To investigate the prevalence of day time urinary incontinence (DUI) and its risk factors in young adults in China by a survey in university students. and provide reference basises for disease control and youth health.

A total of 13,385 first grade students (aged18-22 years, 4,256 boys and 9,129 girls) from two universities of Mainland China were investigated in this study from Sep. 2018 to Dec. 2018. An anonymous questionnaire was used to collect the information: ①gender, date of birth, weight, inhabitation(living in rural or urban areas); ②Whether exist day time urinary incontinence (DUI); ③Types of day time urinary incontinence; ④DUI frequency; ⑤Whether co-exist frequent; ⑥Whether co-exist urgency; ⑦Whether co-exist constipation; ⑧Whether co-exist urinary tract infection; The inclusion criteria of DUI are intermittent or persistent involuntary leakage of urine; Exclusion criteria were obvious organic diseases: such as lower bladder urinary tract obstruction, neurological diseases, incomplete questionnaires, etc.

A total of 13,874 questionnaires (93.7%) were collected and 13,385 of which (90.4%) were qualified for statistical analysis. The overall prevalence of DUI was 4.3%, 2.3% in boys and 5.2% in girls ,and have significant difference between them (p<0.05).The overall prevalence of DUI in different age group is ranged from 4.0% to 4.69% .The overall incidence of DUI in the 18-year-old group was 4.13%, 1.69% in boys and 5.34% in girls. The overall incidence of DUI in the 19-year-old group was 4.21%, 2.48% in boys and 5.11% in girls. The overall incidence of DUI in the 20-year-old group was 4.0%, 1.94%in boys and 5.07% in girls. The overall incidence of DUI in the 21-year-old group was 4.64%, 2.61% in boys and 5.31% in girls. The overall incidence of DUI in the 22-year-old group was 4.34%, 2.36% in boys and 5.01% in girls. The incidence was 3.6%(163 cases) in urban areas and 4.7%(369 cases) in rural areas. Boys with urgency incontinence accounted for 61.9%(60 cases), stress urinary incontinence accounted for 38.1% (37 cases), girls with urgency incontinence accounted for 43.6% (60 cases), and stress urinary incontinence accounted for 56.4%(265 cases) respectively, of all DUI cases. It is found that 7.91%(210 cases) with constipation, 3.46% (360 cases) with no constipation, 24.1%(105cases) with urinary tract infection, 3.74% (465cases) with no urinary tract infection. A total of 76%(433cases) of DUI occurred less than 1 times a week, 13.9% (79 cases) more than 1 times a week, 7.5%(43 cases) daily, 0.9% (5 cases) 2-4 times a day,1.7%(10cases) 5 times a day.

With the development of society and the improvement of people's quality of life, Day time urinary incontinence has been considered as one of the five major diseases affecting human beings since the mid-1990s, seriously affecting people's physical and mental health. It not only plaguing middle-aged and elderly people, but also in the youth. The results of this survey showed a significant differences in the prevalence of day time urinary incontinence between boys and girls. This is consistent with the literature and may related to the different anatomy of lower urinary tract between boys and girls. The risk of DUI has increased by 2.29 times with constipation. The risk of DUI has increased by 6.44 times with urinary tract infection. Repeated urinary tract infections might results in increase in bladder responsiveness resulted in frequent, urgency and DUI increases.

The DUI is common in Chinese young adults, frequently accompanied by frequency, urgency and other symptoms. The main risk factors of DUI are urinary tract infection, constipation, OAB, and living environment (rural and urban). It is suggested that the prevalence of DUI in young adults is expected to be reduced by treatment of urinary tract infection, constipation, OAB and improving the living environment (rural urbanization).