Should thyroid-stimulating hormone goals be reviewed in patients with type 1 diabetes mellitus? Results from the Brazilian Type 1 Diabetes Study Group.

AIMS: To investigate if thyroid-stimulating hormone (TSH) levels are associated with any differences in glycaemic control or diabetes-related complications in individuals with Type 1 diabetes. METHODS: This observational, cross-sectional and multicentre study included patients with Type 1 diabetes for ≥ 5 years, with a recent TSH measurement and without a known previous thyroid disease. Patients were divided into three groups according to TSH levels: 0.4-2.5 mU/l; 2.5-4.4 mU/l; and ≥ 4.5 mU/l. RESULTS: We included 1205 individuals with a mean ± sd age of 23.8 ± 11.3 years. Seven patients had TSH levels <0.4 mU/l and were excluded from the comparison between groups. HbA1c levels, systolic and diastolic blood pressure, LDL cholesterol and disease duration were similar in all groups (P = 0.893, P = 0.548, P = 0.461, P = 0.575 and P = 0.764, respectively). The rates of diabetic retinopathy and GFR < 60/mL/min/1.73 m(2) differed between groups (P = 0.006 and P < 0.001, respectively) and were lower in those with lower TSH levels. Multivariate analysis confirmed these associations. The frequencies of retinopathy and GFR < 60 mL/min/1.73 m(2) were higher not only in patients with TSH ≥ 4.5 mU/l (odds ratio 1.878 and 2.271, respectively) but also in those with TSH levels of 2.5-4.4 mU/l (odds ratio 1.493 and 2.286, respectively), when compared with patients with TSH levels of 0.4-2.5 mU/l. CONCLUSIONS: TSH levels of 0.4-2.5 mU/l are associated with a lower risk of diabetic retinopathy and renal failure in individuals with Type 1 diabetes, independently of glycaemic control and duration of the disease.

Assessment of arterial stiffness in women with gestational diabetes.

AIMS: Gestational diabetes mellitus may precede development of Type 2 diabetes and may be related to cardiovascular disease. Pulse wave velocity measurement is the gold-standard method to evaluate arterial stiffness, a preclinical cardiovascular risk marker. However, the relationship between aortic stiffness and gestational diabetes is unclear. The aim of this study was to evaluate aortic pulse wave velocity in women with gestational diabetes in comparison with a matched control group of healthy pregnant women. METHODS: This case-control study included 24 women with gestational diabetes and 27 matched control subjects. Clinical, demographic and laboratory variables were obtained and aortic pulse wave velocity were measured. RESULTS: Both groups had similar age, gestational age, BMI, ethnicity, smoking status and blood pressure levels. Women with gestational diabetes had aortic pulse wave velocity comparable with control subjects: 7.2 ± 0.9 vs. 7.3 ± 1.2 m/s (P = 0.79). When categorized according to the median value of pulse wave velocity (7.3 m/s), age (P < 0.001), diastolic blood pressure (P = 0.03) and heart rate (P = 0.02) were associated with increased arterial stiffness. In the group with gestational diabetes, there was a non-significant trend towards higher 1-h postprandial glycaemia in patients with higher (above the median) pulse wave velocity (6.5 ± 0.8 vs. 7.1 ± 1.3 mmol/l, P = 0.22) and a lower prevalence of patients with good glycaemic control (38.5 vs. 72.7%, P = 0.09). CONCLUSIONS: Although gestational diabetes may be a risk factor for development of cardiovascular disease, women with gestational diabetes do not have higher aortic stiffness than healthy pregnant women. Time of exposure to hyperglycaemia may have been insufficient to increase central arterial stiffness in women with gestational diabetes.