Low Vitamin D Levels Linked to Reduced Heart Rate Variability in Elderly Diabetic Patients: Study

A new study published in the journal of Frontiers in Endocrinology revealed that low 25-hydroxyvitamin D [25-(OH)D] levels were linked to reduced heart rate variability in elderly diabetic patients. The study identifies key risk factors for reduced heart rate variability (HRV) in elderly diabetic individuals and suggests that 25-(OH)D levels may serve as an early predictive marker for HRV decline in this population.

In addition to posing serious risks to the physical and mental well-being of elderly people, this tendency places a heavy strain on healthcare systems, especially given the myriad difficulties linked to diabetes. Among these, diabetic cardiac autonomic neuropathy (DCAN), which damages the autonomic nerve fibers that innervate the heart and blood vessels, increases the risk of severe cardiovascular events in older diabetes patients. An essential non-invasive metric for evaluating cardiac autonomic function is heart rate variability (HRV), which measures the combined effect of the sympathetic and parasympathetic neural systems on cardiac function.

Vitamin D has emerged as a research hotspot in recent years, and the brain, heart, and blood vessels all contain large amounts of its receptors. Thus, this study assessed the predictive value of 25-hydroxyvitamin D [25-(OH)D] and investigate the risk variables for reduced heart rate variability in senior diabetes patients.

Nearly, 101 senior diabetes patients during 2023–2024 were included in a retrospective research at Anhui Medical University's First Affiliated Hospital. The patients were categorized according to their heart rate variability (HRV) using 24-hour Holter monitoring: normal HRV (standard deviation of all normal RR intervals {SDNN} 100–180 ms) and reduced HRV (SDNN < 100 ms).

Clinical and laboratory data were gathered, including metabolic parameters (e.g., FPG, HbA1c, lipids, renal indicators) and diabetes sequelae (diabetes peripheral neuropathy (DPN), diabetic peripheral vascular disease (DPVD), diabetic nephropathy (DN), and diabetic retinopathy (DR)). HRV risk variables were found using statistical tests (t-test, χ², Mann-Whitney U, and multivariate logistic regression). Their predictive value was assessed using ROC analysis.

The reduced HRV group showed increased prevalence of DN, considerably lower levels of HDL-C and 25-(OH)D, and raised levels of 24-hour urinary total protein (24hUTP), microalbuminuria (MAlb), urinary albumin-to-creatinine ratio (UACR), triglycerides (TG)/high-density lipoprotein cholesterol (HDL-C), and uric acid (UA),/HDL-C (all P < 0.05) in comparison to the normal HRV group. These elements were found to be independent risk factors for older diabetic individuals' decreased HRV. Overall, serum 25-(OH)D levels were lower in older diabetic individuals with decreased HRV than in those with normal HRV, indicating that 25-(OH)D might be a possible biomarker for HRV impairment. 

Source:

Tang, T., Sun, X., Zhang, X., Li, J., Wang, M., Hui, C., Cheng, Y., Kong, X., & Sun, Y. (2025). 25-hydroxyvitamin D as a predictor of reduced heart rate variability in elderly patients with diabetes mellitus. Frontiers in Endocrinology, 16, 1556345. https://doi.org/10.3389/fendo.2025.1556345