Association between childhood asthma and attention deficit hyperactivity or autism spectrum disorders: A systematic review with meta-analysis

The impacts associated with having ADHD: an umbrella review

Introduction

Attention Deficit Hyperactivity Disorder (ADHD) affects up to 5% of the population and is characterised by symptoms of impulsivity, hyperactivity and inattention. These symptoms are significantly impairing and carry additional risks for children and adults with ADHD, including negative mental health (e.g. depression), physical health (e.g. obesity) and societal outcomes (e.g. imprisonment, divorce). Very few studies have attempted to synthesise these risks in one publication due to the breadth of evidence published on the adverse outcomes of ADHD.

Methods

An umbrella review was performed to identify reviews (systematic, meta-analysis and narrative) that investigate the risks arising from having ADHD. We conducted a narrative synthesis of the findings and conducted a quality review of the included publications.

Results

Upon searching five databases, 16,675 records were identified. Of these, 125 reviews met the criteria for inclusion. A narrative synthesis of these findings highlighted three key domains of risks associated with ADHD: mental health, physical health, social and lifestyle. Most reviews were of good and moderate quality.

Discussion

This review highlights the many risks associated with having ADHD, beyond its three key symptom domains and the impact of the condition on daily functioning.

Registration

International Prospective Register of Systematic Reviews (PROSPERO CRD42023404073).

Clarifying the relationship and analyzing the influential factors of bronchial asthma in children with attention-deficit hyperactivity disorder

BACKGROUND

Bronchial asthma is closely related to the occurrence of attention-deficit hyperactivity disorder (ADHD) in children, which can easily have adverse effects on children's learning and social interactions. Studies have shown that childhood asthma can increase the risk of ADHD and the core symptoms of ADHD. Compared with children with ADHD alone, children with asthma and ADHD are more likely to show high levels of hyperactivity, hyperactive-impulsive and other externalizing behaviors and anxiety in clinical practice and have more symptoms of somatization and emotional internalization.

AIM

To explore the relationship between ADHD in children and bronchial asthma and to analyze its influencing factors.

METHODS

This retrospective cohort study was conducted at Dongying People's Hospital from September 2018 to August 2023. Children diagnosed with ADHD at this hospital were selected as the ADHD group, while healthy children without ADHD who underwent physical examinations during the same period served as the control group. Clinical and parental data were collected for all participating children, and multivariate logistic regression analysis was employed to identify risk factors for comorbid asthma in children with ADHD.

RESULTS

Significant differences were detected between the ADHD group and the control group in terms of family history of asthma and allergic diseases, maternal complications during pregnancy, maternal use of asthma and allergy medications during pregnancy, maternal anxiety and depression during pregnancy, and parental relationship status (P < 0.05). Out of the 183 children in the ADHD group, 25 had comorbid asthma, resulting in a comorbidity rate of 13.66% (25/183), compared to the comorbidity rate of 2.91% (16/549) among the 549 children in the control group. The difference in the asthma comorbidity rate between the two groups was statistically significant (P < 0.05). The results of the multivariate logistic regression analysis indicated that family history of asthma and allergic diseases, maternal complications during pregnancy, maternal use of asthma and allergy medications during pregnancy, maternal anxiety and depression during pregnancy, and parental relationship status are independent risk factors increasing the risk of comorbid asthma in children with ADHD (P < 0.05).

CONCLUSION

Children with ADHD were more likely to have comorbid asthma than healthy control children were. A family history of asthma, adverse maternal factors during pregnancy, and parental relationship status were identified as risk factors influencing the comorbidity of asthma in children with ADHD. Clinically, targeted interventions based on these factors can be implemented to reduce the risk of comorbid asthma. This information is relevant for results sections of abstracts in scientific articles.

Associations between symptoms of attention-deficit hyperactivity disorder, socioeconomic status and asthma in children

Socioeconomic status (SES) influences the risk of both physical diseases, such as asthma, and neurodevelopmental conditions, including attention-deficit/hyperactivity disorder (ADHD). Using Causal Mediation Analysis on French birth-cohort data, we found a causal pathway from SES to ADHD symptoms, in part mediated by asthma. An increase in family income at age 3 by one unit resulted in lower ADHD symptoms at age 5, by -0.37 [95% CI: -0.50, -0.24] SDQ-score-points, with additional -0.04 [95% CI: -0.08, -0.01] points reduction indirectly via asthma at age 3, both with statistical significance. Importantly, family income at age 3 exerted both direct and indirect (via asthma) negative effects on later ADHD symptoms with much higher magnitudes for the direct effect. Our findings underscore the importance of apprehending ADHD symptoms in the broader context of socioeconomic disparities, along with their comorbidities with asthma, potentially influencing public health interventions and clinical practice in managing ADHD.

Association between type 2 inflammatory diseases and neurodevelopmental disorders in low-birth-weight children and adolescents

Background

Evidence of the association of certain neurodevelopmental disorder with specific type 2 inflammatory (T2) disease has been found. However, the association of various neurodevelopmental disorders with T2 diseases as a whole remains unclear in low-birth-weight (LBW) infants.

Objective

To evaluate the association of type 2 inflammatory (T2) diseases with intellectual disability (ID), autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and learning disability (LD) in LBW children and adolescents.

Methods

The study sample was derived from 2005 to 2018 National Health Interview Survey sample child files. LBW children and adolescents aged 3-17 were included. History of T2 diseases (including asthma and atopic dermatitis) and four neurodevelopmental disorders were reported by adults in families. The relationship between T2 diseases and the risk of four neurodevelopmental disorders was investigated through multiple-weighted logistic regression. Age, sex, race/ethnicity, region, highest education in family and ratio of family income to the poverty threshold were adjusted as covariates for model estimation. Subgroup analyses were conducted by age stratification (3-11 and 12-17 years), sex (male and female), and race (white and non-white).

Results

11,260 LBW children aged 3-17 years [mean age (SE), 9.73 (0.05) years] were included, in which 3,191 children had T2 diseases. History of T2 diseases was associated with an increased risk of neurodevelopmental disorders, with an OR of 1.35 (95% CI, 0.99-1.84) for ID, 1.47 (95% CI, 1.05-2.05) for ASD, 1.81 (95% CI, 1.51-2.16) for ADHD, and 1.74 (95% CI, 1.49-2.04) for LD following the adjustment of all the covariates. The correlations between T2 disorders and each of the four neurodevelopmental disorders were significantly different by sex and race (all P for interaction < 0.001), and no differences were found in age stratification (all P for interaction > 0.05).

Conclusion

In a nationally representative sample of children, we found a significant association of T2 diseases with ASD, ADHD, and LD, even after adjusting for demographic baseline. We also found that the association of T2 disease with neurodevelopmental disorders differed between sex and race. Further investigation is needed to evaluate causal relationships and elucidate their potential mechanisms.

A systematic meta-review of systematic reviews on attention deficit hyperactivity disorder

BACKGROUND

There are now hundreds of systematic reviews on attention deficit hyperactivity disorder (ADHD) of variable quality. To help navigate this literature, we have reviewed systematic reviews on any topic on ADHD.

METHODS

We searched MEDLINE, PubMed, PsycINFO, Cochrane Library, and Web of Science and performed quality assessment according to the Joanna Briggs Institute Manual for Evidence Synthesis. A total of 231 systematic reviews and meta-analyses met the eligibility criteria.

RESULTS

The prevalence of ADHD was 7.2% for children and adolescents and 2.5% for adults, though with major uncertainty due to methodological variation in the existing literature. There is evidence for both biological and social risk factors for ADHD, but this evidence is mostly correlational rather than causal due to confounding and reverse causality. There is strong evidence for the efficacy of pharmacological treatment on symptom reduction in the short-term, particularly for stimulants. However, there is limited evidence for the efficacy of pharmacotherapy in mitigating adverse life trajectories such as educational attainment, employment, substance abuse, injuries, suicides, crime, and comorbid mental and somatic conditions. Pharmacotherapy is linked with side effects like disturbed sleep, reduced appetite, and increased blood pressure, but less is known about potential adverse effects after long-term use. Evidence of the efficacy of nonpharmacological treatments is mixed.

CONCLUSIONS

Despite hundreds of systematic reviews on ADHD, key questions are still unanswered. Evidence gaps remain as to a more accurate prevalence of ADHD, whether documented risk factors are causal, the efficacy of nonpharmacological treatments on any outcomes, and pharmacotherapy in mitigating the adverse outcomes associated with ADHD.

Prevalence of high-risk conditions for severe COVID-19 among Medicaid-enrolled children with autism and mental health diagnoses in the United States

LAY ABSTRACT

Children are at risk of varying severity of illness and even death from COVID-19. We aim to determine whether autistic children or children with mental health conditions have more underlying health conditions that put people at risk of severe illness from COVID-19. We use data from a national sample of Medicaid-enrolled children for the years 2008-2016. These data include children across the 50 states and the District of Columbia. We compare the prevalence of underlying conditions among autistic children and children with mental health condition to that of other children in Medicaid. This study included 888,487 autistic children, 423,397 with any mental health condition (but not autism), and 932,625 children without any of these diagnoses. We found 29.5% of autistic children and 25.2% of children with mental health conditions had an underlying condition with high risk for severe illness from COVID, compared to 14.1% of children without these diagnoses. Autistic children had over twice the odds of having any underlying conditions, when accounting for age, race, sex, and other characteristics. Children with mental health conditions had 70% higher odds of having these underlying conditions. Mitigation measures in schools and other areas could minimize risk of short- and long-term impacts from COVID for autistic and all children.

Evaluation of the frequency of attention deficit hyperactivity disorder in patients with asthma

BACKGROUND

Asthma is the most prevalent respiratory disease caused by chronic airway inflammation. Attention Deficit Hyperactivity Disorder (ADHD) is children's most common psychological and neurodevelopmental disorder. Increased risk for ADHD in patients with inflammatory and autoimmune diseases supports the role of inflammatory mechanisms in the occurrence of ADHD. However, the association between asthma and ADHD remains unclear.

OBJECTIVE

This study was designed to evaluate the prevalence of ADHD in patients with asthma who were referred to the clinic of allergy and clinical immunology.

METHODS

This cross-sectional study was conducted on children aged 6 to 18 with asthma at Imam Ali hospital, Karaj, Iran. The patient's demographic data, history of childbirth delivery type, premature birth, hospital admission, family income, birth rate, and family history information related to the patient's asthma and medicines were recorded. ADHD diagnosis was made using the Persian version of Conners Parent Behavioral Problems Rating Scale (CPRS-26).

RESULTS

In this study, 677 asthmatic patients were enrolled; 46 patients (6.8%) had ADHD. The probability of ADHD in asthmatic patients inhabited in a rural area, males, and patients with a history of food allergy, allergic rhinitis, urticaria, and eczema was significantly higher (p < 0.05). In addition, our result demonstrated that the likelihood of ADHD in patients with asthma and a history of PICU admission was significantly higher (p < 0.05).

CONCLUSIONS

The present study showed that severe asthma, was the risk factor for ADHD in patients with asthma. Physicians should be aware of this co-morbidity to refer asthmatic patients who have the symptoms of ADHD to a psychologist.

Factors to Consider in Prescribing Asthma Biologic Therapies to Children

The increasing availability of biologics, both by expanding age indications and by development of new therapies, provides additional options to treat children and adolescents with severe asthma. However, the evidence for these biologics in these populations is limited compared with that for adult studies. As such, before initiation of therapy, possible alternative therapies that can also provide asthma control, confirmation of the diagnosis of asthma, management of comorbidities, and assessment of adherence should be explored. The choice of a biologic should be a shared decision-making process between providers and families, balancing biologic efficacy, goals of care, administration, and ability to treat multiple conditions. Response to treatment should be periodically evaluated not only to ensure an ineffective treatment is not continued but also to consider when to potentially discontinue therapy should it be beneficial. The utilization of biologics in children and adolescents with severe asthma also leads to unanswered questions on their role in disease remission and long-term outcomes.

Maternal obesity, diabetes, preeclampsia, and asthma during pregnancy and likelihood of autism spectrum disorder with gastrointestinal disturbances in offspring

LAY ABSTRACT

Autism spectrum disorder is heterogeneous and often accompanied by co-occurring conditions. Previous studies have shown that maternal health conditions during pregnancy including obesity, diabetes, preeclampsia, and asthma were associated with increased likelihood of autism. However, little has been done examining the likelihood associated with autism with co-occurring conditions. This study assessed these maternal health conditions in relationship to autism and gastrointestinal disturbances, a common co-occurring condition in children diagnosed with autism. Data included 308,536 mother-child pairs from one integrated health care system with comprehensive electronic medical records. Among the study cohort, 5,131 (1.7%) children had a diagnosis of autism by age 5. Gastrointestinal disturbances were present in 35.4% of children diagnosed with autism and 25.1% of children without autism diagnoses. Our results showed that each of the four maternal health conditions during pregnancy was associated with increased likelihood of gastrointestinal disturbances, autism without gastrointestinal disturbances, and autism with gastrointestinal disturbances. For all four maternal health conditions, the association was greatest for likelihood of autism with gastrointestinal disturbances. Given that children diagnosed with autism are more likely to have gastrointestinal disturbances and over 80% of gastrointestinal disturbances in this cohort were diagnosed prior to autism diagnosis, this study suggests that there may be common biological pathways between autism and gastrointestinal disturbances impacted by these maternal exposures. Future studies are warranted to assess associations between different exposures and autism with other co-occurring conditions to increase our understanding of autism heterogeneity.

A Randomized, Placebo-Controlled Laboratory Classroom Study of the Efficacy and Safety of Dasotraline in Children With ADHD

OBJECTIVE

To evaluate the efficacy of dasotraline 2 mg/day for treatment of ADHD in children weighing ≤30 kg.

METHOD

Children (ages 6-12) with ADHD were randomized to 14 days of once-daily evening doses of dasotraline 2 mg (n = 47) or placebo (n = 48). Efficacy was assessed at Baseline and day-15 in seven, 30-minutes classroom sessions on each day (8:00 a.m. to 8:00 p.m.; 12-24 hours post-dose). The primary endpoint was change from Baseline at Day-15 in the Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) combined score averaged over the seven, serial timepoints.

RESULTS

Treatment with dasotraline was associated with significant improvement versus placebo in the primary SKAMP-combined score (least squares mean [SE] change from Baseline at Day-15: -3.67 [0.775] vs. +1.57 [0.773]; p < .001; effect size, 1.04).

CONCLUSION

Dasotraline 2 mg/day was found to be efficacious and generally well tolerated in this placebo-controlled, laboratory classroom study of children ages 6 to 12 years with ADHD.

CLINICALTRIALS.GOV IDENTIFIER

NCT03231800.

Pediatric asthma and non-allergic comorbidities: a review of current risk and proposed mechanisms

It is increasingly recognized that children with asthma are at a higher risk of other non‐allergic concurrent diseases than the non‐asthma population. A plethora of recent research has reported on these comorbidities and progress has been made in understanding the mechanisms for comorbidity. The goal of this review was to assess the most recent evidence (2016–2021) on the extent of common comorbidities (obesity, depression and anxiety, neurodevelopmental disorders, sleep disorders and autoimmune diseases) and the latest mechanistic research, highlighting knowledge gaps requiring further investigation. We found that the majority of recent studies from around the world demonstrate that children with asthma are at an increased risk of having at least one of the studied comorbidities. A range of potential mechanisms were identified including common early life risk factors, common genetic factors, causal relationships, asthma medication and embryologic origins. Studies varied in their selection of population, asthma definition and outcome definitions. Next, steps in future studies should include using objective measures of asthma, such as lung function and immunological data, as well as investigating asthma phenotypes and endotypes. Larger complex genetic analyses are needed, including genome‐wide association studies, gene expression–functional as well as pathway analyses or Mendelian randomization techniques; and identification of gene–environment interactions, such as epi‐genetic studies or twin analyses, including omics and early life exposure data. Importantly, research should have relevance to clinical and public health translation including clinical practice, asthma management guidelines and intervention studies aimed at reducing comorbidities.

Pre- and postnatal antibiotic exposure and risk of developing attention deficit hyperactivity disorder-A systematic review and meta-analysis combining evidence from human and animal studies

This study investigated the effects of early antibiotic exposure on ADHD risk by (1) integrating meta-analytical evidence from human observational studies examining the association between prenatal or early postnatal antibiotic exposure on the risk of developing ADHD; and (2) reviewing evidence from experimental animal studies on the effects of early antibiotic exposure on behavior. Sixteen human studies and five rodent studies were reviewed. A quantitative meta-analysis with 10 human studies indicated an increased risk for ADHD after prenatal antibiotic exposure (summary effect estimate Hazard Ratio (HR) 1.23, 95% CI 1.09-1.38; N = 2,398,475 subjects) but not after postnatal exposure within the first two years of life (summary effect estimate HR 1.12, 95% CI 0.95-1.32; N = 1,863,867 subjects). The rodent literature suggested that peri-natal antibiotic exposure has effects on social behavior, anxiety and aggression, alongside changes in gut microbial composition. Human and rodent findings thus suggest prenatal antibiotic exposure as a possible risk factor for ADHD, and suggest that an early disruption of the gut microbiome by antibiotics may interfere with neurodevelopment.

Two meta-analyses of the association between atopic diseases and core symptoms of attention deficit hyperactivity disorder

Studies in the field of neuroscience and psychology have hypothesized that a causal association exists between atopic diseases and attention-deficit/hyperactivity disorder (ADHD). Previous systematic reviews and meta-analyses have reported a higher risk of ADHD in children with atopic diseases; however, the relationship between ADHD symptoms and atopic diseases remains unclear. We systematically reviewed observational cross-sectional and longitudinal studies to investigate the relationship between atopic diseases and ADHD symptom severity (hyperactivity/impulsivity and inattention). The majority of studies showed a statistically significant association between atopic diseases and both ADHD symptoms, with substantial heterogeneity in the outcome of hyperactivity/impulsivity. Remarkably decreased heterogeneity and statistical significance were observed in the second meta-analysis of ADHD-related behavior symptoms in atopic patients without ADHD. Our study indicated that atopic diseases not only associated with ADHD but also ADHD symptoms severity. This association was even observed in children with subthreshold ADHD, indicating that atopic diseases may play a role in the spectrum of ADHD symptom severity. Trial registration: This study was registered on PROSPERO (registration ID: CRD42020213219).

Effects of prenatal nutrient supplementation and early life exposures on neurodevelopment at age 10: a randomised controlled trial - the COPSYCH study protocol

INTRODUCTION

Nutrient deficiency and immune and inflammatory disturbances in early life may compromise neurodevelopment and be implicated in the aetiology of psychiatric disorders. However, current evidence is limited by its predominantly observational nature. COpenhagen Prospective Study on Neuro-PSYCHiatric Development (COPSYCH) is a research alliance between Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research with the overall aim to investigate effects of prenatal and early life exposures on neurodevelopment at 10 years. COPSYCH will investigate the impact of prenatal n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) and high-dose vitamin D supplementation on neurodevelopment reflected by brain development, neurocognition and psychopathology. Moreover, the neurodevelopmental impact of early life exposures such as infections, low grade inflammation and the gut microbiome will be scrutinised.

METHODS AND ANALYSIS

COPSYCH is based on the prospective and ongoing COPSAC2010 birth cohort of 700 mother-child pairs. Randomised controlled trials of supplementation with n-3 LCPUFA and/or high-dose vitamin D or placebo in the third trimester were embedded in a factorial 2×2 design (ClinicalTrials.gov: NCT01233297 and NCT00856947). This unique cohort provides deep phenotyping data from 14 previous clinical follow-up visits and exposure assessments since birth. The ongoing 10-year visit is a 2-day visit. Day 1 includes a comprehensive neurocognitive examination, and assessment of psychopathological dimensions, and assessment of categorical psychopathology. Day 2 includes acquisition of brain structural, diffusion and functional sequences using 3 Tesla MRI. Study outcomes are neurocognitive, psychopathological and MRI measures.

ETHICS AND DISSEMINATION

This study has been approved by the Danish National Committee on Health Research Ethics and The Danish Data Protection Agency. The study is conducted in accordance with the guiding principles of the Declaration of Helsinki. Parents gave written informed consent before enrolment.

Association of Food Allergy, Respiratory Allergy, and Skin Allergy with Attention Deficit/Hyperactivity Disorder among Children

BACKGROUND

Previous studies have predominately examined associations of respiratory allergy and skin allergy with ADHD, but little is known about the association between food allergy and ADHD.

METHODS

We included 192,573 children aged 4-17 years from the National Health Interview Survey (NHIS), a leading health survey in a nationally representative sample of the US population. Allergy conditions and ADHD were defined based on an affirmative response in the NHIS questionnaire. We used weighted logistic regression to estimate the odds ratio (OR) of ADHD.

RESULTS

Among the 192,573 children, 15,376 reported ADHD diagnosis. The prevalence of ADHD was higher among children with allergic conditions: 12.66% vs. 7.99% among children with and without food allergy; 12.16% vs. 7.63% among children with and without respiratory allergy; and 11.46% vs. 7.83% among children with and without skin allergy. After adjusting for covariates, the OR of ADHD was 1.72 (95% CI, 1.55-1.91) comparing children with and without food allergy, 1.50 (95% CI, 1.41-1.59) comparing children with and without respiratory allergy, and 1.65 (95% CI, 1.55-1.75) comparing children with and without skin allergy. The observed associations remained significant after mutual adjustment for other allergic conditions.

CONCLUSIONS

In a nationally representative sample of US children, we found a significant association of common allergic conditions (food allergy, respiratory allergy, and skin allergy) with ADHD.

Developmental disorders in school children are related to allergic diseases

BACKGROUND

In children, relationships between developmental disorders such as attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder and allergic diseases remain controversial, because these diseases show age- and sex-related differences. A proper understanding of the relationships between developmental disorders and allergic diseases should improve medical care for both diseases. We confirmed the prevalence of allergic diseases in elementary school-age children with developmental disorders by grade and sex.

METHODS

The subjects were 446 lower grade and 312 upper grade elementary school-age children who had visited our hospital. The prevalence of allergic diseases among subjects with and without developmental disorders by grade and sex was examined using the diagnostic names on medical records.

RESULTS

The prevalence of allergic diseases was significantly higher in lower grade boys and girls with developmental disorders than in those without developmental disorders (boys: OR 3.22, 95%; CI 1.49-6.95; girls: OR: 3.87, 95% CI: 1.27-11.82). The prevalence of allergic diseases was significantly higher in higher grade boys with developmental disorders than in those without developmental disorders (OR: 3.46, 95% CI: 1.59-7.53). Multiple logistic regression analysis in lower grades revealed that ADHD correlated with bronchial asthma (adjusted OR: 3.72, 95% CI: 1.42-9.69) and that autism spectrum disorder correlated with atopic dermatitis (adjusted OR: 4.26, 95% CI: 1.36-13.36). Analyses of children in the upper grades showed that ADHD correlated with atopic dermatitis (adjusted OR: 5.06, 95% CI: 1.28-20.05).

CONCLUSIONS

Elementary school-age children with developmental disorders were more likely to have allergic diseases. The types of allergic diseases related to developmental disorders differed by grade and sex.

Chlorpyrifos residue level and ADHD among children aged 1-6 years in rural China: A cross-sectional study

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders in childhood and is caused by both genetic and environmental factors. As genetic factors are nonmodifiable, environmental factors have attracted increasing attention.

OBJECTIVE

To investigate the relationships between urinary chlorpyrifos (CPF) levels, blood micronutrient levels, and ADHD prevalence in children living in rural areas of China.

METHODS

This cross-sectional study collected data on CPF exposure (according to urinary levels), blood micronutrient levels, and ADHD prevalence in children aged 1-6 years in rural China. The CPF levels were determined by mass spectrometry. Blood levels of micronutrients, including zinc, iron, calcium, copper, magnesium, and vitamin D, were measured by professional detection kits. ADHD was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition. Descriptive statistics and univariate analysis were conducted using SPSS 21.0, and path analysis was conducted using Mplus 8.0.

RESULTS

Of the 738 children who met the eligibility criteria, 673 children (673/738, 91.2%) were included in the final analysis. Baseline questionnaires and urine samples were collected from all 673 subjects. A total of 672 children provided blood samples for micronutrient testing, and 651 completed the ADHD assessment. Approximately one-fifth of children (144/673, 21.4%) had detectable levels of CPF in their urine, and 6.9% (45/651) were diagnosed with ADHD. Path analysis showed that the total effect of CPF exposure on ADHD risk was 0.166 (P < 0.05), with a direct effect of 0.197 (P < 0.05) and an indirect effect of -0.031 (P < 0.05) via vitamin D. The mediating effect of urinary CPF levels on ADHD risk via vitamin D was 18.67%.

CONCLUSION

Higher levels of CPF exposure are associated with higher risk of ADHD. Additionally, increasing vitamin D levels may have a beneficial effect on the relationship between CPF exposure and ADHD risk. Our findings highlight the importance of modifying environmental factors to reduce ADHD risk and provide insight into future ADHD interventions.

Non-mental diseases associated with ADHD across the lifespan: Fidgety Philipp and Pippi Longstocking at risk of multimorbidity?

Several non-mental diseases seem to be associated with an increased risk of ADHD and ADHD seems to be associated with increased risk for non-mental diseases. The underlying trajectories leading to such brain-body co-occurrences are often unclear - are there direct causal relationships from one disorder to the other, or does the sharing of genetic and/or environmental risk factors lead to their occurring together more frequently or both? Our goal with this narrative review was to provide a conceptual synthesis of the associations between ADHD and non-mental disease across the lifespan. We discuss potential shared pathologic mechanisms, genetic background and treatments in co-occurring diseases. For those co-occurrences for which published studies with sufficient sample sizes exist, meta-analyses have been published by others and we discuss those in detail. We conclude that non-mental diseases are common in ADHD and vice versa and add to the disease burden of the patient across the lifespan. Insufficient attention to such co-occurring conditions may result in missed diagnoses and suboptimal treatment in the affected individuals.

Early Sensory and Temperament Features in Infants Born to Mothers With Asthma: A Cross-Sectional Study

Maternal asthma in pregnancy is associated with an increased risk of adverse perinatal outcomes. Adverse perinatal outcomes may result in poorer infant developmental outcomes, such as temperament and sensory difficulties. This study aimed to (1) assess differences in temperament and sensory features between infants born to mothers with and without asthma and (2) investigate differences in these infant behaviours as a function of maternal asthma severity and asthma control. Mothers completed the Carey Temperament Scales and the Sensory Profile 2 at either 6 weeks, 6 months, or 12 months postpartum. Overall, we observed no significant differences between infants born to mothers with and without asthma in their temperament or sensory features; scores in both domains fell within the normative range. More infants in the asthma group, however, were reported to be highly distractible. When compared with normative data, infants in both groups were reported to have poor predictability of biological functions and fewer infants engaged in low levels of sensory behaviours. Some infants were observed to experience difficulties with hyper-reactivity within several domains. Maternal asthma severity and control during pregnancy were not linked to significant differences between infant temperament and sensory features. The present findings indicate that infants born to mothers with asthma are not at an increased risk overall for temperament or sensory difficulties, compared to control infants. However, a subset of infants across both groups may be at risk for attention or sensory hyper-reactivity difficulties. Further research into the developmental outcomes of infants born to mothers with asthma is warranted.

Attention-deficit/hyperactivity disorder has a state-dependent association with asthma: The role of systemic inflammation in a population-based birth cohort followed from childhood to adulthood

There is a high comorbidity between attention-deficit/hyperactivity disorder (ADHD) and asthma, and inflammation has been proposed as a potential pathophysiological mechanism behind this association. Most studies conducted so far have used a cross-sectional design, and none has evaluated the prevalence of asthma symptoms in patients with ADHD followed from childhood to adulthood. We relied on data from the 1993 Pelotas birth cohort to evaluate the association between ADHD and asthma in patients with distinct patterns of incidence, persistence and remission, and to explore the potential role of inflammatory markers in the comorbidity. We analyzed data from 3281 individuals from the 1993 Pelotas birth cohort collected at birth (1993), 11 years (2004), 18 years (2011), and 22 years (2015). Subjects were first classified according to their ADHD and asthma status as early-onset (EO) persistent (positive screening for ADHD at 11 years and diagnosis of ADHD according to DSM-5, except criterion E, at either 18 or 22 years), EO-remittent (positive screening for ADHD at 11 years only), late-onset (diagnosis of ADHD according to DSM-5, except criterion E, at 18 or 22 years only), or healthy subjects (negative for both conditions in all evaluation). After controlling for confounders, significant associations were observed between EO-remittent ADHD and EO-remittent asthma (OR 1.68, 95% CI 1.11-2.55), EO-persistent ADHD and EO-persistent asthma (OR 4.33, 95% CI 1.65-11.34), and between late-onset ADHD and late-onset asthma (OR 1.86, 95% CI 1.28-2.70), suggesting a state-dependent association. Serum interleukin-6 (IL-6) and C-reactive protein (CRP) were measured at the 18- and 22-year evaluations and compared between subjects positive for ADHD, asthma, and subjects with both or none conditions, regardless of the previously defined trajectories. Subjects with comorbid ADHD and asthma presented higher levels of IL-6 at the 18- and 22-year evaluations when compared to subjects negative for both conditions. Our results demonstrate a state-dependent association between ADHD and asthma despite underlying trajectories. Higher levels of serum IL-6 in patients with both conditions suggest that a pro-inflammatory environment might have a role in the pathophysiological mechanisms underlying the comorbidity.