To investigate the impact of metabolic syndrome on lower urinary tract symptoms in a sample of middle-aged men receiving a health checkup.

Subjects aged 45 years or older who voluntarily underwent a medical checkup were enrolled. Participant demographics and health history were collected by a self-administered questionnaire. All participants were stratified into 2 groups by the presence of metabolic syndrome, as defined according to the updated National Cholesterol Education Program's Adult Treatment Panel III. Prostate volume and prostate-specific antigen levels were used for subgroup analysis.

During January through December of 2010, 708 subjects with a mean age of 55.6 ± 9.72 years were enrolled into the study. Compared to the nonmetabolic syndrome group, the metabolic syndrome group had lower total international prostatic symptoms score (7.89 ± 6.63 vs 6.85 ± 6.52, P = .05) and lower severity of weak urinary stream (1.24 ± 1.60 vs 0.95 ± 1.50, P = .021). In the higher prostate volume group (prostate volume ≥30 mL), total international prostatic symptoms score, storage score, and urinary frequency, urgency and incomplete emptying were lower in men vs those without metabolic syndrome (all P < .05). The negative association between voiding score, severity of lower urinary tract symptoms, and metabolic syndrome became particularly pronounced as the number of metabolic syndrome factors increased (P for trend < .01).

We confirmed that metabolic syndrome had favorable effects on lower urinary tract symptoms, including voiding and storage symptoms in healthy middle-aged men. This beneficial effect was most significant in men with enlarged prostate and/or high prostate specific antigen levels.