Familial co-aggregation of attention-deficit/hyperactivity disorder and autoimmune diseases: a cohort study based on Swedish population-wide registers

Children with a history of both maternal immune activation and prematurity are not at increased risk of ADHD symptoms

Maternal autoimmune diseases (AID) are risk factors for Attention Deficit Hyperactivity Disorder (ADHD). Animal studies suggest that maternal immune activation (MIA) is a disease primer for ADHD, with second environmental factor precipitating the onset of the disease. Prematurity is also a major risk factor for ADHD. In this study, we sought to explore the interaction between parental AID and prematurity on ADHD risk in a community sample. Children of AID parents born prematurely appeared at increased odds of ADHD but these two risk factors do not appear to be additive (OR 1.39 [95 CI 0.75; 2.46]). Longitudinal studies with larger numbers of participants are needed.

Increased Rate of Familial Mediterranean Fever in Children With ADHD: A Population-Based Case-Control Study

OBJECTIVE

There is growing evidence of involvement of inflammatory mechanisms in ADHD. Previous studies found significantly higher rates of ADHD among children with FMF. The present study examined the rate of exposure to FMF in children with a later (within a 5-year period) diagnosis of ADHD compared to non-ADHD children.

METHODS

A population-based case-control study of all children (<18 years) registered in Leumit Health Services during 01.01.2006 to 06.30.2021. All cases met ICD-9/10 criteria for ADHD. They were matched by age, sex, and socioeconomic status on a 1:2 rate to randomly selected non-ADHD controls.

RESULTS

Fifty-six (0.30%) children with ADHD (N = 18,756) were previously diagnosed with FMF compared to 65 of 37,512 controls (0.17%). A significant, independent association existed between a preceding FMF diagnosis and a later ADHD diagnosis [OR = 1.72 (95% CI 1.18-2.51); p = .003].

CONCLUSIONS

The mechanisms underlying the association w between FMF and later ADHD diagnosis merit further elucidation.

Maternal pre-pregnancy and prenatal penicillin, neonatal inflammation and growth factors are associated to ADHD in the offspring

Background

The etiology for Attention Deficit Hyperactivity Disorder (ADHD) is generally unknown, but both genetics, biology and environment have been shown to increase the risk. The purpose of this study was to explore the prenatal risk factors, especially maternal antibiotics consumed before and during pregnancy, for the offspring for later being diagnosed with ADHD, and to find associations with neonatal biomarkers.

Methods

We included new-borns from the CODIBINE study, 465 children were ADHD cases and 10 954 children were controls. Ten biomarkers reflecting inflammation, neonatal stress, and/or neurologic development or damage were measured in dried blood spot samples drawn 2-3 days after birth. Maternal and child prescriptions of medication, birth data, and disorder codes were included in the statistical analyses.

Results

We found that maternal penicillin prescriptions until 2 years before birth increased the risk for offspring ADHD. The risk was higher with multiple prescriptions, both before and during pregnancy. Cases with maternal penicillin prescriptions had lower neonatal levels of epidermal growth factor (EGF) and soluble Tumor Necrosis Factor Receptor I (sTNF RI). Maternal prescriptions for psychotropic medication have, as expected, the highest correlation to offspring ADHD, but we found no differences in biomarkers in this group.

Conclusion

The fact that the offspring risk for ADHD was increased also with pre-pregnancy prescriptions of penicillin, indicates that it is not the penicillin that is the direct cause of the adverse effects. The significant differences in biomarkers strengthens the findings, as these could not be associated to other factors than maternal penicillin and offspring ADHD.

Psychopathology of attention deficit/hyperactivity disorder: from an inflammatory perspective

Background

Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattentiveness, hyperactivity and impulsivity, which may affect one’s cognitive and psychosocial functioning. This review gives an overview of ADHD, particularly from an aetiological and clinical perspective. It also critically examines current evidence on the role of inflammation in ADHD and consolidates key findings in this area of research.

Results

The exact cause of ADHD remains unknown, and the aetiology of the disorder is believed to be multifactorial. Numerous genetic and environmental factors have been linked to the development of ADHD. Like many psychiatric disorders, ADHD has been associated with inflammation that occurs locally and peripherally. A growing body of evidence shows that maternal inflammatory status during pregnancy is associated with diagnosis of ADHD in the offspring, whereas oxidative stress, inflammatory biochemical markers and immune-mediated diseases have been observed in individuals with ADHD.

Conclusions

The underlying inflammatory processes and mechanisms in ADHD are not clearly understood. Therefore, further exploration is warranted in future research. This has clinical implications as inflammation may be a potential target in the treatment of ADHD.

Associations between Allergic and Autoimmune Diseases with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder within Families: A Population-Based Cohort Study

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are commonly comorbid with allergic and autoimmune diseases in children. The aim of the current study was to investigate the association between children’s and first-degree relatives’ (i.e., mother, father, and full sibling) allergic and autoimmune diseases and children’s ASD and ADHD. We enrolled participants from Taiwan’s Maternal and Child Health Database. We used the Cox regression model to examine the associations of familial, siblings’ and children’s allergic and autoimmune diseases with children’s ASD and/or ADHD. In total, we included 1,386,260 children in the current study. We found the significant association between familial allergic or autoimmune disease and development of ASD or ADHD among children. We also identified the predominant impact of familial aggregation on the above associations. The associations between some parental diagnoses of autoimmune or allergic diseases in children’s ASD and/or ADHD were stronger in mothers than those in fathers. Early assessment of the possibility of ASD and ADHD is required for children who have a parent with an allergic or autoimmune disease.

Parental autoimmune and autoinflammatory disorders as multiple risk factors for common neurodevelopmental disorders in offspring: a systematic review and meta-analysis

Epidemiological studies have raised concerns about the risk of neurodevelopmental disorders (NDD) in children of patients with autoimmune or inflammatory disorders (AID). The pathophysiological pathways underlying this association are still unknown and little is known about the specific and distinct risk of each AID. To explore these questions, we investigated the association between the occurrences of several NDD in the offspring of mothers or fathers with different IDA. We conducted a meta-analysis-PROSPERO (CRD42020159250)-examining the risk of NDD in the offspring of mothers or fathers with AID. We performed specific analyses separately in fathers or mothers of NDD patients as well as subgroup analyses for each NDD and AID. We searched MEDLINE, Embase, PsycINFO, Cochrane Central Register of Controlled Trials, and Web of Science Core Collection published until December 2021. From an initial pool of 2074 potentially relevant references, 14 studies were included, involving more than 1,400,000 AID and 10,000,000 control parents, 180,000 children with NDD and more than 14,000,000 control children. We found AID in mothers (Adjusted OR 1.27 [95% CI 1.03; 1.57] p = 0.02, [I² = 65%, Tau² = 0.03 p = 0.01] and adjusted OR 1.31 [95% CI 1.11; 1.55] p = 0.001, [I² = 93%, Tau² = 0.13 p = 0.001] and, although in a lesser extent, in fathers (adjusted OR 1.18 [95% CI 1.07; 1.30] p = 0.01, [I² = 15.5%, Tau² = 0.002 p = 0.47]) and adjusted OR 1.14 [95% CI 1.10; 1.17] p < 0.0001, [I² = 0%, Tau² = 0 p = 0.29]) to be associated with ASD and ADHD in the offspring. This difference in the strength of the association was found in the AID-specific analyses, suggesting that AID increase the risk of NDD by a shared mechanism but that a specific maternal route appears to represent an additional excess risk. Inflammatory bowel disease were not associated with an additional risk (neither in fathers nor in mothers) of NDD in offspring. Our results suggest that complex and multiple AID-specific pathophysiological mechanisms may underlie the association of AID and NDD in offspring. Further, comprehensive studies of the different AID and NDD are needed to draw definitive conclusions about the pathophysiological links between parental AID and NDD in children.