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Cited by 1Vitamin D Research StudiesCardiovascular Effects of ExerciseSports injuries and prevention

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The decline of vitamin D in adolescent athletes: insights from a one-year follow-up and its association with electrocardiographic changes

Open access
Ramadan, Mahmoud Mohammed, Jaber, Abdallah A., Aladwani, Ahmad J., Alayyaf, Abdulrahman E., Sayed-Noor, Arkan Sam, Ghanem, Heba Bassiony, El-Sherbiny, Mohamed, Ebrahim, Hasnaa Ali, Ahmed, Mona Mohamed, Elsherbini, Dalia Mahmoud Abdelmonem·2025·Frontiers in Cardiovascular Medicine

Abstract

Introduction: Annual health evaluations are essential for athletes to ensure fitness for competition and enable the early detection of emerging health issues. Aim: This research aimed to evaluate the longitudinal variations in vitamin D concentrations and associated physical and laboratory parameters among adolescent athletes, as well as to investigate their correlation with electrocardiographic (ECG) alterations following a one-year follow-up period. Subjects and methods: This prospective observational cohort study examined 93 adolescent male athletes (aged 11.6 ± 1.15 years, range 10–14) who underwent baseline health evaluations, including physical examination, laboratory tests [25(OH) vitamin D, parathyroid hormone, and muscle enzyme assays], and cardiovascular (CV) assessment with electrocardiography (ECG). Only patients with normal CV findings were included. Follow-ups were performed after one year. Results: At follow-up, weight, height, and muscle mass increased significantly, whereas fat mass and systolic pressure decreased. Vitamin D levels declined (21.9 ± 10.8 vs. 29.8 ± 8.6 ng/mL; p < 0.001), with compensatory rise in parathyroid hormone (38.8 ± 2.7 vs. 33.9 ± 1.6 pg/mL; p < 0.001). Among vitamin D-deficient athletes ( n = 79), ECG changes occurred in 26.6%, mainly sinus arrhythmia (15/79, 19%) and T-wave inversion (13/79, 16%). Vitamin D deficiency was associated with higher odds of T-wave inversion (OR 4.53; 95% CI 1.11–18.40; p = 0.035) and increased prevalence of U-wave and incomplete right bundle branch block. Conclusions: The drop in vitamin D levels over one year raises concerns, highlighting the need for monitoring and interventions due to vitamin D's role in musculoskeletal and CV health. Regular monitoring and preventive strategies are recommended to maintain optimal vitamin D levels and CV health among young athletes.

Overview

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TL;DR

In 93 adolescent male athletes followed for one year, serum vitamin D declined from 29.8 ± 8.6 to 21.9 ± 10.8 ng/mL and PTH rose, while several ECG changes were more prevalent among vitamin D-deficient athletes. Vitamin D deficiency was associated with higher odds of T-wave inversion, though causality was not established.

Key findings

  • Vitamin D decreased significantly over one year (29.8 ± 8.6 to 21.9 ± 10.8 ng/mL; p < 0.001), a 27% reduction, with a compensatory PTH increase (33.9 ± 1.6 to 38.8 ± 2.7 pg/mL; p < 0.001).
  • Anthropometric changes included increased weight (40.2 ± 6.8 to 42.7 ± 9.2 kg; p = 0.036), height (151.4 ± 9.2 to 155.4 ± 12.1 cm; p = 0.012), and skeletal muscle mass (16.6 ± 1.4 to 17.2 ± 1.6 kg; p = 0.008), plus decreased fat mass (9.4 ± 0.7 to 8.8 ± 0.8 kg; p < 0.001) and systolic blood pressure (113.3 ± 9.7 to 109.3 ± 11.4 mmHg; p = 0.011).
  • Among vitamin D-deficient athletes (n = 79), ECG changes occurred in 26.6%, mainly sinus arrhythmia (15/79, 19%) and T-wave inversion (13/79, 16%). Deficiency was associated with higher odds of T-wave inversion (OR 4.53; 95% CI 1.11–18.40; p = 0.035), with trends for RVCD/incomplete RBBB (OR 8.93; p = 0.082) and U-wave (OR 10.60; p = 0.061).
  • T-wave axis decreased significantly (40.5 ± 7.7° to 38.2 ± 6.4°; p = 0.028); other ECG parameters did not differ significantly. Vitamin D correlated positively with calcium (r = 0.429; p < 0.001) and phosphorus (r = 0.408; p < 0.001), and negatively with PTH (r = −0.215; p = 0.039).

Methods

  • Prospective observational cohort study of 93 adolescent male athletes aged 10–14 years (mean 11.6 ± 1.15 years), recruited from local sports clubs in Japan, with baseline and one-year follow-up assessments; athletes with chronic illness, cardiovascular abnormalities, or prior vitamin D supplementation were excluded.
  • Assessments included physical examination with anthropometrics and blood pressure, fasting laboratory tests for 25(OH) vitamin D, PTH, TSH, ferritin, calcium, phosphorus, muscle enzymes (CK, LDH), and CBC, plus standard 12-lead ECG interpreted by two blinded pediatric cardiologists with a senior electrophysiologist resolving disagreements.
  • Statistical analysis used paired t-tests, chi-square/Fisher’s exact tests, Pearson correlation, linear and logistic regression, ROC curves with Youden’s J, and Firth’s penalized logistic regression for sparse ECG subgroups; power analysis indicated ≥84 participants needed for a medium effect size (d = 0.3).

Limitations

  • Stated: the sample was exclusively adolescent male athletes, excluding females and adults; the one-year follow-up was insufficient for long-term effects; no quantitative data on training schedule, sun exposure, or extravascular vitamin D stores were available; lifestyle and genetic confounders were uncontrolled; ECG subgroup analyses were exploratory and limited by small cell counts, prompting Firth’s penalized logistic regression.
  • Evident from the text: the study was a single cohort without a non-athlete or supplemented control group, and the conclusion notes that vitamin D deficiency was associated with ECG changes but was “not proven to cause these changes.”

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Integrity signals

Registry

Crossref · 10.3389/fcvm.2025.1731919

Cites

37 of 37 references verified0 citation errors · 0 not checkable

Statistics

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Figures

Figure 1 Receiver operating characteristic (ROC) curves of anthropometric variables (body mass index, skeletal muscle mass, and fat mass) for predicting a decline in serum 25-hydroxyvitamin D [25(OH)D] levels after one-year follow-up. The diagonal dashed line represents the line of no discrimination (AUC = 0.5). The corresponding area-under-the-curve (AUC) values were: body mass index = 0.59 (95% CI: 0.42–0.78), skeletal muscle mass = 0.55 (95% CI: 0.37–0.72), and fat mass = 0.54 (95% CI: 0.36–0.70); all non-significant (p > 0.05).
Figure 1 Receiver operating characteristic (ROC) curves of anthropometric variables (body mass index, skeletal muscle mass, and fat mass) for predicting a decline in serum 25-hydroxyvitamin D [25(OH)D] levels after one-year follow-up. The diagonal dashed line represents the line of no discrimination (AUC = 0.5). The corresponding area-under-the-curve (AUC) values were: body mass index = 0.59 (95% CI: 0.42–0.78), skeletal muscle mass = 0.55 (95% CI: 0.37–0.72), and fat mass = 0.54 (95% CI: 0.36–0.70); all non-significant (p > 0.05).CC BY · PubMed Central

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Metadata

Authors
Ramadan, M. M., Jaber, A. A., Aladwani, A. J., Alayyaf, A. E., Sayed-Noor, A. S., Ghanem, H. B., El-Sherbiny, M., Ebrahim, H. A., Ahmed, M. M., & Elsherbini, D. M. A.
Affiliations
  • Mansoura University (EG)
  • University of Sharjah (AE)
  • Jouf University (SA)
  • Princess Nourah bint Abdulrahman University (SA)
  • Cairo University (EG)
Corresponding author
  • Ramadan, Mahmoud Mohammed
  • Elsherbini, Dalia Mahmoud Abdelmonem
Venue
Frontiers in Cardiovascular Medicine
Published
2025-12-08
Volume
12
Pages
1731919-1731919
ISSN
2297-055X (ISSN-L)
OpenAlex
W4417103103
Cited by
1
References
37
Citations by year
2026: 1
FWCI
0.51
Type
journal article
Language
en
Open access
Locations
  • Frontiers in Cardiovascular Medicine (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
Funders
  • AlMaarefa University
  • Princess Nourah Bint Abdulrahman University
Topics
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Vitamin D Research Studies
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Cardiovascular Effects of Exercise
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports injuries and prevention
Keywords
vitamin D deficiency, youth athletes, electrocardiographic changes, T-wave inversion, sinus arrhythmia, parathyroid hormone, right bundle branch block, U wave, cardiovascular health, longitudinal follow-up, anthropometric changes

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