Incidence and risk factors of female urinary incontinence: a 4-years longitudinal study among 24985 adult women in China

Objective To estimate the incidence of urinary incontinence (UI), including its subtype: stress UI (SUI), urgency UI (UUI), and mixed UI (MUI), and to examine risk factors for de novo SUI and UUI in Chinese women. Design Nationwide longitudinal study. Setting Six geographic regions of China PARTICIPANTS: Women aged ≥20 years old were included using a multistage, stratified, cluster sampling method. Methods This study was conducted between May 2014 and March 2016, with follow-up in 2018. Data on demographics, medical history, lifestyle, physiological and anthropometric information were collected. Main outcome measurements incidence, rate ratio (RR) RESULTS: Analyses included 24,985 women ( mean age, 41.9 years old).The follow-up response rate was 55.5%, median follow-up time was 3.7 years. The standardized incidence of UI, SUI, UUI and MUI were 21.2, 13.1, 3.0, and 5.1/1000 person-years, respectively. Risk factors for de novo SUI included delivery pattern (vaginal spontaneous delivery (RR 2.12, 95% confidence interval 1.62-2.78), instrumental delivery (3.30, 1.99-5.45)), high body -mass index (BMI) (overweight (1.52, 1.33-1.74), obesity (1.67, 1.32-2.11)), cigarette smoking (1.54, 1.12-2.12), chronic cough (1.44, 1.17-1.76), diabetes (1.33, 1.10-1.60), and older age (50-59 years (1.49, 1.16-1.90), 60-69 years (1.61, 1.22-2.13)).The risk factors significantly associated with de novo UUI were age (RR increased from 1.21 (0.74-1.99) at 30-39 years to 6.3 (3.85-10.30) at >70 years) and diabetes (1.48, 1.05-2.09). Conclusions The incidence of female UI is 21.2/1000 person-years in China. Delivery (vaginal spontaneous delivery, instrumental delivery), high BMI, cigarette smoking, chronic cough, diabetes, and older age were risk factors.