Male Nocturia Linked to Sodium Excretion Imbalance
Over 80 percent of patients also have nocturnal polyuria
THURSDAY, March 23 (HealthDay News) -- Men with nocturia are more likely than those without the condition to have nocturnal polyuria, which is due to a diurnal rhythm of sodium excretion that results in more dilute urine at night, according to a report in the March issue of Urology.
Alex Lin, M.D., from the National Yang-Ming University School of Medicine in Taipei, Taiwan, and colleagues conducted a prospective study using urinalysis, urodynamic studies, and polysomnography to determine the causes of nocturia in men. The study included 41 older men, average age of 72 years, with nocturia and 11 asymptomatic young men, average age 28 years, as controls.
Men with nocturia had about 3.9 micturitions per night, and 83 percent had nocturnal polyuria. Men without nocturnal polyuria excreted equal amounts of sodium during the day and night, and had higher nighttime urine osmolality than patients. Other factors in male nocturia were small nocturnal bladder capacity (24 of 41 patients), with or without detrusor overactivity, and bladder outlet obstruction (18 of 41).
"Our observations have shown that a significant contributor to male nocturia is nocturnal polyuria, which is due to a disordered diurnal rhythm of sodium excretion and other unknown factors causing nocturnal urinary dilution," the authors write. "However, male nocturia can also be due to a combination of factors."