Asthma linked to later T1D risk in children

Children who have asthma may be more likely to develop type 1 diabetes (T1D), according to a new report, but children with diabetes aren’t necessarily at a higher risk of developing asthma.

The study, published in JAMA Network Open, examined the association between asthma and diabetes using data from nearly 1.3 million children in Sweden.¹ The goal of the study was to further research the long-debated association between atopic and autoimmune disease.

Asthma is the most common chronic disease in childhood, affecting about 11% of children aged 6 to 7 years worldwide. It has been linked in some studies to T1D-one of the most common autoimmune diseases in children. Why this association occurs is unclear, with studies suggesting a range of genetics, involvement of T cells, or environmental factors.

In evaluating the cohort for possible associations, the study team found that 9.5% had asthma and 0.3% had T1D at the onset of the study. The children with asthma had been diagnosed around age 3 years, and those with diabetes were diagnosed at about age 6 years. A small portion of the study group-just 494 children-were diagnosed with both asthma and T1D. These children accounted for 0.4% of all asthma cases, and 13% of all T1D cases in the cohort, according to the report. Additionally, the report found nearly 900,000 siblings with similar disease prevalence.

A one-way relationship

As far as their relationship to one another, the research team found that asthma and T1D were positively associated with one another-but it’s a one-way relationship. The study team reveals that although there was a positive association for the risk of T1D development after an asthma diagnosis, there was not a similar association with T1D patients later developing asthma.

The report also revealed that full siblings with one disease were at an increased risk of developing the other, and there were similar trends-albeit at lower levels-among cousins.

Although there was some link between the 2 diseases in both directions, the research team concluded that the order in which the diseases appeared was important. One theory for the association was that subsequent development of diabetes after an asthma diagnosis could be due in part to the use of inhaled corticosteroids during asthma treatment.

More research is needed to develop clinical guidelines based on the study. Yet the research team shares hope that the study will help clinicians understand the possible association between these 2 diseases.

“An understanding of the comorbidity could be beneficial in terms of avoiding diagnostic delay by recognizing symptoms of asthma that may otherwise be overlooked by caregivers and physicians in the more acute management of patients with T1D,” the study notes.

Previous studies have shown similar associations, including a Finnish report from 2018.² That report also showed a relationship between the 2 diseases based on the sequence in which they developed.

References:

1. Smew AI, Lundholm C, Sävendahl L, Lichtenstein P, Almqvist C. Familial coaggregation of asthma and type 1 diabetes in children. JAMA Netw Open. 2020;3(3):e200834.

2. Metsälä J, Lundqvist A, Virta LJ, et al. The association between asthma and type 1 diabetes: a paediatric case-cohort study in Finland, years 1981-2009. Int J Epidemiol. 2018;47(2):409-416.