Nailfold Capillaroscopy and Endothelial Biomarkers in Healthcare Workers Exposed to Chronic Low-Dose Ionizing Radiation

Chronic occupational exposure to low-dose ionizing radiation may result in subclinical endothelial dysfunction and early microvascular alterations, even in the absence of overt clinical disease. Healthcare workers employed in medical departments where ionizing radiation is routinely used are exposed to cumulative radiation over time. Identifying early vascular changes in this population is important for understanding potential long-term cardiovascular risks associated with occupational radiation exposure.

Nailfold capillaroscopy is a non-invasive and reproducible imaging technique that enables direct visualization of the microcirculation and allows detailed assessment of capillary density, morphology, and structural abnormalities. Additionally, circulating endothelial and inflammatory biomarkers such as asymmetric dimethylarginine (ADMA), von Willebrand factor (vWF), high-sensitivity C-reactive protein (hs-CRP), and D-dimer may reflect endothelial dysfunction, inflammation, and prothrombotic activity at a subclinical level.

This single-center, observational, cross-sectional study will include healthcare workers with chronic occupational exposure to low-dose ionizing radiation and a control group of healthcare workers without radiation exposure from the same institution. Demographic characteristics, occupational exposure duration, and work-related radiation exposure history will be recorded for all participants.

All participants will undergo nailfold capillaroscopy evaluation using standardized assessment criteria, including capillary density, tortuosity, dilatation, dystrophic changes, avascular areas, microhemorrhages, neoangiogenesis, and subpapillary plexus visibility. Venous blood samples will be collected to measure serum ADMA, vWF, hs-CRP, and D-dimer levels using routine laboratory methods and enzyme-linked immunosorbent assay techniques, as appropriate.

The primary objective of this study is to identify microvascular changes detected by nailfold capillaroscopy in healthcare workers exposed to chronic low-dose ionizing radiation. Secondary objectives include evaluating the association between capillaroscopic findings, serum biomarkers, and occupational radiation exposure characteristics. The findings of this study may contribute to improved understanding of early vascular effects of chronic occupational radiation exposure and support the use of nailfold capillaroscopy as a practical screening tool in exposed populations.

Inclusion criteria

• Healthcare workers aged between 18 and 60 years.
• For the control group: Employment in a healthcare institution with either occupational exposure to low-dose ionizing radiation or no occupational radiation exposure.
• For the exposed group: chronic occupational exposure to ionizing radiation for at least 3 years.
• Willingness and ability to provide written informed consent.
• Ability to comply with study procedures, including nailfold capillaroscopy and blood sample collection.

Exclusion criteria

• History of cardiovascular disease, cerebrovascular disease, or peripheral vascular disease.
• Presence of systemic diseases that may affect microvascular structure or endothelial function, including diabetes mellitus, uncontrolled hypertension, dyslipidemia, or chronic kidney disease.
• Known autoimmune, connective tissue, or systemic inflammatory diseases (e.g., systemic sclerosis, lupus erythematosus, vasculitis).
• Active infection or acute inflammatory condition at the time of enrollment.
• Use of systemic medications that may affect endothelial function or microcirculation within the past 4 weeks, including vasodilators, antihypertensive agents, statins, antiplatelet or anticoagulant drugs.
• Current smoking or history of smoking within the past 6 months.
• Pregnancy or breastfeeding.
• History of malignancy or current cancer treatment.
• Previous finger trauma, surgery, or local conditions affecting the nailfold area that may interfere with capillaroscopic evaluation.