Vitamin D insufficiency in infants with increased risk of developing type 1 diabetes: a secondary analysis of the POInT Study.

BACKGROUND: Vitamin D insufficiency (VDI) may be a factor in the development of type 1 diabetes (T1D). The aim of this study is to investigate the presence and persistence of VDI in a large cohort of infants with increased risk of developing T1D, in light of the differences in local supplementation guidelines. METHODS: In the POInT Study, a multicentre primary prevention study between February 2018 and March 2021 in Germany, Poland, Belgium, England and Sweden, including infants aged 4-7 months at high genetic risk of developing ß-cell autoantibodies, vitamin D levels were analysed at each study visit from inclusion (4-7 months) until 3 years, with an interval of 2 months (first three visits) or 4-6 months (visits 4-8). The protocol actively promotes vitamin D sufficiency to optimise immune tolerance. VDI was defined as a concentration below 30 ng/mL and was treated according to local guidelines of participating centres. Recovery from VDI was defined as a concentration above or equal to 30 ng/mL on the subsequent visit after VDI. RESULTS: 1050 infants were included, of which 5937 vitamin D levels were available for analyses. VDI was observed in 1464 (24.7%) visits and 507 (46.1%) of these were not resolved at the next visit. The risk of having VDI was independently associated with season (higher in winter), weight (higher with increased weight), age (higher with increased age) and country (higher in England). The risk of not recovering from VDI was independently associated with the season of the previously determined VDI, which was higher if VDI was identified in winter. CONCLUSIONS: VDI is frequent in infants with increased risk of developing T1D. Treatment guidelines for VDI do not seem effective. Increasing supplementation dosages in this patient population seems warranted, especially during winter, and increasing dosages more aggressively after VDI should be considered.

Prevalence of LDL-hypercholesterolemia and other cardiovascular risk factors in young people with type 1 diabetes.

BACKGROUND: Mortality and morbidity in people with Type 1 diabetes (T1D) is mainly caused by cardiovascular disease (CVD). Early treatment of cardiovascular risk factors (CVRFs) is of great importance. OBJECTIVE: To analyze the prevalence of LDL-hypercholesterolemia and other CVRFs in youth with T1D. METHODS: Clinical and laboratory parameters, and vascular thickness measurement were obtained in youth with T1D (age 6-18 years, T1D duration >1 year) attending a diabetes clinic. LDL-hypercholesterolemia, microalbuminuria and arterial hypertension were defined as CVRFs. RESULTS: A total of 333 youth (48% girls; age: 13.3 years [10.3-15.5], median [interquartile range]) participated in the study. The T1D duration was 5.9 years [3.5-9.4] with HbA1c of 7.4% [6.8-8.0]. Intima media thickness (N=223) was 538.0 µm [470.0-618.0]). LDL-hypercholesterolemia was present in 30 participants (9%; 18 girls; age: 14.3 years [11.2-15.7]). None of the participants had persistent microalbuminuria, although 59 (18.3%) had elevated albumin excretion in a random urine specimen. LDL-hypercholesterolemia was associated with increased blood pressure (p<0.05), insulin requirement (p<0.05), HbA1c (p<0.05), triglyceride (p<0.001) and total cholesterol (p<0.001), and a family history of premature CVD (p<0.001), but negatively correlated with HDL cholesterol levels (p<0.05). Sex, pubertal status, duration of diabetes, type of therapy, and physical activity did not differ between participants with and without LDL- hypercholesterolemia. Arterial hypertension was present in 11 participants (3.3%; 4 girls; age: 14.1 years [11.1-16.1]). CONCLUSION: LDL-hypercholesterolemia affected 9% of youth with T1D in this cohort and was associated with other CVRFs. A holistic therapeutic concept for these young people is essential.