Mediterranean diet adherence and microvascular function assessed by laser speckle contrast imaging: Pilot findings from the Semmelweis study

Abstract Microvascular dysfunction is an early and fundamental manifestation of vascular aging and contributes to the development of cardiovascular disease, stroke, and vascular cognitive impairment. Laser speckle contrast imaging (LSCI) enables non-invasive, real-time assessment of microvascular function and is well suited for large-scale cohort studies. However, determinants of microvascular function in population-based settings, including the influence of dietary patterns such as the Mediterranean diet, remain incompletely understood. We aimed to characterize microvascular function using LSCI and to examine its association with Mediterranean diet adherence in the Semmelweis Study, an occupational cohort study. This pilot analysis included 575 participants of the Semmelweis Study, a prospective workplace cohort investigating determinants of healthy aging in Hungary. Cutaneous microvascular function was assessed using LSCI during post-occlusive reactive hyperemia testing. Three parameters were derived: slope of the early reperfusion, time to maximal hyperemic perfusion, maximal perfusion relative to baseline, and hyperemia was also evaluated using the area under the hyperemic curve (AUC) compared to the baseline area. Mediterranean diet adherence was evaluated using a questionnaire customized to the Hungarian population and modified Mediterranean Diet Adherence Score (MEDAS) was calculated. Multiple linear regression models adjusted for demographic, lifestyle, and cardiometabolic disease covariates were used to assess associations. LSCI-based microvascular assessment was successfully implemented in all participants and revealed substantial inter-individual variability in microvascular function. Mediterranean diet adherence was not significantly associated with slope of hyperemia, time to maximal perfusion or magnitude of the hyperemic response after multivariable adjustment. These findings were consistent across all model specifications. In conclusion, this study demonstrates the feasibility and scalability of LSCI for non-invasive microvascular phenotyping in a large cohort. Although Mediterranean diet adherence was not associated with microvascular function in this pilot sample, the pronounced variability observed underscores the need to investigate the broader determinants and longitudinal implications of microvascular aging. Longitudinal analyses in the Semmelweis Study will help establish microvascular dysfunction as a biomarker and therapeutic target in vascular aging. Importantly, the non-invasive nature, reproducibility, and physiological sensitivity of LSCI support its potential utility as a surrogate endpoint in clinical and pharmacological intervention trials aimed at improving microvascular function and promoting vascular health.