Metabolic syndrome and accompanying hyperinsulinemia have favorable effects on lower urinary tract symptoms in a generally healthy screened population.

Purpose: We assessed the association of metabolic syndrome, insulin resistance and lower urinary tract symptoms in a large, screened adult population.

Materials And Methods: We analyzed 33,841 Korean men 30 years old or older who underwent routine health assessments from October 2003 to February 2010. Metabolic syndrome was defined according to the modified Adult Treatment Panel III guidelines. Lower urinary tract symptoms were assessed using the International Prostate Symptom Score. Blood samples were drawn in the morning after patients had fasted at least 12 hours.

Results: Lower urinary tract symptoms had a marginally negative association with metabolic syndrome after adjusting for age (p = 0.045). This negative association became more significant as the number of metabolic syndrome components increased (p trend <0.01), especially voiding symptoms (p trend <0.01). Increasing the level of fasting insulin and the severity of insulin resistance were associated with a lower age adjusted OR for lower urinary tract symptoms (p <0.01 and 0.03, respectively). However, the diabetes group with high HbA1c (8.0% or greater) had a higher age adjusted OR for lower urinary tract symptoms, especially storage symptoms. The group with metabolic syndrome plus insulin resistance had lower total International Prostate Symptom Score, voiding symptoms, storage symptoms and quality of life scores than those without metabolic syndrome and/or insulin resistance (p <0.01, 0.01, 0.047 and 0.03, respectively).

Conclusions: Metabolic syndrome, insulin resistance and the accompanying hyperinsulinemia may have favorable effects on lower urinary tract symptoms in the early compensatory stage, especially voiding symptoms. However, advanced diabetes may have unfavorable effects on lower urinary tract symptoms, especially storage symptoms. Hyperinsulinemia in patients with metabolic syndrome or insulin resistance may be a key factor in this phenomenon.