- A large population-based study in Sweden recently showed that people with attention deficit hyperactivity disorder (ADHD) had a two-fold higher risk of all types of cardiovascular disease than people without ADHD.
- In adults with ADHD, men, younger people and people with comorbid psychiatric conditions were at increased cardiovascular risk.
- The study highlights the importance of monitoring people with ADHD for cardiovascular risks and developing targeted strategies to reduce their risk of cardiovascular disease.
There is increasing evidence of a link between mental disorders and the risk of cardiovascular disease (CVD). Yet there is limited evidence of a similar association between attention deficit hyperactivity disorder (ADHD) and cardiovascular risk.
A nationwide study published recently in World Psychiatry shows that people with ADHD had an increased risk of cardiovascular disease compared to people without ADHD, even after considering cardiovascular risk factors.
Dr. Carl Lavie, a cardiologist at the University of Queensland School of Medicine in Australia who was not involved in the study, told Medical News Today:
“The study is huge with long follow-up times and even considering potential errors in maintaining such a huge database, the study certainly suggests that ADHD is associated with a potential doubling of CVD risk. Given that this condition [ADHD} appears to be increasing along with early drug use and physical inactivity, these data certainly raise red flags about long-term CVD risks in this patient population.”
ADHD and cardiovascular disease
ADHD is a mental disorder characterized by attention deficits, hyperactivity, and increased impulsivity. As one of the most common mental illnesses in children, ADHD also affects adults. Globally, the prevalence of ADHD among children is 2.2% and 2.5% among adults.
People with ADHD often suffer from co-occurring mental illnesses such as anxiety and depression, as well as physical conditions such as obesity.
Previous studies have shown that various mental health conditions, such as autism, anxiety disorders and depression, are associated with an increased risk of cardiovascular disease. However, there is limited data that suggests an association between ADHD and an increased risk of cardiovascular disease.
There is also no data available on whether people with ADHD are at increased risk of certain cardiovascular conditions such as stroke, cardiac arrest, arrhythmias, atherosclerosis, and heart failure. The prevention and treatment strategies for the different types of cardiovascular disease may differ, which is why it is important to understand the relationship between ADHD and the various cardiovascular diseases.
In addition, it is not fully understood to what extent cardiovascular risk factors in people with ADHD influence the risk of cardiovascular disease in these individuals. Some of the risk factors for cardiovascular disease include:
- Level of education
- Family history of cardiovascular disease
- sleep problems
Because of the prevalence of comorbid psychiatric conditions, individuals with ADHD are receiving medication for other mental illnesses at the same time.
Previous studies suggest that medications used for ADHD and other mental health conditions, such as anxiety and depression, could increase the risk of cardiovascular disease. Therefore, the use of these drugs or the presence of mental illness could potentially increase the risk of cardiovascular disease in individuals with ADHD.
Characterizing the effects of cardiovascular risk factors could help identify individuals with ADHD at increased risk of cardiovascular disease at an early stage.
ADHD and cardiovascular risk
In the present study, the researchers used data from over 5.4 million Swedish adults who were born between 1941 and 1983 without a prior diagnosis of cardiovascular disease.
The researchers used the Swedish national registries to identify people in the study population with an ADHD diagnosis. They also obtained data on other mental illnesses and cardiovascular risk factors, including diabetes, obesity, sleep disorders and smoking, from these registers.
Using national health registries, researchers tracked the incidence of cardiovascular disease in the study population over a 13-year follow-up period, from January 2001 to December 2013. The researchers found that the proportion of people who developed cardiovascular disease was among people with ADHD was higher than her peers without ADHD.
After controlling age and gender, the analysis showed that people with ADHD are twice as likely to develop cardiovascular disease as people without ADHD.
The researchers found that cardiovascular risk factors such as heavy smoking, obesity, diabetes, sleep problems, lower levels of education, and psychiatric illnesses are more common among people with ADHD. However, controlling these cardiovascular risk factors only slightly weakened the association between ADHD and the risk of cardiovascular disease.
Furthermore, the exclusion of people with ADHD taking medications for ADHD or other mental illnesses had no effect on the strength of the link between ADHD and the risk of cardiovascular disease.
These findings suggest that ADHD, regardless of cardiovascular risk factors such as obesity, smoking, and comorbid psychiatric conditions, could be a risk factor for cardiovascular disease.
The study also found that ADHD was associated with an increased risk of all types of cardiovascular disease. The strongest association was observed between ADHD and cardiac arrest, hemorrhagic stroke, and arteriosclerosis.
Subgroups with increased risk
The severity of core ADHD symptoms tends to decrease with age, whereas the risk of cardiovascular disease increases with age. In addition, ADHD and cardiovascular disease are more common in men than in women.
Therefore, the researchers categorized the study population by age and gender to assess the impact of these factors on the risk of cardiovascular disease in individuals with ADHD. They found that the association between ADHD and cardiovascular risk was stronger among men than among women and younger people than among their older colleagues.
In a separate analysis, the researchers found that people with ADHD and co-occurring psychiatric conditions such as eating disorders and substance use disorders also had an increased risk of cardiovascular disease than people with only ADHD.
The results of the study suggest that doctors should monitor the cardiovascular health of individuals with ADHD early on to facilitate implementation of strategies to reduce cardiovascular risk. Among people with ADHD, younger adults, men with ADHD, and people with comorbid psychiatric conditions may have a particularly higher risk of cardiovascular disease.
The study’s co-author, Henrik Larsson, Ph.D., professor of epidemiology at Örebro University, said in a press release:
“Clinicians must carefully consider psychiatric comorbidity and lifestyle factors to reduce CVD risk in individuals with ADHD, but we also need more research to explore plausible biological mechanisms such as common genetic components for ADHD and cardiovascular disease.”
The study authors acknowledged that the new research has some limitations. Because of their observational design, this study does not identify a causal role for ADHD in increasing the risk of cardiovascular disease.
The authors used national registries to identify people with ADHD and cardiovascular disease, which may only consider people with severe symptoms of ADHD or cardiovascular disease. This may have led to an underestimation of the number of people with less severe symptoms of ADHD or cardiovascular disease.
Conversely, people with ADHD visit healthcare facilities more often and may be more likely to be diagnosed with cardiovascular disease.
The average age of the study population was around 50 years. Therefore, it is likely that the study included people with early-onset cardiovascular disease who were diagnosed at or before the age of 60. Therefore, additional studies with older adults are needed to investigate the association between ADHD and late-onset cardiovascular disease.
In addition, data on specific cardiovascular risk factors was either incomplete or missing. Dr. Lavie noted that “details of medications and doses are unknown. There was also no solid data on physical activity, sedentary behavior or fitness, and alcohol and drug use.”