April 24, 2024

Large Six-region Meta-analysis Finds No Association Between ADHD Medications and Cardiovascular Risk

Are attention-deficit/hyperactivity disorder (ADHD) medications associated with risk of cardiovascular disease (CVD)?

An international study team has just explored this question with a meta-analysis of nineteen studies with a total of almost four million participants of all ages. It included 3,931,532 participants from six countries or regions: United States, South Korea, Canada, Denmark, Spain, and Hong Kong. 

Overall, using the entire data set, it found no significant association between any ADHD medication use and any cardiovascular event. 

The same held true when breaking this down by children and adolescents (twelve studies with over 1.7 million participants), young and middle-aged adults (seven studies with over 850,000 participants), and older adults (six studies with over a quarter million participants).

The team then compared the data for stimulant medications with data for non-stimulant medications. A meta-analysis of 17 studies with over 3.8 million participants found no significant association between stimulant medications and cardiovascular risk. Similarly, a meta-analysis of three studies with over 670,000 participants found no significant association between non-stimulant medications and cardiovascular risk.

Distinguishing between types of cardiovascular risk made no difference. For instance, a meta-analysis of nine studies with over 900,000 participants found no effect of stimulant medications on risk of myocardial infarction (heart attack), and a meta-analysis of six studies, also with over 900,000 participants, found no effect of stimulant medications on risk of cerebrovascular disease, including stroke, brain aneurysm, brain bleed, and carotid artery disease. A meta-analysis of eight studies with over 1.1 million participants did find an increase in the occurrence of cardiac arrest and tachyarrhythmias (racing heart rate accompanied by arrhythmias), but it was not statistically significant.

A meta-analysis of eleven studies with over 3.1 million persons with no prior history of cardiovascular disease found absolutely no effect of ADHD medications on subsequent risk for any cardiovascular event. Another meta-analysis, of eight studies encompassing over 1.8 million individuals with a prior history of cardiovascular disease, reported a higher rate of subsequent occurrence, but it was not considered statistically significant.

The team concluded, “Overall, our meta-analysis provides reassuring data on the putative cardiovascular risk with ADHD medications.” An international team of researchers recently investigated whether medications for attention-deficit/hyperactivity disorder (ADHD) are linked to an increased risk of cardiovascular disease (CVD). They conducted a comprehensive review, known as a meta-analysis, which included 19 studies with nearly four million participants from six countries or regions: the United States, South Korea, Canada, Denmark, Spain, and Hong Kong.

The findings from the entire data set showed no significant link between the use of any ADHD medications and the occurrence of cardiovascular events. This lack of association was consistent across all age groups: children and adolescents (12 studies with over 1.7 million participants), young and middle-aged adults (7 studies with over 850,000 participants), and older adults (6 studies with over 250,000 participants).

The researchers also compared the effects of stimulant medications against non-stimulant medications on cardiovascular risk. Both categories showed no significant risks in a meta-analysis of 17 studies with more than 3.8 million participants for stimulants, and three studies with over 670,000 participants for non-stimulants.

Further analysis differentiated between types of cardiovascular risks, such as myocardial infarction (heart attack) and cerebrovascular diseases (like stroke, brain aneurysm, and carotid artery disease). Again, stimulant medications showed no significant impact on these conditions in studies involving over 900,000 participants each. However, a review of eight studies with over 1.1 million participants suggested a slight increase in incidents of cardiac arrest and tachyarrhythmias (a racing heart rate with irregular rhythms), but these findings were not statistically significant.

Additionally, an analysis of 11 studies involving more than 3.1 million people without a prior history of cardiovascular disease found no effect of ADHD medications on the risk of developing cardiovascular events. Likewise, an analysis of eight studies with over 1.8 million individuals who had a history of cardiovascular disease showed a higher occurrence rate of events, but this increase was also not statistically significant.

Conclusion:

The conclusion of the research team was clear: the data is reassuring and does not suggest a substantial cardiovascular risk associated with ADHD medications. Keep in  mind that this reflects current standards of care.  Most guidelines call for monitoring of pulse and blood pressure during treatment so that adverse cardiovascular outcomes can be avoided.

Le Zhang, Honghui Yao, Lin Li, Ebba Du Rietz, Pontus Andell, Miguel Garcia-Argibay, Brian M. D’Onofrio, Samuele Cortese, Henrik Larsson, Zheng Chang, “Risk of Cardiovascular Diseases Associated With Medications Used in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-analysis,” JAMA Network Open (2022) 5(11), e2243597, https://doi.org/10.1001/jamanetworkopen.2022.43597.

Related posts

Study Suggests Certain ADHD Meds May Have Protective Effect On The Brain

Might methylphenidate have a protective effect on brain development?

Methylphenidate, a psychostimulant, is among the drugs most frequently prescribed to children with ADHD.

Using magnetic resonance imaging(MRI), studies have shown that as children mature, those with ADHD differ from controls in developing regionally thinner cortices (the folded outer layer of the cerebrum that is essential to rational thought) and smaller lower basal ganglia(structures linked to the thalamus in the base of the brain and involved in the coordination of movement). The cortical differences were found in the right medial frontal motor region, the left middle/inferior frontal gyrus, and the right posterior parieto-occipital region in children with ADHD who were not taking psychostimulants.

A Dutch/Norwegian team of researchers conducted a randomized, double-blind, placebo-controlled trial with 96 males recruited from Dutch clinical programs. 48 were boys aged 10-12 years, and 47 were men between the ages of 23 and 40. None had previously been on methylphenidate. There were no significant differences in baseline age, ADHD symptom severity, estimated intelligence quotient, the proportion of right-handedness, or region of interest brain characteristics between the placebo and medication groups.

The trial was carried out during the standard 17-week waiting list time for evaluation and treatment to begin so that those receiving a placebo during the trial would not ultimately be at a disadvantage. The same MRI scanner was used for all measurements, both before and after treatment.

Among the boys, the methylphenidate group showed increased thickness in the right medial cortex, while the placebo group showed cortical thinning. In adults, both groups showed cortical thinning. When converted into an estimated mean rate of change in cortical thickness for the right medial cortex, boys taking methylphenidate could expect to lose about 0.01 mm per year, versus about 0.14 mm for boys not on methylphenidate.

In the right posterior cortex, scans also showed reduced thinning in the methylphenidate treatment group, though to a lesser extent. But there was no reduced thinning in the left frontal cortex.

The authors noted several limitations. The sample size was small. Second, "because we did not detect significant relationships between changes in cortical [regions of interest] and changes in symptom severity, the functional significance remains uncertain." Third, the follow-up period was relatively short, not allowing any assessment of the longer-term effects of the medication. Fourth, the differences in effects on the three brain regions examined were uneven, contrary to what had been expected from previous studies. They recommended replication with larger groups and longer follow-ups.

February 11, 2022

ADHD medication and risk of suicide

ADHD Medication and Risk of Suicide

A Chinese research team performed two types of meta-analyses to compare the risk of suicide for ADHD patients taking ADHD medication as opposed to those not taking medication.

The first type of meta-analysis combined six large population studies with a total of over 4.7 million participants. These were located on three continents - Europe, Asia, and North America - and more specifically Sweden, England, Taiwan, and the United States.

The risk of suicide among those taking medication was found to be about a quarter less than for unmediated individuals, though the results were barely significant at the 95 percent confidence level (p = 0.49, just a sliver below the p = 0.5 cutoff point). There were no significant differences between males and females, except that looking only at males or females reduced sample size and made results non-significant.

Differentiating between patients receiving stimulant and non-stimulant medications produced divergent outcomes. A meta-analysis of four population studies covering almost 900,000 individuals found stimulant medications to be associated with a 28 percent reduced risk of suicide. On the other hand, a meta-analysis of three studies with over 62,000 individuals found no significant difference in suicide risk for non-stimulant medications. The benefit, therefore, seems limited to stimulant medication.

The second type of meta-analysis combined three within-individual studies with over 3.9 million persons in the United States, China, and Sweden. The risk of suicide among those taking medication was found to be almost a third less than for unmediated individuals, though the results were again barely significant at the 95 percent confidence level (p =0.49, just a sliver below the p = 0.5 cutoff point). Once again, there were no significant differences between males and females, except that looking only at males or females reduced the sample size and made results non-significant.

Differentiating between patients receiving stimulant and non-stimulant medications once again produced divergent outcomes. Meta-analysis of the same three studies found a 25 percent reduced risk of suicide among those taking stimulant medications. But as in the population studies, a meta-analysis of two studies with over 3.9 million persons found no reduction in risk among those taking non-stimulant medications.

A further meta-analysis of two studies with 3.9 million persons found no reduction in suicide risk among persons taking ADHD medications for 90 days or less, "revealing the importance of duration and adherence to medication in all individuals prescribed stimulants for ADHD."

The authors concluded, "exposure to non-stimulants is not associated with a higher risk of suicide attempts. However, a lower risk of suicide attempts was observed for stimulant drugs. However, the results must be interpreted with caution due to the evidence of heterogeneity ..."

December 13, 2021

Higher Relative Fat Mass (RFM) Associated with Lower ADHD Risk in Boys but Higher ADHD Risk in Girls

Background: 

Traditional measures of obesity, like body mass index (BMI) and waist circumference, have been linked to ADHD risk — but they aren’t great at capturing where fat is actually stored in the body. A newer index called relative fat mass (RFM), which combines height and waist circumference, does a better job of estimating overall body fat and predicting metabolic risks like heart disease and metabolic syndrome. Because those conditions share some underlying biological mechanisms with ADHD, researchers wondered whether RFM might also help explain the relationship between obesity and ADHD — particularly in children. 

That question is complicated by the fact that ADHD doesn't look the same in boys and girls. Boys tend to display more hyperactive and impulsive behavior, making their ADHD easier to spot. Girls more often show inattention, which is quieter and frequently goes undiagnosed. 


The Study: 

A new study set out to test whether RFM is associated with ADHD in children, and whether that association differs between sexes. Using data from the National Health and Nutrition Examination Survey (NHANES) collected between 1999 and 2004, the researchers narrowed a large initial pool of over 31,000 participants down to 5,089 children and adolescents aged 6 to 14 who had complete data on height, waist circumference, ADHD screening, and other relevant variables. 

After adjusting for age, race/ethnicity, Poverty-Income Ratio, maternal age at delivery, maternal smoking during pregnancy, health insurance coverage, and birth weight, the results revealed a striking split along sex lines.  

In boys, higher RFM was associated with lower odds of ADHD. Compared to boys in the lowest fat-mass quartile, those in the second quartile had about 10% lower odds of ADHD, rising to over 30% lower in the third quartile and nearly 40% lower in the highest. In girls, the pattern reversed entirely. While girls in the second quartile showed similar odds to those with the lowest RFM, girls in the third and fourth quartiles had 60% to 70% greater odds of ADHD. 

Conclusion & Why This Matters:  

In recent years, the relationship between obesity and ADHD has become an increasingly important focus in pediatric neurodevelopmental research. Studies have reported higher rates of ADHD symptoms among children and adolescents with obesity compared with their non-obese peers, and difficulties with peer relationships have also been linked to increased obesity risk (Sönmez et al., 2019). From a neurobiological standpoint, both conditions may involve shared underlying mechanisms, particularly dysfunction in dopaminergic pathways.

The authors concluded that higher body fat levels appear to lower ADHD risk in boys while raising it in girls. This finding highlights why sex-specific analysis matters in ADHD research. The underlying biological reasons for this divergence, however, remain an open question and open the door for future research. 

US Study Highlights the Social Roots of ADHD

While ADHD is a developmental disorder, shaped by biology and genetics, growing evidence shows that it is also influenced by the social and environmental conditions in which children grow up. Research on the social determinants of health emphasizes that development is shaped not only by biology but also by factors such as family income, access to healthcare, neighborhood safety, and material stability. These factors can affect both how developmental challenges appear and whether they are recognized and diagnosed. 

Children facing socioeconomic disadvantage consistently show higher risks of developmental and behavioral difficulties. Chronic stress linked to poverty – including financial strain, food insecurity, and limited access to resources – has been associated with problems in attention, emotional regulation, and daily functioning. Children from lower-income families also tend to experience more severe ADHD symptoms and face greater barriers to ongoing care. 

Neighborhood conditions matter as well. Unsafe environments can limit opportunities for play and social interaction while increasing caregiver stress, all of which may influence children’s behavior and development. Material hardships, such as food insecurity, can further undermine stability at home. 

The Study:

The study analyzed six years of data from the National Survey of Children’s Health (2018–2023), covering more than 205,000 U.S. children aged 3 to 17. After accounting for age, sex, race and ethnicity, region, family structure, survey year, and other social factors, the researchers found a strong income gradient in ADHD prevalence. Compared with children in households earning at least four times the federal poverty level, those in households earning two to four times that level had 28 percent higher odds of ADHD. Odds rose to 70 percent higher in households earning one to two times the poverty level, and more than doubled among children living below the poverty line. 

Parental education showed a similar pattern. Compared with children whose parents had completed college, ADHD odds were 20 percent higher among those whose parents had some college education, 40 percent higher among those whose parents had only a high school education, and 80 percent higher among those whose parents had not finished high school. 

Children living in unsafe neighborhoods had nearly twice the odds of ADHD compared with those in safe neighborhoods, and food insecurity was also linked to almost double the odds. 

By contrast, race and ethnicity alone were associated with much smaller differences. Compared with non-Hispanic White children, children in non-Hispanic Black households had an 18 percent higher likelihood of ADHD, while children in Hispanic households had a 25 percent lower likelihood. No substantial differences were observed for children from other or multiracial households. 

Conclusion and Takeaway:

The study team concluded, “Children living in lower-income households, experiencing food insecurity, and residing in unsafe neighborhoods consistently showed higher prevalence and higher adjusted odds of both conditions. … Overall, these findings reinforce the need to view neurodevelopmental disorders within a broader social and structural framework.” 

It should be noted that this study is not aiming to name social factors as direct causes of ADHD. Rather, it points to socioeconomic disparities as contributing to the way ADHD develops and how it is treated. This type of research, as well as acknowledging barriers to care, is crucial for clinicians, counselors, teachers, etc., to consider when working with youth with ADHD. 

 

 

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.”