Association between body mass index and urinary tract infection: a systematic review and meta-analysis of observational cohort studies.

Background and objective Very few studies have investigated the relationship between body mass index (BMI) and risk of urinary tract infection (UTI), and conclusions from these available studies have been inconsistent. To resolve this inconsistency, we performed a systematic review and meta-analysis to precisely examine the association between BMI and UTI. Methods This meta-analysis was performed based on the PRISMA recommendations. PubMed, Web of Science, Scopus, Embase, and Google Scholar databases were searched for all published observational studies that reported the risk of UTI based on BMI categories up to March 2020. Results Fourteen (n = 14) articles comprising 19 studies in different populations met our inclusion criteria. The overall analysis showed a significant increased risk of UTI in subjects affected by obesity vs. individuals without obesity (RR = 1.45; 95% CI: 1.28 - 1.63; I2 = 94%), and a non-significant increased risk of UTI in subjects who were overweight (RR = 1.03; 95% CI: 0.98 - 1.10; I2 = 49.6%) and underweight (RR = 0.99; 95% CI: 0.81 - 21; I2 = 0.0%) when compared to subjects who had normal weight. In the stratified analysis, we showed that obesity increased the risk of UTI in females (RR = 1.63; 95% CI: 1.38 - 1.93) and in subjects below 60 years old (RR = 1.53; 95% CI: 1.33 - 1.75). Conclusion This systematic review and meta-analysis recognized a significant relationship between BMI and incidence of UTI in obese vs. non-obese subjects, as well as in females and in individuals below 60 years old.