December 9, 2021

Nationwide population study finds association between ADHD and poor blood sugar management in type-1 childhood onset diabetes

It is difficult enough for a typical child to manage type-1 diabetes. For a child that also has ADHD, with learning difficulties, attention and memory problems, and limitations in social communication, it can be all the more challenging to carry out the complex tasks necessary to maintain glycemic control (control of blood sugar levels) and avoid diabetic harm.

To explore the additional risk associated with ADHD among children with type-1 diabetes, an international research team used the Swedish national registers to conduct a nationwide population study. Sweden has a single-payer national health insurance system, and assigns unique personal identification numbers to all residents, making it easy to cross-reference through various population and health registers.

The team used the Swedish Diabetes Register to identify all individuals born in Sweden from 1973 onwards with childhood-onset type 1 diabetes diagnosed before age 18. They then restricted the cohort to those who had no diabetic complications at diagnosis and whose HbA1c values had been recorded within 5 years of diagnosis.

Also known as the glycated hemoglobin test, HbA1c is an indicator of the average blood sugar (glucose) level over the past three months. When glucose builds up in the blood, it binds to the hemoglobin in red blood cells. The HbA1ctest measures bound glucose. Since red blood cells live for about 3 months, the test shows the average blood glucose over that period.

The team also searched for records of diabetes-related kidney damage (nephropathy) and damage to the retina (retinopathy). Diabetic retinopathy is the leading cause of blindness among working-age adults.

The nationwide cohort consisted of 11,326 Swedish youths diagnosed with type-1 diabetes, of whom 415 (3.7%) were also diagnosed with ADHD.

Poor glycemic control, defined as mean HbA1c greater than 8.5%, was found in 38% of those with ADHD, twice the 19% found in those without neurodevelopmental disorders. After adjusting for confounders(sex, age at diabetes diagnosis, year of birth and year of diabetes diagnosis, another psychiatric morbidity, parental highest education level, parental psychiatric morbidity, smoking status, mean BMI [body mass index], and mean systolic and diastolic blood pressure), those with ADHD were 2.3 times as likely to have poor glycemic control.

Patients with ADHD were also almost twice as likely to suffer kidney damage, after adjusting for sex, age at diabetes diagnosis, year of birth, year of diabetes diagnosis, another psychiatric morbidity, parental highest education level, parental psychiatric morbidity, mean HbA1c levels, mean BMI, systolic and diastolic blood pressure, and smoking status.

After the same adjustments, patients with ADHD were found to be a third (33%) more likely to suffer retinal damage.

The team concluded, "childhood-onset type 1 diabetes patients with neurodevelopmental disorders, especially those with ADHD or intellectual disability, are more prone to poor glycemic control and a higher risk of chronic diabetic complications compared with those without neurodevelopmental disorders.

Further longitudinal studies with a more comprehensive evaluation of diabetes management and molecular data are needed to provide insight into potential mediators in the association between comorbid neurodevelopmental disorder and diabetes complications in type 1 diabetes."

Shengxin Liu, Ralf Kuja-Halkola, Henrik Larsson, PaulLichtenstein, Jonas F. Ludvigsson, Ann-Marie Svensson, Soffia Gudbjörnsdottir, Magnus Tideman, Eva Serlachius, and Agnieszka Butwicka, "NeurodevelopmentalDisorders, Glycemic Control, and Diabetic Complications in Type 1 Diabetes: a Nationwide Cohort Study," The Journal of Clinical Endocrinology &Metabolism(2021), Vol. 106, No. 11, e4459-e4470, published online,https://doi.org/10.1210/clinem/dgab467.

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Norwegian Nationwide Population Study: Single Umbilical Artery Shows Weak Link to ADHD

Counting umbilical cord vessels is standard in prenatal ultrasounds and confirmed at birth. Single umbilical artery (SUA) occurs in about 1 in 200 cases, with roughly 10% associated with anomalies, including central nervous system defects. Isolated SUA (iSUA) means one artery is missing without other structural issues. 

Research on SUA, especially isolated iSUA, and childhood neurodevelopmental disorders (NDD) is limited and inconclusive. iSUA is linked to preterm birth and small-for-gestational age (SGA), both of which are NDD risk factors.  

This Norwegian nationwide population study aimed to assess NDD risk in children with iSUA at birth, the influence of sex, and how preterm birth and SGA mediate this relationship. 

The nation’s universal single-payer health insurance and comprehensive population registries made it possible to analyze all 858,397 single births occurring from 1999 to 2013, with follow-up continuing through 2019. Among these cases, 3,532 involved iSUA. 

After adjusting for confounders such as parental age, education, and maternal health factors, no overall link was found between iSUA and later ADHD diagnosis. However, females with iSUA had about a 40% higher risk of subsequent ADHD compared to those without iSUA, even after adjustment. 

The authors concluded, “The present study indicates that iSUA is weakly associated with ID [intellectual disability] and ADHD, and these associations are influenced by sex. This association is mediated negligibly through preterm birth and SGA. The associations were not clinically significant, and the absence of associations of iSUA with other NDD is reassuring. This finding can be useful in the counseling of expectant parents of fetuses diagnosed with iSUA.” 

 

Large Cohort Study Reports Association Between Eye Disorders and ADHD

Refractive errors, such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism (distorted vision due to irregular curvature of the eye or lens), are common worldwide. These conditions affect 12%, 5%, and 15% of children, and rise significantly in adults to 26.5%, 31%, and 40%. Additionally, strabismus (misalignment of the eyes) and amblyopia (reduced vision in one eye from uneven image formation, often linked to strabismus) occur globally at rates of 2% and 1.4%, respectively. 

Visual impairment can affect children’s concentration in school, and studies suggest a link between eye disorders and ADHD. 

To investigate this relationship, two researchers – one based in the US and the other in Israel –carried out a nationwide retrospective cohort study using electronic medical records of all insured individuals aged 5 to 30 who were part of Maccabi Health Services, Israel’s second largest health maintenance organization, between 2010 and 2022. 

Of over 1.6 million insured members (2010–2020), inclusion/exclusion criteria and propensity score matching for age and sex were applied, along with a one-year wash-out period between the first eye diagnosis and ADHD diagnosis. In total, 221,707 cases were matched with controls without eye disorders at a 1:2 ratio, resulting in a cohort of 665,121 participants.  

Overall, those with any previous eye diagnosis were 40% more likely to have a subsequent ADHD diagnosis. This was slightly higher for females (45%) than for males (35%). It was also slightly higher for children and adolescents (42%) than for adults (37%).  

More specifically: 

  • Myopia (425,000+ participants): 30% higher ADHD rate. 
  • Hyperopia (120,000+) and astigmatism (175,000+): over 50% higher ADHD rate. 
  • Strabismus (13,000+): over 60% higher ADHD rate. 
  • Amblyopia (14,000+): 40% higher ADHD rate. 

The authors concluded that eye disorders are associated with ADHD. They noted these associations were more marked in females and children and adolescents, although, as noted above, those differences were small. They recommended that primary care providers and neurologists consider risk stratification for early screening, and that ophthalmologists refer high-risk patients for ADHD evaluation. 

 

 

February 10, 2026

South Korean Nationwide Population Study: Prenatal Exposure to Acid-suppressive Medications Not Linked to Subsequent ADHD

Acid-suppressive medications, including proton pump inhibitors (PPIs) and histamine-2 (H2) receptor antagonists, are often prescribed during pregnancy to treat heartburn and gastroesophageal reflux disease. 

Research shows changes in the gut microbiome can negatively affect neurodevelopment. Since acid-suppressive medications alter gut microbiota, maternal use during pregnancy may impact offspring’s neurodevelopment. Because PPIs and H2 receptor antagonists readily cross the placental barrier, they could potentially influence fetal neurodevelopment.  

The link between prenatal exposure to acid-suppressive medications and major neuropsychiatric disorders is not well understood. With the use of these medications during pregnancy rising, it is important to assess their impact on children's long-term neurodevelopment. This study examined whether maternal use of acid-suppressive drugs is associated with increased risk of neuropsychiatric disorders in children, using a large, nationwide birth cohort from South Korea. 

South Korea operates a single-payer health insurance system, providing coverage for over 97% of its citizens. The National Health Insurance Service (NHIS) maintains a comprehensive database with sociodemographic details, medical diagnoses, procedures, prescriptions, health examinations, and vital statistics for all insured individuals. 

A Korean research team analyzed data from over three million mother-child pairs (2010–2017) to assess the risks of prenatal exposure to acid-suppressing medications. They applied propensity scoring to adjust for maternal age, number of children, medical history, and outpatient visits before pregnancy, to minimize confounding factors. That narrowed the cohort to just over 800,000 pairs, with half in the exposed group. 

With these adjustments, prenatal exposure to acid-suppressing medications was associated with 14% greater likelihood of being subsequently diagnosed with ADHD. 

Yet, when 151,737 exposed births were compared to the same number of sibling controls, no association was found between prenatal exposure and subsequent ADHD, which suggests unaccounted familial and genetic factors influenced the preceding results. 

The Take-Away:

Evidence of these medications negatively affecting pregnancies is mixed, mostly observational, and generally reassuring when these medications are used appropriately. Untreated GERD and gastritis, however, have known risks and associations with the development of various cancers. With no evidence of an association with ADHD (or for that matter any other neuropsychiatric disorder), there is no current evidence-based reason for expectant mothers to discontinue use of acid-suppressing medications.  

February 6, 2026