Young-Onset Diabetes: Type 1 vs Type 2

Young-onset T2DM carries a higher risk of microvascular complications and may have a more aggressive disease course than T1DM, according to a study published online in Diabetes Research in Clinical Practice.

“Compared to young-onset T1DM, after adjustment for relevant covariates, young-onset T2DM participants had 2.11 higher risk of developing a diabetes related complication, and this was driven mostly by the microvascular complications,” wrote lead author Mohammed Ali, MBChB, MSc, MBA, of the Emory University Global Diabetes Research Center in Atlanta, GA.

The study was conducted in India, where – like other developing countries – the age of diabetes onset is decreasing. Patients with young-onset diabetes have a higher cumulative exposure to hyperglycemia, which can increase the risk for micro- and macrovascular complications. While studies from the USA and Australia suggests youth with T2DM may have higher risk for certain diabetes complications, scant data exists in non-European populations.

The study took place in a tertiary diabetes center in Chennai, India. It included 108 participants with T1DM and 90 with T2DM, who were followed for a median of 5 years. At the time of diagnosis (between 10 and 25 years of age), participants had no evidence of DM complications. Results were adjusted for age, HbA1c, systolic blood pressure, and serum cholesterol.

Key results:

• Duration of diabetes: Not significantly different between T1DM (10.1 years) vs T2DM (9.5 years), (P=0.543)

• Retinopathy:

♦ T1DM: 77.4/1000 person years

♦ T2DM: 78/1000 person years

• Nephropathy:

♦ T1DM: 62/1000 person years

♦ T2DM: 58.8/1000 person years

• Neuropathy:

♦ T1DM: 7.8/1000 person years

♦ T2DM: 13.9/1000 person years

• Ischemic heart disease:

♦ T1DM: 1.2/1000 person years

♦ T2DM: 5.4/1000 person years

• Risk of any diabetes complication: 2.11 times (95% CI: 1.27–3.51) higher with T2DM vs T1DM

• Risk of microvascular complications: Twice as high with T2DM vs T1DM (OR: 2.05; CI: 1.24–3.41; P=0.005)

• Risk of macrovascular complications: Not calculated due to too few events

Higher incidence of DM complications in T2DM could be related to a number of factors, according to the authors. T2DM has an insidious onset, so those with T2DM may have had the disease longer before diagnosis than those with T1DM, with its more obvious onset. In addition, those with T2DM have worse glycemic control than those with T1DM (average HbA1c reduction: 0.4% vs 1.6%).

However, they noted that increased risk of complications with T2DM occurred even though this group showed more improvements in lipids, and smaller increases in weight, waist circumference, and blood pressure than T1DM patients.

“[These findings] indicate that early onset T2DM may be innately a more aggressive disorder than T1DM,” wrote the authors.

Other studies have suggested that those with young-onset T2DM may develop severe, chronic complications of T2DM by their 40s and lose 15 years of life expectancy, according to background information in the article. 

“The implications of these data are concerning,” the authors concluded, “…This calls for screening for T2DM in youth with a family history of diabetes, obesity or markers of insulin resistance… There is also a need for early and more aggressive control of glucose levels, blood pressure and lipids in young-onset T2DM in order to prevent complications.”

The authors noted that the findings may not generalize to other populations, and may have been limited by the ability to accurately compare duration of diabetes in T1DM and T2DM.

Take-home Points

• A study in India found that those with young-onset T2DM have a 2.11 times increased risk of any diabetes complication compared to those with T1DM.

• T2DM was associated with twice the increased risk of microvascular complications.

• Results suggest that young-onset T2DM may have a more aggressive course than T1DM.

• Increased screening of at-risk youth and more aggressive glucose control in affected youth is needed.

The authors report no conflicts of interest.

Reference: Amutha A, et al. Incidence of complications in young-onset diabetes: comparing type 2 with type 1 (the young diab study). Diabetes Res Clin Pract. 2016 Nov 17;123:1-8.