AUTHOR=Silva Lilian de Souza D’Albuquerque , de Queiroz Natércia Neves Marques , de Melo Franciane Trindade Cunha , Abrahão Neto João Felício , Janaú Luísa Corrêa , de Souza Neto Norberto Jorge Kzan , de Lemos Manuela Nascimento , de Oliveira Maria Clara Neres Iunes , de Alcântara Angélica Leite , de Moraes Lorena Vilhena , da Silva Wanderson Maia , de Souza Ícaro José Araújo , Said Nivin Mazen , de Lemos Gabriela Nascimento , Felício Karem Miléo , Santos Márcia Costa dos , Motta Ana Regina Bastos , dos Reis Melissa de Sá Oliveira , Lobato Isabel Jane Campos , de Figueiredo Priscila Boaventura Barbosa , de Souza Ana Carolina Contente Braga , Piani Pedro Paulo Freire , Felício João Soares TITLE=Improvement in Cardiovascular Autonomic Neuropathy After High-Dose Vitamin D Supplementation in Patients With Type 1 Diabetes JOURNAL=Frontiers in Endocrinology VOLUME=11 YEAR=2020 URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2020.605681 DOI=10.3389/fendo.2020.605681 ISSN=1664-2392 ABSTRACT=Background

Cardiovascular autonomic neuropathy (CAN) is associated with diabetes mellitus, increasing morbidity and mortality. Some cross-sectional studies associated CAN with low 25-hydroxyvitamin D 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) patients.

Methods

We performed a prospective study with 23 patients diagnosed with T1DM and CAN. Subjects with VD levels <30 ng/ml received 10,000 IU/day; the ones with VD levels between 30–60 ng/ml were given 4,000 IU/day for 12 weeks.

Results

There was an improvement in CAN parameters related to resting heart rate variability, such as time domain parameters [Maximum RR interval (0.77 ± 0.11 vs 0.94 ± 0.51 s, p <0.05), Mean length of regular RR intervals (0.71 ± 0.10 vs 0.76 ± 0.09 s, p <0.05) and Standard deviation of all NN intervals (0.02 ± 0.01 vs 0.03 ± 0.02 s; p <0.01)] and frequency domain parameters [Low Frequency (1.9 ± 0.5 vs 2.5 ± 0.9 s, p < 0.001), Total Power (2.5 ± 0.4 vs 2.8 ± 0.6 s, p <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<0.01; r= -0.5, p<0.05, respectively).

Conclusion

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.

Clinical Trial Registration

http://www.isrctn.com/ISRCTN32601947, identifier ISRCTN32601947.