Can a blood test reveal your true age? russian study aims to find out

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Signing the informed consent form to participate in the study. Participant's age was 18 years or older at the time of inclusion in the study. \- Exclusion Criteria: 1. Refusal to participate in the study or to provide informed consent. 2. History or medical records indicating the presence of infectious diseases (Hepatitis C, Hepatitis B, including HBsAg carrier status, HIV infection). 3. Presence of an acute illness/condition, exacerbation of a chronic disease, or surgical intervention within the last month prior to study inclusion. 4. Lack of remission from an oncological disease or ongoing anti-tumor therapy initiated less than three years prior to study inclusion. 5. Severe cognitive or sensory impairments and mental disorders that, in the investigator's opinion, preclude adequate communication with the subject. 6. Severe forms of chronic non-communicable diseases: life-threatening cardiac arrhythmias, chronic heart failure NYHA Class III-IV, left ventricular ejection fraction \<40%, ischemic heart disease CCS Class III-IV, chronic kidney disease Stages 4-5, type 1 diabetes mellitus, type 2 diabetes mellitus with terminal stages of complications, systemic connective tissue diseases, chronic obstructive pulmonary disease with respiratory failure of Grade 1 or higher, bronchial asthma requiring glucocorticosteroid therapy, osteoarthritis Kellgren-Lawrence Grade IV, body mass index (BMI) ≥40 kg/m², as well as documented history of myocardial infarction (MI) or acute cerebrovascular accident (stroke). 7. Pregnancy or lactation (breastfeeding). 8. Any other factors that, in the investigator's opinion, may preclude the participant's inclusion in the study. Additional exclusion criteria for participants undergoing stool sample collection: 9. Use of systemic antibiotics for 3 or more days within the 3 months prior to the study start. 10. Any invasive procedures on the large intestine within the last 3 weeks prior to the study start.