Association between urinary bisphenol A and overactive bladder: Evidence from the NHANES 2003-2016

Bisphenol A (BPA), recognized as an environmental endocrine disruptor, has been implicated in modulating the behavior of urothelial cells, precipitating detrimental effects in the bladder and contributing to lower urinary tract dysfunction in mice. However, the exact link between urinary BPA levels and the development of overactive bladder (OAB) is not yet fully understood. This study aimed to examine the potential association between urinary BPA levels and OAB in a nationally representative group of individuals. The investigation was conducted using extensive datasets from the National Health and Nutrition Examination Survey (NHANES), which covered the years 2003-2016. Urinary BPA concentrations were quantified via solid-phase extraction coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The diagnosis of OAB was established when participants attained a total score of 3 or higher on the Overactive Bladder Symptom Score (OABSS) assessment. The association between urinary BPA and OAB was investigated using survey-weighted logistic regression models and subgroup analyses. The study included a cohort of 9143 participants, 1803 of whom (19.7%) were diagnosed with OAB. Urinary BPA concentrations spanned 0.14 - 965 ng/mL across the cohort. Participants were stratified into tertiles based on these levels. The highest tertile of BPA was found to be linked to a higher risk of OAB by the logistic regression analyses(OR = 1.15; 95% CI: 0.96-1.39; P = 0.12), albeit not statistically significant. Female participants showed a greater risk of OAB compared to male participants (OR = 1.75; 95% CI: 1.42-2.15; P < 0.0001). To explore this further, separate logistic regression analyses were conducted for male and female participants, respectively. Noteworthy, the logistic regression analyses, adjusting for age, ethnicity, education, marital status, BMI category, smoking status, drinking status, hypertension, and diabetes, demonstrated a significant link between elevated urinary BPA tertiles and heightened OAB risk in female participants (OR = 1.34; 95% CI: 1.05-1.71; P = 0.02). This trend of progressively increasing risk across exposure categories was further supported by subgroup analyses. Taken together, these results indicate that greater urinary BPA exposure correlates with elevated OAB susceptibility among women. Thus, minimizing BPA exposure emerges as a potential strategy for OAB risk reduction in this demographic, with implications for both prevention and clinical management.