Dissertation
Dissertation > Medicine, health > Preventive Medicine,Health > Epidemiology and Prevention of Disease > Epidemiology of the basic theory and methods > Special epidemiological each

Analysis on the Morbidity and Mortality of Bladder Cancers of the Population Exposed to Benzidine from1965to2012in Tianjin

Author BaoYaLi
Tutor QiXiuYing
School Tianjin Medical University
Course Epidemiology and Biostatistics,
Keywords Benzidine bladder cancer historical perspective study occupational tumor epidemiological investigation
CLC R181.3
Type Master's thesis
Year 2013
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Objective:To further understand the features of incidence of occupational bladder cancer and malignant tumor through epidemiological investigation in dyeing industry workers exposed to benzidine in Tianjin. It may provide basis for further developing and carrying out medical care for occupational bladder cancer, and improving occupational bladder cancer prevention, treatment, and management.Methods:A historical perspective epidemiological investigation was conducted to analyse bladder cancer incidence or mortality on the1165workers exposed to benzidine of dyes industry in Tianjin from1965to2012. Dose-response relationship was studied between incidence and workages or densites. An survival analysis was carried out, and influencing factors were anlaysed for incidence and prognosis of bladder cancer cases. The distribution of incubation, onset age, age of death, the survival time after diagnosis, recurrence and causes of deaths of bladder cancer cases was described by descriptive analysis method, and all causes of deaths and malignant tumor death was also described.Results:1. There were a total of104cases of bladder cancer in1165dyeing industry workers exposed to benzidine in Tianjin,50times higher than ordinary residents of Tianjin by2012. Working age, exposure density and smoking were risk factors for bladder cancer incidence, and they showed dose-response relationship, the RR of three working age groups for1~4,5~9and≥10were1.0,1.9,2.7, the RR of three different exposure level groups for low, medium and high were1.0,2.7,8.9. The incidence of bladder cancer in the smoking group was higher than non-smoking group, RR was2.2. The incidence of bladder cancer in the manufacturing group was higher than the using group, the bladder cancer incidence of pressure leaching post in the manufacturing group is highest, followed by inversion post of the manufacturing group, field mixed post of the using group, etc.2. Top three death causes among276male workers exposed to benzidine whose death causes were clear were malignant tumor(43.48%), cerebrovascular disease(23.91%) and heart disease(19.20%) respectively. Lung cancer (27.5%), bladder cancer (25.0%), liver cancer (17.5%) and stomach cancer (8.3%) were the first four causes of all120workers dead from cancers.50.85%of59bladder cancer cases that the causes were clear died of the deterioration or metastasis of bladder cancer. From1965to2012, the risk of male workers exposed to benzidine of dyeing industry in Tianjin dead from cancer was1.64times higher than municipal male standard population in our country, and the death risk of bladder cancer was41.65times of bladder cancer death rate of the male population of our country.3. The incubation mean was31.4±11.0years, the onset age mean was59.57±11.32years, compared with smoking group, the onset age of nonsmoking group delayed for4years. The median death age was69-year-old among104bladder cancer cases. Compared with using group, the average incubation of manufacturing group was5.36years shorter. Bladder cancer recurrence rate was33.7%, the recurrence frequency was up to3times.4. Median survival period of bladder cancer cases after diagnosis was more than40years. T2pathological staging of occupational bladder cancer survival rate was higher than the general population. Of81cases with clear pathological diagnosis, bladder transitional-cell carcinoma (TCC) accounted for71.6%. Cumulative survival rate of Ta, T1, T1-2, T2was higher than the T2, T3, T3, T4. Cumulative survival rate of35~59age group was higher than th≥60age group. Cumulative survival rate of35bladder cancer cases by adopting abdominal surgery was slightly higher than45bladder cancer cases with other treatment method. Onset age was an influencing factor for prognosis of bladder cancer.Conclusion:Smoking and benzidine were risk factors for bladder cancer. Of male workers exposed to benzidine in Tianjin dyeing industry, the incidence and mortality of bladder cancer was significantly higher than the general population, death sequence of bladder cancer was ahead of the general population, the death caused by malignant tumor is at the first place for all of the diseases, and the mortality of malignant tumor is higher than the general population. Compared with general population, for occupational bladder cancer, the onset age of diagnosis was younger, incubation was longer, the recurrence rate was higher, tumor malignancy was lower, the prognosis is better with longer lifetime. The same pathological staging survival rate was higher than the general population. Onset age of bladder cancer patients has some influences on prognosis.

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