The frequencies of overactive bladder without incontinence were 3.0% (95% CI, 2.7–3.5) in men and 1.1% (95% CI, 0.9–1.3) in women. The corresponding frequencies for urinary incontinence were 8.3% (95% CI, 7.7–8.9) in men and 10.2% (95% CI, 9.6–10.8) in women (Table 1).
The frequencies of overactive bladder and urinary incontinence increased with age in both sexes. For example, the frequencies of overactive bladder were 2.0% and 1.1% in men and women 51 to 60 years but 3.4% and 1.4% in subjects older than 70 years. The frequency of urinary incontinence also increased with age; this trend was statistically significant (chi square with 1 df, adjusted for sex, P < .05).
Table 2 shows the distribution of subjects with urinary problems stratified by sex, age, and type of problem. Mixed incontinence was the most frequent condition in men older than 60 years, and overactive bladder was more frequent in younger men. The relative frequency of stress incontinence tended to decrease with age. In women, stress incontinence and mixed incontinence were the most common causes of urinary incontinence in all age strata. The frequency of stress incontinence decreased with age, whereas that of mixed incontinence increased.
TABLE 1
Frequency of overactive bladder and urinary incontinence according to sex and age
| Age, y | Men* | Women* | ||||
|---|---|---|---|---|---|---|
| No urinary problem | OB only | UI | No urinary problem | OB only | UI | |
| 40–50 | 3122 (93.6) | 23 (0.7) | 190 (5.7) | |||
| 51–60 | 3160 (93.8) | 69 (2.0) | 139 (4.1) | 323 (90.6) | 38 (1.1) | 299 (8.4) |
| 61–70 | 3071 (88.8) | 116 (3.4) | 273 (7.9) | 3180 (87.5) | 52 (1.4) | 403 (11.1) |
| >70 | 2298 (82.5) | 100 (3.4) | 387 (13.6) | 2320 (82.2) | 39 (1.4) | 463 (16.4) |
| Total | 8529 (88.7) | 285 (3.0) | 799 (8.3) | 11858 (88.7) | 150 (1.1) | 1358 (10.2) |
| *Data are presented as number (%) of subjects.OB, overactive bladder; UI, urinary incontinence. | ||||||
TABLE 2
Frequency of overactive bladder and various types of urinary incontinence in strata by sex and age*
| Age, y | Men† | Women† | ||||||
|---|---|---|---|---|---|---|---|---|
| OB only | UGI | SI | MXI | OB only | UGI | SI | MXI | |
| 40–50 | 23 (11.2) | 31 (15.1) | 93 (45.4) | 58 (28.3) | ||||
| 51–60 | 69 (35.5) | 30 (16.4) | 33 (18.0) | 55 (30.1) | 38 (11.4) | 59 (17.8) | 127 (38.3) | 108 (32.5) |
| 61–70 | 116 (33.1) | 63 (18.0) | 37 (10.6) | 134 (38.3) | 52 (11.9) | 72 (16.5) | 169 (37.8) | 147 (33.7) |
| >70 | 100 (24.1) | 69 (15.7) | 52 (12.5) | 198 (47.7) | 37 (7.6) | 89 (18.3) | 143 (29.4) | 217 (44.7) |
| Total | 285 (29.7) | 162 (16.9) | 122 (12.7) | 391 (40.7) | 150 (10.3) | 251 (17.2) | 532 (36.4) | 530 (36.2) |
| *These totals are not the same as those in Table 1 due to missing values of subjects with OB or urinary incontinence. | ||||||||
| †Data are presented as number (%) of subjects. | ||||||||
| MXI, mixed incontinence; OB, overactive bladder; SI, stress incontinence; UGI, urge incontinence. | ||||||||
Discussion
Before discussing the results, the study limitations must be considered. The study population consisted of men at least 50 years and women at least 40 years identified among patients who asked to be seen by their general practitioners during the study period, but not among all patients registered with these physicians. The general practitioners were not randomly identified among all Italian general practitioners, so their patients cannot be formally considered representative of the Italian population. Nevertheless, general practitioners participating in this study were placed throughout the main areas of the country. The strengths of the study included the opportunity to analyze the prevalence of urinary incontinence and overactive bladder in a large series of subjects with the use of standard methods for recording the symptoms and data collection. Further, the interview was conducted by physicians well known to the subjects, which should increase the reliability of diagnosis, particularly of various types of urinary incontinence.
The limitations of a patient’s history in the diagnosis of type of urinary incontinence are widely recognized. In a review of the literature, a clinical history indicating stress or urge incontinence, when compared with a urodynamically based diagnosis, showed sensitivities of 0.9 and 0.4 and specificities of 0.5 and 0.6, respectively, in clinical studies.19 In epidemiologic studies with self-reported information, these values might be lower. Any misclassification of the type of incontinence would tend to reduce the differences in the frequency of different types.
The frequency of urinary incontinence in this population was consistent with that reported in studies conducted in European and North American areas and in Italy in the general population. For example, the prevalences of urinary incontinence in women 50 to 60 years were approximately 18% in Denmark20 and 12% to 17% in the United Kingdom.1,4 An Italian study of 2767 women found a prevalence of 11.8% for urinary incontinence in women 51 to 60 years old.
In contrast, the rates of urinary incontinence reported in this study were slightly lower than those reported by Lagace and colleagues in a similar ambulatory setting in the United States.6 They found prevalences of 35% for urinary incontinence in women 50 to 59 years and 5% in men in the same age group.
Among men the prevalence of urinary incontinence was similar to or slightly lower than that reported in the general population.1 In the study by Bortolotti and associates, the overall prevalence of urinary incontinence in men older than 50 years was 2.3%, a figure somewhat lower than in the present study.14