Prevalence and trends in urinary incontinence among women in the United States, 2005-2018.

Background: Women are disproportionately affected by urinary incontinence compared with men. Urinary incontinence results in physical and psychological adverse consequences and impaired quality of life and contributes to significant societal and economic burden. Previous studies reported high urinary incontinence burden in the United States. However, the current prevalence and recent trends in urinary incontinence and its subtypes among US women have not been described. In addition, correlates of urinary incontinence among US women have not been systematically evaluated in the contemporary population.

Objective: The purpose of this study was to determine the prevalence and trends in urinary incontinence among adult women in the United States from 2005 to 2018. In addition, this study aimed to investigate the relationship of urinary incontinence subtypes with several sociodemographic, lifestyle, health-related, and gynecologic factors.

Study Design: We used data from the National Health and Nutrition Examination Survey, a nationally representative series of surveys that was designed to evaluate the health status of the US population. Data on urinary incontinence from 7 consecutive 2-year cycles (2005-2006 to 2017-2018) were used for this study. A total of 19,791 participants aged ≥20 years were included. Weighted prevalence estimates and 95% confidence intervals were calculated in each study cycle for stress, urgency, and mixed urinary incontinence. Multivariate-adjusted weighted logistic regression was used to investigate the temporal trends in urinary incontinence, in addition to determining the association between urinary incontinence subtypes with several participants' factors.

Results: In the 2017-2018 cycle, stress urinary incontinence was the most prevalent subtype (45.9%; 95% confidence interval, 42.1-49.7), followed by urgency urinary incontinence (31.1%; 95% confidence interval, 28.6-33.6) and mixed urinary incontinence (18.1%; 95% confidence interval, 15.7-20.5). The prevalence rates of urgency and mixed urinary incontinence were higher in women aged 60 years and older (urgency, 49.5% [95% confidence interval, 43.9-55.2]; mixed, 31.4% [95% confidence interval, 26.2-36.6]) than in those aged 40 to 59 years (urgency, 27.9% [95% confidence interval, 23.6-32.1]; mixed, 15.9% [95% confidence interval, 12.9-19.0]) and those aged 20 to 39 years (urgency, 17.6% [95% confidence interval, 13.8-21.5]; mixed, 8.3% [95% confidence interval, 5.4-11.3]). The overall prevalence of stress and mixed urinary incontinence was stable throughout 2005 to 2018 (both P=.3), with increases in mixed urinary incontinence among women aged 60 years and older (P=.001). The prevalence of urgency urinary incontinence significantly increased, particularly among women aged 60 years and older (both P=.002). Age, obesity, smoking, comorbidities, and postmenopausal hormone therapy were associated with higher prevalence of all types of urinary incontinence. Black women were less likely to report stress urinary incontinence but more likely to report urgency urinary incontinence.

Conclusion: Although the estimated overall prevalence of stress and mixed urinary incontinence remained stable from 2005 to 2018, the prevalence of urgency and mixed urinary incontinence significantly increased among women aged 60 years and older. All subtypes of urinary incontinence were higher among women with obesity and comorbidities, those who used postmenopausal hormone therapy, and those who smoke.