Early pubertal maturation and risk of childhood asthma: A Mendelian randomization and longitudinal study

Child abuse and pubertal timing: what is the role of child sex and identity of the perpetrator?

BACKGROUND

This study investigated the association between child abuse [child neglect (CN), emotional (CEA) and physical abuse (CPA)] and early puberty with special regard to sex-specific effects concerning child and parental perpetrator.

METHODS

Data assessment took place within the framework of the LIFE Child Depression study, a longitudinal study on the development of depressive symptoms and disorders between child- and adulthood in Leipzig, Germany. A sample of 709 children (8-14 years) was recruited from the general population and via psychiatric hospitals. Data on pubertal status were assessed using an instrument for self-assessment of tanner stages (scales of physical pubertal development). Information on menarche was provided by parents. The Parent-Child Conflict Tactics Scales (CTS-PC) served for data on child abuse.

RESULTS

Regarding physical puberty markers, significant correlations were found, especially with child neglect (CN) and child emotional abuse (CEA). Regression analyses, controlling for Body-Mass-Index (BMI) and Socioeconomic Status (SES), revealed that children affected by child neglect perpetrated by mother (CNm) and child emotional abuse (CEA) parent-non-specifically enter puberty significantly earlier. Sex-specific analyses identified child neglect perpetrated by mother (CNm) to be associated with early puberty in girls and child emotional abuse perpetrated by father (CEAf) with early puberty in boys. Concerning the onset of menstruation, there was a significant positive correlation between early menarche and parent-specific and non-specific child neglect (CN), as well as between early menarche and child emotional abuse perpetrated by the mother (CEAm). In regression models that controlled for Body-Mass-Index (BMI) and Socioeconomic Status (SES) no significant associations were maintained. Child physical abuse (CPA) was not associated with early puberty.

CONCLUSION

Results outlined child neglect (CN) and child emotional abuse (CEA) to be sex- and perpetrator-specific risk factors for early pubertal development. Knowledge of sex- and perpetrator-specific effects could help clinicians to specify their diagnostic process and to define differential prevention and treatment goals for children with experiences of CN and CEA. Further research on the sex-specific impact of parental CN and CEA on girls' and boys' puberty is needed.

Relationships among gut microbiota, plasma metabolites, and juvenile idiopathic arthritis: a mediation Mendelian randomization study

Objective

The objective of this study is to investigate the causal relationship between gut microbiota and juvenile idiopathic arthritis, and to identify and quantify the potential role of plasma metabolites as mediators.

Methods

Using summary-level data from genome-wide association studies, a two-sample Mendelian randomization was conducted involving 131 gut microbiota genus, 1,400 plasma metabolites, and juvenile idiopathic arthritis. Additionally, a two-step approach was employed to quantify the proportion of the effect of gut microbiota on juvenile idiopathic arthritis mediated by plasma metabolites. Effect estimation primarily utilized Inverse Variance Weighting, with further validation using Bayesian weighted Mendelian randomization.

Results

In our MR analysis, a positive correlation was observed between Rikenellaceae and the risk of juvenile idiopathic arthritis, while Dorea showed a negative correlation with juvenile idiopathic arthritis risk. Mediation analysis indicated that Furaneol sulfate levels acted as a mediator between Dorea and juvenile idiopathic arthritis, with an indirect effect proportion of 19.94, 95% CI [8.86-31.03%].

Conclusion

Our study confirms a causal relationship between specific microbial genus and juvenile idiopathic arthritis, and computes the proportion of the effect mediated by plasma metabolites, offering novel insights for clinical interventions in juvenile idiopathic arthritis.

Aminopeptidase O Protein mediates the association between Lachnospiraceae and appendicular lean mass

Objective

Investigating the causal relationship between Lachnospiraceae and Appendicular lean mass (ALM) and identifying and quantifying the role of Aminopeptidase O Protein (AOPEP) as a potential mediator.

Methods

The summary statistics data of gut microbiota composition from the largest available genome-wide association study (GWAS) meta-analysis conducted by the MiBioGen Consortium (n = 13,266). Appendicular lean mass data were obtained from the UK-Biobank (n = 450,243). We conducted bidirectional two-sample Mendelian randomization (MR) analysis using summary-level data from GWAS to investigate the causal relationship between Lachnospiraceae and ALM. Additionally, we employed a drug-targeted MR approach to assess the causal relationship between AOPEP and ALM. Finally, a two-step MR was employed to quantitatively estimate the proportion of the effect of Lachnospiraceae on ALM that is mediated by AOPEP. Cochran's Q statistic was used to quantify heterogeneity among instrumental variable estimates.

Results

In the MR analysis, it was found that an increase in genetically predicted Lachnospiraceae [OR = 1.031, 95% CI (1.011-1.051), P = 0.002] is associated with an increase in ALM. There is no strong evidence to suggest that genetically predicted ALM has an impact on Lachnospiraceae genus [OR = 1.437, 95% CI (0.785-2.269), P = 0.239]. The proportion of genetically predicted Lachnospiraceae mediated by AOPEP was 34.2% [95% CI (1.3%-67.1%)].

Conclusion

Our research reveals that increasing Lachnospiraceae abundance in the gut can directly enhance limb muscle mass and concurrently suppress AOPEP, consequently mitigating limb muscle loss. This supports the potential therapeutic modulation of gut microbiota for sarcopenia. Interventions such as drug treatments or microbiota transplantation, aimed at elevating Lachnospiraceae abundance and AOPEP inhibition, synergistically improve sarcopenia in the elderly, thereby enhancing the overall quality of life for older individuals.

Persistent high exposure to exogenous phthalates and endogenous sex hormones associated with early pubertal onset among children: A 3.5-year longitudinal cohort study in China

BACKGROUND

Early onset of puberty could have significant impacts on childhood health, but the extent to which it was affected by phthalate esters (PAEs) and sex hormone disruption was not understood. The aim of this study is to investigate the associations between exposure to PAEs and sex hormone disruption and early onset of puberty in children.

METHODS

A longitudinal cohort study was conducted in China from May 2017 to Oct 2020, involving 740 children during consecutive visits. The onset of puberty was evaluated using Tanner definition, and early puberty was defined as an onset age less than the first 25 %, with cut-offs of 10.33 and 8.97 years for boys and girls, respectively. Serum testosterone (TT), estradiol (E₂) and urinary PAE metabolites were measured during three visits. Generalized linear models were used to explore the associations between PAE and sex hormones with the age of puberty onset, while log-binomial regressions were applied to assess the associations of persistent exposure to PAEs and sex hormones with early pubertal onset.

RESULTS

Approximately 86.0 % of boys and 90.2 % of girls completed puberty onset from pre-puberty, and more than 95 % of participants had PAE concentrations higher than the limit of detection. Boys showed higher exposure to PAE pollutants and higher TT levels. Persistent exposure to PAEs was positively associated with early pubertal onset in girls (ARR = 1.97, 95 %CI = 1.12, 3.46). Moreover, persistent exposure to PAEs and E₂ had synergistic associations with early pubertal onset in both boys (ARR = 4.77, 95 %CI = 1.06, 21.54) and girls (ARR = 7.07, 95 %CI = 1.51, 33.10). However, PAEs and TT had antagonistic associations only in boys (ARR = 0.44, 95 %CI = 0.07, 2.58).

CONCLUSION

Long-term exposure to PAEs might increase the risk of early pubertal onset, and it appears to work in synergy with E₂, while in antagonism with TT in boys' early pubertal onset. Reducing PAEs exposure might promote pubertal health.

Association of maternal physical and mental health characteristics with the hazard of having any medical condition or disability in Australian children: A 15-year birth cohort study

Any long-term medical condition or disability among children is a significant health issue. This study measured the incidence rate of any medical condition or disability among children from a nationally representative birth cohort, then used the random effect parametric survival regression model to assess whether the hazard of any medical condition or disability in children is associated with maternal physical and mental health characteristics (obesity, general health status, having a medical condition, stressful life events or mental illness). The study followed up 5019 children from the Longitudinal Study of Australian Children, assessing their time-to-event data from birth (2004) to 14 or 15 years of age (2018). The hazard rate of any medical condition or disability was 26.11 per 1000 person-years for all the children and 29.29 for the males-a noticeable gender difference. It was the highest (hazard rate: 62.90) among the children when their mothers had a medical condition, while the hazard rate was 22.40 per 1000 person-years among the children whose mothers had no medical conditions. The parametric panel regression results also suggested that the children of mothers with a medical condition during the 15-year study period were more likely to have a medical condition or disability (hazard ratio [HR]: 2.61, 95% confidence interval [CI]: 2.24-3.02) compared to the children of mothers with none. Similar trends were observed among children of mothers who had fair or poor general health (HR: 1.48, 95% CI: 1.15-1.91), obesity (HR: 1.40, 95% CI: 1.18-1.66) or experienced stressful life events (HR: 1.23, 95% CI: 1.06-1.43) over time compared to those whose mothers did not. These findings suggest that additional healthcare interventions targeting mothers with medical conditions, obesity, poor general health, or mental illness would help minimise the risk of medical conditions and disabilities among children.

Socioeconomic status and asthma: A bidirectional Mendelian randomization study

Background

Asthma is closely associated with lower socioeconomic status (SES), while the causal relationship between asthma and SES is undetermined. We aim to examine bidirectional relationships between asthma and SES using two-sample bidirectional Mendelian randomization (MR) for assessing potential causal inference.

Methods

Education attainment (years of schooling), household income, and Townsend deprivation index (TDI) were 3 indicators of SES considered in our study. The genetic summary data for SES and asthma were retrieved from publicly available genome-wide association studies (GWASs) conducted in participants of European ancestry. The MR estimates from each genetic instrument were combined using random effects inverse variance weighted (IVW) meta-analysis, with alternate methods (eg, MR-Egger, weighted median). Horizontal pleiotropy was assessed by sensitivity analyses. Analyses were performed using the package TwoSampleMR in R.

Results

The genetically instrumented years of schooling, household income, and TDI were not associated with the risk of asthma. However, according to the IVW method, 1.72 times increase in the odds ratio (OR) for asthma will lead to 0.024 standard deviation (SD) decrease in the years of schooling, 0.026 SD decrease in the household income, and 0.016 SD increase in the TDI. Although the substantial heterogeneity may undermine the reliability of results to some extent, sensitivity analyses further supported the causation of low household income by asthma.

Conclusion

Our study indicated that genetically predicted asthma may play a causal role in lowering the household income. However, the causal role of lower SES in asthma development was not supported by our MR analyses. Considering the heterogeneity in the current study, additional MR studies are needed to validate the results in the future.

Association of infant and child health characteristics with the hazard of any medical condition or disability in Australian children

Background

The incidence of any medical condition (e.g., sight, hearing, and speech problems, blackouts, chronic pain etc.) or disability (e.g., limited use of arms or fingers, legs, and feet, or other physical long-term health condition limiting everyday activities etc.) have been increasing among Australian children in recent decades.

Objectives

This study assessed whether infant or child health characteristics might be predictors of subsequent medical conditions or disabilities in children in the first 15 years of life.

Methods

Using time to event data of 5107 children, obtained from the Birth cohort of the Longitudinal Study of Australian Children, the study estimated the incidence of any medical condition or disability using the survival analysis technique. This study followed up the children from birth to 14 or 15 years of age (2004–2018) and assessed the association of infant and child health characteristics (birthweight, gestational age, use of intensive care unit or ventilator during their neonatal age and obesity) with hazard of any medical condition or disability using the random effect parametric survival regression model. The infant characteristics were measured in the Wave 1 while the children were aged 0/1 year and obesity characteristics were measured longitudinally over all the waves up to 14/15 years of age.

Results

The hazard rate of any medical condition or disability for all participants was 26.13 per 1000 person-years among children in Australia. This hazard incidence rate was higher among low birthweight (39.07) children compared to the children of normal birthweight (24.89) children. The hazard rate also higher among obese (34.37) children compared to the normal weight children (24.82) and among those who had received after-birth ventilation or intensive care unit emergency services (36.87) compared to those who have not received these services (24.20). The parametric panel regression model also suggests that children with low birthweight were 1.43 times (Hazard Ratio: 1.43, 95% Confidence Interval: 1.05–1.94) more likely to have any medical condition or disability than children with normal birthweight. The time to event analyses also revealed that being recipient of after-birth emergencies (HR: 1.47, 95% CI: 1.23–1.75), being male children (HR: 1.30, 95% CI: 1.14–1.48) or being obese (HR: 1.38, 95% CI: 1.07–1.79) significantly increased the likelihood of the incidence of a medical condition or disability among children. The regression model was adjusted for socio-demographic characteristics of children and mothers..

Conclusions

The study findings suggest that infants with low birth weight, hospital emergency service use and children with obesity would benefit from additional health care monitoring to minimize the risk of any medical condition or disability.

Causal risk factors for asthma in Mendelian randomization studies: A systematic review and meta-analysis

BACKGROUND

Several risk factors for asthma have been proposed; however, the causality of these associations is sometimes unclear. Mendelian randomization is a powerful epidemiological approach that can help elucidate the causality of risk factors. The aim of the present study was to identify causal risk factors for asthma through Mendelian Randomization studies.

METHODS

A systematic search of PubMed and EMBASE was conducted, to identify studies investigating risk factors for asthma or respiratory allergies through Mendelian Randomization. When two or more studies investigated the same risk factor a meta-analysis was conducted. Of 239 studies initially identified, 41 were included.

RESULTS

A causal association between adiposity and adult asthma risk was found in 10 out of 12 studies with a summary risk ratio of 1.05 per kg/m2 increase in BMI (95% CI: 1.03-1.07). Puberty timing (n = 3), alcohol (n = 2), and linoleic acid (n = 1) had causal effects on asthma risk, while vitamins/minerals (n = 6) showed no consistent effect on asthma. The effect of smoking on adult asthma conflicted between studies. Several of the significant associations of asthma with immune related proteins (n = 5) and depression (n = 2) investigated through multiple traits analyses could generally benefit from replications in independent datasets.

CONCLUSION

This systematic review and meta-analysis found evidence for causal effects of adiposity, puberty timing, linoleic acid, alcohol, immune related proteins, and depression on risk of asthma.

Mediators linking obesity to childhood asthma

BACKGROUND

Obesity and asthma are highly associated, but the mechanisms underlying the association remain unknown. We examined five mediators linking obesity with childhood asthma: (1) pulmonary function impairment, (2) airway inflammation, (3) physical fitness, (4) sleep-disordered breathing (SDB), and (5) early puberty.

METHODS

A Mendelian randomization (MR) study with mediation analysis of data obtained from 5965 children as part of the Taiwan Children Health Study. Observational analysis, MR two-stage least-squares method, and MR sensitivity analysis were carried out to investigate each causal pathway. Prospective cohort analyses were used to strengthen the findings.

RESULTS

The increased asthma risk associated with obesity was found to be mostly mediated through impaired pulmonary function, low physical fitness, and early puberty. In the MR analysis, body mass index was negatively associated with FEV1/FVC and physical fitness index (β = -2.17 and -0.71; 95% CI, -3.92 to -0.42 and -1.30 to -0.13, respectively) and positively associated with early puberty (OR, 1.09; 95% CI, 1.02-1.17). High FEV1/FVC and physical fitness index reduced asthma risk (OR, 0.98 and 0.93; 95% CI, 0.97-0.99 and 0.88-0.98, respectively), whereas SDB and early puberty increased the risk of asthma (OR, 1.03 and 1.22; 95% CI, 1.01-1.05 and 1.05-1.42, respectively). Temporal causality was strengthened in prospective cohort analyses. The three main mediators were low physical fitness, impaired pulmonary function, and early puberty, with mediation proportions of 73.76%, 61.63%, and 27.66%, respectively.

CONCLUSIONS

Interventions promoting physical fitness and pulmonary function might effectively reduce obesity-induced asthma risk.

Time-Specific Factors Influencing the Development of Asthma in Children

Susceptibility to asthma is complex and heterogeneous, as it involves both genetic and environmental insults (pre- and post-birth) acting in a critical window of development in early life. According to the Developmental Origins of Health and Disease, several factors, both harmful and protective, such as nutrition, diseases, drugs, microbiome, and stressors, interact with genotypic variation to change the capacity of the organism to successfully adapt and grow in later life. In this review, we aim to provide the latest evidence about predictive risk and protective factors for developing asthma in different stages of life, from the fetal period to adolescence, in order to develop strategic preventive and therapeutic interventions to predict and improve health later in life. Our study shows that for some risk factors, such as exposure to cigarette smoke, environmental pollutants, and family history of asthma, the evidence in favor of a strong association of those factors with the development of asthma is solid and widely shared. Similarly, the clear benefits of some protective factors were shown, providing new insights into primary prevention. On the contrary, further longitudinal studies are required, as some points in the literature remain controversial and a source of debate.

Sex Disparities in Asthma Development and Clinical Outcomes: Implications for Treatment Strategies

A gender-related disparity exists in asthma morbidity and mortality, which shifts at around puberty from a male predominance to a female predominance. This is clinically reflected in the fact that asthma that occurs in childhood (childhood-onset asthma) mainly affects boys, and that asthma that occurs in adulthood (adult-onset asthma) mainly affects women. Adult-onset asthma is often non-atopic, more severe, and associated with a poorer prognosis, thus posing a marked burden to women’s health and healthcare system. Many factors have been indicated to explain this gender-related disparity, including sociocultural and environmental factors as well as biological sex differences (genetic, pulmonary and immunological factors). It has long been suggested that sex hormones may be implicated in at least these biological sex differences. Overall, the evidence remains equivocal for the role of most sex hormones in asthma pathogenesis and clinical outcomes. Well-designed randomized clinical trials are required assessing the potential preventive or therapeutic effects of hormonal contraceptives on asthma in women, thereby helping to advance the evidence to inform future practice guidelines. The mechanisms underlying the role of sex hormones in asthma are complex, and our understanding is not yet complete. Additional mechanistic studies elucidating sex hormone signaling pathways and their interactions involved in the pathogenesis and clinical manifestations of asthma will help to identify potential sex hormone-driven asthma endotypes and novel therapeutic targets, providing the basis for a more personalized asthma management strategy.

Nutrition, Obesity and Asthma Inception in Children. The Role of Lung Function

Obesity is an important public health problem. WHO estimates that about 39 million children younger than 5 years of age are overweighted or obese. On the other hand, asthma is the most prevalent chronic disease in childhood, and thus, many children share those two conditions. In the present paper we review the epidemiology of children with asthma and obesity, as well as the consequences of being obese on the respiratory system. On the one hand obesity produces an underlying T-helper 2 (TH2) low inflammation state in which numerous cytokines, which could have an impact in the respiratory system play, a role. On the other hand, some respiratory changes have been described in obese children and, specially, the development of the so called “dysanapsis” (the disproportionate scaling of airway dimensions to lung volume) which seems to be common during the first stages of life, probably related to the early development of this condition. Finally, this review deals with the role of adipokines and insulin resistance in the inception and worsening of asthma in the obese child.

Evaluating the Causal Association Between Educational Attainment and Asthma Using a Mendelian Randomization Design

Asthma is a common chronic respiratory disease. In the past 10 years, genome-wide association study (GWAS) has been widely used to identify the common asthma genetic variants. Importantly, these publicly available asthma GWAS datasets provide important data support to investigate the causal association of kinds of risk factors with asthma by a Mendelian randomization (MR) design. It is known that socioeconomic status is associated with asthma. However, it remains unclear about the causal association between socioeconomic status and asthma. Here, we selected 162 independent educational attainment genetic variants as the potential instruments to evaluate the causal association between educational attainment and asthma using large-scale GWAS datasets of educational attainment (n = 405,072) and asthma (n = 30,810). We conducted a pleiotropy analysis using the MR-Egger intercept test and the MR pleiotropy residual sum and outlier (MR-PRESSO) test. We performed an MR analysis using inverse-variance weighted, weighted median, MR-Egger, and MR-PRESSO. The main analysis method inverse-variance weighted indicated that each 1 standard deviation increase in educational attainment (3.6 years) could reduce 35% asthma risk [odds ratio (OR) = 0.65, 95% confidence interval (CI) 0.51–0.85, P = 0.001]. Importantly, evidence from other MR methods further supported this finding, including weighted median (OR = 0.55, 95% CI 0.38–0.80, P = 0.001), MR-Egger (OR = 0.48, 95% CI 0.16–1.46, P = 0.198), and MR-PRESSO (OR = 0.65, 95% CI 0.51–0.85, P = 0.0015). Meanwhile, we provide evidence to support that educational attainment protects against asthma risk dependently on cognitive performance using multivariable MR analysis. In summary, we highlight the protective role of educational attainment against asthma. Our findings may have public health applications and deserve further investigation.

Life course body mass index through childhood and young adulthood and risks of asthma and pulmonary function impairment

BACKGROUND

Adiposity is a key risk factor for asthma and impaired pulmonary function.

OBJECTIVES

We aimed to identify the critical period of life course adiposity for asthma in childhood and young adulthood, and to determine whether associations of adiposity and asthma vary across ages.

METHODS

Birth weight and body mass index (BMI) from birth to 17 years of age were assessed in 6130 children from the Taiwan Children Health Study. Logistic regression for asthma outcome and linear regression for pulmonary function outcome were used to investigate associations of adiposity with asthma. Seventeen BMI-related single-nucleotide polymorphisms were used to obtain genetic instrumental variables for adiposity to perform Mendelian randomization (MR) analysis.

RESULTS

Using both regression model and MR analyses, we confirmed that the critical period of adiposity in predicting childhood asthma would be before age 6 years. Further, we discovered that the sensitive period of adiposity gain related to young adulthood asthma was the prepubertal stage. Risks of asthma at age 17 per unit increase in z-score of the BMI increased from 0.94 (95% CI: 0.79-1.11) at birth, and became greater than 1.00 between age 11 and 12, then increased to 1.08 (95% CI: 0.95-1.22) at age 17. The associations of life course BMI with asthma and pulmonary function impairment at age 12 and with asthma at age 17 increased with age. The aforementioned association was most prominent among central obesity indicators.

CONCLUSIONS

To prevent asthma in childhood and young adulthood, we should aim at promoting healthy growth at the toddler period and prepubertal stage.

The impact of obesity on immune function in pediatric asthma

PURPOSE OF REVIEW

Pediatric obese asthma is a complex disease that remains poorly understood. The increasing worldwide incidence of both asthma and obesity over the last few decades, their current high prevalence and the challenges in treating obese asthmatic patients all highlight the importance of a better understanding of the pathophysiological mechanisms in obese asthma. While it is well established that patients with obesity are at an increased risk of developing asthma, the mechanisms by which obesity drives the onset of asthma, and modifies existing asthma, remain unclear. Here, we will focus on mechanisms by which obesity alters immune function in asthma.

RECENT FINDINGS

Lung parenchyma has an altered structure in some pediatric obese asthmatics, known as dysanapsis. Central adiposity is linked to reduced pulmonary function and a better predictor of asthma risk in children than BMI. Obesity in young children is associated with an increased risk of developing asthma, as well as early puberty, and hormonal alterations are implicated in obese asthma. Obesity and asthma each yield immunometabolic dysregulation separately and we are learning more about alterations in these pathways in pediatric obese asthma and the potential impact of bariatric surgery on those processes.

SUMMARY

The recent progress in clarifying the connections between childhood obesity and asthma and their combined impacts on immune function moves us closer to the goals of improved understanding of the pathophysiological mechanisms underpinning obese asthma and improved therapeutic target selection. However, this common inflammatory disease remains understudied, especially in children, and much remains to be learned.

Advances and recent developments in asthma in 2020

In this review, we discuss recent publications on asthma and review the studies that have reported on the different aspects of the prevalence, risk factors and prevention, mechanisms, diagnosis, and treatment of asthma. Many risk and protective factors and molecular mechanisms are involved in the development of asthma. Emerging concepts and challenges in implementing the exposome paradigm and its application in allergic diseases and asthma are reviewed, including genetic and epigenetic factors, microbial dysbiosis, and environmental exposure, particularly to indoor and outdoor substances. The most relevant experimental studies further advancing the understanding of molecular and immune mechanisms with potential new targets for the development of therapeutics are discussed. A reliable diagnosis of asthma, disease endotyping, and monitoring its severity are of great importance in the management of asthma. Correct evaluation and management of asthma comorbidity/multimorbidity, including interaction with asthma phenotypes and its value for the precision medicine approach and validation of predictive biomarkers, are further detailed. Novel approaches and strategies in asthma treatment linked to mechanisms and endotypes of asthma, particularly biologicals, are critically appraised. Finally, due to the recent pandemics and its impact on patient management, we discuss the challenges, relationships, and molecular mechanisms between asthma, allergies, SARS-CoV-2, and COVID-19.