A large multinational study has found that adults with type 2 diabetes who also had ADHD experienced a higher rate of death from any cause than adults with type 2 diabetes without ADHD. The finding was based on national health records from more than 1.9 million people in seven high-income countries.
The researchers did not find a clear overall association between ADHD and major adverse cardiac events, or MACE—a combined measure of heart attack, stroke and cardiovascular death. The study was observational, however, so it cannot show that ADHD causes an increased risk of death or identify a direct cause.
What the study found
The analysis included 1,929,027 adults newly diagnosed with type 2 diabetes, or receiving a first prescription for a non-insulin diabetes medicine, between 2010 and 2020. Participants came from Australia, Denmark, the Netherlands, Norway, Sweden, the United Kingdom and the United States. People with a previous heart attack or stroke were excluded.
By the end of follow-up, 44,748 people—2.3% of the study population—had an ADHD diagnosis or an ADHD medication prescription. Overall, 115,945 people died and 120,439 had a major heart or stroke event. Follow-up lasted a median of about two to four years for the ADHD group and three to five and a half years for the non-ADHD group, depending on the country.
After accounting for age, sex and year of diabetes diagnosis, the all-cause mortality hazard ratio for people with ADHD was 2.42. After additional adjustment for psychiatric history, psychiatric and heart or metabolic medicines, and diabetes medication use during follow-up, the estimate fell to 1.71, with a 95% confidence interval of 1.21 to 2.43.
The association was statistically significant in Denmark, the Netherlands, Sweden and the United States, with fully adjusted hazard ratios ranging from 1.53 to 3.81. It was seen in both men and women. Adults with ADHD were generally younger when diabetes was diagnosed, and they had more psychiatric conditions and used more psychiatric medicines.
No clear overall increase in major cardiac events
Across all seven countries, ADHD was not associated with a higher rate of MACE. The pooled hazard ratio was 1.04 before full adjustment and 0.90 after adjustment; both confidence intervals included the possibility of no difference.
Results varied substantially between countries. For example, the reported hazard ratio was 1.44 in Sweden and 0.73 in the United States. The researchers said the countries differed more than would be expected by chance. Differences in how ADHD and diabetes were recorded may have contributed to that variation.
What the medication analysis can—and cannot—show
The researchers also examined 33,301 adults whose ADHD was recorded by the time of their diabetes diagnosis. Periods when people were prescribed ADHD medication were compared with periods when they were not recorded as taking it.
Across the full group, medication periods were not associated with either MACE or death. The hazard ratio was 1.12 for MACE and 1.00 for death, with confidence intervals that included no difference. The medicines examined included methylphenidate, amphetamine, dexamphetamine, lisdexamfetamine, atomoxetine and guanfacine.
Among people diagnosed with diabetes between ages 18 and 44, medication periods were associated with a higher rate of MACE after adjustment. The estimate was 1.58 in one analysis and 1.53 after additional adjustment for diabetes medicines. However, this younger-adult analysis used data from only four of the seven countries, and only the middle estimate remained significant after the study’s strict correction for multiple testing.
For people diagnosed with diabetes at age 45 or older, ADHD medication periods were not associated with MACE. The researchers described the younger-adult finding as an early signal that needs confirmation in larger studies.
Why the results need careful interpretation
Health records can reveal patterns across very large populations, but they cannot account for every factor that may affect health. The study lacked information on smoking, body weight, blood pressure, blood sugar control, kidney function and substance use. Prescription refill records were used to infer medication exposure and may not reflect how medicines were actually taken.
The study also did not establish the causes of death beyond identifying cardiovascular deaths within the MACE measure. The researchers pointed to accidents and challenges with diabetes self-management as possible explanations for some of the mortality difference, but these remain proposed pathways rather than proven causes.
The findings may not apply to lower-income settings because all seven countries were high-income countries, and follow-up lasted only a few years.
What this means for people with ADHD and diabetes
The results support closer coordination between diabetes care and mental health care. Recognizing ADHD may help clinicians and patients identify where diabetes self-management needs additional support, without assuming that ADHD itself determines an individual’s outcome.
- People with both conditions should discuss diabetes care, mental health and medicines with their healthcare team.
- Anyone concerned about heart risk or ADHD treatment should speak with their prescriber rather than stopping medication independently.
- The medication findings, especially in younger adults, should be treated as a question for further research rather than proof that treatment causes heart problems.
A separate 2023 meta-analysis cited in the study found that people with ADHD had more than twice the odds of developing type 2 diabetes. The source noted that other psychiatric conditions explained much of that association in Swedish register data, underscoring how closely linked—and difficult to separate—these health factors can be.
AI tools were used to assist with the preparation of this article.
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