Volume 30 Number 4

Did you know... that 43.5% of New Zealand women between the ages of 16 and 74 report at least some urinary incontinence?

A recent publication in the New Zealand Medical Journal¹ describes the results of questions regarding urinary incontinence into the annual New Zealand national health survey conducted by the New Zealand Ministry of Health. The survey data is available, on application, and is held by Statistics New Zealand. The survey is a sophisticated representative sample survey of New Zealanders designed to estimate and track the prevalence of important health conditions. The survey consists of a set of standard questions and additional ‘modules’. We realised that the results of the two continence questions in the survey had not been published when we were asked to advise the New Zealand Ministry of Health of suitable questions to add to a module in the upcoming 2024/2025 survey. Although the results are relatively old, based on data collected a decade ago; the survey design is robust and representative, with the ability to appropriately weight by sampling probabilities, and includes useful ancillary information such as measured body size, parity, and ethnicity.

The two continence questions in the 2014/2015 survey were adapted from those used in the 2003 United States of America Nurses Health Study and were about the frequency and amount of urinary incontinence. The continence questions comprised two questions: about frequency of incontinence in relation to month, week and day; and amount of incontinence, categorised as “a few drops”, “enough to wet your underwear”, “enough to wet your outer clothing” and “enough to wet the floor.” For reporting we used ‘any’ reported continence and explored overall prevalence and prevalence in relation to age, body size, parity, and ethnicity. Overall, about 5500 survey respondents answered questions about continence. The headline result was that 43.5% of respondents reported at least some incontinence. Unsurprisingly, the prevalence of urinary continence increased as age increased, affecting 21% of those aged between 16 and 29 compared to 51% of those aged 50 to 74. Urinary incontinence prevalence increased as body size increased, affecting 13% of those with a BMI of less than 18.5 kg/m² and 52% with a BMI of greater than 30. Finally, urinary incontinence prevalence increased with parity, affecting 34% who were nulliparous and just over 50% of those with parity of 2 or more. After adjustment for age, body size, and parity; urinary incontinence prevalence was not associated with parity.

Although the described associations are not new, the survey has revealed the high prevalence of continence problems among New Zealand women and provides reasonably contemporary estimates that may help health funders and planners in planning and providing appropriate services.

Author(s)

Mark Weatherall
University of Otago, Wellington, New Zealand
Email mark.weatherall@otago.ac.nz

References

1. Weatherall M, Hay-Smith J, Wilson D. Prevalence of urinary incontinence in New Zealand women from the cross-sectional Sexual and Reproductive Health module of the New Zealand Health Survey 2014/2015. NZ Med J. 2024;137(1598):59–72. doi: 10.26635/6965.6575. Erratum in: NZ Med J. 2024 Jul 19;137(1599):114. doi: 10.26635/6965.er1599