Objective: To evaluate changes in insulin physiology in euglycemic pregnancy and gestational diabetes mellitus (GDM).
Research design and methods: Participants underwent oral glucose tolerance tests at ≤15 weeks' gestation (early pregnancy), 24-32 weeks' gestation (mid-late pregnancy), and 6-24 weeks postpartum. We evaluated longitudinal changes in insulin secretory response (log Stumvoll first-phase estimate) and insulin sensitivity (log Matsuda index) using linear mixed models. We then evaluated participants who met GDM criteria in early pregnancy (early GDM) and mid-late pregnancy (classic GDM) separately from those without GDM. We derived the pregnancy insulin physiology (PIP) index to quantify β-cell compensation for insulin resistance.
Results: Among 166 participants, 21 had early GDM and 24 developed classic GDM. Insulin sensitivity was reduced slightly in early pregnancy (β = -0.20, P < 0.001) and substantially in mid-late pregnancy (β = -0.47, P < 0.001) compared with postpartum. Insulin secretory response (adjusted for insulin sensitivity) was augmented in early pregnancy (β = 0.16, P < 0.001) and mid-late pregnancy (β = 0.16, P = 0.001) compared with postpartum. Compared with postpartum, the PIP index was augmented in early pregnancy (β = 215, P = 0.04) but not mid-late pregnancy (β = 55, P = 0.64). Early GDM was distinguished by a substantial reduction in early pregnancy insulin sensitivity (β = -0.59, P < 0.001) compared with postpartum. Both early and classic GDM lacked evidence of early pregnancy augmentation of insulin secretory response (adjusted for insulin sensitivity) and the PIP index (P > 0.1 vs. postpartum). Early pregnancy PIP index predicted GDM independent of participant characteristics (area under the curve without PIP index 0.70 [95% CI 0.61-0.79], area under the curve with PIP index 0.87 [95% CI 0.80-0.93]).
Conclusions: β-Cell function is enhanced in early pregnancy. Deficient first-trimester β-cell function predicts GDM.
Objective: To evaluate the metabolic alterations associated with gestational diabetes mellitus (GDM) in women with overweight or obesity.
Research design and methods: We compared fasting and postprandial plasma glucose and free fatty acid (FFA) concentrations, insulin sensitivity (IS; Matsuda index), and β-cell function (i.e., β-cell responsiveness to glucose) by using a frequently sampled oral glucose tolerance test (OGTT) at 15 and 35 weeks' gestation in women with overweight or obesity who had GDM (n = 29) or did not have GDM (No-GDM; n = 164) at 35 weeks.
Results: At 15 weeks, IS and β-cell function were lower, and fasting, 1-h, and total area-under-the-curve plasma glucose concentrations during the OGTT were higher (all P < 0.05) in the GDM than in the No-GDM group. At 35 weeks compared with 15 weeks, IS decreased, β-cell function increased, and postprandial suppression of plasma FFA was blunted in both the GDM and No-GDM groups, but the decrease in IS and the increase in postprandial FFA concentration were greater and the increase in β-cell function was less (all P ≤ 0.05) in the GDM than in the No-GDM group. A receiver operating characteristic curve analysis showed that both fasting plasma glucose and 1-h OGTT glucose concentration at 15 weeks are predictors of GDM, but the predictive power was <30%.
Conclusions: Women with overweight or obesity and GDM, compared with those without GDM, have worse IS and β-cell function early during pregnancy and a greater subsequent decline in IS and blunted increase in β-cell function. Increased fasting and 1-h OGTT plasma glucose concentration early during pregnancy are markers of increased GDM risk, albeit with weak predictive power.
Objective: The primary purpose of the current study was to test the hypothesis that the proinsulin-to-C-peptide (PI-to-CP) ratio, as an index of proinsulin secretion, would be higher and associated with indices of β-cell function in African American adults relative to European American adults without type 2 diabetes.
Research design and methods: Participants were 114 African American and European American adult men and women. A 2-h oral glucose tolerance test was conducted to measure glucose, insulin, C-peptide, and proinsulin and derive indices of β-cell response to glucose. The Matsuda index was calculated as a measure of insulin sensitivity. The disposition index (DI), the product of insulin sensitivity and β-cell response, was calculated for each phase of β-cell responsivity. Pearson correlations were used to investigate the relationship of the PI-to-CP ratio with each phase of β-cell response (basal, Φb; dynamic, Φd; static, Φs; total, Φtot), disposition indices (DId, DIs, DItot), and insulin sensitivity. Multiple linear regression analysis was used to evaluate independent contributions of race, BMI, and glucose tolerance status on PI-to-CP levels before and after adjustment for insulin sensitivity.
Results: African American participants had higher fasting and 2-h PI-to-CP ratios. The fasting PI-to-CP ratio was positively associated with Φb, and the fasting PI-to-CP ratio and 2-h PI-to-CP ratio were inversely associated with DId and insulin sensitivity only in African American participants.
Conclusions: The PI-to-CP ratio could be useful in identifying African American individuals at highest risk for β-cell dysfunction and ultimately type 2 diabetes.
Objective: Innate immune responses may be involved in the earliest phases of type 1 diabetes (T1D).
Research design and methods: To test whether blocking innate immaune cells modulated progression of the disease, we randomly assigned 273 individuals with stage 1 T1D to treatment with hydroxychloroquine (n = 183; 5 mg/kg per day to a maximum of 400 mg) or placebo (n = 90) and assessed whether hydroxychloroquine treatment delayed or prevented progression to stage 2 T1D (i.e., two or more islet autoantibodies with abnormal glucose tolerance).
Results: After a median follow-up of 23.3 months, the trial was stopped prematurely by the data safety monitoring board because of futility. There were no safety concerns in the hydroxychloroquine arm, including in annual ophthalmologic examinations. Preplanned secondary analyses showed a transient decrease in the glucose average area under the curve to oral glucose in the hydroxychloroquine-treated arm at month 6 and reduced titers of anti-GAD and anti-insulin autoantibodies and acquisition of positive autoantibodies in the hydroxychloroquine arm (P = 0.032).
Conclusions: We conclude that hydroxychloroquine does not delay progression to stage 2 T1D in individuals with stage 1 disease. Drug treatment reduces the acquisition of additional autoantibodies and the titers of autoantibodies to GAD and insulin.
Objective: Experimental evidence suggests that metabolic syndrome (MetS) is associated with changes in cardiac metabolism. Whether this association occurs in humans is unknown.
Research design and methods: 821 asymptomatic individuals from the Progression of Early Subclinical Atherosclerosis (PESA) study (50.6 [46.9-53.6] years, 83.7% male) underwent two whole-body 18F-fluorodeoxyglucose positron emission tomography-magnetic resonance (18F-FDG PET-MR) 4.8 ± 0.6 years apart. Presence of myocardial 18F-FDG uptake was evaluated qualitatively and quantitatively. No myocardial uptake was grade 0, while positive uptake was classified in grades 1-3 according to target-to-background ratio tertiles.
Results: One hundred fifty-six participants (19.0%) showed no myocardial 18F-FDG uptake, and this was significantly associated with higher prevalence of MetS (29.0% vs. 13.9%, P < 0.001), hypertension (29.0% vs. 18.0%, P = 0.002), and diabetes (11.0% vs. 3.2%, P < 0.001), and with higher insulin resistance index (HOMA-IR, 1.64% vs. 1.23%, P < 0.001). Absence of myocardial uptake was associated with higher prevalence of early atherosclerosis (i.e., arterial 18F-FDG uptake, P = 0.004). On follow-up, the associations between myocardial 18F-FDG uptake and risk factors were replicated, and MetS was more frequent in the group without myocardial uptake. The increase in HOMA-IR was associated with a progressive decrease in myocardial uptake (P < 0.001). In 82% of subjects, the categorization according to presence/absence of myocardial 18F-FDG uptake did not change between baseline and follow-up. MetS regression on follow-up was associated with a significant (P < 0.001) increase in myocardial uptake.
Conclusions: Apparently healthy individuals without cardiac 18F-FDG uptake have higher HOMA-IR and higher prevalence of MetS traits, cardiovascular risk factors, and early atherosclerosis. An improvement in cardiometabolic profile is associated with the recovery of myocardial 18F-FDG uptake at follow-up.
Objective: Diabetic ketoacidosis (DKA) is a life-threatening but preventable complication in people with type 1 diabetes. We aimed to quantify the incidence of DKA according to age and describe the time trend of DKA among adults with type 1 diabetes in Denmark.
Research design and methods: Individuals aged ≥18 years with type 1 diabetes were identified from a nationwide Danish diabetes register. Hospital admissions due to DKA were ascertained from the National Patient Register. The follow-up period was from 1996 to 2020.
Results: The cohort consisted of 24,718 adults with type 1 diabetes. The incidence rate of DKA per 100 person-years (PY) decreased with increasing age for both men and women. From 20 to 80 years of age, the DKA incidence rate decreased from 3.27 to 0.38 per 100 PY. From 1996 to 2008, the incidence rate of DKA increased for all age-groups, with a subsequent minor decrease in incidence rate until 2020. From 1996 to 2008, the incidence rates increased from 1.91 to 3.77 per 100 PY for a 20-year-old individual and from 0.22 to 0.44 per 100 PY for an 80-year-old individual living with type 1 diabetes. From 2008 to 2020 the incidence rates decreased from 3.77 to 3.27 and from 0.44 to 0.38 per 100 PY, respectively.
Conclusions: The incidence rates of DKA are declining for all ages, with an overall decline from 2008 for both men and women. This likely reflects improved diabetes management for individuals with type 1 diabetes in Denmark.
Objective: Nutrition therapy for gestational diabetes mellitus (GDM) has conventionally focused on carbohydrate restriction. In a randomized controlled trial (RCT), we tested the hypothesis that a diet (all meals provided) with liberalized complex carbohydrate (60%) and lower fat (25%) (CHOICE diet) could improve maternal insulin resistance and 24-h glycemia, resulting in reduced newborn adiposity (NB%fat; powered outcome) versus a conventional lower-carbohydrate (40%) and higher-fat (45%) (LC/CONV) diet.
Research design and methods: After diagnosis (at ∼28-30 weeks' gestation), 59 women with diet-controlled GDM (mean ± SEM; BMI 32 ± 1 kg/m2) were randomized to a provided LC/CONV or CHOICE diet (BMI-matched calories) through delivery. At 30-31 and 36-37 weeks of gestation, a 2-h, 75-g oral glucose tolerance test (OGTT) was performed and a continuous glucose monitor (CGM) was worn for 72 h. Cord blood samples were collected at delivery. NB%fat was measured by air displacement plethysmography (13.4 ± 0.4 days).
Results: There were 23 women per group (LC/CONV [214 g/day carbohydrate] and CHOICE [316 g/day carbohydrate]). For LC/CONV and CHOICE, respectively (mean ± SEM), NB%fat (10.1 ± 1 vs. 10.5 ± 1), birth weight (3,303 ± 98 vs. 3,293 ± 81 g), and cord C-peptide levels were not different. Weight gain, physical activity, and gestational age at delivery were similar. At 36-37 weeks of gestation, CGM fasting (86 ± 3 vs. 90 ± 3 mg/dL), 1-h postprandial (119 ± 3 vs. 117 ± 3 mg/dL), 2-h postprandial (106 ± 3 vs. 108 ± 3 mg/dL), percent time in range (%TIR; 92 ± 1 vs. 91 ± 1), and 24-h glucose area under the curve values were similar between diets. The %time >120 mg/dL was statistically higher (8%) in CHOICE, as was the nocturnal glucose AUC; however, nocturnal %TIR (63-100 mg/dL) was not different. There were no between-group differences in OGTT glucose and insulin levels at 36-37 weeks of gestation.
Conclusions: A ∼100 g/day difference in carbohydrate intake did not result in between-group differences in NB%fat, cord C-peptide level, maternal 24-h glycemia, %TIR, or insulin resistance indices in diet-controlled GDM.