Noise and/or Ultrafine Particulate Matter Induced Cerebral and Cardiovascular Damage: Experimental and Epidemiological Studies (MARKOPOLO) and Lifestyle Intervention to Attenuate Cardiovascular Health Risk (METSGREEN)

The METSGREEN study is a hybrid biomedical research project combining an observational environmental-epidemiological study with an experimental clinical trial of healthy behavior. It is implemented under the international MARKOPOLO project framework, funded by the European Commission through the Horizon Europe program. The study is led in Lithuania by Vytautas Magnus University (VMU), with contributions from 15 academic institutions across Europe and North America. METSGREEN aims to explore the impact of ultrafine particulate matter (PM0.1) and noise exposure on cardiometabolic health in middle-aged urban populations and assess whether targeted lifestyle interventions can mitigate these effects.

Scientific Background and Rationale: Environmental pollution is increasingly recognized as a major contributor to chronic non-communicable diseases. Ultrafine particles (diameter <0.1 µm) are especially harmful due to their ability to penetrate deep into the respiratory tract, cross alveolar membranes, and enter systemic circulation. These particles trigger oxidative stress, systemic inflammation, endothelial dysfunction, and coagulation disorder processes implicated in the pathogenesis of metabolic syndrome and cardiovascular diseases (CVD). Epidemiological studies suggest a strong link between long-term exposure to PM0.1 and increased incidence of hypertension, diabetes, central obesity, and other metabolic risk factors. Moreover, urban noise exposure has been shown to exacerbate cardiovascular risks through stress-mediated neuroendocrine pathways. However, many of these associations remain insufficiently understood, particularly in populations with specific vulnerabilities, such as older age or lower socioeconomic status.

Nature-based interventions such as physical activity in green spaces are a promising strategy to counteract these effects. Regular exposure to nature has been shown to improve autonomic nervous system balance, reduce cortisol levels, and promote cardiovascular resilience. Dietary interventions, particularly the Mediterranean diet, rich in unsaturated fats, antioxidants, and anti-inflammatory nutrients, are also recognized for their cardioprotective effects. Despite this, very few studies integrate objective environmental exposure assessments with clinical lifestyle interventions and biomarker-based outcomes.

Study Objectives: The study is divided into two core components with distinct but complementary objectives:

1. Observational Study (n = 1,000): Model and map environmental exposure to PM0.1 and noise across Kaunas city using land-use regression (LUR) based on data collected at 20 strategic locations. Link environmental exposure estimates to self-reported health status, lifestyle factors, and socioeconomic characteristics using a standardized, anonymized online questionnaire. Assess associations between PM0.1/noise exposure and key cardiometabolic indicators: prevalence of cardiovascular disease, blood pressure, waist circumference, and anthropometric data. Investigate potential effect modifiers such as sex, age, residential environment, and economic status.
2. Experimental Clinical Trial (n = 180): Assess the short-term impact of a healthy lifestyle intervention on metabolic health indicators and biological markers in individuals with early signs of metabolic syndrome (central obesity and/or elevated blood pressure). Compare three groups (1:1:1 allocation): control (no intervention), physical activity in green space (daily 30-minute brisk walk), and Mediterranean diet intervention (dietary counselling and meal planning). Evaluate changes in biological markers (HDL, triglycerides, fasting glucose, body composition, blood pressure, etc.) and omics-level indicators (metabolomics, proteomics, DNA methylation). Determine the interaction between environmental exposure levels and response to lifestyle changes.