Descriptive Epidemiology

The majority of population-based epidemiology studies that evaluated LUTS among men were designed to report prevalence and not incidence of these symptoms. Most of these studies admin-istered the International Prostate Symptom Score (IPSS) questionnaire to assess the prevalence of seven common LUTS. While, these studies describe proportions of individuals with moderate to severe symptoms (IPSS >7 points), they do not convey the prevalence of each individual LUTS, nor do they evaluate a wider spectrum of LUTS that includes all storage, voiding, and post-micturition symptoms.

Studies have shown that moderate (IPSS 8–19 points) to severe (IPSS >19 points) LUTS has a preva-lence ranging from 16% to 52% (5–15). These studies demonstrated that LUTS are common among men and that the prevalence increases with age (5–12,16). Many publications focused specifically on the prevalence of urinary incontinence (UI) among community-dwelling men (16). Approximately 11% of men over the age of 40 had experienced an incontinent episode during the prior year, and the prevalence of daily UI may be as high as 9% among men over the age of 60 (16). A variety of question-naires have shown UI prevalence estimates ranging from 5% among ages 19–44 years to 32% among those older than 80 years (16). Some country-specific disparities in LUTS and UI prevalence have been noted; however, these are most likely due to study design or methodological differences rather than true geographic variations (5–16).

During the past several years, population-based studies have reported both the prevalence of seven symptoms captured by the IPSS and a more complete list of voiding, storage, and post-micturition symptoms (17–23). These studies report variation in prevalence, ranging from 47% to 89% of the general male population reporting at least one lower urinary tract symptom (Table 1). In general, the most commonly reported storage symptom was nocturia, and the most common voiding symp-tom was terminal dribble. Post-micturition sympsymp-toms were reported less often than voiding or stor-age symptoms. These patterns are constant across countries (19). Several studies have confirmed a significant increase in prevalence with advancing age for both individual LUTS and for the total number of individual LUTS reported by men (17–19,22–24).

TABLE 1 Population-based Prevalence (%) of LUTS Among Men

Symptom Sweden

NR=gender specific prevalence not reported; *nocturia 2 or more times per night unless otherwise specified; ^§nocturia greater than 3x per night; ^‡nocturia frequency not defined; ^†nocturia defined as mild, moderate, or severe; ^||prevalence defined as ‘at least sometimes’, SUI due to laughing, sneezing, coughing=1.2%; SUI due to physical activity=1.3%, other UI=leak for no reason; +some prevalence numbers extrapolated from graphs.

continued on page 7

Symptom Sweden

NR=gender specific prevalence not reported; *nocturia 2 or more times per night unless otherwise specified; ^§nocturia greater than 3x per night; ^‡nocturia frequency not defined; ^†nocturia defined as mild, moderate, or severe; ^||prevalence defined as ‘at least sometimes’, SUI due to laughing, sneezing, coughing=1.2%; SUI due to physical activity=1.3%, other UI=leak for no reason; +some prevalence numbers extrapolated from graphs.

Lower urinary tract symptoms often occur in clusters and not in isolation (24–27). Overactive blad-der (OAB) is a common symptom cluster. The International Continence Society (ICS) defines OAB as urinary urgency, with or without urinary incontinence, usually with frequency and nocturia (28).

The prevalence of these symptoms was the focus of at least 20 population-based studies during the past few years (19,22,23,29–46). Again, a wide variation in OAB prevalence rates (6%–84%) exists, with some geographic variation (Table 2). The majority of these studies (77%) reported the general population prevalence of OAB in men to be 10%–25% (Table 2). Several studies show that OAB prevalence among men increases with age, with the most dramatic increase occurring during the 6th and 7th decade of life (19,22–24,32,34,35,41–46). Except for one study, OAB with incontinence was reported less frequently than OAB without incontinence (Table 2).

TABLE 1 Population-based Prevalence (%) of LUTS Among Men, Cont’d

TABLE 2 Population-based Prevalence (%) of OAB Among Men

Country Ref OAB Total OAB without UI OAB with UI

Europe and the Americas

France, Germany, Italy, Spain, Sweden,

and UK (survey year not stated [n=7,048]) 29 16 NR NR

Austria (survey year not stated [n=1,199]) 30 10 8 2

Canada (survey year not stated [n=1,566]) 38 15 13* 2

Sweden 1992 (n=7,763) 22 16 14 2

USA 2000–2001 (n=2,469) 34 16 13 3

Canada 2002 (n=475) 39 13 9* 4

Brazil 2003–2004 (n=399) 40 14 NR NR

Finland 2003–2004 (n=1,649) 32 7 6 1

Spain 2004 (n=824) 31 15 5* 10

Italy, Germany, UK, Sweden, and Canada 2005

(n=7,210) 19 11 8 3

Italy 12 9 3

Germany 12 9 3

UK 9 6 3

Sweden 14 9 5

Canada 9 5 4

USA 2005 (n=73,145) 35 24 15* 9

Portugual 2008 (n=451) 33 35 NR NR

Sweden, UK, and USA 2007–2008 (n=14,139) 36 NR NR NR

Sweden 37 22 NR NR

UK 24 NR NR NR

USA 27 NR NR NR

*Inputted from published data; NR=gender-specific prevalence was not reported; UK=United Kingdom.

continued on page 9

Country Ref OAB Total OAB without UI OAB with UI

Asia

Asia 1998 (n=2,369) 41 30 13 17

China 30 NR NR

Hong Kong 84 NR NR

India 14 NR NR

Indonesia 43 NR NR

Malaysia 27 NR NR

Pakistan 24 NR NR

Philippines 20 NR NR

Singapore 29 NR NR

Taiwan 23 NR NR

Thailand 63 NR NR

Taiwan 2000 (n=902) 43 16 NR NR

Korea 2000 (n=1,000) 44 21 13 8

Japan 2002–2003 (n=2,100) 42 14 8 6

Japan 2003 (n=414) 45 18 NR NR

Korea 2006 (n=888) 23 10 9 1

China 2009–2010 (n=7,359) 46 6 4 2

*Inputted from published data; NR=gender-specific prevalence was not reported; UK=United Kingdom.

Studies of LUTS prevalence are difficult to compare for several reasons. There is evidence that results from self-reported LUTS data maybe be influenced by questionnaire administration method (e. g.

mail surveys, telephone surveys, face-to-face interviews), which lead to sampling or measurement error due to differential response rates and data completeness (47–49). In addition, variations among study results may be attributed to the questionnaires administered and the operational LUTS defini-tions applied during analysis. The International Prostate Symptom Score, the most commonly used metric, lacks questions on incontinence and pain, two symptoms that often negatively affect HRQOL in men seeking medical care for LUTS (50). Population-based prevalence studies of self-reported LUTS are not necessarily reflective of medical diagnoses. Only about 50% of individuals reporting symptoms recall these symptoms as being bothersome, and an even smaller percentage of bothered individuals seek treatment (21,51). Future studies should implement standardized LUTS definitions and include consistent measurements of symptom burden, which will allow for better comparisons across settings.

TABLE 2 Population-based Prevalence (%) of OAB Among Men, Cont’d

There is a paucity of population-based research examining the incidence of individual LUTS. Thus, data on potential risk factors are restricted to cross-sectional studies. Longitudinal studies provide stronger evidence to better understand LUTS burden and elucidate LUTS risk factors for etiologic research. Once these risk factors have been clearly recognized, potential targets for prevention of symptom development can be identified.