Nailfold Capillary Morphology as a Potential Biomarker of Cardiovascular or Metabolic Risk in Children Aged 3–17 Years Prenatally Exposed to Alcohol

BACKGROUND: Emerging evidence indicates that individuals with prenatal alcohol exposure (PAE) may be at risk for cardiometabolic dysfunction. Nailfold capillaroscopy (NFC) is a noninvasive method for visualizing microvascular dysfunction, which often precedes clinical disease. In this study, we examined whether children and adolescents with confirmed PAE differed in nailfold capillary morphology from unexposed peers. METHODS: We used a cross-sectional design to compare nailfold capillary morphology in children and adolescents aged 3-17 years with confirmed PAE versus no or minimal PAE, enrolled as part of a multi-site Collaborative Initiative on Fetal Alcohol Spectrum Disorders (CIFASD) study. Participants completed nailfold capillaroscopy using a high-resolution video microscope (Optilia Instruments). Quantitative measures included capillary density, average capillary width (μm), and average inter-capillary distance (μm). Morphological abnormalities (enlarged, branched, broken, crossed, and multi-crossed capillaries) were also assessed. Separate multivariable linear regression models were fit for each outcome, adjusting for child age and sex. RESULTS: The sample included 27 children with PAE (mean age = 8.3 ± 4.0 years; 52% male; 70% White; 66% Hispanic) and 10 with no/minimal PAE (mean age = 11.2 ± 4.7 years; 50% male; 70% White; 60% non-Hispanic). After adjusting for age and sex, participants with PAE showed lower capillary density (mean = 9.4 ± 2.6 vs. 13.2 ± 3.0; p < 0.001), greater average intercapillary distance (mean = 171.3 μm ± 28.9 vs. 136.6 μm ± 27.3; p < 0.01), greater average capillary width (mean = 43.9 μm ± 11.4 vs. 35.2 μm ± 6.1; p < 0.01), and a higher percentage of enlarged capillaries (mean = 71.4 ± 19.1 vs. 46.6 ± 13.8; p < 0.001) compared to controls. Age was negatively associated with density (p < 0.05), whereas the child's sex was associated with width (p < 0.01), with females exhibiting wider capillaries. CONCLUSION: These findings, to our knowledge, provide the first characterization of nailfold microvascular morphology in children and adolescents with PAE and support NFC as a potential early biomarker of cardiometabolic risk.