medwireNews: A nationwide population-based study reveals a link between obesity in adolescence and an increased risk for type 1 diabetes in young adulthood.
“Physicians should be aware that adolescent obesity is related to an increased risk for incident type 1 diabetes as well as type 2 diabetes in young adulthood, and attaining a normal weight among adolescents at high risk for developing type 1 diabetes may be important for prevention,” say Gilad Twig (Tel Aviv University, Israel) and co-researchers.
The study included 834,050 male and 592,312 female adolescents, aged 16 to 19 years, who underwent a medical exam prior to undertaking compulsory military service.
A total of 777 of these adolescents were diagnosed with type 1 diabetes during an average follow-up of 11 years, at an average age of 25 years. The rate per 100,000 person–years rose from 3.6 among people in the underweight category (BMI <5th percentile) to 8.4 among those in the obese category (BMI ≥95th percentile).
This pattern persisted after accounting for birth year, age at study entry, sex, education, and cognitive performance. Specifically, compared with adolescents with BMI in the 5th–49th percentiles, the risk for type 1 diabetes was elevated a significant 1.41-fold, 1.54-fold, and 2.05-fold among adolescents with BMI in the 75th–84th, 85th–94th, and 95th or higher categories.
This amounted to a 1.25-fold increase in diabetes risk per unit increase in BMI, the researchers report in Diabetologia.
“The accelerator hypothesis predicts that increased obesity prevalence lowers the threshold of genetic susceptibility, causing more individuals with a low-risk genetic profile to develop type 1 diabetes,” they write.
“Indeed, independent studies from Finland and the UK showed that the proportion of low-risk HLA haplotypes has increased among cases of incident type 1 diabetes over recent decades.”
A subgroup of 194 diabetes cases had autoantibody data available, and when the team restricted the analysis to cases who were positive for islet autoantibodies the association between BMI and type 1 diabetes risk persisted, at a 2.90-fold risk increase for those in the obese category.
“When the analysis was restricted to individuals with at least two types of islet autoantibodies, the association was even more robust,” say Twig and colleagues, who also presented their findings in a poster session at the 82nd ADA Scientific Sessions in New Orleans, Louisiana.
The researchers observe that “[t]he prevalence of adolescent obesity is rising worldwide at an alarming rate, with dire projections for the near future.”
They call for further studies to “unravel” the association between obesity and type 1 diabetes “so that we can better address the full spectrum of risks posed by the obesity epidemic or identify common environmental factors affecting both weight and type 1 diabetes.”
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