Children's Attention-Deficit/Hyperactivity Disorder Symptoms Predict Lower Diet Quality but Not Vice Versa: Results from Bidirectional Analyses in a Population-Based Cohort

Short-term effects of an elimination diet and healthy diet in children with attention-deficit/hyperactivity disorder: a randomized-controlled trial

An Elimination Diet (ED) may be effective in reducing symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD), but has never been compared to an active control condition [i.e., Healthy Diet (HD)]. In a two-armed RCT, a total of N = 165 children (5-12 years) with ADHD were randomized by means of minimization (1:1) to either an ED (N = 84) or HD (N = 81) within two Dutch child and adolescent psychiatry centers. The design included a non-randomized comparator arm including N = 58 children being treated with Care as Usual (CAU). Treatment allocation was unblinded. The primary outcome was a 5-point ordinal measure of respondership based on a combination of parent and teacher ratings on ADHD and emotion regulation, determined after 5 weeks of treatment. Ordinal regression analyses were done on an intention-to-treat basis. Fewer ED (35%) than HD (51%) participants showed a partial to full response, despite overall good-to-excellent treatment adherence (> 88%) and comparable high parental prior believes. A younger age and higher problem severity predicted a better respondership. CAU-preferring participants responded more often favorably (56%) compared to ED-but not HD-participants. Small-to-medium improvements in physical health (blood pressure, heart rate, and somatic complaints) were found in response to ED/HD versus decrements in response to CAU (74% received psychostimulants). The lack of superiority of the ED versus HD suggests that for the majority of children, dietary treatment response is not rooted in food-allergies/-sensitivities. The comparable results for treatment with HD and CAU are remarkable given that CAU participants were probably 'easier to treat' than HD (and ED) participants with proportionally fewer with a (suboptimal/non-response to) prior treatment with medication (4% versus 20%). Further assessment of long-term effects is needed to evaluate the potential place of dietary treatment within clinical guidelines. The trial is closed and registered in the Dutch trial registry, number NL5324 ( https://www.onderzoekmetmensen.nl/en/trial/25997 ).

Treatment response to supplemental nutrients for ADHD is independent of diet quality: the MADDY Study RCT

OBJECTIVES

The 8-week Micronutrients for ADHD in Youth (MADDY) randomized controlled trial (N = 126, age 6-12) of broad-spectrum multinutrients for ADHD with emotional dysregulation found 3 times as many responders with multinutrients (54%) compared to placebo (18%) by Clinical Global Impression-Improvement (CGI-I). Our primary aim for this analysis tests the hypothesis that those with poor overall diet quality at baseline benefit more. The second aim is to explore whether specific components of diet quality moderate treatment response.

METHODS

124 children (69 multinutrients, 55 placebo) had diet quality assessed using the Healthy Eating Index-2015 (HEI-2015). For each potential moderator, the outcome CGI-I at week 8 (RCT-end), was modeled two ways: (1) as a dichotomous variable: responder/non-responder, with responders defined by a rating of 1 or 2 'very much' or 'much improved,' all else equals non-responder using logistic regression, and (2) as a dimensional improvement outcome from 1 = very much improved to 7 = very much worse, using linear regression.

RESULTS

HEI-2015 total score did not moderate treatment response [odds ratio = 1.00 (95% CI: 0.90,1.10), p = 0.984] or improvement [β = -0.01 (95% CI: -0.06,0.04), p = 0.648]. However, total vegetable intake moderated level of improvement in exploratory analysis [β = -0.48 (95% CI: -0.82, -0.13), p = 0.007]: those with higher baseline vegetable intake showed greater benefit from multinutrients compared to placebo.

CONCLUSIONS

Multinutrients may benefit children with ADHD and irritability regardless of overall diet quality. The finding that higher baseline vegetable intake may improve response to multinutrients deserves further exploration, including dietary effect on gut microbiota and absorption of multinutrients and parental factors.

Association between relative age at school and persistence of ADHD in prospective studies: an individual participant data meta-analysis

BACKGROUND

The youngest children in a school class are more likely than the oldest to be diagnosed with ADHD, but this relative age effect is less frequent in older than in younger school-grade children. However, no study has explored the association between relative age and the persistence of ADHD diagnosis at older ages. We aimed to quantify the association between relative age and persistence of ADHD at older ages.

METHODS

For this meta-analysis, we searched MEDLINE, Embase, CINAHL, PsycINFO, and PubPsych up to April 1, 2022, with terms related to "cohort" and "ADHD" with no date, publication type, or language restrictions. We gathered individual participant data from prospective cohorts that included at least ten children identified with ADHD before age 10 years. ADHD was defined by either a clinical diagnosis or symptoms exceeding clinical cutoffs. Relative age was recorded as the month of birth in relation to the school-entry cutoff date. Study authors were invited to share raw data or to apply a script to analyse data locally and generate anonymised results. Our outcome was ADHD status at a diagnostic reassessment, conducted at least 4 years after the initial assessment and after age 10 years. No information on sex, gender, or ethnicity was collected. We did a two-stage random-effects individual participant data meta-analysis to assess the association of relative age with persistence of ADHD at follow-up. This study was registered with PROSPERO, CRD42020212650.

FINDINGS

Of 33 119 studies generated by our search, we identified 130 eligible unique studies and were able to gather individual participant data from 57 prospective studies following up 6504 children with ADHD. After exclusion of 16 studies in regions with a flexible school entry system that did not allow confident linkage of birthdate to relative age, the primary analysis included 41 studies in 15 countries following up 4708 children for a period of 4 to 33 years. We found that younger relative age was not statistically significantly associated with ADHD persistence at follow-up (odds ratio 1·02, 95% CI 0·99-1·06; p=0·19). We observed statistically significant heterogeneity in our model (Q=75·82, p=0·0011, I2=45%). Participant-level sensitivity analyses showed similar results in cohorts with a robust relative age effect at baseline and when restricting to cohorts involving children with a clinical diagnosis of ADHD or with a follow-up duration of more than 10 years.

INTERPRETATION

The diagnosis of ADHD in younger children in a class is no more likely to be disconfirmed over time than that of older children in the class. One interpretation is that the relative age effect decreases the likelihood of children of older relative age receiving a diagnosis of ADHD, and another is that assigning a diagnostic label of ADHD leads to unexplored carryover effects of the initial diagnosis that persist over time. Future studies should be conducted to explore these interpretations further.

FUNDING

None.

Nutrition in the Management of ADHD: A Review of Recent Research

PURPOSE OF REVIEW

Various nutrients and diet quality have been suggested to be involved in the pathophysiology of ADHD. The purpose of this review was to examine data from recent cohort studies and dietary interventions to determine whether nutrition may play a role in the management of ADHD.

RECENT FINDINGS

Preliminary evidence suggests that minerals might have beneficial effects on ADHD symptomatology. Probiotics might offer novel strategies to prevent or treat ADHD. Inverse associations between adherence to "healthy" diets and ADHD symptoms have been observed. Children with ADHD responding to the few-foods diet (or oligoantigenic diet) with an elimination of individually identified food items show substantially improved behavior and cognitive functioning. Evidence from recent research does not allow any recommendations regarding the use of micronutrients or probiotics in the management of ADHD. The few-foods diet may become an additional therapeutic option for children with ADHD.

[Physical growth and dietary characteristics of children with attention deficit hyperactivity disorder: a cross-sectional study]

OBJECTIVES

To investigate the physical growth and dietary characteristics of children with attention deficit hyperactivity disorder (ADHD), and to analyze their relationship with core symptoms of ADHD.

METHODS

A total of 268 children who were newly diagnosed with ADHD in Children's Hospital of Nanjing Medical University from June to December 2020 were included in the ADHD group, and 102 healthy children who underwent physical examination during the same period were selected as the control group. Physical evaluations and dietary surveys were conducted for both groups. ADHD diagnosis and scoring were performed according to the Diagnostic and Statistical Manual of Mental Disorders (5th edition). Factor analysis, Spearman correlation analysis, and mediation analysis were used to study the relationship between core symptoms of ADHD, dietary patterns, and physical growth.

RESULTS

The rate of overweight/obesity in the ADHD group was significantly higher than that in the control group (35.8% vs 21.6%, P<0.05). Three dietary patterns were extracted from the food frequency questionnaire: vegetarian dietary pattern, traditional dietary pattern, and snack/fast food pattern. The factor score for the snack/fast food pattern in the ADHD group was higher than that in the control group (P<0.05). There was a significant positive correlation between ADHD symptom scores, snack/fast food pattern factor scores, and body fat percentage (P<0.05). The mediation analysis showed that the snack/fast food pattern played a partial mediating role in the relationship between ADHD symptom scores and body fat percentage, with a mediation proportion of 26.66%.

CONCLUSIONS

The rate of overweight/obesity in children with ADHD is higher than that in non-ADHD children. Core symptoms of ADHD are related to dietary patterns and physical growth, with the snack/fast food pattern playing a partial mediating role in the relationship between core symptoms of ADHD and physical growth.

Fruit and vegetable intake is inversely associated with severity of inattention in a pediatric population with ADHD symptoms: the MADDY Study

OBJECTIVES

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with a U.S. pediatric prevalence of 8-10%. It presents with inattention and hyperactivity/impulsivity; frequently associated with emotional dysregulation (ED) symptoms common in Oppositional Defiant Disorder and Disruptive Mood Dysregulation Disorder. The etiology of ADHD is multi-factorial; symptom severity is associated with diet. This study examines the association of diet quality with ADHD and ED symptoms within a pediatric research cohort.

METHODS

Baseline data were analyzed for 134 children aged 6-12 years with symptoms of ADHD and ED enrolled in an RCT of multinutrient supplementation. Diet quality was based on Healthy Eating Index-2015 (HEI-2015). ADHD and ED symptoms were assessed using Child and Adolescent Symptom Inventory-5 and Strengths and Difficulties Questionnaire. Linear regression models, adjusting for covariates when necessary, determined association.

RESULTS

The mean HEI Total Score of 63.4 (SD = 8.8) was not significantly associated with any outcome symptoms. However, after adjusting for covariates, HEI component scores for total fruit intake (β =  -0.158, p = .037) and total vegetable intake (β =  -0.118, p = .004) were negatively associated with inattention.

CONCLUSIONS

The lack of association with total diet quality could be explained by the relatively good baseline diet quality and mild symptom severity in this sample, along with measurement error from dietary intake estimates and relatively small sample size. These findings suggest that dietary intake may impact inattention in children with ADHD and ED: those eating less fruits and vegetables were likely to have more severe symptoms of inattention. Causality is not established by this cross-sectional analysis.

Child ADHD and autistic traits, eating behaviours and weight: A population-based study

BACKGROUND

Children with Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) have an increased obesity risk. Although these conditions commonly co-occur, shared factors relating to obesity risk are unknown.

OBJECTIVES

To examine the shared and unique associations of ADHD and autistic traits with eating behaviours and BMI.

METHODS

Children (N = 4134) from the population-based Generation R Study were categorized into subgroups based on parent-reported ADHD and autistic traits scores at 6 years: ADHD_High , ASD_High , ADHD+ASD_High and REF (reference group: ADHD+ASD_Low ). Multiple linear regressions examined the associations between subgroups and eating behaviours (at 10 years) and BMIz (at 14 years), relative to REF. Mediation analyses tested the indirect effect of subgroup and BMIz through eating behaviours.

RESULTS

ADHD + ASD_High children expressed both food approach (increased food responsiveness and emotional overeating) and avoidant eating behaviours (increased emotional undereating, satiety responsiveness/ slowness in eating and picky eating, and decreased enjoyment in food). ASD_High children were more food avoidant, while ADHD_High children had more food approach behaviours and greater BMIz. ADHD_High and BMIz were indirectly associated with food responsiveness and emotional overeating.

CONCLUSIONS

ADHD and autistic trait phenotypes show distinct associations with potential obesity risk factors, and further research is needed to improve targeted early intervention.

Social-Emotional Functioning and Dietary Intake among Children Born with a Very Low Birth Weight

Very low birth weight infants (VLBW, <1500g) are at elevated risk of neurodevelopmental disorders, later obesity and cardiometabolic disease; if and how neurodevelopmental disorders impact chronic disease risk is poorly understood. The most common neurodevelopmental disorders experienced by VLBW children are those of social-emotional functioning. We compared dietary patterns and body composition between VLBW children with poor vs. typical social-emotional functioning using linear mixed models adjusted for sex, gestational age, cognitive impairment, parental education and BMI. VLBW children (n=158) attending the Donor Milk for Improved Neurodevelopmental Outcomes trial 5.5-year follow-up participated. Poor social-emotional functioning was based on standardized parent-rated questionnaires and/or parent-reported physician diagnosis of autism spectrum or attention-deficit/hyperactivity disorders. Most children had diets categorized as 'needs improvement' (67%) or 'poor' (27%) and 29% of children exhibited poor social-emotional functioning. Poor social-emotional functioning was positively associated with 100% fruit juice (β=0.3 cup equivalents/day; 95% CI 0.1, 0.5) and energy intake (β=118.1 kcals/day; 95% CI 0.9, 235.2). Children with poor social-emotional functioning were more likely to have a limited food repertoire (p=0.02), but less likely to exceed dietary fat recommendations (p=0.04). No differences in overall diet quality or body composition were observed. Diet counselling and research are essential to improving the nutrition of VLBW children to mitigate chronic disease risk. Novelty: • Overall diet quality and body composition did not differ between VLBW children with poor vs. typical social-emotional functioning. • Most had diets "needing improvement" or "poor" according to the HEI 2010. • Diet counselling may help mitigate chronic disease risk in this vulnerable population.

Associations between T cells and attention problems in the general pediatric population: The Generation R study

Objective

The pathogenesis of attention-deficit/hyperactivity disorder (ADHD) is currently unclear. We hypothesized that chronic immune activation, as indexed by T and B cells, plays a role in the pathophysiology of attention problems. Therefore, we examined T and B cell subsets in a general pediatric population with information on attention problems.

Methods

We included 756 10-year-old children from the Generation R population-based cohort. Eleven-color flow cytometry was performed on peripheral blood samples to determine T and B cell subsets. The Child Behavior Checklist rated by parents was used to measure attention problems. Data were analyzed using linear regression analyses, adjusting for maternal and child covariates and co-occurring childhood psychopathology.

Results

For T helper 1 (Th1) cells, one standard deviation (SD) increase was associated with 5.3% (95%CI 0.3; 10.5) higher attention problem scores. Furthermore, 1SD increase in CD8+ T cells was associated with 7.5% (95%CI 2.4; 12.7) higher attention problem scores. Within total CD8+ T cells, 1SD increase in naive or central memory cells was associated with 6.9% (95%CI 2.0; 12.1) and 6.4% (95%CI 1.5; 11.6) higher attention problem scores, respectively. No associations between Th2, Treg or B memory cells and attention problem scores were observed.

Conclusion

Higher Th1 and cytotoxic T cell numbers are associated with higher attention problem scores independent of co-occurring psychopathology. This might indicate a possible role of a pro-inflammatory immune profile in childhood attention problems.

The associations between maternal and child diet quality and child ADHD - findings from a large Norwegian pregnancy cohort study

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental disorder. Effective long-term treatment options are limited, which warrants increased focus on potential modifiable risk factors. The aim of this study was to investigate associations between maternal diet quality during pregnancy and child diet quality and child ADHD symptoms and ADHD diagnosis.

METHODS

This study is based on the Norwegian Mother, Father and Child Cohort Study (MoBa). We assessed maternal diet quality with the Prenatal Diet Quality Index (PDQI) and Ultra-Processed Food Index (UPFI) around mid-gestation, and child diet quality using the Diet Quality Index (CDQI) at 3 years. ADHD symptoms were assessed at child age 8 years using the Parent Rating Scale for Disruptive Behaviour Disorders. ADHD diagnoses were retrieved from the Norwegian Patient Registry.

RESULTS

In total, 77,768 mother-child pairs were eligible for studying ADHD diagnoses and 37,787 for ADHD symptoms. Means (SD) for the PDQI, UPFI and CDQI were 83.1 (9.3), 31.8 (9.7) and 60.3 (10.6), respectively. Mean (SD) ADHD symptom score was 8.4 (7.1) and ADHD diagnosis prevalence was 2.9% (male to female ratio 2.6:1). For one SD increase in maternal diet index scores, we saw a change in mean (percent) ADHD symptom score of - 0.28 (- 3.3%) (CI: - 0.41, - 0.14 (- 4.8, - 1.6%)) for PDQI scores and 0.25 (+ 3.0%) (CI: 0.13, 0.38 (1.5, 4.5%)) for UPFI scores. A one SD increase in PDQI score was associated with a relative risk of ADHD diagnosis of 0.87 (CI: 0.79, 0.97). We found no reliable associations with either outcomes for the CDQI, and no reliable change in risk of ADHD diagnosis for the UPFI.

CONCLUSIONS

We provide evidence that overall maternal diet quality during pregnancy is associated with a small decrease in ADHD symptom score at 8 years and lower risk for ADHD diagnosis, with more robust findings for the latter outcome. Consumption of ultra-processed foods was only associated with increased ADHD symptom score of similar magnitude as for overall maternal diet quality, and we found no associations between child diet quality and either outcome. No causal inferences should be made based on these results, due to potential unmeasured confounding.

Unique Trans-fatty Acid Profile in Children With Attention Deficit Hyperactivity Disorder

Background: Attention deficit hyperactivity disorder (ADHD) is the most common developmental disorder in children. Studies suggest an association between fatty acids composition and ADHD pathogenesis. We aimed to investigate whether children diagnosed with ADHD present unique fatty acid profiles in red blood cells (RBC), as compared to children without ADHD. Method: We examined 60 children aged 6-14 years, out of which 32 were diagnosed with ADHD, and 28 were not. Blood was collected from all children to quantify an array of 26 fatty acids from RBC membranes. Fatty acid methyl esters were generated by acid transesterification and analyzed by gas chromatography. Results: We found that children with ADHD presented unique fatty acid profiles on RBC membranes with significantly higher levels of most of the trans-fatty acids (Total trans-fatty acids 0.64 ± 0.21 vs. 0.49 ± 0.18 p = 0.003) and lower levels of docosahexaenoic acid (DHA), as compared to controls (4.06 ± 0.79 vs. 4.68 ± 1.37 p = 0.040). Additionally, total trans-fatty acids were higher in children with extremely severe clinical ADHD condition score, as compared to milder ADHD scores and to control children (0.72 ± 0.18, 0.64 ± 0.20, 0.61 ± 0.22, 0.49 ± 0.18, p = 0.010, accordingly). Conclusion: Children with ADHD have higher levels of trans-fatty acids in RBCs, compared to children without ADHD. This study points to a possible link between trans-fatty acids and ADHD. Understanding these findings and the clinical meaning will potentially contribute to a more targeted dietary intervention.

Attention-deficit/hyperactivity disorder symptoms and dietary habits in adulthood: A large population-based twin study in Sweden

Associations between adult attention-deficit/hyperactivity disorder (ADHD) symptoms and dietary habits have not been well established and the underlying mechanisms remain unclear. We explored these associations using a Swedish population-based twin study with 17,999 individuals aged 20-47 years. We estimated correlations between inattention and hyperactivity/impulsivity with dietary habits and fitted twin models to determine the genetic and environmental contributions. Dietary habits were defined as (a) consumption of food groups, (b) consumption of food items rich in particular macronutrients, and (c) healthy and unhealthy dietary patterns. At the phenotypic level, inattention was positively correlated with seafood, high-fat, high-sugar, high-protein food consumptions, and unhealthy dietary pattern, with correlation coefficients ranging from 0.03 (95%CI: 0.01, 0.05) to 0.13 (95% CI: 0.11, 0.15). Inattention was negatively correlated with fruits, vegetables consumptions and healthy dietary pattern, with correlation coefficients ranging from -0.06 (95%CI: -0.08, -0.04) to -0.07 (95%CI: -0.09, -0.05). Hyperactivity/impulsivity and dietary habits showed similar but weaker patterns compared to inattention. All associations remained stable across age, sex and socioeconomic status. Nonshared environmental effects contributed substantially to the correlations of inattention (56-60%) and hyperactivity/impulsivity (63-80%) with dietary habits. The highest and lowest genetic correlations were between inattention and high-sugar food (r_A = .16, 95% CI: 0.07, 0.25), and between hyperactivity/impulsivity and unhealthy dietary pattern (r_A = .05, 95% CI: -0.05, 0.14), respectively. We found phenotypic and etiological overlap between ADHD and dietary habits, although these associations were weak. Our findings contribute to a better understanding of common etiological pathways between ADHD symptoms and various dietary habits.