LDL cholesterol level as a risk factor for retinopathy and nephropathy in children and adults with type 1 diabetes mellitus: A nationwide cohort study.

BACKGROUND: Microvascular complications are common in people with diabetes, where poor glycaemic control is the major contributor. The aim of this study was to explore the association between elevated LDL cholesterol levels and the risk of retinopathy or nephropathy in young individuals with type 1 diabetes. METHODS: This was a nationwide observational population-based cohort study, including all children and adults with a duration of type 1 diabetes of ≤ 10 years, identified in the Swedish National Diabetes Register between 1998 and 2017. We calculated the crude incidence rates with 95% confidence intervals (CIs) and used multivariable Cox regression to estimate crude and adjusted hazard ratios (HRs) of retinopathy or nephropathy in four LDL cholesterol categories: <2.6 (Reference), 2.6-3.4, 3.4-4.1 and > 4.1 mmol L-1 . RESULTS: In total, 11 024/12 350 (retinopathy/nephropathy, both cohorts, respectively) children and adults (median age 21 years, female 42%) were followed up to 28 years from diagnosis until end of study. Median duration of diabetes when entering the study was 6 and 7 years in the retinopathy and nephropathy cohort, respectively. Median LDL cholesterol was 2.4 mmol L-1 , and median HbA1c level was 61 mmol mol-1 (7.7 %). After multivariable adjustment, the HRs (95% CI) for retinopathy in individuals with LDL cholesterol levels of 2.6-3.4, 3.4-4.1 or > 4.1 mmol L-1 were as follows: 1.13 (1.03-1.23), 1.16 (1.02-1.32) and 1.18 (0.99-1.41), compared with the reference. The corresponding numbers for nephropathy were as follows: 1.15 (0.96-1.32), 1.30 (1.03-1.65) and 1.41 (1.06-1.89). CONCLUSIONS: Young individuals with type 1 diabetes exposed to high LDL cholesterol levels have an increased risk of retinopathy and nephropathy independent of glycaemia and other identified risk factors for vascular complications.

Earlier intensified insulin treatment of Type 1 diabetes and its association with long-term macrovascular and renal complications.

AIMS: To investigate the incidence of all-cause mortality, composite mortality and morbidity in people with Type 1 diabetes formerly randomized in the Stockholm Diabetes Intervention Study. METHODS: A total of 102 people with Type 1 diabetes were randomized in the period 1982-1984 to intensified conventional treatment or standard treatment with insulin for a mean of 7.5 years. We prospectively re-evaluated this cohort for the period until 2011 with regard to all-cause mortality and composite mortality, which consisted of myocardial infarction, stroke and end-stage renal disease as primary endpoints. Secondary endpoints were first-time hospitalization for myocardial infarction and stroke or end-stage renal disease. Data on HbA1c levels (mean of 22 values/person) were retrospectively collected between 1996 and 2011. RESULTS: During the median follow-up of 28 years, 22 people died: seven in the intensified conventional insulin group compared with 15 in the standard treatment group (P = 0.30). With regard to composite mortality, six people in the intensified conventional insulin group died compared with 11 in the standard treatment group (P = 0.56). For the secondary endpoints, 11 people in the intensified conventional insulin group developed myocardial infarction or stroke compared with 17 in the standard treatment group (P = 0.72), and one person in the intensified conventional insulin compared with seven people in the standard treatment group developed end-stage renal disease (P = 0.09). Mean HbA1c levels did not differ between groups during the follow-up years. CONCLUSIONS: All-cause mortality, cardiovascular morbidity and progression to end-stage renal disease did not differ in people with Type 1 diabetes earlier randomized to intensified insulin treatment.