Background
Methods
Prevalence of risk factors
Risk factor | Population at risk | Reference | Relative risk | Reference | ||
---|---|---|---|---|---|---|
Smoking | Males | Females | [19] | Males | Females | [22] |
Ex-smokers | 6.9% | 3.3% | 1.5 | 0.92 | ||
Current smokers | 46.8% | 31.6% | 2 | 1.73 | ||
Trihalomethanes | 94.7% | [20] | 1.1–1.4 |
Risk factor: Smoking
Risk factor: THM
Statistical method
Results
Formula application | Gender | 25–34 | 35–44 | 45–54 | 55–64 | ALL |
---|---|---|---|---|---|---|
Smoking | M | 29.5% | 34.3% | 37.5% | 34.7% | 33.4% |
F | 11.2% | 19.2% | 24.7% | 24.2% | 18.6% | |
Trihalomethanes | Both | NA | NA | NA | NA | 8.65% |
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Smoking:By applying the modified Levin formula, we used as P1 the percent of males that were current smokers (46.8%) and RR1 the relative risk due to smoking which is 2 and used as P2 the percent of males that were ex-smokers (6.9%) and RR2 the relative risk due to ex-smoking which is 1.5. Bladder cancer cases that were the result of smoking in Lebanon among males were 33.4% of cases for all age groups. Similarly, we applied the formula for females and found that bladder cancer cases that were the result of smoking among females were 18.6% of cases for all age groups if we consider the smokers percentage in 2009 and its implication by 2018. The risk impact is not immediate; we need a 10-year lag to draw any conclusions. For specific age groups of males and females, the percent of smokers and ex-smokers for each age category were obtained from the WHO’s Chronic Disease Risk Factor Surveillance data for Lebanon [19] and formula applied. Results are shown in Table 2.
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THM contamination:Chlorination is the most adopted method of water sanitization in Lebanon, it is economical, quick and accessible. To calculate the percentage of bladder cancer cases attributed to mid-term exposure to THM contamination of drinking water we used the value of 94.7% for the Pe and value of 1.1 for RR since exposure to THM in Lebanon is midterm exposure. By applying the formula, we found that around 8.6% of bladder cancer cases in Lebanon could be attributed to THMs.