Urinary incontinence has been defined by the International Continence Society as 'the involuntary loss of urine which is a social and hygienic problem and can be objectively demonstrated'. This is a useful definition, although the subjective component leaves it open to variable interpretation, with consequent difficulty in establishing its prevalence. This is further contributed to by prevalence differences between populations and inconsistency of questions used. Thus, for example, studies have used such diverse questions as 'do you have difficulty in controlling your water?', 'do you have involuntary loss of urine on two or more occasions per month?', 'have you had involuntary loss of urine at any time in the previous year?' or 'have you ever suffered from bladder problems?'.