The influence of age, parity, oral contraception, hysterectomy and menopause on the prevalence of urinary incontinence in women.

The influence of age, parity, duration of previous oral contraceptive use, hysterectomy and menopause on the prevalence of urinary incontinence was evaluated by means of a postal questionnaire in women 46 to 86 years old who resided in the city of Göteborg, Sweden. A sample of 10,000 women from the 7 birth cohorts of 1900 to 1940 was obtained at random from the population register. The overall response rate was 74.6%. The prevalence of urinary incontinence increased (p < 0.001) in a linear fashion from 12.1% in the 1940 birth cohort to 24.6% in the 1900 birth cohort. The prevalence of urinary incontinence in nulliparous women was 7.7% in the 1930 birth cohort and 5.5% in the 1940 birth cohort. The corresponding figures for women who had experienced 1 delivery were 11.1% and 10.6%, compared to 14.0% and 16.4% among women who had had 3 or more deliveries. Urinary incontinence was more prevalent in women who had undergone hysterectomy (p < 0.05). The prevalence of urinary incontinence was unaffected by the duration of previous oral contraceptive use and there was no evidence to suggest that the prevalence of urinary incontinence increased at the time of the last menstrual period.