Abstract
Objectives
A large‐scale nationwide epidemiological survey of lower urinary tract symptoms (LUTS) was conducted via the Internet in 2023 to clarify the current prevalence of LUTS and evaluate its impact on daily life in Japan.
Methods
The survey was conducted among individuals aged 20–99 years old who had anonymously registered with a Japanese online research company. The survey consisted of 48 questions related to LUTS and daily life.
Results
A total of 6210 participants (3088 females and 3122 males), who were selected by probability sampling based on the composition of the Japanese population (age range: 20–99), were recruited. The overall prevalence of LUTS was 77.9% among the subjects aged ≥20 and 82.5% among those aged ≥40. The prevalence of LUTS differed between the sexes and trends toward significant increases in prevalence with age were seen for almost all LUTS. Furthermore, the prevalence of overactive bladder (OAB) was 11.9% among the subjects aged ≥20 and 13.8% among those aged ≥40. This study also showed that LUTS negatively affected daily life. However, the percentage of subjects who visited a physician to receive treatment for LUTS was low, including for participants with a history of treatment for LUTS, although this increased with age.
Conclusion
The prevalence of LUTS, including OAB, increased with age and negatively affected daily life. However, since the percentage of patients who visit a physician to receive treatment for LUTS remains low, further educational activities regarding LUTS are necessary.
Keywords: daily life, JaCS 2023, LUTS, OAB, super‐aging society
Abbreviations & Acronyms
- LUTS
lower urinary tract symptoms
- OAB
overactive bladder
- OABSS
overactive bladder symptom score
INTRODUCTION
Lower urinary tract symptoms (LUTS) consist of storage, voiding, and postvoiding symptoms. As LUTS affect daily life, their status is evaluated, and then appropriate treatment is provided. 1 , 2
Many epidemiological studies of LUTS have been conducted in various countries. 3 , 4 , 5 , 6 , 7 In Japan, an epidemiological survey was conducted in 2002 and it revealed the prevalence of LUTS in Japan and their impact on daily life. 8 , 9 The data of this epidemiological survey have been widely cited. In general, the prevalence of LUTS increases with age and treating LUTS is important for achieving a long and healthy life, especially in Japan, which is experiencing a super‐aging society. However, more than 20 years have passed since that survey, and Japan has become an unprecedentedly aging society compared with other developed countries. Therefore, it is necessary to clarify the current prevalence of LUTS in Japan and the impact of such symptoms on daily life. Furthermore, it is also necessary to survey younger generations (people in their 20s and 30s) and ask new questions that had not been asked in the previous survey, such as regarding postvoiding incontinence/postmicturition leakage or straining to void at the beginning or throughout urination.
The Japanese Continence Society decided to conduct an epidemiological survey on LUTS through Internet research in 2023, which marked its 50th anniversary.
PARTICIPANTS AND METHODS
Participants and data collection
An online survey of individuals aged 20–99 years old, who had anonymously registered with the web panel of an online Japanese research company (Macromill, Inc., Tokyo, Japan) and had the ability to read, write, and understand Japanese, was conducted between May 31 and June 5, 2023. Macromill was used because its panel included many people of both sexes and the target age range. 10 , 11 To recruit respondents, e‐mails were sent by Macromill to potential participants for this survey, who were selected by probability sampling based on the composition of the Japanese population according to the National Census of the Statistics Bureau, Ministry of Internal Affairs and Communications in 2020. The survey participants included people divided into 10‐year age groups from 20 to 99 years old and were classified by sex, age, region, and other factors (https://www.stat.go.jp/data/kokusei/2020/index.html). The participants provided their consent through the opt‐in consent method. The survey consisted of 48 questions.
This study was approved by the Nihon University Itabashi Hospital Clinical Research Judging Committee and was approved on May 10, 2023 (ID 2023‐04).
Questionnaire about LUTS
A previously developed questionnaire was used in this study. 9 Furthermore, several new questions, such as regarding postvoiding incontinence/postmicturition leakage or straining to void at the beginning or throughout urination, were added. The questionnaire included items assessing demographic characteristics, LUTS, daily life, and treatment‐seeking. All questions concerning LUTS and daily life referred to the previous month. The examined demographic characteristics were age, sex, parity (women only), functional status, general health condition, and comorbid diseases in the past and/or at present. The following LUTS were assessed: daytime urinary frequency, nocturia, urgency, urgency urinary incontinence, and stress urinary incontinence as storage symptoms; hesitancy, a slow stream, intermittency, and straining to void as voiding symptoms; a feeling of incomplete emptying and postvoiding incontinence/postmicturition leakage as postvoiding symptoms; and bladder pain. The descriptions of the symptoms were consistent with the International Continence Society terminology. 1 , 2 Questions about daytime urinary frequency and nocturia were answered in terms of the actual number of urinations, and the other symptoms were rated using a frequency scale (none, less than once a week, once or more a week, approximately once daily, several times daily, or always). Respondents were considered to have LUTS if they met any of the following criteria: a daytime urinary frequency of ≥8 times, nocturia (≥1 time/night), or other symptoms (≥1 time/week). Likewise, when at least one of the storage, voiding, or postvoiding symptoms met the definition of LUTS, participants were considered to have LUTS.
In this study, overactive bladder (OAB) was diagnosed according to the OAB symptom score (OABSS) definition, which is based on the presence of urgency (once or more/week) and any symptoms of daytime urinary frequency (≥8 times/daytime), nocturia (≥1 time/night), urgency, or urgency urinary incontinence. 4 , 12
Questions about daily life
The global impact of urinary symptoms on daily life was assessed using the following question: “During the past month, how much influence on your general daily life have you felt due to urinary problems?” The response was none, slight, modest, or severe. When a subject responded with “slight”, “modest,” or “severe,” additional questions were asked regarding the specific symptoms associated with the impact and which symptoms had the strongest impact on their daily life.
The questions assessing attitudes toward treatment‐seeking included whether the subject had sought medical care and any reasons they had for not seeking medical care.
Statistical analysis
Data are expressed as frequency distributions. The Cochran‐Armitage trend test was used to evaluate trends in the relationships between the response scores and age. All statistical analyses were performed using JMP, version 10, and p‐values <0.05 were considered significant.
RESULTS
Functional status was reported as totally or almost independent in 98% of subjects, and 88% of respondents categorized their general health as fair, good, or very good. The subjects' comorbid conditions are shown in Table 1.
TABLE 1.
Characteristics of participants.
| The number of participants, n (%) | Total | Males | Females |
|---|---|---|---|
| 20s | 731 (11.8) | 387 (12.4) | 344 (11.1) |
| 30s | 838 (13.5) | 442 (14.2) | 396 (12.8) |
| 40s | 1091 (17.6) | 573 (18.4) | 518 (16.8) |
| 50s | 990 (15.9) | 514 (16.5) | 476 (15.4) |
| 60s | 938 (15.1) | 476 (15.2) | 462 (15.0) |
| 70s | 967 (15.6) | 465 (14.9) | 502 (16.3) |
| 80s | 545 (8.8) | 224 (7.2) | 321 (10.4) |
| 90s | 110 (1.8) | 41 (1.3) | 69 (2.2) |
| Comorbidities | n (%) |
|---|---|
| Hypertension | 1338 (21.5) |
| Hyperlipidemia | 752 (12.1) |
| Diabetes mellitus | 467 (7.5) |
| Heart failure | 140 (2.3) |
| Angina pectoris/cardiac infarction | 197 (3.2) |
| Chronic renal disease | 143 (2.3) |
| Cerebral infarction/bleeding | 153 (2.5) |
| Spine disorder/spinal cord disease | 171 (2.8) |
| Neurological diseases | 107 (1.7) |
| Depression/neurosis | 402 (6.5) |
| Sleep apnea syndrome | 209 (3.4) |
| Insomnia | 452 (7.3) |
| Benign prostatic hyperplasia (only men) | 234 (7.5) |
| Symptomatic pelvic organ prolapse (only women) | 142 (4.9) |
| Fecal incontinence | 156 (2.5) |
| Constipation | 704 (11.3) |
Abbreviation: n, number.
Prevalence of LUTS
The overall prevalence of LUTS was 77.9% among the subjects aged ≥20s, and 82.5% among those aged ≥40s (Figure 1). The most common symptoms were storage symptoms (77.9% in ≥20s and 79.1% in ≥40s), followed by voiding symptoms (28.6% in ≥20s and 32.5% in ≥40s) and postvoiding symptoms (17.4% in ≥20s and 18.5% in ≥40s). There was almost no difference in the prevalence of storage symptoms between the sexes, whereas the prevalence rates of voiding symptoms and postvoiding symptoms were higher in males than in females (Figure S1a–c).
FIGURE 1.
Prevalence of LUTS. The overall prevalence of LUTS was 77.9% (females: 76.5%, males: 79.4%) among the subjects aged ≥20 years, and 82.5% (females: 80.1%, males: 85.0%) among those aged ≥40 years. The prevalence of LUTS gradually increased with age.
The prevalence rates for each symptom are shown in Table 2. Nocturia, urgency, and all voiding symptoms were reported more often in males than in females. Postvoiding symptoms, such as a feeling of incomplete emptying and postvoiding incontinence/postmicturition leakage were also observed more frequently in males than in females. On the other hand, stress and urgent urinary incontinence were seen more frequently in females. These differences between the sexes occurred more in older age groups. Daytime urinary frequency and bladder pain showed almost the same rates in both sexes.
TABLE 2.
Prevalence of symptoms in Japanese subjects aged 20–99 years.
| (%) | Males | Females | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 20s | 30s | 40s | 50s | 60s | 70s | 80s | 90s | p for trend | p for trend (≥40s) | 20s | 30c | 40s | 50s | 60s | 70s | 80s | 90s | p for trend | p for trend (≥40s) | ||
| Daytime urinary frequency | 8 times/daytime | 25.1 | 32.4 | 36.0 | 42.8 | 46.2 | 51.4 | 53.6 | 34.1 | <0.0001 | <0.0001 | 31.7 | 34.8 | 41.9 | 48.7 | 47.0 | 47.6 | 40.5 | 36.2 | <0.0001 | 0.2905 |
| 11 times/daytime | 3.4 | 7.2 | 6.3 | 6.2 | 9.5 | 6.0 | 8.0 | 7.3 | 0.0203 | 0.2198 | 8.1 | 6.6 | 6.8 | 8.4 | 6.9 | 7.8 | 6.9 | 7.2 | 0.4761 | 0.4970 | |
| Nocturia | 1 time/night | 39.5 | 48.6 | 55.1 | 66.5 | 73.5 | 83.4 | 92.9 | 82.9 | <0.0001 | <0.0001 | 40.1 | 48.5 | 50.6 | 50.6 | 61.9 | 69.7 | 83.2 | 73.9 | <0.0001 | <0.0001 |
| 2 times/night | 14.0 | 16.5 | 20.6 | 23.7 | 30.7 | 38.7 | 59.4 | 51.2 | <0.0001 | <0.0001 | 10.8 | 11.9 | 14.5 | 12.2 | 14.3 | 23.7 | 38.6 | 36.2 | <0.0001 | <0.0001 | |
| 3 times/night | 6.2 | 8.4 | 8.4 | 9.7 | 13.0 | 15.7 | 31.7 | 26.8 | <0.0001 | <0.0001 | 5.5 | 5.3 | 7.1 | 4.4 | 4.3 | 4.6 | 16.5 | 17.4 | <0.0001 | <0.0001 | |
| Urgency | 1 time/week | 7.8 | 6.1 | 8.2 | 11.5 | 15.5 | 26.0 | 30.8 | 34.1 | <0.0001 | <0.0001 | 6.1 | 6.3 | 8.1 | 7.4 | 9.1 | 12.5 | 19.3 | 27.5 | <0.0001 | <0.0001 |
| 1 time/day | 3.9 | 1.6 | 2.6 | 6.2 | 6.5 | 11.2 | 15.2 | 19.5 | <0.0001 | <0.0001 | 2.6 | 2.5 | 3.5 | 3.8 | 3.5 | 4.8 | 8.4 | 11.6 | <0.0001 | <0.0001 | |
| Urgency urinary incontinence | (+) | 9.8 | 9.3 | 9.8 | 11.5 | 17.2 | 29.2 | 34.4 | 43.9 | <0.0001 | <0.0001 | 7.3 | 8.6 | 11.6 | 14.7 | 20.1 | 33.7 | 44.2 | 44.9 | <0.0001 | <0.0001 |
| 1 time/week | 5.9 | 3.6 | 3.7 | 4.1 | 3.6 | 10.5 | 11.2 | 24.4 | <0.0001 | <0.0001 | 3.5 | 2.8 | 3.5 | 4.4 | 6.3 | 9.6 | 19.0 | 26.1 | <0.0001 | <0.0001 | |
| 1 time/day | 2.6 | 0.7 | 1.4 | 2.1 | 2.1 | 5.2 | 4.9 | 7.3 | <0.0001 | <0.0001 | 0.6 | 0.5 | 1.4 | 1.3 | 2.6 | 4.0 | 9.0 | 13.0 | <0.0001 | <0.0001 | |
| Stress urinary incontinence | (+) | 12.4 | 10.0 | 9.2 | 7.0 | 8.6 | 12.0 | 8.5 | 14.6 | 0.3185 | 0.0756 | 12.2 | 24.5 | 26.6 | 28.6 | 28.8 | 34.1 | 45.5 | 42.0 | <0.0001 | <0.0001 |
| 1 time/week | 4.9 | 4.3 | 3.8 | 1.8 | 1.5 | 2.6 | 3.1 | 4.9 | 0.0060 | 0.3183 | 2.6 | 6.8 | 7.1 | 6.1 | 6.9 | 10.4 | 15.6 | 18.8 | <0.0001 | <0.0001 | |
| 1 time/day | 3.1 | 0.5 | 1.4 | 1.2 | 1.1 | 1.5 | 1.8 | 0.0 | 0.1696 | 0.4384 | 0.6 | 2.0 | 3.3 | 0.8 | 1.9 | 3.4 | 4.7 | 13.0 | <0.0001 | 0.0003 | |
| Hesitancy | 1 time/week | 11.9 | 10.2 | 12.0 | 14.2 | 17.2 | 25.4 | 28.6 | 19.5 | <0.0001 | <0.0001 | 5.8 | 5.3 | 4.8 | 2.9 | 6.7 | 6.8 | 13.7 | 27.5 | <0.0001 | <0.0001 |
| 1 time/day | 6.5 | 4.8 | 5.9 | 9.1 | 9.7 | 15.7 | 17.9 | 9.8 | <0.0001 | <0.0001 | 2.6 | 3.0 | 3.1 | 1.3 | 2.8 | 4.6 | 8.7 | 11.6 | <0.0001 | <0.0001 | |
| Slow stream | 1 time/week | 8.5 | 10.0 | 14.5 | 26.3 | 35.5 | 51.6 | 61.2 | 39.0 | <0.0001 | <0.0001 | 8.4 | 7.6 | 11.2 | 10.7 | 15.2 | 24.1 | 30.8 | 29.0 | <0.0001 | <0.0001 |
| 1 time/day | 4.4 | 5.0 | 8.2 | 16.3 | 24.4 | 36.8 | 47.3 | 26.8 | <0.0001 | <0.0001 | 3.5 | 3.8 | 6.0 | 6.9 | 9.5 | 14.9 | 23.1 | 17.4 | <0.0001 | <0.0001 | |
| Intermittency | 1 time/week | 11.4 | 9.5 | 11.9 | 16.9 | 20.0 | 29.7 | 39.3 | 31.7 | <0.0001 | <0.0001 | 5.8 | 5.1 | 5.6 | 4.4 | 9.5 | 8.6 | 19.3 | 29.0 | <0.0001 | <0.0001 |
| 1 time/day | 5.2 | 3.8 | 6.5 | 9.9 | 13.2 | 20.6 | 29.0 | 26.8 | <0.0001 | <0.0001 | 2.6 | 1.8 | 3.5 | 2.7 | 4.1 | 4.2 | 13.4 | 15.9 | <0.0001 | <0.0001 | |
| Straining to void (to begin urination) | 1 time/week | 11.6 | 10.0 | 11.2 | 13.4 | 16.4 | 21.7 | 30.8 | 19.5 | <0.0001 | <0.0001 | 6.4 | 6.1 | 5.8 | 3.4 | 6.9 | 7.6 | 14.0 | 20.3 | <0.0001 | <0.0001 |
| 1 time/day | 5.2 | 5.7 | 6.3 | 8.2 | 9.7 | 16.1 | 20.1 | 14.6 | <0.0001 | <0.0001 | 2.6 | 4.0 | 4.1 | 1.9 | 4.3 | 4.6 | 10.3 | 10.1 | <0.0001 | <0.0001 | |
| Straining to void (during urination) | 1 time/week | 7.5 | 7.2 | 8.4 | 11.9 | 15.3 | 22.8 | 28.1 | 24.4 | <0.0001 | <0.0001 | 3.5 | 5.6 | 5.2 | 4.0 | 6.3 | 6.0 | 14.0 | 11.6 | <0.0001 | <0.0001 |
| 1 time/day | 4.1 | 3.2 | 4.4 | 7.4 | 9.2 | 13.8 | 20.5 | 17.1 | <0.0001 | <0.0001 | 1.2 | 3.3 | 3.1 | 2.5 | 3.2 | 2.6 | 10.0 | 7.2 | <0.0001 | <0.0001 | |
| Feeling of incomplete emptying | 1 time/week | 15.2 | 13.1 | 16.1 | 19.5 | 22.1 | 24.7 | 32.6 | 29.3 | <0.0001 | <0.0001 | 10.2 | 6.8 | 9.8 | 6.3 | 6.7 | 6.6 | 14.0 | 23.2 | 0.0363 | 0.0038 |
| 1 time/day | 7.5 | 5.2 | 6.1 | 8.9 | 10.5 | 14.0 | 18.8 | 22.0 | <0.0001 | <0.0001 | 4.1 | 3.0 | 3.7 | 2.5 | 2.8 | 3.6 | 7.8 | 14.5 | 0.0011 | <0.0001 | |
| Postvoiding incontinence (men) Postmicturition leakage (women) | (+) | 23.3 | 23.8 | 28.4 | 34.6 | 36.1 | 35.1 | 33.9 | 29.3 | <0.0001 | 0.0390 | 9.0 | 4.8 | 9.1 | 7.8 | 10.0 | 13.9 | 22.1 | 44.9 | <0.0001 | <0.0001 |
| 1 time/week | 12.7 | 11.8 | 13.1 | 17.7 | 17.2 | 15.3 | 17.9 | 17.1 | 0.0029 | 0.1030 | 2.9 | 1.5 | 3.5 | 2.3 | 2.8 | 4.4 | 5.9 | 15.9 | <0.0001 | <0.0001 | |
| 1 time/day | 5.7 | 5.0 | 5.8 | 9.5 | 9.5 | 9.7 | 10.7 | 12.2 | <0.0001 | 0.0107 | 1.7 | 1.0 | 1.9 | 1.3 | 1.3 | 2.0 | 3.1 | 5.8 | 0.0204 | 0.0247 | |
| Bladder pain | 1 time/week | 8.5 | 5.4 | 3.5 | 3.1 | 1.1 | 1.5 | 2.7 | 7.3 | <0.0001 | 0.1124 | 4.7 | 4.3 | 3.3 | 1.1 | 1.3 | 1.2 | 3.4 | 14.5 | 0.1532 | 0.0161 |
| 1 time/day | 3.6 | 1.4 | 0.9 | 1.6 | 0.4 | 0.6 | 1.8 | 4.9 | 0.0179 | 0.2054 | 1.7 | 1.3 | 1.4 | 0.2 | 0.4 | 0.2 | 1.9 | 8.7 | 0.2668 | 0.0056 | |
Note: “20s”, “30s”, etc.: Subjects in their 20s, 30s, etc. p for trend for subjects aged 20–99 years and p for trend (≥40s) for subjects aged 40–99 years.
Significant increases in prevalence with age were seen for almost all LUTS, except stress urinary incontinence in males and daytime urinary frequency in females. Bladder pain was observed in the younger generation. Postvoiding incontinence/postmicturition leakage was also observed in a relatively large percentage (around 24%) of young males.
Prevalence of OAB
The prevalence of OAB is shown in Figure 2. It was 11.9% in the subjects aged ≥20s and 13.8% in those aged ≥40s. The prevalence of OAB gradually increased with age. Among the subjects with OAB symptoms, urgency urinary incontinence was identified in 69.8% (males: 64.3%, females: 77.6%). The prevalence of urgency urinary incontinence in individuals with OAB also increased with age.
FIGURE 2.
Prevalence of OAB. The prevalence of OAB symptoms was 11.9% (males: 13.9%, females: 9.8%) in the subjects aged ≥20 years and 13.8% (males: 16.6%, females: 11.0%) in those aged ≥40 years. Although there was no difference in the prevalence of OAB symptoms among the participants under 40 years of age, they were more common in males aged ≥50 years.
Impact of LUTS on daily life
The results regarding the global impact of LUTS on daily life are shown in Figure 3. LUTS were reported to impact on daily life in 12.4% of subjects (slightly affected, 10.4%; moderately affected, 1.5%; and severely affected, 0.5%). The impact rate increased with age in both sexes and was particularly marked after age 70.
FIGURE 3.
Impact of LUTS on daily life. The global impacts of LUTS on daily life in males and females are shown. The percentage of subjects reporting that LUTS had a negative impact increased with age.
The number of symptoms affecting daily life ranged from 1 to 8 (median: 2). Among the participants with symptoms that affected daily life, the symptom that had an impact on daily life most often was nocturia (60.0%), followed by daytime urinary frequency (40.1%), urinary urgency (38.8%), a slow stream (27.4%), urgency urinary incontinence (22.2%), postvoiding incontinence (21.7%), hesitancy (17.8%), and stress urinary incontinence (17.0%).
The symptom that was most frequently reported to have the greatest impact on daily life was nocturia (35.9%), followed by daytime urinary frequency (17.5%), urinary urgency (16.9%), urgency urinary incontinence (7.4%), stress urinary incontinence (7.0%), postvoiding incontinence/postmicturition leakage (5.0%), a slow stream (4.3%), and hesitancy (3.0%). Nocturia was the most distressing symptom in both sexes in all age groups (Figure 4).
FIGURE 4.
Symptoms with the greatest impact on daily life. Among LUTS, nocturia was reported to have the greatest impact on daily life most often, which means that nocturia was the most distressing symptom in both males and females in all age groups.
Physician visits for the treatment of LUTS
In this survey, only 4.9% of participants with LUTS (7.2% of males and 2.5% of females) were visiting medical doctors to receive treatment for them. When participants with a history of visiting a physician to receive treatment for LUTS were included in this figure, the percentage of physician visits remained only 13.2% (15.3% in males and 11.1% in females). The percentage of subjects who visited a physician to receive treatment for LUTS increased with age, and this was particularly marked for males aged ≥70s (Figure S2). Even among participants with OAB symptoms, only 16.0% (20.3% of males and 9.9% of females) were visiting medical doctors to receive treatment for OAB. This increased with age in both sexes (Figure S3).
The most commonly reported reasons (including multiple responses) for not visiting a physician to receive treatment for LUTS were not being bothered by symptoms (86.4%), the belief that LUTS are not diseases (16.9%), the belief that LUTS are a normal consequence of aging (15.0%), embarrassment about symptoms (6.0%), being unaware that treatment is available (2.8%), and having no access to medical services (2.1%). All of these reasons were reported at similar frequencies in both sexes.
DISCUSSION
The Japanese Continence Society conducted an epidemiological survey of LUTS through Internet research in 2023. Compared with the 2002 epidemiological survey, 9 the present epidemiological survey clarified the prevalence of LUTS and its impact on daily life in individuals aged ≥40s, and also revealed the prevalence of LUTS and its impact on daily life in individuals in their 20s or 30s as new results. The overall prevalence of LUTS was 77.9% in individuals aged ≥20s and 82.5% in individuals aged ≥40s, which indicates that there are >80 million people with at least one LUTS in Japan. In addition, LUTS were found to negatively affect daily life.
Among storage symptoms, the prevalence rates of daytime urinary frequency and stress incontinence did not increase significantly with age in the 2002 epidemiological survey. 9 The present epidemiological survey also did not show a significant increase in the prevalence of daytime urinary frequency in females or in stress incontinence in males. In the prevalence of stress incontinence in females, including mild cases, which reached 30%–40% in those aged ≥70s, we consider that the management of stress incontinence in females is becoming more important in Japan's super‐aging society. Regarding other storage symptoms, such as nocturia, urgency, and urgency urinary incontinence, the prevalence of these symptoms increased with age. Nocturia (≥1 time/night), including severe nocturia, was identified more often in males than females, the prevalence of which reached 80%–90% in males aged ≥80s. Urgency was also identified more often in males than in females. On the other hand, stress and urgency urinary incontinence were identified more frequently in females, which may have been derived from anatomical differences between the sexes. Overall, the prevalence of storage symptoms was slightly lower in the present survey than in the 2002 epidemiological survey. 9 We speculate that this may have been related to the fact that the previous survey was conducted in winter, whereas the present survey was conducted in early summer.
As for voiding symptoms, the prevalence of all symptoms, such as hesitancy, a slow stream, intermittency, and straining to void, increased with age in both sexes. All voiding symptoms were identified more frequently in males than females, possibly due to bladder outlet obstruction. The results of the present epidemiological survey revealed the same trends in voiding symptoms as the 2002 epidemiological survey. 9
Regarding postvoiding symptoms, the prevalence of a sensation of incomplete emptying increased with age in both sexes and was higher in males than in females. The same age‐dependent trend was reported in the 2002 epidemiological survey. 9 On the other hand, our findings regarding the prevalence of postvoiding incontinence/postmicturition leakage were new. Although there was a trend toward the prevalence of this symptom increasing with age, 20%–30% of younger males also experienced it (including mild cases). Since no effective treatment for postvoiding incontinence/postmicturition leakage has been established yet, 13 the development of new effective treatments for this symptom remains a challenge in the future.
Concerning the prevalence of LUTS in other countries, particularly at the results of the EPIC study, which involved a large‐scale survey, 6 , 7 the trends in LUTS in Japan were similar. However, daytime urinary frequency, stress urinary incontinence, and urgency urinary incontinence were observed more frequently in the present study than in the study by Irwin et al., which was conducted in Western countries, 6 although the prevalence rates of other LUTS were almost the same in both studies. Furthermore, there were also some differences in the effects of sex on the prevalence of each symptom between the studies. These discrepancies between our study and previous studies may have been due to racial differences.
In the present epidemiological survey, OAB was diagnosed according to the OABSS definition. 12 The prevalence of OAB was 11.9% in the subjects aged ≥20s and 13.8% among those aged ≥40s. Based on the vital statistics of Japan for 2022, there could be 12.5 million OAB patients aged ≥20s and 10.8 million aged ≥40s. This result is comparable to recently reported results, 6 , 7 , 14 , 15 , 16 , 17 including those of the 2002 epidemiological survey. 8 , 9 Interestingly, the present epidemiological survey revealed that among the subjects aged 20–39, the prevalence of OAB was 6%–7% in both males and females. In addition, there were no sex‐related differences in the prevalence rates of OAB symptoms under age 40s, but it was more common in males than females after age 50s, which may be related to benign prostatic hyperplasia. Thus, there are many males and females of all ages with OAB. Further, urgency urinary incontinence was identified in 69.8% of the subjects with OAB symptoms in this study, which is higher than 2002 epidemiological survey. 8 This may be derived from different definitions of OAB.
Regarding the percentage of subjects that were visiting physicians to receive treatment for LUTS, only 4.9% of participants with LUTS were visiting medical doctors to receive treatment for them, although this increased with age in both sexes. We believe that further educational activities about LUTS, including OAB, are necessary because some of these patients considered that LUTS are not diseases or that LUTS are a normal consequence of aging.
LUTS were reported to have an impact on daily life in 12.4% of subjects, and the percentage of subjects that reported such an impact increased with age. In all age groups, the participants reported that nocturia (35.9%) was the most distressing symptom, which was consistent with findings of the 2002 epidemiological survey. 9 Furthermore, as a new result that was not reported in the 2002 epidemiological survey, 9 the present survey revealed that postvoiding incontinence/postmicturition leakage also had one of the greatest impacts on daily life, particularly in males. Since no effective medications for the condition have been developed, we need to consider the optimal management strategy for male patients with postvoiding incontinence/postmicturition leakage.
This study had some limitations. First, the present epidemiological survey was conducted via the Internet, unlike the 2002 epidemiological survey, 9 which was conducted by mail. When survey methods vary, the results may not be comparable. Further, since there may be some biases in online research, particularly in older generations, the current data may not reflect the real super‐aging society of Japan. However, the results of the present survey were almost the same as those of the 2002 epidemiological survey, 9 and we believe that the survey method did not have a major impact on the study's results. Second, since the present survey was conducted in June, early summer in Japan, the respondents' urine storage symptoms may have been mild. However, this survey revealed that there are still more than 10 million people suffering from OAB in Japan, demonstrating the importance of treatment for OAB in a super‐aging society. The data from the present epidemiological survey could be analyzed further, and we would like to report more data in the near future.
In conclusion, the present survey revealed the prevalence of LUTS and their impact on daily life in Japan. The prevalence of LUTS increased with age, and the treatment of LUTS is becoming increasingly important in Japan, which is a super‐aging society. On the other hand, since the percentage of individuals who were visiting physicians to receive treatment for LUTS remains low, further educational activities regarding LUTS are required.
AUTHOR CONTRIBUTIONS
Takahiko Mitsui: Conceptualization; Methodology; Writing—original draft; Writing—review & editing; Investigation; Project administration; Validation; Formal analysis; Visualization; Data curation. Noritoshi Sekido: Conceptualization; Methodology; Funding acquisition; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Naoya Masumori: Conceptualization; Methodology; Funding acquisition; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Nobuhiro Haga: Conceptualization; Methodology; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Kenji Omae: Conceptualization; Methodology; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Motoaki Saito: Conceptualization; Methodology; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Yasue Kubota: Conceptualization; Methodology; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Ryuji Sakakibara: Conceptualization; Methodology; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Mikako Yoshida: Conceptualization; Methodology; Writing—review & editing; Investigation; Project administration; Validation; Data curation. Satoru Takahashi: Conceptualization; Methodology; Funding acquisition; Writing—review & editing; Investigation; Project administration; Validation; Data curation.
CONFLICT OF INTEREST STATEMENT
The authors declare that they have no conflicts of interest.
APPROVAL OF THE RESEARCH PROTOCOL BY AN INSTITUTIONAL REVIEWER BOARD
The protocol for this research project has been approved by a suitably constituted ethics institutional committee (The Nihon University Itabashi Hospital clinical research judging committee, Approval No. ID 2023‐04), and it conforms to the provisions of the Declaration of Helsinki.
INFORMED CONSENT
The participants provided their consent through the opt‐in consent method.
REGISTRY AND THE REGISTRATION NO. OF THE STUDY/TRIAL
N/A.
ANIMAL STUDIES
N/A.
Supporting information
Figure S1.
Figure S2.
Figure S3.
ACKNOWLEDGMENTS
This article was supported by the 50th Anniversary Project of the Japanese Continence Society. We thank Sachiko Ogura and Chiaki Sakai, staff members of the Japanese Continence Society, for their valuable contributions to the project.
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Associated Data
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Supplementary Materials
Figure S1.
Figure S2.
Figure S3.