medwireNews: People with type 1 diabetes should be screened for other autoimmune diseases, a Finnish research team suggests, after finding these individuals particularly vulnerable to additional disorders.
The study of more than 4000 Finnish individuals with type 1 diabetes revealed that 22.8% had at least one additional autoimmune disease, with the most prevalent being hypothyroidism, celiac disease, and hyperthyroidism.
And women were more than twice as likely as men to have at least one additional autoimmune disease, at a corresponding 31.6% versus 14.9%, the researchers note in Diabetes Care.
The risk for celiac disease was associated with early-onset diabetes, with the risk increasing by 1.5% with each decreasing year at onset. Children diagnosed before the age of 10 years were at greatest risk, being 1.38 times more likely to have celiac disease than other diabetic individuals.
“Screening for celiac disease is important during childhood, since age ≤10 years at onset of [type 1 diabetes] but not ageing, per se, increases the risk of celiac disease,” comment Per-Henrik Groop (University of Helsinki and Helsinki University Hospital) and co-workers.
Conversely, they note that the risk for hypothyroidism increased by 1.7% with each additional year of diabetes onset, and by 1.3% with each additional year of age.
The findings are based on 4758 individuals with type 1 diabetes from the Finnish Diabetic Nephropathy Study (FinnDiane), who were matched for sex, age, and residence at diabetes diagnosis with 12,710 people without diabetes from the Population Register Center. Both groups were tracked for autoimmune diseases from 1970 to 2015 using Finnish nationwide health registries.
FinnDiane participants had a mean age of 51.4 years by the end of follow-up or death in 2015 and a median diabetes duration of 35.5 years.
Groop et al identified an additional 1245 autoimmune diseases in 1087 of the individuals with type 1 diabetes. The most prevalent of these was hypothyroidism, which was observed in 18.1% of the diabetes cohort versus just 6.0% of control individuals, giving an odds ratio (OR) of 3.43.
This was followed in prevalence by celiac disease, observed in a corresponding 4.40% versus 0.99% of participants (OR=4.64), then hyperthyroidism at 2.4% versus 0.8% (OR=2.98), atrophic gastritis at 1.03% versus 0.20% (OR=5.08), and Addison disease at 0.380% versus 0.016% (OR=24.13).
Women with type 1 diabetes were significantly more likely than men with the condition to have hypothyroidism (OR=2.96), hyperthyroidism (OR=2.83), and celiac disease (OR=1.52).
The female preponderance for autoimmune diseases among people with type 1 diabetes was most obvious for hyperthyroidism, which was seen in 71.4% of women.
Nonetheless, the researchers conclude that autoimmune diseases “should be screened throughout life equally for both sexes and more often in those with a family history of [type 1 diabetes]”.
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