Literature on overactive bladder (OAB) prevalence and its risk factors in adolescent are limited. The aim of this study is to investigate the prevalence of OAB in Chinese adolescent by survey the first grad of university students.

From September 2018 to December 2018, 14800 students (22±12.9y) from two universities in Henan Province were investigated. Students come from 368 cities and 23 provinces of all over the country. After the informed consent, anonymous questionnaires were used to obtain the prevalence of OAB and information of risk factors. The questionnaire included general items such as gender, date of birth, birthplace, height, weight, and college entrance examination scores, history of urinary infection, defecation, and overactive bladder score (OABSS).OAB is defined as urinary urgency with or without urgent urinary incontinence, usually with increased frequency of urine and nocturnal urine, but without urinary tract infections or other exact lesions. The Overactive Bladder Symptom Scale is used to assess the presence and severity of OAB. Urinary emergency score of OABSS (> 2 points) and total score (> 3 points) can be diagnosed as OAB. 3 < score < 5 is mild OAB, 6 < score < 11 is moderate OAB, and 12 is severe OAB. In addition, many variables including gender, age, place of residence, body mass index, constipation, history of urinary tract infection and enuresis were evaluated. Simple and multiple logistic regression analysis with complex sampling were used to analyze the correlation between these variables and the prevalence of OAB.

A total of 13416 questionnaires (4287 from boys and 9129 from girls) were qualified for statistical analysis The overall prevalence of OAB was 6.1% (823/13416) , of which  754 cases were mild OAB patients (91.6%) and 69 cases were moderate OAB patients (8.4%),patients without severe OAB. The prevalence OAB of the 18, 19, 20, 21, 22 and 23 age groups were 6.6%, 6.3%, 6.5%, 6.7%, 5.2% and 4.6%, respectively, and no significant difference were found between them. A total of 782 (95.0%) cases with OAB suffered from urgency, 436 (53.0%) frequency, 184 (22.4%) nocturia, 73 (16.4%) urgent urinary incontinence. The prevalence of OAB was 4.8% in boys and 6.8% in girls. The prevalence of OAB in constipation patients was 8.7%, higher than that in non-constipation patients. The prevalence of OAB in patients with anal dehiscence, anal fissure, urinary tract infection and enuresis was higher than that in other groups (P < 0.05). Multivariate and unconditional logistic regression analysis of the univariate analysis of meaningful indicators found that gender, constipation, rectal prolapse, anal fissure, history of urinary tract infection and enuresis were significantly associated with OAB. There were 9128 people with normal weight (18.5 < BMI < 24), of which 525 (5.8%) suffered from OAB, 1237 were overweight (24 < BMI < 28), 89 (7.2%) suffered from OAB, 199 were obese (BMI < 28) and 13 (6.5%) suffered from OAB, but there was no significant difference among the three groups (P > 0.05). There are 7583 people who meet the standard weight, including 447 (5.9%) with OAB, 854 with obesity (defined as 20% over standard body weight), 52 (6.5%) with OAB. Group differences were not statistically significant. Moreover, the prevalence of OAB was not related to the place of residence and age.

The prevalence of OAB in this study is lower than that in other countries, which may be related to differences in race and lifestyle. The intake of caffeine and alcohol in Westerners is significantly higher than that in China. Caffeine and alcohol are mild diuretics, which can also excite detrusors and induce excessive detrusor activity. The higher prevalence in girls than in boys may be related to the unique anatomical structure of girls, such as female urethra. Short, prone to urinary tract infection; Constipation patients with high prevalence of OAB, may be associated with feces in the rectum stay too long, leading to rectal dilatation, detrusor hyperactivity; Anal declamation and anal fissure are risk factors for OAB, may be related to the disease easily lead to bacterial proliferation, cause urinary inflammation; Urinary infection history and enuresis are significantly related to OAB, the reason may be related to It is related to bladder dysfunction.

OAB is common in Chinese adolescents and gender, constipation, anal prolapse, anal fissure, history of urinary tract infection and enuresis were its risk factors.