 production by CD4⁺ T cells compared to unexposed mice; early-life amoxicillin exposure led to fewer abnormalities. To test that the microbiota contained the immunological cues to alter IgE and cytokine production after HDM challenge, germ-free mice were gavaged with fecal samples of the antibiotic-perturbed microbiota. Gavage of adult germ-free mice did not result in altered HDM responses, however, their offspring, which acquired the antibiotic-perturbed microbiota at birth showed elevated IgE levels and CD4⁺ cytokines in response to HDM, and altered airway reactivity. These studies indicate that early-life microbiota composition can heighten allergen-driven Th2/Th17 immune pathways and airway responses in an age-dependent manner.

Antibiotic exposure and adverse long-term health outcomes in children: a systematic review and meta-analysis

BACKGROUND

Antibiotics are among the most commonly used drugs in children. In addition to inducing antibiotic resistance, antibiotic exposure has been associated with long-term adverse health outcomes.

METHODS

A systematic search using PRISMA Guidelines to identify original studies reporting associations between antibiotic exposure and long-term adverse health outcomes in children. Overall pooled estimates of the odds ratios (ORs) were obtained using fixed or random-effects models.

RESULTS

We identified 160 observational studies investigating 21 outcomes in 22,103,129 children. Antibiotic exposure was associated with an increased risk of atopic dermatitis (OR 1.40, 95% confidence interval (CI) 1.30-1.52, p<0.01), allergic symptoms (OR 1.93, 95%CI 1.66-2.26, p<0.01), food allergies (OR 1.35, 95%CI 1.20-1.52, p<0.01), allergic rhinoconjunctivitis (OR 1.66, 95%CI 1.51-1.83, p<0.01), wheezing (OR 1.81, 95%CI 1.65-1.97, p<0.01), asthma (OR 1.96, 95%CI 1.76-2.17, p<0.01), increased weight gain or overweight (OR 1.18, 95%CI 1.11-1.26, p<0.01), obesity (OR 1.21, 95%CI 1.05-1.40, p<0.01), juvenile idiopathic arthritis (OR 1.74, 95%CI 1.21-2.52, p<0.01), psoriasis (OR 1.75, 95%CI 1.44-2.11, p<0.01), autism spectrum disorders (OR 1.19, 95%CI 1.04-1.36, p=0.01) and neurodevelopment disorders (OR 1.29, 95%CI 1.09-1.53, p<0.01). Dose-response effects and stronger effects with broad-spectrum antibiotic were often reported. Antibiotic exposure was not associated with an altered risk of allergic sensitisation, infantile colic, abdominal pain, inflammatory bowel disease, celiac disease, type 1 diabetes, fluorosis, and attention deficit hyperactivity disorder.

CONCLUSION

Although a causal association cannot be determined from these studies, the results support the meticulous application of sound antibiotic stewardship to avoid potential adverse long-term health outcomes.

Association of infant antibiotic exposure and risk of childhood asthma: A meta-analysis

Background

Infant antibiotic exposure may be associated with childhood asthma development.

Objective

To examine and detail this association considering potential confounders.

Study design

PubMed, EMBASE, Web of Science, and the Cochrane Library were searched for publications from January 2011 to March 2021. Eligible studies were independently reviewed to extract data and assess quality. Random effect model was used to pool odds ratio (OR) and corresponding 95% confidence intervals (CIs).

Results

A total of 52 studies were included. The association of infant antibiotic exposure and childhood asthma was statistically significant for overall analysis (OR, 1.37; 95% CI, 1.29-1.45) and for studies that addressed reverse causation (RC) and confounding by indication (CbI) (1.19; 95% CI, 1.11-1.28). Significance remained after stratification by adjustment for maternal antibiotic exposure, medical consultation, sex, smoke exposure, parental allergy, birth weight, and delivery mode. In detailed analyses, macrolides (OR, 1.56; 95% CI, 1.31-1.86), antibiotic course≥5 (OR, 1.79; 95% CI, 1.36-2.36), exposure within 1 week of birth (OR, 1.82; 95% CI, 1.34-2.47), asthma developed among 1-3 years (OR, 1.84; 95% CI, 1.63-2.08), short time lag between exposure and asthma onset (OR, 2.05; 95% CI, 1.91-2.20), persistent asthma (OR, 2.61; 95% CI, 1.49-4.59), and atopic asthma (OR, 2.14; 95% CI, 1.58-2.90) showed higher pooled estimates.

Conclusion

Infant antibiotic exposure is associated with increased risk of childhood asthma considering confounding, and the association varied with different settings of exposure and outcomes. This highlights the need for prevention of asthma after early antibiotic exposure. Heterogeneity among studies called for caution when interpretation.

Maternal antibiotic use during pregnancy and asthma in children: population-based cohort study and sibling design

Antibiotic use during pregnancy may affect asthma risk in offspring. However, epidemiological studies yielded conflicting findings, with an observed association possibly confounded by shared familial factors. We sought to assess the association between maternal antibiotic use during pregnancy and childhood asthma in the offspring, by accounting for time-stable familial factors.We conducted a population-based cohort study and sibling study using data from Danish nationwide registers, which comprised 407 804 liveborn singletons from 2005 to 2011. Antibiotic use during pregnancy was defined as at least one antibiotic prescription filled by the mother from 1 month prior to pregnancy up until delivery, identified in the National Prescription Registry. First-time asthma in the offspring was determined by hospital treatment or asthma medication treatment after age 5 years. We estimated hazard ratios (HRs) of asthma using Cox regression in the population-based cohort and stratified Cox regression in the sibling cohort.Approximately 36.5% of pregnant women redeemed antibiotic prescriptions. Antibiotic use during pregnancy was associated with childhood asthma in cohort analyses (HR 1.21, 95% CI 1.18-1.24), but not in sibling analyses (HR 0.96, 95% CI 0.90-1.03). In the population-based analyses, higher risks of asthma were seen with longer duration of maternal antibiotic use, a higher number of prescriptions and prescriptions of multiple types of antibiotics. All these associations disappeared in the sibling analyses.The associations observed by previous studies for prenatal exposure to antibiotics and offspring asthma risk are likely to be due to confounding factors shared within families.

First-Year Antibiotics Exposure in Relation to Childhood Asthma, Allergies, and Airway Illnesses

Background: Associations of early antibiotics exposures with childhood asthma, allergies, and airway illnesses are debated. Objectives: We aimed to investigate associations of first-year antibiotics exposure with childhood asthma, allergies, and airway illnesses. Methods: A cross-sectional study was conducted among preschoolers in Shanghai, China during 2011–2012. A questionnaire regarding household environment and lifestyles and childhood health outcomes was reported by the child’s parents. Results: In total, 13,335 questionnaires (response rate: 85.3%) were analyzed and 3049 (24.1%) children had first-year antibiotics exposure. In the multivariate logistic regression analyses, first-year antibiotics exposure had significant associations with the higher odds of lifetime-ever pneumonia (adjusted OR, 95% CI: 2.15, 1.95–2.37), croup (1.46, 1.24–1.73), wheeze (1.44, 1.30–1.60), asthma (1.38, 1.19–1.61), food allergy (1.29, 1.13–1.46), and allergic rhinitis (1.23, 1.07–1.41), and as well as current (one year before the survey) common cold (≥3 times) (1.38, 1.25–1.52), dry cough (1.27, 1.13–1.42), atopic dermatitis (1.25, 1.09–1.43), wheeze (1.23, 1.10–1.38), and rhinitis symptoms (1.15, 1.04–1.26). These associations were different in children with different individual characteristics (age, sex, family history of atopy, and district) and other early exposures (breastfeeding, home decoration, pet-keeping, and environmental tobacco smoke). Conclusions: Our results indicate that first-year antibiotics exposure could be a strong risk factor for childhood pneumonia, asthma, allergies, and their related symptoms. The individual characteristics and other early exposures may modify effects of early antibiotic exposure on childhood allergies and airway illnesses.

The relationship of prenatal antibiotic exposure and infant antibiotic administration with childhood allergies: a systematic review

Background

Early antibiotic exposure may be contributing to the onset of childhood allergies. The main objective of this study was to conduct a systematic review on the relationship between early life antibiotic exposure and childhood asthma, eczema and hay fever.

Methods

Pubmed and Embase were searched for studies published between 01-01-2008 and 01-08-2018, examining the effects of (1) prenatal antibiotic exposure and (2) infant antibiotic administration (during the first 2 years of life) on childhood asthma, eczema and hay fever from 0 to 18 years of age. These publications were assessed using the Newcastle Ottawa Scale (NOS) and analysed narratively.

Results

(1) Prenatal antibiotics: Asthma (12 studies): The majority of studies (9/12) reported significant relationships (range OR 1.13 (1.02–1.24) to OR 3.19 (1.52–6.67)). Three studies reported inconsistent findings. Eczema (3 studies): An overall significant effect was reported in one study and in two other studies only when prenatal antibiotic exposure was prolonged. (2) Infant antibiotics: Asthma (27 studies): 17/27 studies reported overall significant findings (range HR 1.12 (1.08–1.16) to OR 3.21 (1.89–5.45)). Dose-response effects and stronger effects with broad-spectrum antibiotic were often reported. 10/27 studies reported inconsistent findings depending on certain conditions and types of analyses. Of 19 studies addressing reverse causation or confounding by indication at least somewhat, 11 reported overall significant effects. Eczema (15 studies): 6/15 studies reported overall significant effects; 9 studies had either insignificant or inconsistent findings. Hay fever (9 studies): 6/9 reported significant effects, and the other three insignificant or inconsistent findings. General: Multiple and broad-spectrum antibiotics were more strongly associated with allergies. The majority of studies scored a 6 or 7 out of 9 based on the NOS, indicating they generally had a medium risk of bias. Although most studies showed significant findings between early antibiotic exposure and asthma, the actual effects are still unclear as intrapartum antibiotic administration, familial factors and confounding by maternal and child infections were often not addressed.

Conclusions

This review points to a moderate amount of evidence for a relationship between early life antibiotics (especially prenatal) and childhood asthma, some evidence for a relationship with hay fever and less convincing evidence for a relationship with eczema. More studies are still needed addressing intra-partum antibiotics, familial factors, and possible confounding by maternal and childhood infections. Children exposed to multiple, broad-spectrum antibiotics early in life appear to have a greater risk of allergies, especially asthma; these effects should be investigated further.

Infection, antibiotic exposure and development of atopic dermatitis: A nationwide case-control study

Previous studies suggest an association between atopic dermatitis (AD) and exposure to microorganisms and antibiotics. However, these studies have limitations, and the sole influence on the development of AD was elusive. We performed a nationwide population-based case-control study in a Korean population to investigate the association between AD and early-life infection or antibiotic exposure. A total of 244 805 children with AD from the 2 283 601 children born between January 2010 and December 2014 and an equal number of sex- and age-matched healthy children were enrolled. A conditional logistic regression analysis showed that the episode of infection and antibiotic exposure were associated with an increased risk of AD (odds ratio [OR], 1.60; 95% confidence interval [CI], 1.58-1.63 for infection; and OR, 1.11; 95% CI, 1.09-1.13 for antibiotic exposure). A dose-dependent relationship was observed between risk for AD, the number of infection episodes and antibiotic cycles and the duration of antibiotic exposure. On further analysis using a conditional logistic model, the risk of AD was less when the antibiotics were used during the infection episode than that without the use of antibiotics, especially if the duration of the infection was short. Although our study could not consider the effect of cause or severity of infection, class of antibiotics and genetic or environmental factors of enrolled subjects, our results suggested that infection and antibiotic exposure were associated with an increased risk of AD. In addition, the results also implied that the use of antibiotics during an infection episode can decrease the risk of AD induced by the infection and that appropriate management of infections can minimize the risk of AD induced by infection or antibiotics.

Early Childhood Antibiotic Treatment for Otitis Media and Other Respiratory Tract Infections Is Associated With Risk of Type 1 Diabetes: A Nationwide Register-Based Study With Sibling Analysis

OBJECTIVE

The effect of early-life antibiotic treatment on the risk of type 1 diabetes is debated. This study assessed this question, applying a register-based design in children up to age 10 years including a large sibling-control analysis.

RESEARCH DESIGN AND METHODS

All singleton children (n = 797,318) born in Sweden between 1 July 2005 and 30 September 2013 were included and monitored to 31 December 2014. Cox proportional hazards models, adjusted for parental and perinatal characteristics, were applied, and stratified models were used to account for unmeasured confounders shared by siblings.

RESULTS

Type 1 diabetes developed in 1,297 children during the follow-up (median 4.0 years [range 0-8.3]). Prescribed antibiotics in the 1st year of life (23.8%) were associated with an increased risk of type 1 diabetes (adjusted hazard ratio [HR] 1.19 [95% CI 1.05-1.36]), with larger effect estimates among children delivered by cesarean section (P for interaction = 0.016). The association was driven by exposure to antibiotics primarily used for acute otitis media and respiratory tract infections. Further, we found an association of antibiotic prescriptions in pregnancy (22.5%) with type 1 diabetes (adjusted HR 1.15 [95% CI 1.00-1.32]). In general, sibling analysis supported these results, albeit often with statistically nonsignificant associations.

CONCLUSIONS

Dispensed prescription of antibiotics, mainly for acute otitis media and respiratory tract infections, in the 1st year of life is associated with an increased risk of type 1 diabetes before age 10 years, most prominently in children delivered by cesarean section.

Dose, Timing, and Type of Infant Antibiotic Use and the Risk of Childhood Asthma

BACKGROUND

Aspects of infant antibiotic exposure and its association with asthma development have been variably explored. We aimed to evaluate comprehensively and simultaneously the impact of dose, timing, and type of infant antibiotic use on the risk of childhood asthma.

METHODS

Singleton, term-birth, non-low-birth-weight, and otherwise healthy children enrolled in the Tennessee Medicaid Program were included. Infant antibiotic use and childhood asthma diagnosis were ascertained from prescription fills and healthcare encounter claims. We examined the association using multivariable logistic regression models.

RESULTS

Among 152 622 children, 79% had at least 1 antibiotic prescription fill during infancy. Infant antibiotic use was associated with increased odds of childhood asthma in a dose-dependent manner, with a 20% increase in odds (adjusted odds ratio [aOR], 1.20 [95% confidence interval {CI}, 1.19-1.20]) for each additional antibiotic prescription filled. This significant dose-dependent relationship persisted after additionally controlling for timing and type of the antibiotics. Infants who had broad-spectrum-only antibiotic fills had increased odds of developing asthma compared with infants who had narrow-spectrum-only fills (aOR, 1.10 [95% CI, 1.05-1.19]). There was no significant association between timing, formulation, anaerobic coverage, and class of antibiotics and childhood asthma.

CONCLUSIONS

We found a consistent dose-dependent association between antibiotic prescription fills during infancy and subsequent development of childhood asthma. Our study adds important insights into specific aspects of infant antibiotic exposure. Clinical decision making regarding antibiotic stewardship and prevention of adverse effects should be critically assessed prior to use during infancy.

Too much? Mortality and health service utilisation among Danish children 1999-2016: A register-based study

OBJECTIVES

To describe the temporal development of mortality and health service utilisation defined as in- and outpatient hospital contacts, contacts with general practitioner and specialists, and prescribed dispensed medication among Danish children 0-5 years of age from 1999 to 2016.

DESIGN

Register-based descriptive study.

PARTICIPANTS

All children born in Denmark in the period 1994-2016 followed until 5 years of age.

MAIN OUTCOME MEASURES

Annual incidence rates of mortality and health service utilisation outcomes, and incidence rate ratios compared to the reference calendar year 1999. The new measure of post-discharge mortality is presented.

RESULTS

Post-discharge mortality decreased from 1999 to 2016, IRR2016 = 0.49 (95% CI: 0.36 to 0.66). Total contacts did not change much over time, IRR2016 = 1.02 (1.02 to 1.03), but increased among neonates, IRR2016 = 3.69 (3.63 to 3.75), and decreased among children with chronic disease IRR2016 = 0.94 (0.93 to 0.94). In- and out-patient hospitalisations increased, IRR2016 = 1.26 (1.24-1.27) resp. IRR2016 = 1.62 (1.60-1.63), contacts with medical specialists increased, IRR2016 = 1.43 (1.42 to 1.43), whilst contacts with general practitioner decreased, IRR2016 = 0.91 (0.91 to 0.91). Medication use decreased, IRR2016 = 0.82 (0.82 to 0.82).

CONCLUSIONS

Our measure of post-discharge mortality was halved during the study period indicating improved health. Overall health service utilisation did not change much, but the type of utilisation changed, and the development over time differed between subgroups defined by age and chronic disease status. Our findings call for considerations about the benefit of increased specialisation and increased use of health services among 'healthy' children not suffering from chronic disease.

Early-Life Exposure to Oral Antibiotics and Lung Function Into Early Adulthood

BACKGROUND

Although there is ongoing debate regarding the impact of early postnatal exposure to antibiotics on the development of asthma, the possibility that antibiotic exposure may impair lung function has not previously been examined. Furthermore, it is unclear if specific types of antibiotics may have a greater effect, or if children with genetic mutations in the oxidative stress response glutathione S-transferase (GST) superfamily may be at greater risk.

METHODS

Parent-reported data of childhood antibiotic use from birth to 2 years, including type and indication, were collected from a birth cohort of 620 infants with a family history of allergy. Spirometry was performed at age 12 and 18 years, and results are presented as z scores. Participants were genotyped for GST-P, GST-M, and GST-T polymorphisms. Linear regression models were used to investigate the associations while adjusting for confounding factors.

RESULTS

Neither increasing days of exposure nor earlier exposure to antibiotics was associated with reduced FEV₁ (at 18 years, per doubling of days of exposure = -0.03 z score units; 95% CI, -0.11 to 0.04) or FVC (< 0.01; 95% CI, -0.08 to 0.07). There was no evidence that GST-risk polymorphisms (M1, P1, and T1) increased susceptibility, and specific types of antibiotics also did not increase risk of lung function deficits.

CONCLUSIONS

Increasing exposure to oral antibiotics in early postnatal life was not associated with reduced lung function in children with a family history of allergic diseases. Although unwarranted use of antibiotics in children should be minimized, concerns regarding long-term lung health should not be a driving influence for this rationalization of use.

Association between early-childhood antibiotic exposure and subsequent asthma in the US Medicaid population

BACKGROUND

Although socioeconomically disadvantaged children have an increased risk of asthma, the association between early-childhood antibiotics and the incidence of asthma among such children has had limited study.

OBJECTIVE

To examine the association between antibiotic fills in the first 2 years of life and risk of developing asthma among children enrolled in Medicaid plans.

METHODS

This retrospective cohort study of children with continuous medical and pharmacy coverage from birth to 2.5 years of age was performed from July 1, 2012, to November 31, 2018. We excluded children with a diagnosis of asthma before 2.5 years of age. Hazard ratios (HRs) and 95% CIs were estimated from Cox proportional hazards regression models. Covariates included sex, preterm birth, cesarean delivery, and mother's asthma status.

RESULTS

There were 79,582 children in the study cohort of whom 29,931 (37.6%) had 0 antibiotic prescriptions filled, 27,403 (34.4%) had 1 or 2 prescriptions filled, and 22,248 (28.0%) had 3 or more prescriptions filled. A total of 2381 new cases of asthma were observed in 89,545 person-years of follow-up. After adjustment, receipt of 1 or 2 antibiotics was associated with an increased risk of developing asthma, relative to 0 antibiotics (HR, 1.34; 95% CI, 1.21-1.49), and receipt of 3 or more antibiotics was associated with greater increased risk relative to 0 antibiotics (HR, 1.71; 95% CI, 1.54-1.90). After adjustment, the absolute risk of developing asthma by age 4.0 years increased from 2.7% (0 antibiotics) to 3.6% (1-2 antibiotics) and 4.5% (≥3 antibiotics).

CONCLUSION

Antibiotic prescriptions filled in the first 2 years of life were associated with an increased risk of asthma diagnosis from 2.5 to 5 years of age in a Medicaid population.

Antibiotics and autoimmune and allergy diseases: Causative factor or treatment?

The newborn infant emerges from an almost sterile environment into a world of bacteria. Bacteria colonize the infant's skin, lungs, and, of most importance, the gut. The process of bacterial colonization is coordinated, and each body niche acquires a unique composition of bacteria. In the gut, most bacteria belong to the Firmicutes and Bacteroidetes phyla, while Actinobacteria and Proteobacteria are far less abundant. Some of these bacteria possess strong immunoregulatory properties. Bacterial colonization is essential to skew the newborn's immune response away from the allergy-favoring Type-2 response towards a Type-1 immune response, which is essential for pathogen elimination. Imbalance between Type 1 and Type 2 responses, however, can promote autoimmunity. In addition, the microbiota shapes immune responses in adults. Autoimmune and allergic diseases are commonly associated with an altered composition of resident bacteria, which is known as dysbiosis. Perhaps the most common cause of disruption and alteration of the bacterial colonization of newborns is the use of antibiotics. It is not known whether the dysbiosis precedes or is the consequence of allergic and autoimmune disorders, and whether antibiotics can be a trigger for these disorders, depending on the type of antibiotic used and the maturity of immune system. In this review, we discuss the development of the microbiota in different body niches and their immunomodulatory potential. We evaluate the impact of antibiotics, both in mice and in humans, on microbial communities and how that may impact the development and manifestation of diseases through all stages of life: the prenatal period, childhood, and adulthood.

Assessment of Medication Safety Using Only Dispensing Data

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of the published studies that have been used to generate evidence on the safety of medicine use when only medication dispensing data are available.

RECENT FINDINGS

Medication dispensing databases are increasingly available for research on large populations, particularly in countries that provide universal coverage for medicines. These data are often used for drug utilisation studies to identify inappropriate medicine use at the population level that may be associated with known safety issues. Lack of coded diagnoses, to identify outcomes, and lack of data on confounders can limit use of these data in practice for medication safety assessment. To overcome these issues, studies have exploited the fact that symptoms of adverse effects of medications can be treated with other medications, for example antidepressants to treat depression or oxybutynin to treat urinary incontinence. The challenge of unmeasured confounding has been addressed by implementing self-controlled study designs that use within-person comparisons and provide inherent control for confounding. Prescription sequence symmetry analysis (SSA) is a within-person study design that has been demonstrated as a useful tool for safety signal generation in dispensing data.

SUMMARY

Using medicine initiation as a proxy for the development of adverse events can help to generate evidence of the safety of medicines when only medication dispensing data are available. Careful consideration, however, should be given to the sensitivity and specificity of the proxy medicine for the adverse event and potential for time-varying confounding due to trends in medicine utilisation. Data-mining approaches using dispensing data have the potential to improve safety assessments; however, the challenge of unmeasured confounding with these methods remains to be investigated.

Prenatal antibiotic exposure and childhood asthma: a population-based study

Antibiotic use during infancy alters gut microbiota and immune development and is associated with an increased risk of childhood asthma. The impact of prenatal antibiotic exposure is unclear. We sought to characterise the association between prenatal antibiotic exposure and childhood asthma.We performed a population-based cohort study using prescription records, hospitalisation records and physician billing claims from 213 661 mother-child dyads born in Manitoba, Canada between 1996 and 2012. Associations were determined using Cox regression, adjusting for maternal asthma, postnatal antibiotics and other potential confounders. Sensitivity analyses evaluated maternal antibiotic use before and after pregnancy.36.8% of children were exposed prenatally to antibiotics and 10.1% developed asthma. Prenatal antibiotic exposure was associated with an increased risk of asthma (adjusted hazard ratio (aHR) 1.23, 95% CI 1.20-1.27). There was an apparent dose response (aHR 1.15, 95% CI 1.11-1.18 for one course; aHR 1.26, 95% CI 1.21-1.32 for two courses; and aHR 1.51, 95% CI 1.44-1.59 for three or more courses). Maternal antibiotic use during 9 months before pregnancy (aHR 1.27, 95% CI 1.24-1.31) and 9 months postpartum (aHR 1.32, 95% CI 1.28-1.36) were similarly associated with asthma.Prenatal antibiotic exposure was associated with a dose-dependent increase in asthma risk. However, similar associations were observed for maternal antibiotic use before and after pregnancy, suggesting the association is either not directly causal, or not specific to pregnancy.

Antibiotic Treatment and Length of Hospital Stay in Relation to Delivery Mode and Prematurity

Aim

To investigate how 1) maternal delivery mode and 2) prematurity in infants are associated to antibiotic treatment and length of hospital stay.

Methods

Women having given birth and infants 0–12 months discharged from hospital between July 2005 and November 2011 were identified from the Swedish National Patient Register. Medical records were reviewed for 203 women and 527 infants. The risk ratio (RR) between antibiotic treatment and 1) delivery mode in women; 2) prematurity in infants was calculated. Length of stay and days of antibiotic therapy were compared by Wilcoxon rank-sum test.

Results

Women: There was an association between emergency caesarean section (CS) and antibiotic treatment (RR 5.0 95% confidence interval (CI) 2.2–11.5), but not for elective CS. Length of stay was longer for CS (emergency and elective) compared to vaginal delivery (p<0.01). Infants: RR for antibiotic treatment in preterm compared to term infants was 1.4 (95% CI 1.0–1.9). Length of stay (p<0.01), but not days of therapy (p = 0.17), was higher in preterm compared to term infants.

Conclusion

We found that emergency CS increased the probability of maternal antibiotic treatment during hospitalisation, but no difference was found between term and preterm infants. The results are well aligned with current guidelines and may be considered in future studies on the effects of antibiotics.

Prenatal and early-life predictors of atopy and allergic disease in Canadian children: results of the Family Atherosclerosis Monitoring In earLY life (FAMILY) Study

Prenatal and early-life environmental exposures play a key role in the development of atopy and allergic disease. The Family Atherosclerosis Monitoring In earLY life Study is a general, population-based Canadian birth cohort that prospectively evaluated prenatal and early-life traits and their association with atopy and/or allergic disease. The study population included 901 babies, 857 mothers and 530 fathers. Prenatal and postnatal risk factors were evaluated through questionnaires collected during the antenatal period and at 1 year. The end points of atopy and allergic diseases in infants were evaluated through questionnaires and skin prick testing. Key outcomes included atopy (24.5%), food allergy (17.5%), cow’s milk allergy (4.8%), wheezing (18.6%) and eczema (16%). The association between infant antibiotic exposure [odds ratio (OR): 2.04, 95% confidence interval (CI): 1.45–2.88] and increased atopy was noted in the multivariate analysis, whereas prenatal maternal exposure to dogs (OR: 0.60, 95% CI: 0.42–0.84) and acetaminophen (OR: 0.68, 95% CI: 0.51–0.92) was associated with decreased atopy. This population-based birth cohort in Canada demonstrated high rates of atopy, food allergy, wheezing and eczema. Several previously reported and some novel prenatal and postnatal exposures were associated with atopy and allergic diseases at 1 year of age.

Childhood allergies and asthma: New insights on environmental exposures and local immunity at the lung barrier

While certain bacteria and respiratory viruses promote local inflammation and disease onset, a more diverse colonization of the different species in the (gut) microbiome may be linked to more regulatory responses and protection against asthma and allergies. These processes are also influenced in part by food intake, both targeting the composition of the gut microbiome and influencing the immune system via metabolites. Early life environmental microbial exposure also contributes to protection against asthma and allergy and is linked with an early activation of the innate immune system and the development of regulatory immune responses. Although greater mechanistic insight is needed, it is tempting to speculate that part of the environmental effect can be explained by modulation of the microbiome composition at mucosal surfaces, epithelial barrier function and/or local immunity. A review of the latest studies is provided.

Prenatal and post-natal exposure to antibiotics and risk of asthma in childhood

BACKGROUND

Evidence on the association between post-natal exposure to antibiotics and the development of asthma is extensive, but inconsistent and even less is known about prenatal exposure.

OBJECTIVE

The aim of this study was to examine the associations between prenatal and post-natal exposure to different antibiotics and the risk of childhood asthma in a population- and register-based nested case-control study.

METHODS

All children who were born in 1996-2004 in Finland and diagnosed with asthma by 2006 were identified from a national health register. For each case, one matched control was selected. Information on asthma diagnoses, purchased anti-asthmatic drugs and antibiotics as well as putative confounders was obtained from national health registries. The associations were analysed using conditional logistic regression for children diagnosed at the age of 3 years or later (n = 6 690 case-control pairs).

RESULTS

Maternal use of any antibiotics during pregnancy was associated with an increased risk of asthma in the offspring [adjusted odds ratio (OR) = 1.31 (95% confidence interval (CI): 1.21-1.42)]. Several maternal specific antibiotics were associated with the risk of asthma, and the strongest association was observed for cephalosporins [OR = 1.46 (95% CI 1.30-1.64)]. Child's use of antibiotics during the first year of life was associated with an increased risk of asthma [OR = 1.60 (95% CI 1.48-1.73)]. Child's use of cephalosporins [OR = 1.79 (95% CI 1.59-2.01)], sulphonamides and trimethoprim [OR = 1.65 (95% CI 1.34-2.02)], macrolides [OR = 1.61 (95% CI 1.46-1.78)] and amoxicillin [OR = 1.46 (95% CI 1.35-1.58)] was associated with an increased risk of asthma.

CONCLUSIONS AND CLINICAL RELEVANCE

Both prenatal and post-natal exposure to antibiotics was associated with an increased risk of asthma. The potential role of adverse effects of antibiotics on the gut microbiota and the development of asthma should be further explored.

Prevalence, Severity, and Treatment of Recurrent Wheezing During the First Year of Life: A Cross-Sectional Study of 12,405 Latin American Infants

PURPOSE

This study aimed to determine the prevalence and severity of recurrent wheezing (RW) defined as ≥3 episodes of wheezing, risk factors, and treatments prescribed during the first year of life in Latin American infants.

METHODS

In this international, cross-sectional, and community-based study, parents of 12,405 infants from 11 centers in 6 South American countries (Argentina, Brazil, Chile, Colombia, Peru, and Uruguay) completed a questionnaire about wheezing and associated risk/protective factors, asthma medications, and the frequency of and indications for the prescription of antibiotics and paracetamol during the first year of life.

RESULTS

The prevalence of RW was 16.6% (95% CI 16.0-17.3); of the 12,405 infants, 72.7% (95% CI 70.7-74.6) visited the Emergency Department for wheezing, and 29.7% (27.7-31.7) was admitted. Regarding treatment, 49.1% of RW infants received inhaled corticosteroids, 55.7% oral corticosteroids, 26.3% antileukotrienes, 22.9% antibiotics ≥4 times mainly for common colds, wheezing, and pharyngitis, and 57.5% paracetamol ≥4 times. Tobacco smoking during pregnancy, household income per month <1,000 USD, history of parental asthma, male gender, and nursery school attendance were significant risk factors for higher prevalence and severity of RW, whereas breast-feeding for at least 3 months was a significant protective factor. Pneumonia and admissions for pneumonia were significantly higher in infants with RW as compared to the whole sample (3.5-fold and 3.7-fold, respectively).

CONCLUSIONS

RW affects 1.6 out of 10 infants during the first year of life, with a high prevalence of severe episodes, frequent visits to the Emergency Department, and frequent admissions for wheezing. Besides the elevated prescription of asthma medications, there is an excessive use of antibiotics and paracetamol in infants with RW and also in the whole sample, which is mainly related to common colds.

Antibiotic exposure in the first year of life and later treated asthma, a population based birth cohort study of 143,000 children

Several epidemiological studies reported an association between antibiotic consumption in the first year of life and later asthma, but results are conflicting and affected by potential biases. We examined this controversial issue in a population-based birth cohort. Using administrative data, we identified 143,163 children born in 1995-2011 in Friuli-Venezia Giulia (Italy) (median follow-up 5.25 years, 927,350 person-years). Antibiotic prescriptions in the first year of life and subsequent treated asthma (defined as ≥2 anti-asthmatic drug prescriptions within a 12-month period) were retrieved from drug prescription records. We estimated incidence rate ratios (IRR) using Poisson regression models, adjusted for perinatal variables and for hospitalizations for infections in the first year of life. We identified 34,957 new-onset asthma cases. Antibiotic consumption in the first year of life increased the risk of new-onset asthma [IRR 1.51, 95% confidence interval (CI) 1.48-1.54] with a dose-response relationship (p-trend <0.001). The risk was highest for asthma identified at 13-35 months of life (IRR 2.07, 95% CI 2.00-2.14), but remained statistically significant for asthma identified at 36-71 months (IRR 1.17, 95% CI 1.14-1.21) and at ≥72 months (IRR 1.15, 95% CI 1.08-1.22). Antibiotics increased the risk of current asthma at ≥6 years (IRR 1.35, 95% CI 1.30-1.41) and at ≥13 years of age (IRR 1.19, 95% CI 1.08-1.33). Antibiotic exposure in infancy is associated with an increased risk of asthma up to adolescence. The association detected at older ages is not explained by reverse causation; however, confounding by respiratory infections not leading to hospital admission cannot be excluded.

Individual maternal and child exposure to antibiotics in hospital - a national population-based validation study

AIM

Exposure to antibiotics in early life may affect future health. Most antibiotics are prescribed in outpatient care, but inpatient exposure is also important. We estimated how specific diagnoses in hospitals corresponded to individual antibiotic exposure.

METHODS

All pregnant women and children from birth to 5 years of age with infectious diseases and common inpatient diagnoses between July 2005 and November 2011 were identified from the Swedish National Patient Register. Random samples of individuals from predefined groups were drawn, and medical records received from the clinics were manually reviewed for antibiotics.

RESULTS

Medical records for 4319 hospital visits were requested and 3797 (88%) were received. A quarter (25%) of children diagnosed as premature had received antibiotics, and in children from one to 5 years of age, diagnoses associated with bacterial infections were more commonly treated with antibiotics (62.4-90.6%) than those associated with viruses (6.3-22.2%). Pregnant women who had undergone a Caesarean section were more likely to be treated with antibiotics than those who had had a vaginal delivery (40.1% versus 11.1%).

CONCLUSION

This study defines the proportion of new mothers and young children who received individual antibiotic treatment for specific inpatient diagnoses in Sweden and provides a useful basis for future studies focusing on antibiotic use.

Antibiotics in fetal and early life and subsequent childhood asthma: nationwide population based study with sibling analysis

OBJECTIVE

To investigate the association between exposure to antibiotics in fetal and early life and asthma in childhood, with adjustment for confounding factors.

DESIGN

Nationwide prospective population based cohort study, including sibling control design.

SETTING

Swedish population identified from national demographic and health registers.

PARTICIPANTS

493,785 children born 2006-10; 180,894 of these were eligible for sibling analyses.

MAIN OUTCOME MEASURE

Asthma defined as having both an asthma diagnosis and dispensed asthma drugs. The association between antibiotic exposure and asthma was investigated in the whole cohort with Cox proportional hazard regression. A stratified proportional hazards model conditional on sibling group was used to adjust for shared factors within families. Confounding by respiratory infections was assessed by investigating whether specific groups of antibiotics were associated with asthma.

RESULTS

Antibiotic exposure in fetal life was associated with an increased risk of asthma in cohort analyses (hazard ratio 1.28, 95% confidence interval 1.25 to 1.32), but not in sibling analyses (0.99, 0.92 to 1.07). In cohort analyses, antibiotics used to treat respiratory infections in childhood were associated with a more pronounced increased risk of asthma (4.12, 3.78 to 4.50) than antibiotics used for urinary tract and skin infections (1.54, 1.24 to 1.92). In sibling analyses, the excess risks after exposure to antibiotics for respiratory infections decreased (2.36, 1.78 to 3.13) and disappeared for antibiotics for urinary tract and skin (0.85, 0.47 to 1.55).

CONCLUSIONS

Previous positive associations between exposure to antibiotics in fetal and early life and subsequent childhood asthma could have been caused by confounding by shared familial factors, in addition to confounding by respiratory infections.

Assessing the association of early life antibiotic prescription with asthma exacerbations, impaired antiviral immunity, and genetic variants in 17q21: a population-based birth cohort study

BACKGROUND

The relationship between early-life antibiotic use and the development of wheeze and asthma has been reported in several studies but might arise as a consequence of bias rather than causal relationship. We investigated the association between antibiotic prescription and subsequent development of atopy, wheeze, and asthma exacerbations, and the relation of early life antibiotic prescription with anti-infective immunity and genetic variants on asthma susceptibility locus 17q21.

METHODS

Children in a population-based birth cohort were followed from birth to age 11 years. Information on antibiotic prescription, wheeze, and asthma exacerbations was extracted from medical records, and the effect of antibiotic prescription assessed with longitudinal analyses. We assessed immune responses of peripheral blood mononuclear cells, taken at age 11 years, to viruses (rhinovirus and respiratory syncytial virus; RSV) and bacteria (Haemophilus influenzae and Streptococcus pneumoniae) in children who either received at least one or no antibiotic prescriptions in infancy. Finally, we assessed the association of 17q21 polymorphisms with antibiotic prescription.

FINDINGS

Of 984 families who gave consent, we extracted data for 916 children. We noted significantly higher risk of physician-confirmed wheezing after antibiotic prescription (hazard ratio [HR] 1·71, 95% CI 1·32-2·23; p<0·0001) and severe wheeze or asthma exacerbation after antibiotic prescription (HR 2·26, 95% CI 1·03-4·94; p=0·041). In children who wheezed, the hazards of exacerbations (2·09, 1·51-2·90; p<0·0001) and admissions to hospital (2·64, 1·49-4·70; p=0·0009) were significantly increased in the 2 years after the first antibiotic prescription. Children who received antibiotics in infancy had significantly lower induction of cytokines, which are important in host defence against virus infections to both RSV and rhinovirus; there were no differences in antibacterial responses. Variants in 17q21 were associated with an increased risk of early life antibiotic prescription.

INTERPRETATION

The association between antibiotics and asthma might arise through a complex confounding by indication. Hidden factors that may increase the likelihood of both early life antibiotic prescription and later asthma are an increased susceptibility to viral infections consequent upon impaired antiviral immunity and genetic variants on 17q21.

FUNDING

Moulton Charitable Foundation and Medical Research Council.

Use of antibiotics in infancy and childhood and risk of recurrent abdominal pain--a Swedish birth cohort study

BACKGROUND

The etiology of recurrent abdominal pain of functional origin (AP) is largely unknown. Antibiotic treatment influences the intestinal microbiota, and a few studies have indicated an increased risk of AP in adults after antibiotic treatment. Corresponding data in children are lacking. The aim of this study was to explore the association between antibiotic treatment during childhood and AP at 12 years.

METHODS

Two thousand seven hundred and thirty-two children from a Swedish, population-based birth cohort. Parents reported antibiotic use for the children between birth and 2 years. Antibiotic use between 9 and 12 years was collected from the Swedish Prescribed Drug Register. The children answered questionnaires regarding AP at age 12. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for AP at 12 years as a function of antibiotic use.

KEY RESULTS

Antibiotic treatment between 9 and 12 years was not associated with AP at 12. Children who had received ≥3 courses, or broad-spectrum antibiotics between 9 and 12 years had an increased risk of AP at 12, but these associations failed to reach statistical significance. Antibiotic treatment during both the first and the second year of life increased the risk of AP in girls at 12 (OR 1.65; 95% CI: 1.09-2.49), but not in boys or the whole cohort.

CONCLUSIONS & INFERENCES

Antibiotic treatment does not seem to be a major risk factor for AP at 12 years. However, we cannot exclude that repeated courses, especially to infant girls, or use of broad-spectrum antibiotics between 9 and 12 years may be associated with an increased risk of AP.

Acetaminophen and/or antibiotic use in early life and the development of childhood allergic diseases

BACKGROUND

Our understanding of whether the use of acetaminophen and/or antibiotics in early life can cause allergic diseases in later childhood remains inconclusive. The objective of this study was to investigate the temporal relationship between exposure to acetaminophen and/or antibiotics in early life and the development of allergic diseases in later childhood, using two independent birth cohorts derived from the National Health Insurance Research Database (NHIRD) in Taiwan.

METHODS

The authors conducted a prospective birth cohort study of 263 620 children born in 1998 and 9910 children born in 2003, separately, from the NHIRD. Exposure status of acetaminophen and/or antibiotics and potential confounding factors were included in the analyses. Cox proportional hazards models were applied to determine the temporal relationship between acetaminophen and/or antibiotic exposure and the development of allergic diseases.

RESULTS

We observed a positive relationship between acetaminophen and/or antibiotic exposure during the 1st year of life and the subsequent development of the three examined allergic diseases (atopic dermatitis, asthma and allergic rhinitis) in the 1998 birth cohort, but the observed relationship of drug exposure in the 2003 cohort, especially for atopic dermatitis and asthma, was lower than for those in the 1998 cohort and was not statistically significant.

CONCLUSIONS

Our findings provide suggestive evidence that the temporal effect of exposure to acetaminophen and/or antibiotics influences the development of common allergic diseases in later childhood. Further functional studies and/or animal studies are needed to better understand the underlying regulatory mechanisms driving this important clinical and public health issue.

Consequences of antibiotics and infections in infancy: bugs, drugs, and wheezing

BACKGROUND

The prevalence of asthma has increased alarmingly in the past 2 to 3 decades. Increased antibiotic use in infancy has been suggested to limit exposure to gastrointestinal microbes and to predispose to asthma in later life.

OBJECTIVE

To evaluate the association between antibiotic exposure during the first year of life and the development of asthma up to the age of 7 years.

METHODS

A retrospective population-based study of a cohort of children enrolled in a nationwide employer-provided health insurance plan from January 1, 1999, through December 31, 2006, in the United States (n = 62,576). We evaluated the association between antibiotic exposure during the first year of life and subsequent development of 3 asthma phenotypes: transient wheezing (began and resolved before 3 years of age), late-onset asthma (began after 3 years of age), and persistent asthma (began before 3 years of age and persisted through 4-7 years of age).

RESULTS

Antibiotic use in the first year of life was associated with the development of transient wheezing (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.9-2.2; P < .001) and persistent asthma (OR, 1.6; 95% CI, 1.5-1.7; P < .001). A dose-response effect was observed. When 5 or more antibiotic courses were received, the odds of persistent asthma doubled (OR, 1.9; 95% CI, 1.5-2.6; P < .001). There is no association between antibiotic use and late-onset asthma.

CONCLUSION

Antibiotic use in the first year life is associated with an increased risk of early-onset childhood asthma that began before 3 years of age. The apparent effect has a clear dose response. Heightened caution about avoiding unnecessary use of antibiotics in infants is warranted.

Randomized Controlled Trials and real life studies. Approaches and methodologies: a clinical point of view

Randomized Controlled Trials (RCTs) are the "gold standard" for evaluating treatment outcomes providing information on treatments "efficacy". They are designed to test a therapeutic hypothesis under optimal setting in the absence of confounding factors. For this reason they have high internal validity. The strict and controlled conditions in which they are conducted, leads to low generalizability because they are performed in conditions very different from real life usual care. Conversely, real life studies inform on the "effectiveness" of a treatment, that is, the measure of the extent to which an intervention does what is intended to do in routine circumstances. At variance to RCTs, real life trials have high generalizability, but low internal validity. Recently the number of real life studies has been rapidly growing in different areas of respiratory medicine, particularly in asthma and COPD. The role of such studies is becoming a hot topic in respiratory medicine, attracting research interest and debate. In the first part of this review we discuss some of the advantages and disadvantages of different types of RCTs and analyze the strengths and weaknesses of real life trials, considering the recent examples of some studies conducted in COPD. We then discuss methodological approaches and options to overcome some of the limitations of real life studies. Comparing the conclusions of effectiveness and efficacy trials can provide important pieces of information. Indeed, these approaches can result complementary, and they can guide the interpretation of each other results.

Validation of asthma and eczema in population-based Swedish drug and patient registers

PURPOSE

Validated measures of asthma and eczema at the population level remain a challenge. Our aim was to ascertain if register-based information on asthma/eczema medication can function as a proxy for an asthma/eczema diagnosis and to validate register-based asthma diagnoses.

METHODS

Information was requested on all 0-45-year-old individuals with reported asthma/eczema medication and/or diagnoses in the Swedish Prescribed Drug Register and National Patient Register, between July 2005 and December 2009 (N = 250 691). Medical records for 1952 randomly selected individuals were reviewed to estimate the proportion of individuals with the following: (1) asthma/eczema medication that fulfilled predefined criteria of asthma/eczema (positive predictive value (PPV)) and (2) a register-based asthma diagnosis verified as asthma by predefined criteria.

RESULTS

Positive predictive value for asthma by predefined criteria ranged between 0.75 (95%CI: 0.70-0.78) to 0.94 (95%CI: 0.91-0.96), depending on age group. In pre-school children, PPV for asthma in combination with obstructive bronchitis was 0.87 (95%CI: 0.83-0.90), and PPV for eczema was estimated to 0.45 (95%CI: 0.38-0.51). Eighty percent of children 0-4.5 years and 99% of children >4.5-17 years with a register-based diagnosis of asthma were verified as asthmatics.

CONCLUSION

Asthma medication is a suitable proxy for asthma in older children and adults; the same approach is insufficient for eczema. This validation study of two Swedish registers opens for future large nation-wide register-based studies on asthma.

The case of drug causation of childhood asthma: antibiotics and paracetamol

AIM

The rising prevalence of bronchial asthma has led to world-wide efforts to understand and stem this development. Cross-sectional studies appear to show that early childhood use of antibiotics may be an important contributory factor, with paracetamol as an additional suspected cause. However, mounting evidence, which is reviewed here, points to various confounding factors as the major reasons for these reported associations.

METHODS

PubMed and EMBASE were systematically searched for studies on associations between antibiotics and/or paracetamol with asthma and/or wheezing, published up to November 2012. A total of 64 pertinent studies were identified, 35 focusing on antibiotics, 19 on paracetamol, and ten addressing both antibiotics and paracetamol, bringing the number of relevant datasets to 74.

RESULTS

Numerous studies were cross-sectional and made no adjustment for the indication of antibiotics or paracetamol; consequently, they were unable to dismiss possible confounding by indication. Where such adjustments could be performed (mostly in longitudinal studies), they substantially weakened or entirely eliminated the association with asthma or asthma surrogates present in the unadjusted data.

CONCLUSION

The weight of evidence of the collected studies in our review strongly suggests that the association of antibiotics with childhood asthma reflects various forms of bias, the most prominent of which is confounding by indication. Recent studies and meta-analyses support the same conclusion for paracetamol. Truly indicated antibiotics should not be withheld from infants or young children for fears they might develop asthma. Likewise, there is no sound reason to replace paracetamol as the preferred pain relief and fever medication in this age group.

Early fish introduction and neonatal antibiotics affect the risk of asthma into school age

BACKGROUND

The early introduction of fish has been reported to reduce the risk of wheezing disorder in early childhood, while broad-spectrum antibiotics in the first week have been associated with an increased risk. However, it is uncertain whether the effects remain into school age. The aim was to explore these risk factors for doctor-diagnosed asthma at 8 years.

METHODS

Data were obtained from a prospective, longitudinal study of a cohort of children born in western Sweden. The parents answered questionnaires at 6 months and 1, 4.5 and 8 years of age. The response rate at 8 years was 80% of the questionnaires distributed (4051/5044), that is, 71% of the families entering the study (4051/5654).

RESULTS

At 8 years, 5.7% reported current doctor-diagnosed asthma. Of these, 65% had atopic asthma and 35% non-atopic asthma. In the multivariate analysis, atopic heredity, male gender and own allergic disease during infancy were risk factors for doctor-diagnosed asthma at 8 years. In addition, the introduction of fish before the age of 9 months independently reduced the risk (adjusted OR 0.6; 95% CI 0.4-0.96), while broad-spectrum antibiotics in the first week independently increased the risk of current asthma at school age (aOR 2.3; 1.2-4.2). Regarding types of asthma, the effects were significant in atopic asthma but not in non-atopic asthma.

CONCLUSION

The early introduction of fish and neonatal antibiotic treatment influence the risk of asthma into school age. The significant effect on atopic asthma is of particular importance, as this phenotype is of major clinical significance.

Recent advances in the epidemiologic investigation of risk factors for asthma: a review of the 2011 literature

The present review aims to identify and summarize epidemiologic investigations published during 2011 on the environmental risk factors for asthma. Potentially eligible papers were identified by a MEDLINE search. In total, 1,130 items were retrieved. Based on a broad definition of environment, the following topics were included: obesity, diet, vitamin D, air pollution, farming environment, and social factors. Some of the more relevant contributions included evidence that 1) obesity precedes asthma, 2) fruit consumption is longitudinally associated with a lower risk of asthma and atopy, 3) a comprehensive statewide smoking ban was followed by a reduction in hospital admissions for asthma, 4) asthma is one of the diseases showing the largest burdens due to environmental tobacco smoke, 5) traffic-related urban air pollution is associated with bronchial inflammation as measured by fractional exhaled nitric oxide and uncontrolled asthma, 6) aeroallergens and desert dust may contribute to the short-term effects of air pollution and asthma, and 7) maternal exposure to air pollution before and during pregnancy may alter the immune competence in offspring.

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.

Acute obstructive respiratory tract diseases in a pediatric emergency unit: evidence-based evaluation

OBJECTIVES

The objective of this study was to determine the evidence-based performance of the pediatric emergency unit in the diagnosis of and treatment approach to the patients with asthma, bronchiolitis, and croup.

METHODS

In this study conducted in a retrospective cross-sectional way, emergency cards and computer data have been used. In the performance evaluation, the National Hospital Ambulatory Medical Care Survey criteria were considered. In the evaluation of performance in diagnosis, the rates of chest x-ray studies and use of corticosteroids and antibiotics were examined. Use of antibiotics in the cases not having a fever or any symptoms of bacterial infection and failure in prescribing steroids to the cases with moderate-to-severe symptoms were considered as bad performance criteria. χ(2) test was used for the data, which can be classified; Mann-Whitney U and Student t tests were used for the data with normal distribution and for the continuous variables.

RESULTS

Study groups were composed of 2795 patients (1742 cases with asthma, 115 cases with croup, 938 cases with bronchiolitis) aged between 3 and 140 months (mean [SD], 41.2 [31] months). Chest x-ray study was requested significantly more often in the cases of bronchiolitis and croup with severe symptoms. In asthma cases, chest x-ray study was requested in those with severe clinical symptoms. In all 3 groups, a significant difference between the severity levels of the cases, from whom hemogram was requested, was determined. Biochemical tests were requested more often in those with severe bronchiolitis or asthma. Antibiotics were prescribed to none of the mild bronchiolitis cases. However, steroids were recommended more often to patients with moderate and severe bronchiolitis. They were administered to all patients with croup. Systemic steroids were prescribed more often to those with moderate or severe asthma.

CONCLUSIONS

In our unit, both antibiotics administration and chest x-ray studies requested in patients with bronchiolitis, croup, and asthma were in low rates. Steroids in asthma attacks were found to be high in severe cases and in croup cases as well.

House dust allergy and immunotherapy

HDM allergy is associated with asthma, allergic rhinitis and atopic dermatitis. In many countries childhood asthma is predominantly found in HDM-allergic children with their probability of developing disease being proportional to their IgE antibody titers and the early development of Th2 responses. While the pathogenesis is complex and increasingly linked to infection the immunologically-based allergen immunotherapy and anti-IgE antibody therapy are highly beneficial. Immunotherapy could be a short-term treatment providing lifelong relief but the current regimens depend on repeated administration of allergen over years. Immunological investigations point to a contribution of responses outside the Th2 pathway and multiple potential but unproven control mechanisms. Over half of the IgE antibodies are directed to the group 1 and 2 allergens with most of remainder to the group 4, 5, 7 and 21 allergens. This hierarchy found in high and low responders provides a platform for introducing defined allergens into immunotherapy and defined reagents for investigation.

Re-analysis of Ranch Hand study supports reverse causation hypothesis between dioxin and diabetes

A dose-response relationship between serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) and adult diabetes risk has been reported among U.S. Vietnam veterans in the Ranch Hand (RH) cohort. We examine the hypothesis that diabetes progression leads to higher serum dioxin (reverse causation) rather than higher serum dioxin leading to diabetes (causation) across the longitudinal medical monitoring data on these airmen. Lipid-adjusted serum dioxin levels and clinical parameters relating to diabetes progression were examined. Potential confounding due to age, race, diabetes family history, serum total lipid, and body mass index (BMI) was accounted for. The similar incidence of diabetes in RH and Comparison veterans, along with generally similar incidence trends with dioxin decile and lipid decile despite the large differential in serum dioxin, is evidence consistent with reverse causation. Of 135 RH diabetics with at least two dioxin measurements, 32.6% had a temporary serum dioxin increase more than a decade after Vietnam tour and another 22.2% had an interval of unusually slow half-life (>15.5 years); these diabetes-related changes shifted more diabetics into the higher dioxin deciles. Further, the increased diabetes odds ratio among the generally younger RH veterans in the highest dioxin decile is associated with a higher incidence of adult obesity in this RH subgroup, both at tour of duty and decades later. Change in serum dioxin levels is likely due to diabetes progression or poor control and is not independently related to serum dioxin concentrations. In summary, the data from the Ranch Hand studies does not indicate that dioxin increases adult diabetes risk.