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Background Sex differences characterize cardiovascular outcomes in patients with type 1 diabetes. Cardioautonomic neuropathy is a common complication of type 1 diabetes that associates increased morbi-mortality. Data regarding the interplay between sex and cardiovascular autonomic neuropathy are scarce and controversial in these patients. We aimed to address sex-related differences in the prevalence of seemingly asymptomatic cardioautonomic neuropathy in type 1 diabetes, and their associations with sex steroids. Methods We conducted a cross-sectional study including 322 consecutively recruited patients with type 1 diabetes. Cardioautonomic neuropathy was diagnosed using Ewing's score and power spectral heart rate data. We assessed sex hormones by liquid chromatography/tandem mass spectrometry. Results When considering all subjects as a whole, asymptomatic cardioautonomic neuropathy prevalence was not significantly different between women and men. When age was taken into account, the prevalence of cardioautonomic neuropathy was similar among young men and those > 50 years. However, in women > 50 years, the prevalence of cardioautonomic neuropathy doubled that of young women [45.8% (32.6; 59.7) vs. 20.4% (13.7; 29.2), respectively]. The OR of having cardioautonomic neuropathy was 3.3 higher in women > 50 years than in their younger counterparts. Furthermore, women presented more severe cardioautonomic neuropathy than men. These differences were even more marked when women were classified according their menopausal status instead of age. Peri- and menopausal women had an OR 3.5 (1.7; 7.2) of having CAN compared with their reproductive-aged counterparts [CAN prevalence: 51% (37; 65) vs. 23% (16; 32), respectively]. A binary logistic regression model (R2: 0.161; P = 0.001) displayed age > 50 years as a significant determinant of cardioautonomic neuropathy only in women. Androgens were positively associated with heart rate variability in men, and negatively in women. Accordingly, cardioautonomic neuropathy was associated with increased testosterone/estradiol ratio in women but to decreased testosterone concentrations in men. Conclusions Menopause in women with type 1 diabetes is accompanied by an increase in the prevalence of asymptomatic cardioautonomic neuropathy. This age-related excess risk of cardioautonomic neuropathy is not observed in men. Men and women with type 1 diabetes have opposite associations between circulating androgens and indexes of cardioautonomic function. Trial registration ClinicalTrials.gov Identifier: NCT04950634.

We aimed to determine, in patients with type 1 diabetes (T1DM), the impact of excluding hyperglycemia as a criterion from the International Diabetes Federation (IDF) definition of the metabolic syndrome (MetS), both on its prevalence and on its association with micro and macrovascular complications and markers of subclinical inflammation.A cross-sectional design, including 280 patients with T1DM. We defined MetS by three different models: (i) the standard IDF criteria, (ii) a modification consisting of excluding of hyperglycemia as a criterion (modified IDF criteria) and (iii) a modification consisting in changing the hyperglycemia by insulin resistance (MetS + IR model) defined by the estimated glucose disposal rate. Microvascular complications and cardioautonomic neuropathy were assessed. We measured an inflammatory panel including high sensitivity C reactive protein, erythrocyte sedimentation rate, homocysteine, and fibrinogen concentrations.After excluding hyperglycemia, the prevalence of MetS was 6.4% (95%CI: 4.1 to 9.9) compared with 20.7% (95%CI: 16.3 to 25.8) using standard IDF criteria. After adjusting for duration of diabetes, all three MetS definitions increased the odds for having microvascular complications [OR: 6.012 (2.208-16.307) for modified definition; OR: 5.176 (2.555-10.486) for standard definition and [OR: 3.374 (1.649-8.456) for MetS+IR model]. However, the both modified IDF models for MetS showed better predictive performance than standard criteria for suffering from neuropathy, nephropathy, cardiovascular disease and were associated with markers of subclinical inflammation.The prevalence of MetS significantly varies as a function whether or not hyperglycemia is included as a diagnostic criterion. The subset of patients fulfilling the modified MetS definitions may reflect better the concept of metabolic syndrome in T1DM. These modified definitions were accompanied by a poorer metabolic control and lipid profile, showing the worse inflammatory biomarker profiles and higher odds for micro- and macrovascular complications. In patients with T1DM, the inclusion of insulin resistance instead of hyperglycemia as a criterion of MetS may be of interest in routine clinical practice.