The Contrast Meta-analyzes Of Digestive System Neoplasm And Drinking Water-related Factors Between China And America

ObjectiveTo understand the discrepancy of burden of digestive system neoplasm between Chinaand America, we described and contrasted epidemiological situation of diseases containingstomach cancer, esophagus cancer, and colorectal cancer in these own countries. To explainthe causes of theses epidemiological discrepancy in terms of drinking water, the risk factorsrelated to drinking water were analyzed and compared between two countries.MethodsMortality-related data were collected in various resources, and mortality changetendency over20years were illustrated in China and America. Then, literatures of relativecohort study and case-control study were searched in various databases. Meta-analyzescalculated pooled odds ratio of risk factors in terms of water sources, nitrate pollution,disinfection by-products, and pesticide pollution. Sensitivity analysis was conducted to teststability of analysis, and fail safe numbers were calculated to test publication bias.Results1. There was an upward tendency for digestive system neoplasm mortality in Chinesepopulation, while a downward tendency in American population. The age-standard mortalitymanifested that Chinese population was higher than American population in male and femalewith both P value less than0.001. 2. In Chinese population, the pooled odds ratio for tap water was0.76(0.64,0.89), fordeep well water was0.49(0.28,0.86), for shallow well water was1.98(1.26,3.12), forsurface water was3.43（2.30,5.12）, for ditch water was1.92(1.02,3.60), for raw water was1.40（0.90,2.16）, for nitrate pollution was1.13（1.04,1.22）, for disinfection by-productspollution was1.24（0.97,1.57）, and for pesticides pollution was1.28（0.89,1.83）. inAmerican population, the pooled odds ratio for surface water was1.32（1.13,1.53）, fornitrate pollution was1.27（1.02,1.58）, for disinfection by-products pollution was1.21（1.13,1.29）, and for pesticide pollution was1.06（0.92,1.22）.Conclusion1. Chinese digestive system neoplasm mortality is in upward tendency, while Americanis in downward tendency.2. The standard mortality of digestive system neoplasm is higher for Chinese than forAmerican.3. Surface water, nitrate pollution are risk factors for digestive system neoplasm in bothChina and America.4. Disinfection by-products is risk factor in American population, but this relationshipwithout statistically significant in Chinese population.5. No significant association of pesticide pollution with digestive system neoplasm wasdetected in this meta-analysis.