Prenatal antimicrobial use and early-childhood body mass index

Obesogenic effects of six classes of emerging contaminants

There is growing concern about the concept that exposure to environmental chemicals may be contributing to the obesity epidemic. However, there is no consensus on the obesogenic effects of emerging contaminants from a toxicological and environmental perspective. The potential human exposure and experimental evidence for obesogenic effects of emerging contaminants need to be systematically discussed. The main objective of this review is to provide recommendations for further subsequent policy development following a critical analysis of the literature for humans and experimental animals exposed to emerging contaminants. This article reviews human exposure to emerging contaminants (with a focus on antimicrobials, preservatives, water and oil repellents, flame retardants, antibiotics and bisphenols) and the impact of emerging contaminants on obesity. These emerging contaminants have been widely detected in human biological samples. Epidemiological studies provide evidence linking exposure to emerging contaminants to the risks of obesity in humans. Studies based on animal models and adipose cells show the obesogenic effects of emerging contaminants and identify modes of action by which contaminants may induce changes in body fat accumulation and lipid metabolic homeostasis. Some knowledge gaps in this area and future directions for further investigation are discussed.

Prevalence of systemic antibacterial use during pregnancy worldwide: A systematic review

OBJECTIVES

In this study, we aimed to systematically review the literature of the prevalence of systemic antibacterial use during pregnancy and to perform a descriptive analysis focused on methodological characteristics.

MATERIALS AND METHODS

This study was registered in PROSPERO under protocol number CRD42022376634. Medline, Embase, Scientific Electronic Library Online, Biblioteca Virtual em Saúde, Cumulative Index to Nursing and Allied Health Literature, and Web of Science databases were searched (published studies until November 3rd, 2022). Selected studies were population-based cross-sectional or cohort, carried out with pregnant women, and providing information about the prevalence of systemic antibacterial use at least in one trimester of pregnancy. Reviewers conducted in pairs the title and abstract screening, eligibility criteria check, and data extraction of selected studies. Quality appraisal was performed with an adapted version of the Joanna Briggs Institute Critical Appraisal Checklist for Prevalence Studies. Data of included studies were pooled into a graphical and tabular summary.

RESULTS

A total of 16,251,280 pregnant women and 5,169,959 pregnancy registers were identified. The prevalence estimates of systemic antibacterial use during pregnancy ranged from 2.0% (95%CI 2.0-2.0) to 64.3% (95%CI not reported) in the 79 included studies. The majority were performed in high-income countries (91.5%). Overall, the studies revealed considerable prevalence heterogeneity in terms of study type and dataset used. The 95% confidence intervals were not reported in 41% of studies.

CONCLUSION

The disparities in the prevalence of systemic antibacterial use during pregnancy can be related to methodological issues and different health policies. Lack of uniform databases and changes in data collection methods over time should be taken into account in public health strategy planning. The scarce evidence in low- and middle-income settings hampers the comprehensiveness of the global prevalence of antibacterial use during pregnancy.

Global prevalence of antibiotic consumption during pregnancy: A systematic review and meta-analysis

BACKGROUND

Antibiotic use during pregnancy is widespread with notable variations across regions.

METHODS

This systematic review and meta-analysis (Prospero protocol CRD42023418979) examines the prevalence and variability of antibiotic use in pregnancy globally and regionally, considering different methodologies and maternal characteristics. We searched Embase, PubMed, and Web of Science for observational studies published in English from the year 2000 and onwards. Random-effect meta-analyses were used to pool the prevalence of antibiotic consumption during pregnancy, presented as percentages with 95% confidence intervals (CI). Joanna Briggs Institute Critical appraisal checklist for prevalence studies was used for bias assessment.

FINDINGS

Overall, 116 studies (14 from Africa, 24 from the Americas, six from Eastern Mediterranean, 57 from Europe, four from South-East Asia and 11 from Western Pacific) were included (33,821,194 pregnancies). The majority of studies (84.5%) were appraised with a low risk of bias. The prevalence of antibiotic consumption during pregnancy ranged between 0.04 to 90%, with a pooled estimate of 23.6% (95% CI: 20.1-27.5, I2 =100%). Low-income countries had the highest pooled prevalence (45.3%, 95% CI: 15.4-79.1, I2 =99.6%). Regionally, the Western Pacific had the highest pooled prevalence (34.4%, 95% CI: 13.4-64.1, I2 =100%). The prevalence of antibiotic consumption during pregnancy increased over time in the Americas and Western Pacific. The studies exhibited considerable heterogeneity (I2 >95%), and the trim-and-fill method estimated a potential 10% underestimation of the overall pooled prevalence, suggesting publication bias.

INTERPRETATION

This meta-analysis suggests that about 1/4 of women worldwide use antibiotics during pregnancy. This study suggests a high prevalence of antibiotic consumption during pregnancy with disparities according to region and level of country income, ethnicity and whether antibiotics were prescribed or self-medicated. There was a variability in reported findings across age categories, potential bias from small sample sizes, and language bias from including only studies published in English.

Early-life exposure to antibiotics and excess body weight in childhood and adolescence: A systematic review and meta-analysis

BACKGROUND

The association between early-life exposure to antibiotics and overweight/obesity is unclear. We conducted a systematic review and meta-analysis to address this issue.

METHODS

We searched PubMed, Web of Science, Scopus, and grey literature from inception to August 10, 2022, for cohort studies investigating the association between early-life exposure to antibiotics and weight outcomes. Two independent reviewers screened studies for eligibility, extracted data, assessed risk of bias, and examined the certainty of the evidence. Random-effects meta-analyses was used for pooling the data. The review was registered in PROSPERO, CRD42021265417.

RESULTS

We included 42 studies and data from 28 of them were pooled in the quantitative synthesis. Overall antenatal (OR 1.10, 95% CI 1.04-1.16; 518,095 children, very low certainty) and second trimester (OR 1.11, 95% CI 1.08-1.14, 248,469 children, low certainty) exposure to antibiotics were associated with increased risk of overweight/obesity in childhood/adolescence. Overall early postnatal antibiotic exposure was also associated with increased likelihood of overweight/obesity in childhood/adolescence (OR 1.09, 95% CI 1.05-1.12, 1,488,316 children, very low certainty). The magnitude of the association increased from exposure to one (OR 1.07, 95% CI 1.00-1.15, 512,954 children) to four or more courses of antibiotics (OR 1.31, 95% CI 1.17-1.46, 543,627 children).

CONCLUSION

Antenatal and early postnatal exposure to antibiotics is associated increased likelihood of overweight/obesity, although the findings are limited by the very low certainty of evidence. We highlight the need for homogeneous prospective studies addressing potential confounding factors to further explore the link between exposure to antibiotics and the risk of excess body weight.

Association between prenatal antimicrobial use and offspring attention deficit hyperactivity disorder

BACKGROUND

Gut-brain cross-talk may play an important role in modulating neurodevelopment. Few studies have examined the association between antimicrobials that influence infant gut microbiota assemblage and attention deficit hyperactivity disorder (ADHD).

OBJECTIVE

To examine the association between maternal prenatal antimicrobial use and ADHD in offspring at 10 years of age.

METHODS

Data are from the Wayne County Health, Environment, Allergy and Asthma Longitudinal Study, a racially and socioeconomically diverse birth cohort in metropolitan Detroit, Michigan. Maternal antimicrobial use was extracted from the medical record. ADHD diagnoses were based on parental report at the 10-year study visit. Poisson regression models with robust error variance were used to calculate risk ratios (RR). Cumulative frequency of exposure to antibiotics, and effect modification were also evaluated.

RESULTS

Among the 555 children included in the analysis, 108 were diagnosed with ADHD. During pregnancy, 54.1% of mothers used antibiotics while 18.7% used antifungals. Overall, there was no evidence of an association between prenatal antibiotic exposure and ADHD (RR [95% CI] = 0.98 [0.75, 1.29]), but there was an increased risk of ADHD among those with mothers using 3+ courses of antibiotics (RR [95%CI] = 1.58 [1.10, 2.29]). Prenatal exposure to antifungals was associated with a 1.6 times higher risk of ADHD (RR [95% CI] = 1.60 [1.19, 2.15]). In examining effect modification by child sex for antifungal use, there was no evidence of an association among females (RR [95% CI] = 0.97 [0.42, 2.23]), but among males, prenatal antifungal use was associated with 1.82 times higher risk of ADHD (RR [95% CI] = 1.82 [1.29, 2.56]).

CONCLUSIONS

Maternal prenatal antifungal use and frequent prenatal antibiotic use are associated with an increased risk of ADHD in offspring at age 10. These findings highlight the importance of the prenatal environment and the need for careful use of antimicrobials.

Prenatal and Perinatal Antibiotic Exposure and Long-Term Outcome

Antibiotics are frequently administered during pregnancy. Although necessary to address acute infections, their use facilitates antibiotic resistance. Other associations have also been found with the use of antibiotics, such as perturbations of gut bacteria, delays in microbial maturation, and increased risks of allergic and inflammatory diseases. Little is known about how the prenatal and perinatal administration of antibiotics to mothers affects the clinical outcomes of their offspring. A literature search was conducted of the Cochrane, Embase, and PubMed engines. The retrieved articles were reviewed by two authors and verified for relevance. The primary outcome was the effect of pre- and perinatal maternal antibiotic use on clinical outcomes. Thirty-one relevant studies were included in the meta-analysis. Various aspects are discussed, including infections, allergies, obesity, and psychosocial factors. In animal studies, antibiotic intake during pregnancy has been suggested to cause long-term alterations in immune regulation. In humans, associations have been found between antibiotic intake during pregnancy and different types of infections and an increased risk of pediatric infection-related hospitalization. A dose-dependent positive association between pre- and perinatal antibiotic use and asthma severity has been reported in animal and human studies, while positive associations with atopic dermatitis and eczema were reported by human studies. Multiple associations were identified between antibiotic intake and psychological problems in animal studies; however, relevant data from human studies are limited. However, one study reported a positive association with autism spectrum disorders. Multiple animal and human studies reported a positive association between pre- and perinatal antibiotic use by mothers and diseases in their offspring. Our findings have potentially significant clinical relevance, particularly considering the implications for health during infancy and later in life as well as the related economic burden.

Feasibility of a Food Delivery Intervention during Pregnancy in a Rural US Population: The PEAPOD Pilot Study

Pregnancy nutrition is important for maternal and child health and may affect the development of the infant gut microbiome. Our objective was to assess the feasibility of implementing a food-based intervention designed to increase fiber intake among pregnant women in a rural setting. Participants were enrolled (N = 27) mid-pregnancy from a prenatal care clinic in rural Michigan, randomized to intervention (N = 13) or usual care (N = 14), and followed to 6 weeks postpartum. The intervention was designed to be easily replicable and scalable by partnering with hospital foodservices and included non-perishable high fiber foods and recipes, as well as weekly delivery of salads, soup, and fresh fruit. Surveys, maternal blood, urine, and stool were collected at 24- and 36-weeks gestation and at 6 weeks postpartum. Infant stool was collected at 6 weeks. Participants were 100% White (7% Hispanic White, 7% Native American and White); 55% with education < 4-year college degree. Data on dietary intake and urinary trace elements are presented as evidence of feasibility of outcome measurement. Retention was high at 93%; 85% reported high satisfaction. The intervention described here can be replicated and used in larger, longer studies designed to assess the effects of pregnancy diet on the establishment of the infant gut microbiome and related health outcomes.

The impact of early-life antibiotics and probiotics on gut microbial ecology and infant health outcomes: a Pregnancy and Birth Cohort in Northwest China (PBCC) study protocol

BACKGROUND

Unreasonable use of antibiotics and probiotics can alter the gut ecology, leading to antibiotic resistance and suboptimal health outcomes during early life. Our study aims are to clarify the association among antibiotic and probiotic exposure in early life, the microecology of the gut microbiota, and the development of antibiotic resistance; to investigate the long-term impact of antibiotics and probiotics on the health outcomes of infants and young children; and to provide a theoretical basis for the rational use of antibiotics and probiotics from a life course perspective.

METHODS

The study is a prospective, longitudinal birth cohort study conducted in Shaanxi Province, China from 2018 to 2024. A total of 3,000 eligible mother-child pairs will be enrolled from rural, suburban, and urban areas. The recruitment of the participants begins at pregnancy, and the newborns will be followed up for 2 years at successive timepoints: within 3 days after birth, 42 days after birth, and at 3, 6, 12, 18, and 24 months of age. Sociodemographic data, environmental exposures, dietary patterns, psychological conditions, and medical and drug histories are collected. Cognitive and behavioural development among infants and young children and questionnaires on antibiotic knowledge and behaviour among caregivers will be collected at 12 and 24 months of age. The faecal samples are collected and analysed by 16S rRNA high-throughput sequencing and quantitative PCR (qPCR) for antibiotic resistance genes.

DISCUSSION

The findings will inform antibiotic and probiotic use for pregnant women and infants and contribute to establishing rational use strategies of antibiotics and probiotics for paediatricians, health practitioners, and drug administration policy-makers.

TRIAL REGISTRATION

The study was registered on the Chinese Clinical Trial Registry (ChiCTR) platform, http://www.chictr.org.cn (Record ID: ChiCTR2100047531, June 20, 2021).

Maternal High-Fat Diet Programs White and Brown Adipose Tissues In Vivo in Mice, with Different Metabolic and Microbiota Patterns in Obesity-Susceptible or Obesity-Resistant Offspring

Maternal obesity causes metabolic dysfunction in the offspring, including dysbiosis, overeating, obesity, and type 2 diabetes. Early-life phases are fundamental for developing subcutaneous (SAT) and brown adipose tissues (BAT), handling energy excesses. Imaging of ¹⁸F-fluorodeoxyglucose by positron emission tomography (PET) and radiodensity by computerized tomography (CT) allows assessing adipose tissue (AT) whitening and browning in vivo and the underlying metabolic efficiency. Our aim was to examine these in vivo traits in SAT and BAT concerning gut microbiota composition in 1- and 6-month-old mice born to normal (NDoff) and high-fat diet-fed dams (HFDoff), accounting for body weight responses. We found low radiodensity (high lipids) in HFDoff SAT at 1 month, relating to an increased abundance of Dorea genus in the caecum and activation of the fatty acid biosynthetic pathway. Instead, low BAT radiodensity and glucose uptake were seen in adult HFDoff. Glucose was shifted in favor of BAT at 1 month and SAT at 6 months. In adults, unclassified Enterococcaceae and Rikenellaceae, and Bacillus genera were negatively related to BAT, whereas unclassified Clostridiales genera were related to SAT metabolism. Stratification of HFDoff based on weight-response, namely maternal induced obesity (MIO-HFDoff) or obesity-resistant (MIOR-HFDoff), showed sex dimorphism. Both subgroups were hyperphagic, but only obese mice had hyper-leptinemia and hyper-resistinemia, together with BAT dysfunction, whereas non-obese HFDoff had hyperglycemia and SAT hypermetabolism. In the caecum, unclassified Rikenellaceae (10-fold enrichment in MIO-HFDoff) and Clostridiales genera (4-fold deficiency in MIOR-HFDoff) were important discriminators of these two phenotypes. In conclusion, SAT whitening is an early abnormality in the offspring of HFD dams. In adult life, maternal HFD and the induced excessive food intake translates into a dimorphic phenotype involving SAT, BAT, and microbiota distinctively, reflecting maternal diet*sex interaction. This helps explain inter-individual variability in fetal programming and the higher rates of type 2 diabetes observed in adult women born to obese mothers, supporting personalized risk assessment, prevention, and treatment.

Prenatal and infant antibiotic exposure and childhood growth, obesity and cardiovascular risk factors: The Rhea mother-child cohort study, Crete, Greece

BACKGROUND

Early-life antibiotic use has been hypothesized to promote weight gain and increase the risk of childhood obesity.

OBJECTIVES

To examine the associations of prenatal and infant antibiotics with childhood growth, adiposity and cardiometabolic traits in the Greek Rhea cohort.

METHODS

We used data from 747 mother-child pairs with anthropometric measurements drawn from medical records or measured at 4 and 6 years of age. Antibiotic exposure was assessed by maternal report during pregnancy and at the first year of life. Children were classified as exposed to antibiotics prenatally if the mother received at least one course of oral antibiotics during pregnancy and postnatally if the mother reported that the child received at least one oral antibiotic treatment during the first year of life. Outcomes included repeated weight, body mass index (BMI), waist circumference, body fat (%), total cholesterol and blood pressure. We applied mixed effects, linear and log-binomial regression models after adjusting for important covariates.

RESULTS

Around 14.6% of the participating children were prenatally exposed to antibiotics and 32.4% received antibiotics during the first year of life. Prenatal exposure to antibiotics was associated with a twofold increase in the risk for obesity (risk ratio [RR]; 95% confidence interval [CI]: 2.09 [1.58, 2.76]) and abdominal obesity (RR [95% CI]: 2.56 [1.89, 3.47]) at 6 years. Postnatal exposure to antibiotics was associated with increased weight (beta [95% CI]: 00.25 [0.06, 0.44]) and BMI (beta [95% CI]: 0.23 [0.003, 0.45]) SD scores from 2 to 7 years of life.

CONCLUSION

Early-life antibiotic use was associated with accelerated childhood growth and higher adiposity.

Prenatal exposure to antibiotics and risk of childhood overweight or obesity: A systematic review and meta-analysis

Infant antibiotic use has been modestly associated with childhood overweight, while evidence on prenatal exposures remains less clear. A systematic review and meta-analysis were conducted to examine associations between maternal antibiotic exposure and subsequent risk of childhood overweight/obesity. Publications were retrieved from PubMed and Web of Science databases up to December 2019. A random effects model was used to summarize risk estimates, overall, and by period and frequency of exposure. Ten observational studies were included in the narrative synthesis. We did not observe a clear pattern of association between prenatal antibiotic use and childhood overweight/obesity. There were suggestive associations for repeated exposures (≥3 courses) and those taking place during the second trimester of gestation, which were also pointed out in our meta-analysis (relative risk, RR_2T  = 1.15 (95% CI 1.04; 1.28, I²  = 18%), and RR_3courses  = 1.31 (95% CI 1.03; 1.67, I²  = 65%), respectively). In most studies, however, confounding by underlying infections cannot be ruled out. Overall, current data do not conclusively support the hypothesis that prenatal exposure to antibiotics is a risk factor for childhood obesity/overweight. Further studies, controlling for underlying infections and exploring the association according to frequency, period (both prenatal and intrapartum) and type of antibiotic, are needed to clarify this association.

Intrauterine antibiotic exposure affected neonatal gut bacteria and infant growth speed

Although abundant evidence has suggested that early-life antibiotic exposure was associated with adipogenesis later in life, limited data were available on the effect of intrauterine antibiotic exposure on infant growth and growth speed. Additionally, few studies have investigated the role of the neonatal gut microbiota in the above association. In this study, we examined the association between intrauterine cumulative antibiotic exposure and infant growth and explored the potential role of the neonatal gut microbiota in the association. 295 mother-child pairs from the Shanghai Maternal-Child Pairs Cohort (MCPC) study were included, and meconium samples and infant growth measurements were assessed. Z-scores of length-for-age, weight-for-age (weight-for-age), and body mass index (BMI)-for-age (BMI-for-age) were calculated. Eighteen common antibiotics were measured in meconium. Multivariable linear regression models were applied to test the interrelationships between antibiotic exposure, diversity indicators, and the relative abundance of selected bacterial taxa from phylum to genus levels from least absolute shrinkage and selection operator (LASSO) and infant growth indicators. The detection rates of the 18 antibiotics, except for chlortetracycline, penicillin, and chloramphenicol, were below 10 %. Penicillin was found to be positively associated with infant growth at birth and with growth speed from 2 to 6 months. The Pielou and Simpson indexes were negatively associated with meconium penicillin. Nominally significant associations between penicillin and the relative abundances of several bacterial taxa from the phyla Proteobacteria, Bacteroidetes, and Firmicutes were found. The Pielou and Simpson indexes were also found to be negatively associated with infant growth. Among taxa selected from LASSO regression, the relative abundances of the phyla Actinobacteria and Firmicutes and order Bifidobacteriales were found to be significantly associated with weight and BMI growth speeds from 2 to 6 months. In conclusion, intrauterine antibiotic exposure can affect infant growth. The neonatal gut microbiota might play a role in the abovementioned association.

Effect of exposure to antibiotics on the gut microbiome and biochemical indexes of pregnant women

INTRODUCTION

Exposure to antibiotics (ABX) during pregnancy can have a systematic effect on both fetal and maternal health. Although previous biomonitoring studies have indicated the effects on children of extensive exposure to ABX, studies on pregnant women remain scarce. To explore the effect on pregnant women of environmental exposure to ABX through accidental ingestion and identify potential health risks, the present study investigated 122 pregnant women in East China between 2019 and 2020.

RESEARCH DESIGN AND METHODS

The presence of six categories of ABX (quinolones, sulfonamides, lincosamides, tetracyclines, amide alcohol ABX, and β-lactams) in plasma samples taken from the pregnant women was investigated using an ABX kit and a time-resolved fluorescence immunoassay.

RESULTS

All six ABX were detected in the plasma, with a detection rate of 17.2%. It was discovered that the composition of intestinal flora in pregnant women exposed to ABX was different from that of pregnant women who had not been exposed to ABX. The intestinal flora of pregnant women exposed to ABX also changed at both the phylum and genus levels, and several genera almost disappeared. Furthermore, the metabolic levels of glucose and insulin and the alpha diversity of pregnant women exposed to ABX were higher than those of pregnant women not exposed to ABX.

CONCLUSION

Pregnant women are potentially at higher risk of adverse microbial effects. Glucose metabolism and insulin levels were generally higher in pregnant women exposed to ABX than in unexposed women. Also, the composition and color of the gut microbiome changed.

Exposure to antibiotics during pregnancy alters offspring outcomes

INTRODUCTION

The composition of microorganisms is closely related to human health. Antibiotic use during pregnancy may have adverse effects on the neonatal gut microbiome and subsequently affect infant health development, leading to childhood atopy and allergic diseases, intestinal, metabolic and brain disorders, and infection.

AREAS COVERED

This review includes the effect of maternal antibiotic use during pregnancy on potential diseases in animals and human offspring.

EXPERT OPINION

Exposure to antibiotics during pregnancy alters offspring outcomes. Alterations in the microbiome may potentially lower the risk of a range of problems and may also be a novel therapeutic target in children later in life.

The impact of maternal exposure to antibiotics on the development of child gut microbiome

Antibiotics are widely prescribed for mothers in the peripartum period today. Approximately 40% of pregnant women at term are exposed to antibiotics. Antibiotics are useful against infectious conditions such as chorioamnionitis; however, they alter the maternal microbiome. The maternal microbiome, particularly the gut microbiome, is transmitted to their neonates and is one of the major sources that shape the child's gut microbiome. The gut microbiome early in life plays a crucial role in the development of the gut microbiome itself as well as the host health over the entire life. Microbes structure the commensal ecosystem in the host. Simultaneously, microbial components and metabolites influence the host organ functions including the immune system, and vice versa, the various factors of the host impact the microbiome. The alterations of the gut microbiome induced by antibiotics in mothers can lead to gut dysbiosis in children eventually resulting in chronic disease conditions including immune disorders. Knowledge of the lasting impacts of maternal peripartum exposure to antibiotics on the gut microbiome and health in offspring and reconsideration of the adequate use of antibiotics in clinical practice are needed. Avoiding and restoring neonatal dysbiosis following maternal antibiotics-induced dysbiosis could be a new preventive strategy for various diseases.

Association between the use of antibiotics during pregnancy and obesity in 5-year-old children

BACKGROUND

Obesity is an epidemic that must arouse our attention. The purpose of this research is to investigate the relationship between antibiotic use during pregnancy and childhood obesity in 5-year-old Chinese children.

METHODS

A total of 132 5-year-old children born in our hospital from January 2014 to January 2016 were included. The children's genders, nationalities, chronic diseases, and other factors were collected as adjusted covariates. We also collected the pre-pregnancy body mass indexes (BMIs) of pregnant women, diagnosis of diabetes mellitus or gestational diabetes mellitus (GDM), maternal smoking, mode of delivery (cesarean section and vaginal delivery), and weight gain during pregnancy, which may affect childhood obesity. A linear mixed effect regression model was used to test the correlation between antibiotic use during pregnancy and the BMI of 5-year-old children, and a logistic mixed effect regression model was used to evaluate the correlation between antibiotic use during pregnancy and obesity outcome.

RESULTS

When adjusted for the child's gender, birth weight, cesarean section, chronic diseases, maternal smoking during pregnancy, pre-pregnancy BMI, diagnosis of diabetes or GDM, mode of delivery (cesarean section and vaginal delivery), and weight gain during pregnancy (Model 3), antibiotic use during pregnancy was positively correlated with the BMI of 5-year-old children (β=0.01, 95% CI: 0.01-0.03, P=0.04). Antibiotic use during pregnancy increased the risk of obesity by 4% in 5-year-old children (OR =1.04, 95% CI: 1.01-1.16, P=0.02).

CONCLUSIONS

The use of antibiotics during pregnancy is positively correlated with the risk of obesity in 5-year-old children.

KEYWORDS

Antibiotics; pregnancy; obesity; children.

Brown Adipose Tissue: New Challenges for Prevention of Childhood Obesity. A Narrative Review

Pediatric obesity remains a challenge in modern society. Recently, research has focused on the role of the brown adipose tissue (BAT) as a potential target of intervention. In this review, we revised preclinical and clinical works on factors that may promote BAT or browning of white adipose tissue (WAT) from fetal age to adolescence. Maternal lifestyle, type of breastfeeding and healthy microbiota can affect the thermogenic activity of BAT. Environmental factors such as exposure to cold or physical activity also play a role in promoting and activating BAT. Most of the evidence is preclinical, although in clinic there is some evidence on the role of omega-3 PUFAs (EPA and DHA) supplementation on BAT activation. Clinical studies are needed to dissect the early factors and their modulation to allow proper BAT development and functions and to prevent onset of childhood obesity.

Impact of the factors shaping gut microbiota on obesity

Obesity is considered as a risk factor for chronic health diseases such as heart diseases, cancer and diabetes 2. Reduced physical activities, lifestyle, poor nutritional diet and genetics are among the risk factors associated with the development of obesity. In recent years, several studies have explored the link between the gut microbiome and the progression of diseases including obesity, with the shift in microbiome abundance and composition being the main focus. The alteration of gut microbiome composition affects both nutrients metabolism and specific gene expressions, thereby disturbing body physiology. Specifically, the abundance of fibre-metabolizing microbes is associated with weight loss and that of protein and fat-metabolizing bacteria with weight gain. Various internal and external factors such as genetics, maternal obesity, mode of delivery, breastfeeding, nutrition, antibiotic use and the chemical compounds present in the environment are known to interfere with the richness of the gut microbiota (GM), thus influencing weight gain/loss and ultimately the development of obesity. However, the effectiveness of each factor in potentiating the shift in microbes' abundance to result in significant changes that can lead to obesity is not yet clear. In this review, we will highlight the factors involved in shaping GM, their influence on obesity and possible interventions. Understanding the influence of these factors on the diversity of the GM and how to improve their effectiveness on disease conditions could be keys in the treatment of metabolic diseases.

The impact of early life antibiotic use on atopic and metabolic disorders: Meta-analyses of recent insights

BACKGROUND AND OBJECTIVES

The impact of antibiotics use early in life on later-in-life morbidities has received substantial attention as explanations for atopic and metabolic disorders with a surge as modern lifestyle diseases. The objective of this study was to perform meta-analyses to determine if antibiotics administration during the first 2 years of infant life is associated with increased risks of atopic or metabolic disorders later in life.

METHODOLOGY

We screened more than 100 English-language prospective and retrospective studies published between January 2002 and March 2020 and assessed study quality using the Newcastle-Ottawa scale. We performed overall and subgroup meta-analyses on 31 high-quality comparable studies on atopic and 23 on metabolic disorders, involving more than 3.5 million children.

RESULTS

Antibiotic exposure prenatally and during the first 2 years of life significantly impacts the risk of developing atopic and metabolic disorders. Exposure during the first 6 months of life appears most critical, consistent with this being the time when the microbiome is most susceptible to irreversible perturbations. The presence of dose-response associations and stronger impacts of broad- than narrow-spectrum antibiotics further point to effects being mediated by microbiota-induced changes.

CONCLUSIONS AND IMPLICATIONS

Our findings support that antibiotics use is a mismatch to modernity that can negatively affect the symbiotic associations we rely on for proper immune function and metabolism. Improving our understanding of these associations, the underlying proximate mechanisms and the impact of antibiotics use on future human-symbiont evolution will be important to improve human health.

LAY SUMMARY

The use of antibiotics in infancy has been suggested to increase the risks of atopic and metabolic disorders later in life. Through meta-analyses of more than 100 studies of >3.5 million children, we confirm these risks, and show that patterns are consistent with effects being due to microbiota-driven changes.

Exposure to group B Streptococcal antibiotic prophylaxis and early childhood body mass index in a vaginal birth cohort

Purpose: Perinatal antibiotic exposure may be associated with changes in both early infancy gut microbiota and later childhood obesity. Our objective was to evaluate if group B Streptococcus (GBS) antibiotic prophylaxis is associated with higher body mass index (BMI) in early childhood.Materials and methods: This is a retrospective cohort study of mother/child dyads in a single hospital system over a 6-year period. All women with term, singleton, vertex, vaginal deliveries who received no antibiotics or received antibiotics only for GBS prophylaxis and whose children had BMIs available at 2-5 years of age were included. Children were divided into three groups for comparison: children born to GBS positive mothers that received antibiotics solely for GBS prophylaxis, children born to GBS negative women that received no antibiotics (healthy controls), and children born to GBS positive mothers who received no antibiotics. The primary outcome was the earliest available child BMI Z-score at 2-5 years of age. Multivariable linear regression was used to estimate differences in child BMI Z-scores between groups, adjusted for maternal BMI, age, race, parity, tobacco use, and child birthweight.Results: Of 4825 women, 786 (16.3%) were GBS positive and received prophylactic antibiotics, 3916 (81.2%) were GBS negative and received no antibiotics, and 123 (2.5%) were GBS positive but received no antibiotics. Childhood BMI Z-scores were similar between children exposed to intrapartum GBS prophylaxis and healthy controls who were unexposed in both unadjusted (mean (SE), 0.04 (0.04) versus -0.3 (0.02), p = .11) and adjusted (0.01 (0.05) versus -0.04 (0.03), p = .3) models.Conclusions: Exposure to intrapartum antibiotic prophylaxis for GBS was not associated with higher early childhood BMI Z-scores compared to healthy controls.

Maternal antibiotic use and vaginal infections in the third trimester of pregnancy and the risk of obesity in preschool children

BACKGROUND/OBJECTIVES

Several exposures during pregnancy are associated with offspring body mass index (BMI). The objective of this study was to evaluate whether third trimester antibiotic use and vaginal infections are associated with BMI in preschool children.

SUBJECTS/METHODS

The study population included singletons from the NINFEA birth cohort with available anthropometric measurements at the age of 4 (3151 born with vaginal and 1111 born with caesarean delivery). Self-reported use of antibiotics and the presence of vaginal infection in the third trimester were analysed in association with the child's BMI, classified into three categories: thinness, normal and overweight/obesity, using both the International Obesity Task Force (IOTF) and the World Health Organization (WHO) recommended cut-offs.

RESULTS

Maternal vaginal infections in the third trimester of pregnancy were associated with higher relative risk ratios (RRR) for overweight/obesity at age of four in children delivered vaginally: 1.92 (95% confidence interval [CI]: 1.37 to 2.70). This association appeared stronger for children born to women with pre-pregnancy BMI >25 kg/m² (RRR: 4.78; 95% CI 2.45 to 9.35), and was robust when different obesity cut-offs were used. The results regarding third trimester antibiotic use in vaginal deliveries were less conclusive (RRRs for overweight/obesity: 1.43 (0.92 to 2.21) and 1.11 (0.57 to 2.20), for the IOTF and WHO cut-offs, respectively). Third trimester vaginal infections were not associated with BMI in children delivered by caesarean section.

CONCLUSIONS

Maternal third trimester vaginal infections are associated with an increased overweight/obesity risk in children born by vaginal delivery, and especially in children of mothers with pre-pregnancy overweight/obesity.

Early and frequent exposure to antibiotics in children and the risk of obesity: systematic review and meta-analysis of observational studies

Background: This study aimed to systematically evaluate the available evidence on prenatal and early infancy antibiotic exposure and the association with overweight and obesity in later childhood.

Methods: We conducted a comprehensive search of Embase, MEDLINE, and Web of Science for observational studies assessing prenatal and early antibiotic exposure on the risk of overweight and obesity. We independently assessed the risk of bias using the ROBINS instrument and the overall quality of evidence using the GRADE approach.

Results: Our search identified thirteen observational studies including 554,983 participants; most studies were at moderate risk of bias. We found a statistically significant impact of early antibiotic exposure and the risk of being overweight later in childhood (OR 1.18; 95% CI 1.05 to 1.34) (very low quality evidence). We also found that early childhood antibiotic exposure was associated with the risk for childhood obesity (OR 1.14; 95% CI 1.04 to 1.24) (very low quality evidence).

Conclusions: Very low quality evidence suggests that exposure to antibiotics early in life may be associated with an increased risk of being overweight and obese in later childhood.  However, very low quality evidence raises serious questions about the plausibility of prenatal and early infancy antibiotic exposure being causally related to weight in children.

PROSPERO registration: CRD42016050011 (14/12/2016)

Prenatal exposure to antibiotics and timing of puberty in sons and daughters: A population-based cohort study

OBJECTIVE

To investigate if prenatal exposure to antibiotics is associated with earlier timing of pubertal development in sons and daughters.

STUDY DESIGN

This population-based cohort study is based upon the Puberty Cohort and includes a sample of 15,638 children born 2000-2003 in Denmark. Information on maternal use of antibiotics was collected around gestational week 30 and 6 months postpartum. The children were followed-up half-yearly from 11 years of age and throughout sexual maturation providing information on Tanner stages, acne and axillary hair, in addition to voice break and first ejaculation in sons and menarche in daughters. Due to the half-yearly collection of data on pubertal timing, the data was censored and therefore analysed using a multivariable censored time-to-event regression model. We examined both prenatal exposure to antibiotics at any time in pregnancy and trimester-specific prenatal exposure to antibiotics and pubertal timing, adjusting for maternal baseline socioeconomic and lifestyle characteristics. Mean age differences for the pubertal milestones between exposure groups were estimated. A combined estimate for overall pubertal timing was calculated based on combining all pubertal milestones into one model for sons and daughters, using Huber-White robust variance estimation which handles the risk of type 1 errors due to multiple testing of correlated outcomes. An active comparator approach with restriction to women reporting to have a urinary tract infection (cystitis) treated with either penicillin or sulfonamides was employed in a sub-analysis.

RESULTS

The prevalence of any maternal use of antibiotics in pregnancy was 21.1 %. There was no association between prenatal exposure to antibiotics and timing of pubertal development for the individual milestones. The adjusted combined estimate for pubertal timing in sons prenatally exposed to antibiotics at any point in pregnancy was -0.4 (95 % confidence interval (CI): -1.2; 0.4) months compared to unexposed sons. The adjusted combined estimate for pubertal timing in daughters prenatally exposed to antibiotics at any point in pregnancy was -0.1 (95 % CI: -0.9; 0.7) months compared to unexposed daughters. Both the trimester-specific analyses and the active comparator analysis revealed similar results.

CONCLUSION

Prenatal exposure to antibiotics was not associated with pubertal timing.

Impact of Exposure to Antibiotics During Pregnancy and Infancy on Childhood Obesity: A Systematic Review and Meta-Analysis

OBJECTIVE

This study aimed to investigate whether antibiotic exposure during pregnancy and infancy was associated with childhood overweight or obesity.

METHODS

PubMed, Embase, and Cochrane Library databases were searched from the inception date to April 18, 2019, to identify observational studies that investigated the association between antibiotic exposure during pregnancy and infancy and childhood overweight or obesity. After study selection and data extraction, the meta-analysis was conducted using Stata software version 12.0 (StataCorp LP, College Station, Texas). The evaluation of the methodological quality was carried out by AMSTAR 2 (Bruyère Research Institute, Ottawa, Ontario, Canada).

RESULTS

A total of 23 observational studies involving 1,253,035 participants were included. The meta-analysis showed that prenatal exposure to antibiotics was not significantly associated with childhood overweight or obesity, whereas an increased risk of overweight or obesity was seen in subgroup analysis of the second trimester (risk ratio = 1.13; 95% CI: 1.06-1.22; P = 0.001). In contrast, antibiotic exposure during infancy could increase the risk of childhood overweight or obesity (risk ratio = 1.14; 95% CI: 1.06-1.23; P = 0.001).

CONCLUSIONS

This meta-analysis found that antibiotic exposure during the second trimester and infancy could increase the risk of childhood overweight or obesity.

Childhood inflammatory and metabolic disease following exposure to antibiotics in pregnancy, antenatally, intrapartum and neonatally

Background: There are concerns that the use of antibiotics before, during or immediately after pregnancy may have adverse effects on the neonatal gut microbiome and adversely affect the development of the infant immune system, leading to the development of childhood allergy, asthma, atopic disease and obesity. Methods: In this narrative review, we have explored a number of hypotheses, including the "Barker hypothesis", the "hygiene hypothesis", the link between inflammation and metabolic disease, and the influence of the neonatal gut microbiota on the development of the immune system in infants. Results: We found evidence to link the use of antibiotics before, during or immediately after pregnancy with an increased risk of childhood allergy, asthma, atopy and obesity. Conclusions: Although we found robust evidence to link antibiotic use in pregnancy with obesity and an "allergic triad" of asthma, eczema and hay fever, care must be taken when interpreting the findings because of the lack of adjustment for confounding variables in published studies. These may be (i) whether or not the mother had the same outcome variable (for example, asthma) as the infant, for which the mother may have received the antibiotics; (ii) the indication, timing or number of antibiotic courses given; (iii) the use of broad-spectrum or narrow-range antibiotics; (iv) the dose-dependent nature of the effector; and (v) the class of antibiotics used.

Microbiome-immune-metabolic axis in the epidemic of childhood obesity: Evidence and opportunities

Obesity epidemic responsible for increase in diabetes, heart diseases, infections and cancer shows no signs of abating. Obesity in children is also on rise, indicating the urgent need of strategies for prevention and intervention that must begin in early life. While originally posited that obesity results from the simple concept of consuming more calories, or genetics, emerging research suggests that the bacteria living in our gut (gut microbiome) and its interactions with immune cells and metabolic organs including adipose tissues (microbiome-immune-metabolic axis) play significant role in obesity development in childhood. Specifically, abnormal changes (dysbiosis) in the gut microbiome, stimulation of inflammatory cytokines, and shifts in the metabolic functions of brown adipose tissue and the browning of white adipose tissue are associated with increased obesity. Many factors from as early as gestation appear to contribute in obesity, such as maternal health, diet, antibiotic use by mother and/or child, and birth and feeding methods. Herein, using evidence from animal and human studies, we discuss how these factors impact microbiome-immune-metabolic axis and cause obesity epidemic in children, and describe the gaps in knowledge that are warranted for future research.

Antibiotic use during pregnancy and childhood overweight: A population-based nationwide cohort study

Studies in mice suggest that early life represents a critical time window, where antibiotics may exert profound and lasting effects on the gut microbiota and metabolism. We aimed to test the hypothesis that prenatal antibiotic exposure is associated with increased risk of childhood overweight in a population-based cohort study. We linked 43,365 mother-child dyads from a nationwide cohort of pregnant women and their offspring to the Danish National Prescription Registry. Linear and logistic regression models were used to examine associations between prenatal exposure to antibiotics and BMI z-score and overweight (including obesity) at age seven and 11 years. Prenatal antibiotic exposure and childhood overweight were both associated with high pre-pregnancy BMI, maternal diabetes, multi-parity, smoking, low socioeconomic status, high paternal BMI, and short duration of breastfeeding. After adjustment for confounders, no associations were observed between prenatal antibiotic exposure and odds of overweight at age seven and 11 years. Whereas no association was observed between broad-spectrum antibiotics and overweight at age 11 years, exposure to broad-spectrum antibiotics was associated with higher odds of overweight at age seven years with an odds ratio of 1.27 (95% CI, 1.05–1.53) for ampicillin and an odds ratio of 1.56 (95% CI, 1.23–1.97) for amoxicillin. As we did not account for underlying infections, the observed associations with early childhood overweight could be explained by confounding by indication. In conclusion, our population-based study suggests that prenatal exposure to narrow-spectrum antibiotics is not associated with overweight in offspring. Exposure to some broad-spectrum antibiotics may increase the odds of overweight in early childhood, but the association does not persist in later childhood.

Association of prenatal antibiotics with measures of infant adiposity and the gut microbiome

BACKGROUND

Prenatal antibiotic exposure has been associated with an altered infant gut microbiome composition and higher risk of childhood obesity, but no studies have examined if prenatal antibiotics simultaneously alter the gut microbiome and adiposity in infants.

METHOD

In this prospective study (Nurture: recruitment 2013-2015 in North Carolina, United States), we examined in 454 infants the association of prenatal antibiotic exposure (by any prenatal antibiotic exposure; by trimester of pregnancy; by number of courses; by type of antibiotics) with infant age- and sex-specific weight-for-length z score (WFL-z) and skinfold thicknesses (subscapular, triceps, abdominal) at 12 months of age. In a subsample, we also examined whether prenatal antibiotic exposure was associated with alterations in the infant gut microbiome at ages 3 and 12 months.

RESULTS

Compared to infants not exposed to prenatal antibiotics, infants who were exposed to any prenatal antibiotics had 0.21 (95% confidence interval [CI] 0.02, 0.41) higher WFL-z at 12 months, and 0.28 (95% CI 0.02, 0.55) higher WFL-z if they were exposed to antibiotics in the second trimester, after adjustment for potential confounders, birth weight, and gestational age. We also observed a dose-dependent association (P-value for trend = 0.006) with infants exposed to ≥ 3 courses having 0.41 (95% CI 0.13, 0.68) higher WFL-z at 12 months. After further adjustment for delivery method, only second-trimester antibiotic exposure remained associated with higher infant WFL-z (0.27, 95% CI 0.003, 0.54) and subscapular skinfold thickness (0.49 mm, 95% CI 0.11, 0.88) at 12 months. Infants exposed to second-trimester antibiotics versus not had differential abundance of 13 bacterial amplicon sequence variants (ASVs) at age 3 months and 17 ASVs at 12 months (false discovery rate adjusted P-value < 0.05).

CONCLUSIONS

Prenatal antibiotic exposure in the second trimester was associated with an altered infant gut microbiome composition at 3 and 12 months and with higher infant WFL-z and subscapular skinfold thickness at 12 months.

Prevention of allergy with diverse and healthy microbiota: an update

PURPOSE OF REVIEW

Microbiota consist of symbiotic microscopic neighbors that interact on and within our bodies in diverse and incompletely understood ways throughout our lifetime. Though various associations with allergic disease have been described, clear effective therapeutic interventions to prevent allergy have been elusive.

RECENT FINDINGS

The human microbiome is influenced by multiple factors, including: mode of infant delivery (vaginal vs. cesarean section), breastfeeding, diet, presence of siblings and pets, exposure to antibiotics and other medications (particularly antacids), lifestyle, and developmental context. Microbial species promoting atopic responses and tolerance have been described. Specific microbiota likely act through distinct metabolic pathways to promote the health of their human hosts, optimally directing the developing immune system away from pro-allergic, Th2-dominated responses to more T-regulatory-influenced behaviors.

SUMMARY

Evidence suggests that specific healthy infant microbiome signatures may influence development of some components of the allergic march of childhood by decreasing atopic dermatitis, asthma, and food allergy. Further understanding of factors that influence healthy microbiota may lead to specific strategies tailored for early intervention and disease prevention.

The role of antimicrobial treatment during pregnancy on the neonatal gut microbiome and the development of atopy, asthma, allergy and obesity in childhood

INTRODUCTION

The use of antibiotics prenatally, during pregnancy, or neonatally may have adverse effects on the neonatal gut microbiome, and adversely affect the development of the infant immune system, leading to childhood atopy, asthma, allergy and obesity.

AREAS COVERED

Vaginal eubiosis and dysbiosis from molecular-based, cultivation-independent techniques, and how this affects the neonatal gut microbiome and early development of the immune system, the association between maternal antibiotics and the beneficial role of vitamin D in the development of atopy, asthma, allergy and obesity, efforts to reduce the use of antibiotics in pregnancy and therapeutic interventions such as vaginal 'seeding', probiotics, breastfeeding and neonatal dietary supplementation.

EXPERT OPINION

Currently available research gives insufficient attention to confounding variables. There remains uncertainty as to whether it is relevant that the mother suffered from the same condition as the purported infant outcome variable, for which she may have received antibiotics. In most studies, there is a lack of control for the number of antibiotic courses administered, the timing of use, the use of broad spectrum or narrow range antibiotics, the indication for antibiotics, the dose-dependent nature of the effect, the class of antibiotics used, or a varying degree of risk.

Maternal antibiotic use during pregnancy and childhood obesity at age 5 years

Objective:

The benefits of antibiotic treatment during pregnancy are immediate, but there may be long-term risks to the developing child. Prior studies show an association between early life antibiotics and obesity, but few have examined this risk during pregnancy.

Subjects:

To evaluate the association of maternal antibiotic exposure during pregnancy on childhood BMI-z at five years, we conducted a retrospective cohort analysis. Using electronic health record data from seven health systems in PCORnet, a national distributed clinical research network, we included children with same-day height and weight measures who could be linked to mothers with vital measurements during pregnancy. The primary independent variable was maternal outpatient antibiotic prescriptions during pregnancy (any versus none). We examined dose response (number of antibiotic episodes), spectrum and class of antibiotics, and antibiotic episodes by trimester. The primary outcome was child age- and sex-specific BMI-z at age five years.

Results:

The final sample was 53 320 mother-child pairs. During pregnancy, 29.9% of mothers received antibiotics. In adjusted models, maternal outpatient antibiotic prescriptions during pregnancy were not associated with child BMI-z at age five years (β=0.00, 95% CI −0.03, 0.02). When evaluating timing during pregnancy, dose-response, spectrum and class of antibiotics, there were no associations of maternal antibiotics with child BMI-z at age five years.

Conclusion:

In this large observational cohort, provision of antibiotics during pregnancy was not associated with childhood BMI-z at five years.

The effects of gut microbiota on metabolic outcomes in pregnant women and their offspring

Metabolic diseases such as gestational diabetes mellitus and obesity during pregnancy have become severe health issues due to adverse pregnant outcomes in recent years. Maternal metabolic disorders can influence the long-term health of mothers and their offspring. Current evidence demonstrated that gut microbiota plays a crucial role in metabolic dysfunction during gestation. Maternal status is associated with alterations in the compositions and diversity of the intestinal microbiota community during gestation. Antibiotic treatments may disturb the gut microbiota of pregnant women, and scientific probiotic and prebiotic supplements have positive effects on mothers and their offspring. This review discusses the role of gut microbiota on metabolic outcomes in pregnant women and their offspring, and further illustrates the impact of interventions on metabolic disorders in pregnancy. Our study may provide a novel target for health management during pregnancy.

Air Pollution, Early Life Microbiome, and Development

PURPOSE OF REVIEW

We review how an altered microbiome in early life impacts on immune, metabolic, and neurological development, focusing on some of the most widespread diseases related to each of these processes, namely atopic disease, obesity, and autism.

RECENT FINDINGS

The early development of the microbial communities that inhabit the human body is currently challenged by factors that range from reduced exposure to microbes, antibiotic use, and poor dietary choices to widespread environmental pollution. Recent work has highlighted some of the long-term consequences that early alterations in the establishment of these microbiotas can have for different aspects of human development and health. The long-term consequences of early microbiome alterations for human development and health are only beginning to be understood and will require in-depth investigation in the years to come. A solid understanding of how present day environmental conditions alter microbiome development, and of how an altered microbiome in early life impacts on life-long health, should inform both public health policies and the development of dietary and medical strategies to counteract early microbiota imbalances.

Prenatal Exposure to Antibiotics and Risk of Childhood Obesity in a Multicenter Cohort Study

Mounting evidence has linked postnatal antibiotic use with body mass index (BMI) in children, but the influence of prenatal antibiotic use on offspring obesity risk remains unclear. We aimed to assess the association between fetal exposure to antibiotics and obesity at ages 4 and 7 years among 43,332 children using a multicenter prospective cohort of the US Collaborative Perinatal Project (1959-1976). Antibiotic use was ascertained for mothers during pregnancy. Modified Poisson regression models were used to estimate risk ratios for obesity (BMI >95th percentile), and linear mixed models were applied to assess the association with BMI z score. Repeated prenatal exposure to antibiotics was associated with childhood obesity at age 7 years, and risk of obesity tended to increase with an increasing number of antibiotic exposures (for 2-3 exposures, risk ratio (RR) = 1.22, 95% confidence interval (CI): 1.04, 1.44; for ≥4 exposures, RR = 1.34, 95% CI: 1.03, 1.73). The magnitude of association was strongest for repeated exposures in the second trimester (RR = 1.40, 95% CI: 1.16, 1.71). Prenatal antibiotic use was not associated with obesity or BMI z score at age 4 years. These findings support an increased risk of mid-childhood obesity with repeated use of antibiotics during pregnancy.