Results from a population-based Swedish study published in Diabetes Care found that a parental history of type 1 diabetes was associated with a 29% increased risk for attention-deficit hyperactivity disorder (ADHD) in offspring.
Jianguang Ji, MD, PhD, associate professor at the Center for Primary Health Care Research at Lund University in Lund, Sweden, and colleagues identified individuals with type 1 diabetes from the nationwide Swedish National Hospital Discharge Register and Swedish Outpatient Register in Sweden and linked them with the Swedish Multi-Generation Register to identify their offspring. They then used Cox regression to calculate the hazard ratio (HR) of ADHD in offspring of patients with type 1 diabetes compared with the general population.
The researchers found 15,615 individuals who were born after their patients had been diagnosed with type 1 diabetes and compared them with 1,380,829 children who were born to parents without type 1 diabetes. After a median of 25 years of follow-up, 267 (2.4%) of those born to a parent with a type 1 diabetes diagnosis were diagnosed with ADHD, compared with only 1.5% of the matched controls. After controlling for confounding factors, the investigators found that these offspring had a significantly increased risk for ADHD, with an HR of 1.29 (P <.0001). Risk for ADHD was also slightly higher when mothers had type 1 diabetes (HR 1.35) compared with when fathers had type 1 diabetes (HR 1.20), but this difference was not statistically significant.
The authors noted that one limitation of the study is that the cases of ADHD were not validated in the Swedish National Hospital Discharge Register and the Swedish Outpatient Register. Furthermore, information for some individual-level risk factors such as lead contamination and viral infection was not in the databases, which could have confounded the findings.
The strengths of the study included the high quality of the Swedish registers used, the large study population, the prospective study design, and the completeness of the follow-up.
The researchers suggested that the underlying mechanisms of this association need to be explored in further studies.
Ji J, Chen T, Sundquist J, Sundquist K. Type 1 diabetes in parents and risk of attention deficit hyperactivity disorder in offspring: a population-based study in Sweden [published online January 26, 2018]. Diabetes Care. doi:10.2337/dc17-0592