The Impact of Nicotinamide Mononucleotide Sustained-release Tablets on Immunosenescence and Metablism in Middle-aged and Elderly Individuals With Metabolic Disorders.

Inclusion Criteria: 1. Age 50-70 years with overweight or obesity (BMI 24kg/m2); 2. At least one of the following three: metabolism-related fatty liver disease (diagnosed by ultrasound); pre-diabetes; type 2 diabetes mellitus with HbA1c \<7% without glucose-lowering drug therapy; 3. Agreed to participate in the trial and could adhere to the follow-up and visit the hospital on their own; signed the informed consent form. Exclusion Criteria: 1. Patients with tumours; 2. Patients with autoimmune diseases (excluding Hashimoto's thyroiditis); 3. Severe cardiovascular disease or cardiac insufficiency; 4. Systolic blood pressure \> 160 mmHg or diastolic blood pressure \> 100 mmHg; 5. Chronic obstructive pulmonary disease; 6. Chronic active hepatitis or cirrhosis; 7. Chronic renal insufficiency; 8. Stroke patients 9. Severe haematological diseases; 10. Infectious diseases; 11. Mental illness; 12. Other conditions that, in the opinion of the investigator, may affect the results of the study; 13. Those who have used NMN or other anti-aging agents within six months. 14. Premenopausal woman 15. ALT, AST values are more than three times higher than the upper limit of the normal reference range