{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T01:51:22Z","timestamp":1790214682606,"version":"4.1.0"},"reference-count":51,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2020,11,19]],"date-time":"2020-11-19T00:00:00Z","timestamp":1605744000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>Cardiovascular autonomic neuropathy (CAN) is associated with diabetes <jats:italic>mellitus<\/jats:italic>, increasing morbidity and mortality. Some cross-sectional studies associated CAN with low <jats:italic>25-hydroxyvitamin D<\/jats:italic> levels. The aim of our study was to evaluate the effect of high-dose vitamin D (VD) supplementation on CAN in Type 1 Diabetes Mellitus (T1DM)\u00a0patients.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>We performed a prospective study with 23 patients diagnosed with T1DM and CAN. Subjects with VD levels &amp;lt;30 ng\/ml received 10,000 IU\/day; the ones with VD levels between 30\u201360 ng\/ml were given 4,000 IU\/day for 12 weeks.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>There was an improvement in CAN parameters related to resting heart rate variability, such as time domain parameters [Maximum RR interval (0.77 \u00b1 0.11 vs 0.94 \u00b1 0.51 s, p &amp;lt;0.05), Mean length of regular RR intervals (0.71 \u00b1 0.10 vs 0.76 \u00b1 0.09 s, p &amp;lt;0.05) and Standard deviation of all NN intervals (0.02 \u00b1 0.01 vs 0.03 \u00b1 0.02 s; p &amp;lt;0.01)] and frequency domain parameters [Low Frequency (1.9 \u00b1 0.5 vs 2.5 \u00b1 0.9 s, p &amp;lt; 0.001), Total Power (2.5 \u00b1 0.4 vs 2.8 \u00b1 0.6 s, p &amp;lt;0.05)]. In addition, there was a correlation between absolute VD level variation and posttreatment High Frequency (%), as well as among percent variation in VD level and end-of-study Low Frequency\/High Frequency ratio (r=0.6, p&amp;lt;0.01; r= -0.5, p&amp;lt;0.05, respectively).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Our pilot study is the first to suggest a strong association between high-dose vitamin D supplementation and improved cardiovascular autonomic neuropathy in T1DM patients. It occurred without any variation in HbA1C, blood pressure levels, lipids, and insulin dose.<\/jats:p><\/jats:sec><jats:sec><jats:title>Clinical Trial Registration<\/jats:title><jats:p><jats:uri>http:\/\/www.isrctn.com\/ISRCTN32601947<\/jats:uri>, identifier ISRCTN32601947.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fendo.2020.605681","type":"journal-article","created":{"date-parts":[[2020,11,19]],"date-time":"2020-11-19T08:13:22Z","timestamp":1605773602000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":15,"title":["Improvement in Cardiovascular Autonomic Neuropathy After High-Dose Vitamin D Supplementation in Patients With Type 1 Diabetes"],"prefix":"10.3389","volume":"11","author":[{"given":"Lilian de Souza D\u2019Albuquerque","family":"Silva","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nat\u00e9rcia Neves Marques","family":"de 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