Prevalence of lower urinary tract symptoms in men aged 45–79 years: a population-based study of 40 000 Swedish men

Authors

  • Swen-Olof Andersson,

    1. Department of Urology and Centre for Assessment of Medical Technology (CAMTÖ), University Hospital Örebro, Örebro, *The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, and †Department of Urology, Västerås Central Hospital, Vasterås, Sweden
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  • Bahram Rashidkhani,

    1. Department of Urology and Centre for Assessment of Medical Technology (CAMTÖ), University Hospital Örebro, Örebro, *The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, and †Department of Urology, Västerås Central Hospital, Vasterås, Sweden
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  • Lars Karlberg,

    1. Department of Urology and Centre for Assessment of Medical Technology (CAMTÖ), University Hospital Örebro, Örebro, *The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, and †Department of Urology, Västerås Central Hospital, Vasterås, Sweden
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  • Alicja Wolk,

    1. Department of Urology and Centre for Assessment of Medical Technology (CAMTÖ), University Hospital Örebro, Örebro, *The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, and †Department of Urology, Västerås Central Hospital, Vasterås, Sweden
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  • Jan-Erik Johansson

    1. Department of Urology and Centre for Assessment of Medical Technology (CAMTÖ), University Hospital Örebro, Örebro, *The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, and †Department of Urology, Västerås Central Hospital, Vasterås, Sweden
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Bahram Rashidkhani, The Institute of Environmental Medicine (IMM), Karolinska Institutet, PO Box281, SE-171 77 Stockholm, Sweden.
e-mail: Bahram.Rashidkhani@imm.ki.se

Abstract

There is a strong epidemiological background to this section. In the first article, a Swedish group assess the prevalence of LUTS in a population-based study of 40 000 Swedish men aged 45–79 years. The second is a community-based study from India into the natural history of LUTS. Both papers contain some surprising results which are of interest to urologists, add to the general debate and to our knowledge of the symptoms associated with prostatic disease.

OBJECTIVE

To estimate the age-specific prevalence and severity of lower urinary tract symptoms (LUTS) among Swedish men, the intercorrelations between different symptoms, and to assess quality of life and health-seeking behaviour among men with LUTS.

SUBJECTS AND METHODS

In 1997, an International Prostate Symptom Score (IPSS) questionnaire, together with other questions about lifestyle, was mailed to all men aged 45-79 years living in two counties in Sweden; the analyses included 39 928 men.

RESULTS

Overall, 18.5% and 4.8% of the men were moderately and severely symptomatic; the prevalence of at least one symptom was 83%. LUTS were strongly age-dependent, with 1.8% of severe symptoms among men aged 45–49 years and increasing to 9.7% among those 75–79 years old. Frequent urination was the most common symptom among men aged <70 years and nocturia among those aged >70 years. Symptoms like hesitancy, poor flow and intermittency were highly correlated with each other (Spearman coefficients 0.56–0.60). There was a high correlation between the IPSS and a poor score for quality of life resulting from the bothersomeness of LUTS (r = 0.70). Among symptomatic subjects, 36% reported a poor quality of life (fairly bad, very bad or terrible). Only 29% of symptomatic subjects (IPSS >7) reported that they had been diagnosed previously for their urinary problems, and only 11% received medication for that.

CONCLUSION

Although the prevalence of LUTS in Sweden is high, the percentage of men whose quality of life is substantially affected is much lower.

INTRODUCTION

LUTS are a common problem of ageing men and with the increasing mean age of the general population the number of individuals with LUTS is likely to increase, and must be considered when resources are planned for medical care. The term BPH has traditionally been used to describe a constellation of obstructive and irritative voiding symptoms that occur in men as they age. Such symptoms may result from a various causes, including prostatic enlargement, and thus the term LUTS has replaced BPH to describe this symptom complex [1]. Since the WHO International consultation committee on BPH recommended estimating the incidence and prevalence of symptomatic BPH in various populations worldwide [2], a few studies in different countries have been reported [3–7].

These studies are difficult to compare because there are no uniform definitions and many variations in the methods. Although the histopathological definition of BPH as a condition affecting both the glandular and stromal components of the prostate, which often characterized by enlargement of the prostate, is clear [7–8], the clinical diagnosis criteria are still controversial [9]. Also, not all cases of BPH are symptomatic; moreover, LUTS are not specific and not necessarily indicative of BPH, and might be affected by other factors not directly associated with prostatic conditions.

Differences in methods lie in the scoring systems, with variations in the wording and number of questions, differences in techniques of obtaining information (e.g. self-administration, telephone or personal interview), different age ranges and differences in design and study populations.

Thus the purpose of the present large population-based study was to estimate the prevalence of LUTS, as measured by the IPSS, in different age groups of men 45–79 years old living in two counties (Örebro and Vastmanland) in central Sweden. We also assessed the intercorrelations between different symptoms, and between LUTS severity and quality of life, and evaluated health-seeking behaviour among men with LUTS in this population.

SUBJECTS AND METHODS

A population-based prospective cohort of Swedish men, including 48 645 living in Västmanland and Örebro counties, was established during the autumn of 1997 and winter/spring of 1998. These two counties are of similar size, characterized by a mix of urban and rural living areas, with a male population that can be regarded as representative of that in Sweden. An invitation to participate in the study, with the questionnaire about life-style behaviour, was mailed to all men aged 45–79 years living in the two counties in 1997; the response rate was 48%. In the analyses we included 39 928 men with complete information on all seven questions about current presence and severity of urinary symptoms.

The questionnaire included questions based on the IPSS, eliciting the presence and severity of seven urination symptoms, i.e. fullness (incomplete emptying), frequency (frequent urination), intermittency (urinary stream starts and stops), urgency (sudden, compelling urge to urinate), poor flow (weak stream), hesitancy (difficulty in starting a urinary stream) and nocturia (frequent need to urinate at night). This numerical symptom scoring system grades the presence of seven symptoms on a discrete scale of 0–5 (0, not at all; 1, less than one in 5; 2, less than half the time; 3, about half the time; 4, more than half the time; 5, almost always). The disease-specific quality-of-life (QoL) question was phrased as follows ‘If you have to spend the rest of your life with your urinary condition just the way it is now, how would you feel about it?’, with the answer scale from 0 (very good) to 6 (terrible). We also asked about the subject's medical history of urination disorders, with the time of the first diagnosis, past or current medication with at least one of six drugs indicated for the medical treatment of BPH in Sweden, and the duration of this medication. Additional questions referred to demographic data, medical history and medication for other disorders, anthropometric factors, physical activity and dietary habits. The questions about LUTS were derived from the AUA-7 BPH questionnaire [10], adopted by the WHO as the IPSS [11]. These questionnaires have been validated for test/retest reliability, validity and clarity [10]. The index used to measure LUTS was the Swedish version of the IPSS. Based on the total symptom score, three symptom subclasses were established for the resulting total score, i.e. minor (0–7 points), moderate (8–19) and severe (20–35) [10]. The seven possible answers to the QoL question were divided into four categories, i.e. unaffected (very good; good feeling for living with the current LUTS), mildly affected (acceptable feeling), moderately affected (neither good nor bad; fairly bad feeling) and severely affected (very bad; terrible) [9].

The result were analysed statistically using the frequency procedure in a commercial statistical package. A correlation matrix of the scores for each of the seven symptoms was constructed to quantify the correlation among them, using the Spearman rank coefficient (r), as many of the variables had a skewed distribution.

RESULTS

The frequency distribution of the level of severity according to age is shown in Table 1. Among respondents, 83% reported at least one symptom and 41% reported at least one symptom ‘less than half the time’ or more often (irritative symptoms 32%, obstructive symptoms 9%). If a total score of ≥ 8 is regarded as symptomatic [12] the prevalence of symptomatic men in Sweden is 12%, 18%, 27%, 38% in the age groups of 45–49, 50–59, 60–69, 70–79 years, respectively, and overall 23%. The IPSS was significantly positively correlated with age (Spearman coefficient 0.25, P < 0.001).

Table 1.  The frequency distribution of the severity of LUTS with age in the cohort of Swedish men aged 45–79 years in 1997
Age group,NoneMildModerateSevereAge group %
Score 0 1–7 8–1920–35 
45–4928.360.010.0 1.8 16.8
50–5422.062.313.1 2.5 20.0
55–5918.161.616.5 3.7 16.5
60–6413.262.119.8 4.8 13.3
65–6912.157.723.4 6.7 13.6
70–74 8.955.527.1 8.6  11.5
75–79 7.551.930.9 9.7  8.2
Total, %17.259.518.5 4.8100

The frequency of symptoms occurring ≥ ‘less than half the time’ was 4–35% among the different age subgroups (Fig. 1). These percentages tended to increase with age for all symptoms. Frequency was the most common symptom for the men aged <70 years and nocturia for those >70 years. The correlation of age with the nocturia severity score was higher than that with other symptoms (0.36, P < 0.001) and the corresponding correlation of age with the frequency severity score was the lowest (0.09, P < 0.001). The distribution of the symptom index was strongly skewed to the left (Fig. 2); no symptoms at all (IPSS 0) were reported by 17% of men and 17% had an IPSS of 1.

Figure 1.

The prevalence (percentage) of specific LUTS occurring ≥ ‘less than half the time’ in the cohort of 39 928 Swedish men aged 45–79 years, by age.

Figure 2.

The distribution of the IPSS in the cohort of 39 928 Swedish men aged 45–79 years in 1997.

The intercorrelations between the seven specific LUTS are shown in Table 2. Hesitancy, poor flow and intermittency were highly correlated with each other (r = 0.56–0.60). Among all men, 11%, and among symptomatic subjects 29%, reported that they had been diagnosed previously for their urinary problems. Only 11% of symptomatic subjects received medication for their problem.

Table 2.  Spearman correlations between LUTS specific with each other in the cohort of Swedish men aged 45–79 years in 1997
 FullnessFrequencyIntermittencyUrgencyPoor flowHesitancyNocturiaQoL*
  • *

    QoL related to the bothersomeness of LUTS.

Fullness1.000.400.520.350.520.520.280.48
Frequency 1.000.450.470.430.370.370.49
Intermittency  1.000.380.600.560.300.49
Urgency   1.000.390.310.330.46
Poor Flow    1.000.590.320.56
Hesitancy     1.000.240.44
Nocturia      1.000.52

The extent to which men were bothered by their symptoms, i.e. how their QoL was affected by LUTS, was concluded from their perception of the future when asked about spending the rest of life with their current symptoms (Table 3). The Spearman correlation between the IPSS and poor QoL caused by the bothersomeness of LUTS was 0.70 (P < 0.001). Among those with mild symptoms only 2.6% felt that they had a fairly bad, very bad or terrible perception about the future if they were to live with the way they urinate now, and among men with moderate or severe symptoms this perception was reported by 35.7% (Fig. 3).

Table 3.  Frequency distribution of the QoL index related to bothersomeness of LUTS according to age in the cohort of Swedish men aged 45–79 years in 1997
QoL*45–4950–5960–6970–79
  • *

    QoL related to the bothersomeness of LUTS.

Unaffected83 1 3 4
Mildly affected12192835
Moderately affected 4 61013
Severely affected 1 1 34
Figure 3.

The distribution of the self-perception of how quality of life is affected by the severity of LUTS in the cohort of 39 928 Swedish men.

DISCUSSION

These self-reports of almost 40 000 Swedish men aged 45–79 years indicate that overall 23% had moderate to severe LUTS, as measured by the IPSS. The severity of LUTS was positively correlated with age; in the youngest group (45–49) the prevalence of moderate and severe symptoms was 12% and in the oldest group 40.6%. Frequency was the most common symptom in men aged <70 years and nocturia in those aged >70 years. Among symptoms, hesitancy, poor flow and intermittency were highly correlated with each other. The correlation between the severity of LUTS and the poor QoL score was high.

The strength of this study is the precision of the estimates because there were many men in this cross-sectional survey. Furthermore, the subjects were representative of the Swedish male population in age composition, educational status and prevalence of overweight. The proportion of younger men (45–64 years) was 67% in the cohort and 68% in the entire Swedish population over the same sampled age range in 1997 [13]. The proportion of overweight (body mass index ≥ 25 kg/m2) was 58% among men aged 45–64 and 54% among older men (65–79 years) in the study cohort; this is similar to a Swedish national survey of living conditions in 1996/1997, where 59% of younger men and 52% of the older men (65–84 years) were overweight [14]. The proportion of participants in the study cohort with college/university education was 21% among younger and 10% among older men; in the entire Swedish population the respective values were 23% and 13% (65–74 years) [13].

It might be also an advantage that the men in the study reported their LUTS using a mailed questionnaires. Some men may be too embarrassed to report directly during face-to-face interview the true state of their urinary function, and may answer the questions more frankly if presented with a self-administered questionnaire [15].

However some limitations should be considered. Although the age composition, education and prevalence of overweight in the study cohort was representative of the Swedish male population aged 45–79 years, there is still a possibility that those who did not respond to the survey may differ in some other way from those who did. The participants may be more attentive in recording their symptoms, and this might lead to a slight overestimate of the prevalence of men with symptomatic LUTS.

Second, these data cannot be used to measure the prevalence of BPH specifically, because the symptoms associated with BPH can also result from other urinary conditions, e.g. prostate cancer, urethral stricture and neurological bladder disturbances [1].

Third, some studies have excluded men who reported a history of prostatic surgery [16]. We have no information available from the questionnaire but in 10–30% of prostatectomies there would be no change in the symptoms after surgery [17]. Moreover, a proportion of men undergoing surgery may later be recommended a second prostatectomy or medical treatment.

The prevalence of all single symptoms increased with age. Nocturia was almost seven times as common in 70–79-year-old men (35%) as in 40–49-year-olds (5%). This high dependence on age may be caused by several factors. It may reflect the higher fluid excretion in 70-year-old men than in younger men. As a consequence of age-associated diminished renal-concentrating capacity, diminished sodium-conserving ability, loss of the circadian rhythm of antidiuretic hormone secretion, decreased secretion of renin-angiotensin-aldosterone, and increased secretion of atrial natriuretic hormone, there is an age-related alteration in the circadian rhythm of water excretion, leading to increased night-time urine production in older people [16–17]. One further explanation for nocturia among elderly men may be an alteration of sleep pattern with age [16].

Although 23% of men had moderate or severe LUTS this does not reflect the degree of concern that they expressed about their QoL caused by LUTS. Only a third of symptomatic men (IPSS >7) expressed dissatisfaction (fairly bad, very bad or terrible perception) about spending the rest of their lives with their current urinary condition, i.e. most men seem to tolerate a certain level of symptoms with no complaint. This finding is in agreement with a previous report from Scotland [18] about observed stoicism in men with LUTS.

The reason for this uncomplaining endurance is not clear, and this issue needs more research. One explanation would be that older subjects regard LUTS as part of normal ageing. Jolleys et al.[19] studied 423 men aged 40–79 years in the UK, finding that the symptoms associated with the greatest degree of bothersomeness were frequency, nocturia and those causing incontinence leading to social embarrassment. Men with greater severity of symptoms tend to be worried and embarrassed about their symptoms [20]. Moreover, men with impaired health conditions (physical or emotional problems) may be more sensitive to prevalent urinary symptoms and more likely to report them [21]. Moreover, other factors will probably affect the willingness to express the bothersomeness of LUTS, e.g. cultural characteristics, attitudes toward the physician, emotional distress, cost and risk of overestimation.

Although LUTS were more common among those aged 60–79 years than in men aged 45–59 years, the prevalence of LUTS was also high in the latter group (31% reported at least one symptom ≥‘less than half the time’). Thus, LUTS affect not only the elderly but also middle-aged men. Most of those aged 45–59 years in the study (88%) were wage-earning and therefore fulfilling their daily duties while having LUTS may involve difficulties.

The prevalence of LUTS in different countries is shown in Table 4. This comparison indicates that Swedish men have apparently a lower prevalence of moderate to severe LUTS than Asian and American men. However, these observations do not simply imply that Swedish men are less symptomatic, because the differences in score are not necessarily equal to differences in clinically symptomatic magnitude, and they may reflect differences in the perception of discomfort and reporting, through cultural influences [22].

Table 4. . The prevalence of men with moderate to severe IPSS in different countries
 SwedenSpain [3]Netherlands [18]Denmark [19]USA [20]Canada [21]Asia [6]
Symptom scoreIPSSIPSSIPSSModifiedRescaled IPSS
AUA-7AUA-7AUA-7MadsenAUA-7AUA-7AUA-7
Data collectionMailedDirectMailedMailedMailedTelephoneMailed
Response rate, %    48  68 65 65  55 55
Sample size39 9281953502368 21195084072
Age groups    45–79  50–85 55–74 20–79  40–80 50–70  40–79
% prevalence
40–49     7  24   18
45–49    12      
50–59    18   18  31 15  29
50–54    16  18     
55–59    20  19 26    
60–69    27   23  36 27  40
60–64    25  28 30    
65–69    30  33 30    
70–79    38     44 31  56
70–74    36  36 36    
75–79    41      

In addition, the studies differ in design, with data collected by a questionnaire administered by face-to-face interview [3],by telephone or self-administered by mail [5], as in the present study. In the USA [15] the symptom scores were highest when a mailed self-report was used (as in the present study) and were lowest using a telephone interview. On this issue it is conceivable that the present data, obtained using mailed questionnaires, reflect a true difference in the prevalence of LUTS between Sweden and other countries, especially the USA and Asian countries.

In Sweden, irrespective of the reasons, it is apparent that few men seek help for their urinary symptoms. Only a third of symptomatic men reported that they had been diagnosed for urinary problems previously. This issue emphasizes the important need for better public education and awareness of the relatively high prevalence of LUTS in society.

ACKNOWLEDGEMENTS

The study was supported by research grants from the Swedish Council for Working Life and Social Research, the Swedish Research Council/Longitudinal Studies, Örebro County Council Research Committee and Örebro Medical Center Research Foundation, Örebro, Sweden.

CONFLICT OF INTEREST

None declared. Source of funding: Swedish Council for Working Life and Social Research, Swedish Research Council/Longitudinal Studies; Örebro County Council Research Committee, Örebro Medical Center Research Foundation.

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