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Type 2 Diabetes Can Begin 20 Years Prior to Diagnosis

Feb 24, 2018
 

Subtle elevations in fasting glucose and triglycerides associated with developing type 2 diabetes.

Risk of developing type 2 diabetes (T2D) is associated with subtle elevations of glucose and lipids more than 20 years before diagnosis, according to a study published online Feb. 5 in Diabetes, Obesity and Metabolism.

The cohort study group consisted of 812,073 individuals, about 95% Caucasians, who went through this study. All the individuals with at least one fasting glucose measurement in the baseline period, and without a documented diagnosis of T2D or a fasting glucose > 126 mg/dL.at the baseline period, and without a documented diagnosis of T2D or a fasting glucose > 126 mg/dL. at the baseline examination (n=14,000) were included in the current study population (n=296,439, 47% women).  The first measurement that was taken during the baseline period constituted the index examination. The study population was followed from the index exam until a diagnosis of T2D, death or at end of 2012, whichever came first.

Development of T2D has been associated with subtle elevations of glucose and lipids more than 20 years before diagnosis. This suggests that the diabetes processes tied to chronic insulin resistance operate for decades prior to the development of T2D.

For years we have witnessed that blood sugars and lipids don’t rise overnight, that it could take years to actually become diagnosed with type 2 diabetes.

From a cohort they included about 300,000 individuals with a fasting glucose from a health examination during 1985-96. All the subjects were then followed for development of T2D through 2012. For the incident of T2D, the 20-year T2D risk based on age, sex, body mass index, fasting glucose and triglycerides was estimated for biomedical risk factors of T2D going back more than 20 years before diagnosis. And the difference in fasting glucose increased over time.

28,244 new cases of T2D occurred during the study period with an average 20-year risk of 8.1%. The risk was substantially increased in those who had excess weight or obesity.

Among the new T2D diagnoses, 63% were men and 37% were women. The mean age at diagnosis was 63.4 years. The average time from the index examination to the recorded diagnosis/selection as control was close to 14 years.  Low socioeconomic status was more frequent in subjects who had diabetes. T2D cases had higher levels of glucose, lipids, and inflammation biomarkers at the index examination, versus controls.

For both men and women, the estimated 20-year risk of T2D increased markedly with higher BMI and was doubled with triglycerides >124 mg/dL irrespective of BMI and fasting glucose. With a BMi <25 kg/m2, fasting triglycerides <124 mg/dL and fasting glucose <81mg/dL the estimated 20-year risk was 2.2% and 1.3% respectively for men and women ages 40-49 years. The corresponding risk with a BMI>30kg/m2, fasting triglycerides>124mg/dL and a fasting glucose between 100-125mg/dL was 63.5% and 69.6% for men and women respectively. The total, for men and women, 15.58% and 5.8% respectively had a 20% or higher 20-year risk of T2D according to these estimates. Corresponding 10-year risks were in general lower.

Practice Pearls:

  • Screening for small rises in glucose or lipids can provide means to begin diabetes education.
  • There are many risk factors for diabetes, but the three major ones would be BMI greater than 25g/m2 elevated lipids and elevated fasting blood sugars.

This suggests that diabetogenic processes tied to chronic insulin resistance operate for decades prior to the development of T2D.

Resources:

Diabetes, Obesity and Metabolism

Unit of Epidemiology, Institute of Environmental Medicine, Karolinska institutet, Stockholm

Swedish Orphan Bovitrum AB, Stodkholm, Sweden

Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway

Medical Evidence & Observational Research, Global Medical Evidence and Observational Research, AstraZeneca