Phase II Clinical Trial of Vitamin D3 for Reducing Recurrence of Recurrent Lower Urinary Tract Infections

Inclusion Criteria: 1. Male or female aged 18 to 75 years, including 18 and 75 years; 2. at least 3 episodes of lower urinary tract infection in the last 12 months or at least 2 episodes of lower urinary tract infection in the last 6 months; 3. The symptoms of the latest recurrence of lower urinary tract infection have disappeared after treatment, and the treatment dosage of antibiotics has been stopped, and at least one of the following two conditions has been met:A) The middle urinary bacterial culture is less than 10\^5 CFU/mL (accept the examination results after the last improvement);B) Urine white blood cell count is less than 5 /HP, and if it can be measured in routine urine examination, it should be less than 25 /μL; 4. Signed written informed consent; 5. Be able to follow the research protocol. Exclusion Criteria: 1. Complicated with cardio-cerebrovascular and hematopoietic system and other serious primary diseases; 2. Poor glycemic control (HbA1c \>7.5%) with diabetes; 3. Patients with genital tract malformation or acute genital tract infection and genital tract tumor; 4. Patients with urinary system tuberculosis and acute pyelonephritis; 5. Patients with cysto-ureteral reflux or urethral reflux; 6. Patients with polycystic kidney disease, neurogenic bladder, indwelling urethral catheterization, urinary tract stones, tumors or fibrous degeneration, etc., determined by the investigator as urinary tract obstruction; 7. Glomerular filtration rate (MDRD formula).20 mL/min/1.73m2, dialysis or kidney transplantation patients; 8. Chronic liver disease may have potential influence on liver function (bilirubin \>;1.5 times upper limit of normal value, aspartate aminotransferase or alanine aminotransferase \>2 times the upper limit of normal); 9. Patients with vitamin D3 contraindications, such as hypercalcemia, hypervitaminism, hyperphosphatemia with renal rickets, etc.; 10. Patients with diseases that affect the absorption of vitamin D3 in the small intestine, such as Crohn's disease; 11. receiving immunosuppressive agents or GT;10 mg/d glucocorticoids; 12. had received any other investigational drug therapy or participated in another interventional clinical trial within 30 days prior to screening; 13. Have a history of alcohol or drug abuse or suffer from mental illness; 14. Women of child-bearing age who have planned to become pregnant within 2 years (women of child-bearing age are defined as all women with physical ability to become pregnant), or women who are pregnant or lactating; 15. Circumstances in which subjects are judged by the investigator to be unsuitable for inclusion.