Association of occupational exposure to chemical substances with bladder cancer in Ethiopia: A multi-center matched case-control Study

BackgroundBladder cancer (BC) is the 10th most common cancer worldwide and ranks 13th in incidence in Ethiopia. Occupational exposure is the second leading cause of BC after smoking, accounting for 21%-27% of BC cases in men and 11% in women. This study aims to investigate the association between occupational exposure to chemical substances and bladder cancer among patients in selected hospitals in Ethiopia. MethodsA multi-center matched case-control study was conducted among patients admitted to four teaching hospitals in Addis Ababa, Ethiopia from May 01 to August 31 2023. Underlying characteristics between cases and controls were compared using Chi-square test and Mann-Whitney U test with statistical significance set at p [&le;] 0.05. A multivariable binary logistic regression analysis was run where adjusted odds ratios (AOR) with 95% confidence intervals (CIs), and p-values were used for significance testing and result interpretation. ResultsAmong the 303 patients studied, 90 (29.7%) were cases and 213 (70.3%) were controls. Age ({+/-}5 years), sex, and smoking status were matched in 68% of participants. The majority of the participants were age 60 years and above (62.2% of cases, 59.1% of controls), male (72% of cases, 73% of controls) and non-smokers (61.1% of cases, 64.8% of controls). Occupational exposure was not found to be significantly associated with BC (AOR:1.09; 95%CI= 0.44, 2.74; P=0.85). On the other hand, having a primary level education or higher (AOR:0.12 95%CI= 0.05, 0.30; P<0.001), consuming coffee for more than 20 years (AOR:2.36; 95% CI=1.22, 4.56; P=0.01) and regular analgesics use (AOR: 6.60; 95% CI=3.34, 13.02; p<0.001) were found to be significantly associated with BC. ConclusionsOccupational exposure to chemical substances was not found to be significantly associated with BC. However, having primary education or higher was protective, while long-term coffee consumption and regular analgesic use were significantly associated with BC. Health care professionals are advised to educate patients about safe analgesic use. Furthermore, future multicenter case-control studies should be conducted to further explore the potential associations of these factors with bladder cancer.