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Over the past decades, there has been a major upward shift in the prevalence of cardiometabolic risk (CMR) factors (central obesity, insulin resistance, hypertension and dyslipidemia) in patients with type 1 diabetes, which could have either an additive or a synergistic effect on risk for cardiovascular disease. These metabolic changes are occurring in parallel to the worldwide obesity epidemic and the widespread use of intensive insulin therapy. Poor lifestyle habits (poor diet quality, sedentary behaviours and smoking) are known to be driving factors for increased CMR factors in the general population. The objective of this review is to explore the lifestyle habits of adults with type 1 diabetes and its potential association with CMR factors. Evidence suggests that adherence to dietary guidelines is low in subjects with type 1 diabetes with a high prevalence of patients consuming an atherogenic diet. Sedentary habits are also more prevalent than in the general population, possibly because of the additional contribution of exercise-induced hypoglycemic fear. Moreover, the prevalence of smokers is still significant in the population with type 1 diabetes. All of these behaviours could trigger a cascade of metabolic anomalies that may contribute to increased CMR factors in patients with type 1 diabetes. The intensification of insulin treatment leading to new daily challenges (e.g. carbohydrates counting, increase of hypoglycemia) could contribute to the adoption of poor lifestyle habits. Preventive measures, such as identification of patients at high risk and promotion of lifestyle changes, should be encouraged. The most appropriate therapeutic measures remain to be established.

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In a context of significantly reduced insulin secretion, variations of insulin sensitivity are associated with variations of glucose tolerance in adult patients with CF.

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Background: Aging cystic fibrosis (CF) patients are at high risk of developing CF-related diabetes (CFRD). Decrease in insulin secretion over time is the main hypothesis to explain this increasing prevalence but mechanisms are still not well elucidated. The objective is to assess evolution of glucose tolerance and insulin secretion/sensitivity in aging CF patients. Methods: This is a retro-prospective observational analysis in the older adult CF patients from the Montreal Cystic Fibrosis Cohort (n = 46; at least 35 years old at follow-up) and followed for at least 4 years. Baseline and followup (last visit to date) 2-h oral glucose tolerance test (OGTT with glucose and insulin measurements every 30 min) were performed. Pulmonary function test (FEV 1 ) and anthropometric data were measured the same day. Insulin sensitivity was measured by the Stumvoll index. Results: After a mean follow-up of 9.9 ± 2.6 years, mean age at follow-up was 43.5 ± 8.1 years old. An increase of body weight (+2.6 ± 6.5 kg, p = 0.01) and a decrease in pulmonary function (FEV 1 ; 73.4 ± 21.2% to 64.5 ± 22.4%, p ≤ 0.001) were observed. Overall, insulin secretion is maintained at follow-up but all OGTT glucose values increased (for all values, p ≤ 0.028). At follow-up, 28.3% of patients had a normal glucose tolerance while 71.7% had abnormal glucose tolerance (AGT). AGT patients decreased their insulin sensitivity over time (p = 0.029) while it remained the same in NGT patients (p = 0.917). Conclusion:In older CF patients, the progression of impaired glucose tolerance is occurring with stable insulin secretion but reduced insulin sensitivity.

With improved life expectancy of cystic fibrosis (CF) patients, CF-related diabetes (CFRD) has become a major complication. The oral glucose tolerance test (OGTT) is the standard test to detect it. However, the use of OGTT is controversial, in addition to being a burden for patients and the treatment team. Research to find alternative ways of testing is ongoing. While some propose that glycated hemoglobin (HbA1c) may be an effective alternative, our past results suggest otherwise. A new analysis involving the OGTT and HbA1c values of 207 patients, between 2004 and 2015, proposes that the threshold of a lower value of HbA1c of ≥5.8%(39.9 mmol/mol) gives a sensitivity of 68.2% and a specificity of 60.5%. With such sensitivity to identify patients in need of an OGTT, 31.8% of CFRD diagnosis would be missed if the suggested HbA1c value of ≥5.8% was used as a screening tool to identify patients in need of OGTTs. Considering our results, we believe the HbA1c does not possess the characteristics of a suitable screening test for CFRD.

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