[A paired case-control study for assessing the relationship between the incidence of malignant lymphomas and the viruses infections].

OBJECTIVE: To evaluate the relationships between the viruses infections and the incidence of malignant lymphomas (ML) in Sichuan province. METHODS: A hospital-based paired case-control study was designed with two controls per case. The case group comprised 97 cases diagnosed as ML by pathological examination; the control group A consisted of 194 subjects randomly selected from those with non-malignancies by matching on both gender and age in the corresponding period. Additionally, a control group B for Epstein-Barr virus(EBV), including 80 subjects, were chosen from other non-malignant diseases at the same time. Enzyme-linked immunosorbent assay(ELISA) was employed to test the serum antibodies and antigens of hepatitis C virus (HCV), human immunodeficiency virus (HIV), cytomegalovirus (CMV), and hepatitis B virus (HBV). The EBV was confirmed by the EBER in situ-hybridization (EBER-ISH) of pathological tissue. RESULTS: The positive rate of EBV in ML group was 70.1%(68/97) and that of control group was 7.5%(6/80). The difference between these two groups showed a statistical significance by conditional logistic regression analysis (OR = 6.58, 95% CI: 16.164-82.846, P = 0.0001). The differences in HCV, CMV and HBV infections between case group and control group demonstrated no statistical significance with P-values of 0.260, 0.258 and 0.399 respectively. We found no positive results of HIV antibody in case group and control group. CONCLUSION: The incidence of ML in Sichuan displayed a significant association with EBV infection. However, there were no relationships between the incidence of ML and the HCV, HBV, HIV, CMV infections in the area.

[A case-control study for assessing the relation between the incidence of malignant lymphomas and environmental factors in Sichuan province].

OBJECTIVE: To evaluate the relationships of malignant lymphoma (ML) and exposure factors, including environmental, drug using, socioeconomic level and life style etc. METHODS: (1) Hospital-based case-control study with 1:2 matching was used; (2) 150 cases of ML and 300 controls were resulted; (3) logistic regression was used. RESULTS: (1) Adjust odds ratios (aOR) regarding contact to organic solvents were: benzene aOR = 2.78, P = 0.001;banana oil aOR = 2.28, P = 0.043; paint aOR = 1.96, P = 0.023; (2) aOR on pesticides contact: organic phosphorus aOR = 1.98, P = 0.034; chrysanthester aOR = 2.57, P = 0.013; organic nitride aOR = 2.55, P = 0.003; (3) aOR of using aspirin was 2.36, P = 0.005; (4) dog-raising: aOR = 1.76, P = 0.034; (5) the aORs of interval-term exposure to small dosage X-ray was 0.49, P = 0.015, and frequently catching cold was 0.67, P = 0.024; (6) the P-value of different occupations was more than 0.05; cigarette smoking OR = 1.01, P = 0.897; giving up smoking OR = 1.17, P = 0.073; alcohol-drinking aOR = 1.01, P = 0.414; hair-dyes OR = 1.06, P = 0.850; hair-perms OR = 1.26, P = 0.438; socioeconomic level OR = 1.00, P = 1.000 and with introversive character OR = 1.26, P = 0.266. CONCLUSIONS: (1) Factors that might increase the risk of suffering from malignant lymphomas would include direct contact to organic solvents and some pesticides (organic phosphorus, chrysanthester and organic nitride), intake of aspirin, as well as dog-raising. (2) Regular exposure to small dosage X-ray and frequently catching cold seemed to decrease the risk of suffering from ML. (3) Occupation, smoking, giving up smoking, alcohol-drinking, hair-dyes, hair-perms, socioeconomic level and introversive character showed no significant relations to the risk of suffering from ML in this study.