50 per cent of type 1 diabetes cases occur after age 30, researchers say

Half of all cases of type 1 diabetes develop after the age of 30, according to new research.
The findings, presented at the European Association for the Study of Diabetes (EASD), challenge the long-held belief that type 1 diabetes generally develops in childhood.
Scientists at the University of Exeter Medical School came to this conclusion following a review of data from the UK Biobank.
A research team led by Dr Nicholas JM Thomas applied a type 1 diabetes genetic risk score to a cohort of 120,000 British white adults aged between 40 and 70 years.
They found that, after adjusting for age, nearly all the diabetes cases below age 30 were type 1 diabetes, and prevalence of type 2 diabetes rose significantly with increasing age.
The surprise came when they also found that the number of type 1 diabetes cases remained constant from age 30 to 60. Roughly half of type 1 cases occurred after age 30, but the prevailing type 2 cases “drowned out” this statistic.
“I think it’s an eye-opener and obviously has implications for how we diagnose and manage people and also the education people receive,” Thomas told Medscape Medical News.
“We very much focus on childhood and adolescence and perhaps people diagnosed later don’t get the same education. So really, we were reassured we were capturing type 1 diabetes.”
Thomas stressed that type 1 diabetes is evenly distributed within the first 60 years of life, but that age after age 30, the increase in type 2 makes type 1 harder to diagnose and treat correctly.
“In childhood, almost all the cases of diabetes are type 1 diabetes, so they’re easier to spot because they stand out, whereas later in life we see a dramatic increase in the prevalence of type 2 diabetes, so the cases of type 1 diabetes are drowned out and less easy.”
Dr Catharine Owe, Oxford Centre for Diabetes, Endocrinology and Metabolism, who wasn’t involved in the study, added: “It’s absolutely a basic misunderstanding. I think we have work to do in this area. [The new study] does highlight the issue in a nice way, although it doesn’t help us identify these specific individuals.
“I think it’s absolutely crucial for people to be aware that type 1 diabetes can present at any age. Physicians shouldn’t be complacent when people aren’t responding to oral agents, or they’re not bringing HbA1c down to target when they should.”