The results suggest that very early identification of dysglycemia may provide at-risk individuals with ample time to make long-lasting lifestyle changes that could prevent future diabetes….
The Bogalusa Heart Study is an ongoing community-based study that has been collecting data on residents of Bogalusa, Louisiana, since 1978. Between 1978 and 1994, 6 cross-sectional studies of school-aged children were conducted, and 8 surveys were conducted between 1978 and 2002 among young adults who had been examined as children. Examinations conducted in conjunction with the surveys included fasting plasma glucose (FPG) tests, lipid profiles, height, weight, and blood pressure measurements.
For this analysis, a total of 1,849 of these young adults were selected from the final 3 surveys (1995-2002), resulting in a mean follow-up of 21 years. On the basis of data from their last survey, patients were considered normoglycemic (n = 1723) if they had a fasting glucose level of 99 mg/dL or lower, prediabetic (n = 79) if their fasting glucose was between 100 mg/dL and 125 mg/dL, or diabetic (n = 47) if they had a fasting glucose level ≥ 126 mg/dL or had a history of treatment for diabetes. Logistic regression was used to examine the cardiometabolic risk-factor variables by status of adult diabetes, adjusted for age, race, and sex. From sensitivity and specificity data, receiver operating characteristic curve analysis determined that the optimal glucose level for prediction of prediabetes and diabetes was 86 mg/dL; therefore, this level was used to define high and low values. The trends of hyperglycemic status by baseline FPG quartile levels were also examined.
In age-, sex-, and race-adjusted analyses of baseline data, patients who developed prediabetes were older (12.4 years vs 10.7 years, P < .001) and had higher fasting glucose levels (88 mg/dL vs 85 mg/dL, P < .01) compared with patients who remained normoglycemic. Patients who developed diabetes were older (12.4 vs 10.7, P < .01), had a higher body mass index (22.0 kg/m2 vs 18.2 kg/m2, P < .001), lower high-density lipoprotein (HDL) cholesterol level (52 mg/dL vs 62 mg/dL, P < .001), and higher triglycerides (79 mg/dL vs 65 mg/dl, P < .01). Nearly 7% of patients with baseline FPG in the third and fourth quartiles (≥ 86 mg/dL) developed prediabetes compared with about 2% in the first and second quartiles, and about 3.5% of patients in the top 2 quartiles developed diabetes vs about 1.5% of patients in the lower 2 quartiles. In multivariate models, childhood FPG ≥ 50th percentile increased the probability of developing prediabetes by over 3-fold (odds ratio 3.40, 95% confidence interval 1.87-6.18), and doubled the probability of developing diabetes (odds ratio 2.06, 95% confidence interval 1.01-4.23).
Previous studies in adults have reported that higher "normal" FPG is associated with an increased risk for diabetes. The current study by Nguyen and colleagues is fascinating because they were able to find a similar association between childhood FPG and future diabetes in adults who were still relatively young (< 45 years). Furthermore, the same variables that predict diabetes in adults — obesity, low HDL cholesterol, and high triglycerides — were associated with future dysglycemia even though the levels were far from abnormal.
Although the main findings were strongest for prediabetes, it is likely that additional follow-up into age ranges in which onset of diabetes is more typical would produce equally strong results. It is fascinating that the current study found an FPG cutoff of 86 mg/dL as the apparent threshold for elevated risk. The American Diabetes Association asserts that risk for diabetes associated with FPG is continuous, an assertion that is based on some evidence. However, at least 2 previous studies, one in young adult men and another in a more general population, identified a threshold of about 87 mg/dL, nearly identical to the 86 mg/dL reported in the current analysis.
These results suggest that very early identification of dysglycemia may provide at-risk individuals with ample time to make long-lasting lifestyle changes that could prevent future diabetes. The fact that elevated FPG level in childhood, even within the normoglycemic range, is a predictor of Type 2 diabetes in younger adulthood has implications for health care policy.