SAN FRANCISCO—Nocturia, defined as two or more urinations per night, is associated with an increased risk of death, even after adjusting for comorbidities known to increase mortality, according to two new studies presented at the American Urological Association annual meeting.

The first study, conducted by researchers at the New England Research Institutes (NERI) in Watertown, Mass., showed that even after adjusting for recognized co-morbidities associated with nighttime voiding, both men and women with nocturia are at increased risk of mortality compared with those without the condition. The findings emerged from an analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III, conducted between 1988 and 1994). 

Overall, nocturia in men and women was associated with a 1.49 and 1.32 times increased risk of death, after adjusting for age, BMI, marital status, education, smoking, cardiovascular disease, diabetes, hypertension and other potential confounders.

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Among men aged 20-49 and 50-64 years, nocturia was associated with a 2.56 and 1.60 times increased risk of death. Men aged 65-90 had a 1.35 increased risk. Nocturia in women aged 20-49 and 50-64 years was associated with a 1.10 and 1.94 increased risk of death, respectively. Women aged 65-90 with nocturia had a 1.19 increased risk.

Lead investigator Varant Kupelian, PhD, a research scientist at NERI, said one hypothesized mechanism of action relates to sleep deprivation. “We know nocturia causes sleep deprivation, which in turn has been shown to have adverse effects on metabolic function and endocrine function leading to obesity and type 2 diabetes, which in turn increase mortality risk,” Dr. Kupelian said. “So, the results from this study suggest that nocturia may be a marker of overall health.”

The second study, led by Haruo Nakagawa, MD, of Tohoku Graduate School of Medicine in Sendai, Japan, was a population-based, cross-sectional survey of 788 subjects living in an urban district of north Japan. The study demonstrated that as nighttime urination in the elderly becomes more frequent, the risk of mortality increases, even after adjusting for factors known to influence mortality risk.

Compared with individuals who voided once or not at all at night, those who voided two, three, and four times a night had a 1.59, 2.34, and 3.60 times increased risk of death, respectively.

The subjects ranged in age between 70 and 97 years (mean 74.9 years). The group consisted of 429 women and 359 men.

Commenting on the new studies, Jeffrey Weiss, MD, Professor of Urology at the State University of New York Downstate Medical School in Brooklyn, N.Y., observed: “Nocturia can negatively impact a person’s overall health due to frequent nighttime visits to the bathroom that may result in fatigue as a result of interrupted sleep, as well as falls. This common condition is often under-diagnosed and misunderstood by the medical community and should be taken more seriously.”