Prevalence of overactive bladder and incontinence in Canada

The main objectives of the study were to measure the prevalence of overactive bladder (OAB) with its sub-types (wet OAB, dry OAB, mixed OAB) in the Canadian population and to assess prevalence variations in according to gender and age.

The prevalence of OAB in Canada was investigated via a validated, computer-assisted telephone interview (CATI) system. The interviews were conducted in two steps: an initial questionnaire evaluating if respondents suffered from OAB, followed by a detailed questionnaire completing the assessment. The final data were weighted according to the census of metropolitan areas and by gender, on the basis of Canadian population statistics.

A sample of 3249 adults, aged 35 years and older, was interviewed with the CATI system. Six hundred and three respondents were found to suffer from wet OAB, dry OAB or mixed OAB. The overall prevalence of OAB in this Canadian population was evaluated to be 18.1%. It was lower in men (14.8%) than in women (21.2%). Dry OAB was assessed to be the highest sub-type, with a rate of 13.6%, 11.7% in men and 15.6% in women. The prevalence of wet OAB was estimated to be 2.3%, 2% in men and 2.6% in women. Finally, the prevalence of mixed OAB was found to be 1.2% in this population, with a much lower prevalence in men (0.3%) than in women (2.1%). Dry OAB increased with age in both men and women; wet OAB was markedly higher in both men and women over the age of 75 years. No correlation was observed between age and prevalence of mixed OAB in women, whereas a linear relationship was noted between the two variables in men.

This is the first large study of OAB symptoms prevalence in the Canadian population aged 35 years and older. We established that OAB prevalence was higher in women than in men, with women experiencing more dry OAB and mixed OAB than men.