Aims of the Study: 

This study was conducted to determine the prevalence of nocturia (frequent nighttime urination) among the adult U.S. population, a bothersome condition thought to cause disruption of sleeping patterns that impacts the quality of life of those who awaken to urinate at night.  In this study, nocturia was defined as getting up specifically to urinate at least 2 or more times a night or 15 or more times a week, a definition consistent with that of numerous clinical trials.  The study also sought to identify gender differences, age cohorts most likely to be affected, and the likelihood of seeking treatment. 

 

Methods: 

The study, conducted between December 1999 and January 2000, involved a national telephone survey employing random digit dialling.  Using advanced probability sampling techniques, subjects were asked questions regarding the frequency of nighttime urination, the impact of nocturia on daily life, and how bothersome they found this condition.  Completed interviews were weighted by four variables to ensure a reliable and accurate representation of the total population, 18 years and older:  age, gender, geographic region, and race. 

 

Results: 

In total, 7,070 adults over the age of 18 (3,527 men; 3,543 women) were surveyed about the frequency of nighttime urination.  Of those surveyed, 49% reported they do not get up at night to urinate and 49% reported that they do. In subjects who reported they do get up to urinate, 21% met the criteria for nocturia (getting up 2 or more times a night or 15 or more times a week).  The average length of time subjects had suffered from frequent nighttime urination was 6.5 years.

 

Age appears to be a significant factor in nocturia.  In the study, 47.4% of those with nocturia were over the age of 45.  Although prevalence increased with age, frequent nighttime urination was found to be most bothersome for adults in the middle age cohorts, with 34% of those ages 45–54 and 31% of those ages 55-64 rating nocturia as extremely bothersome.  Gender also appears to be a key factor in nocturia.  The study revealed a greater proportion of women are affected than men (59% vs. 41%).  Women reported finding nocturia more bothersome than did men, with 33% rating it as extremely bothersome as opposed to 20% of men rating it so.  Across all age cohorts, loss of sleep appears to be the major consequence of nocturia—the mean hours of sleep lost per night being 1 hour.  However, the middle-age cohorts reported being more affected by sleep loss, with 18% ages 45–54 and 15% ages 55–64 reporting sleep loss due to nocturia seriously impacted their daytime activities. Women appear to be more affected by lost sleep than are men.  In the study, 14% reported a significant impact on their daily lives vs. 8% of men.  Finally, the likelihood of consulting a physician and taking a medication for nocturia increased with age, with those over 45 being most likely to do so. 

 

Conclusions: 

Nighttime urination is a problem for nearly half of the adult U.S. population.  The study indicates 99.8 million people get up at night to urinate, and 21 million of those get up 2 or more times a night or 15 or more times a week.  Despite the fact that nocturia is most prevalent in those over age 65, it is most bothersome for those ages 45–64.  This age cohort also tends to be most affected by the resulting sleep loss.  Significantly, nocturia is more prevalent in women and is more bothersome to them than it is to men.  Women also tend to be more affected by loss of sleep in their daily quality of life.  Finally, while the mean length of time most adults have experienced frequent nighttime urination is 6.5 years, only half of sufferers have discussed the problem with a physician.  Based on the results of this study, nocturia is a very common condition among adults, yet remains largely underdiagnosed and undertreated.  More education, as well as additional research, needs to be initiated to increase awareness of nocturia and its potential consequences on sleep patterns and quality of life.  (Sponsored by Aventis Pharmaceuticals.)