What is the precursor of sweet-smelling urine?

　　Sweet-smelling urine may be a precursor to conditions such as elevated blood glucose, kidney disease, or gestational diabetes.

　　1. Elevated Blood Glucose

　　When blood glucose levels rise, glucose in the urine passes through the kidney's filtration system and enters the renal tubules. The renal tubules actively reabsorb glucose, but only up to a certain capacity. If the glucose concentration in the urine is too high, the kidneys cannot fully reabsorb it, resulting in glucose-containing (sweet) urine. Treatment may include antidiabetic medications such as metformin tablets, repaglinide tablets, or acarbose tablets, taken as directed by a physician.

　　2. Kidney Disease

　　Kidney diseases—including familial diabetes, chronic nephritis, nephrotic syndrome, and neonatal diabetes—can lower the renal threshold for glucose and impair the tubules' ability to reabsorb glucose. As a result, excess glucose is excreted in the urine, leading to sweet-smelling urine. Treatment may involve medications such as captopril tablets, irbesartan tablets, or hydrochlorothiazide tablets, used under medical supervision.

　　3. Gestational Diabetes

　　Sweet-smelling urine may also result from gestational diabetes. During pregnancy, approximately 10%–15% of women develop diabetes due to transiently elevated blood glucose levels, typically in the second and third trimesters. A balanced and varied diet is recommended in daily life. Individuals with severe symptoms should seek medical attention promptly.

　　Additionally, sweet-smelling urine could be caused by Fanconi syndrome. Patients are advised to engage in moderate physical activity such as walking, yoga, or jogging, ensure adequate rest, and avoid excessive fatigue.