sodium-nitrite and Leukemia

The objective of this study is to investigate the risk of esophageal carcinoma in a cohort with long-term occupational exposure to sodium nitrite. The method used was a retrospective cohort study. A small wood screw manufacturer was founded in 1977 and closed down in 2000. In their production process, the sodium nitrite solution was used to serve as anticorrosive and coolant fluid. One hundred sixty workers in turning and milling shops had direct exposure to sodium nitrite through skin, mouth, and airway because of lack of occupational protective knowledge (study group), whereas 255 workers from other workshops without direct contact with sodium nitrite served as control group. The incidence, diagnosis, and treatment of esophageal carcinoma as well as other malignant tumors in these two groups were followed until the end of 2007. The sodium nitrite exposure time in the study group ranged from 16 to 23 years, with an average of 22.1 years. During 30 years of follow-up, there were 11 esophageal carcinomas and 10 other malignant tumors (4 hepatic cell carcinomas, 3 lung cancers, 2 breast cancers, and 1 leukemia) documented in the study group, while no cancer developed in the control group. The risk for esophageal carcinoma was significantly increased in the study group compared with the control group (relative risk = 1.26, 95% confidence interval = 1.08-1.46, chi-square = 116.83, P < 0.001). Long-term exposure to sodium nitrite markedly increases the risk of esophageal carcinoma in human body.

Topics: Adolescent; Adult; Aged; Breast Neoplasms; Carcinoma; Chi-Square Distribution; China; Construction Materials; Esophageal Neoplasms; Female; Follow-Up Studies; Humans; Incidence; Kaplan-Meier Estimate; Leukemia; Liver Neoplasms; Lung Neoplasms; Male; Middle Aged; Occupational Exposure; Retrospective Studies; Risk; Sodium Nitrite; Young Adult

Chronic sodium nitrite (SN) treatment potentiated spontaneous and 1,2-dimethylhydrazine (DMH)-induced carcinogenesis. Mice injected with SN alone showed a higher incidence of leukemia and lung cancer than in controls. Combined treatment with DMH and SN induced most of benign and malignant tumors (hepatic hemangioendothelioma, hepatocarcinoma, renal adenoma, etc.). The difference in the numbers of DMH- and SN-induced tumor bearers was not significant until a concentration of 500 mg/l was reached (64.7%). The level of multiple tumor incidence increased when SN 50 and 500 mg/l was used. Unlike DMH alone, cumulative incidence of DMH-specific tumors and leukemia after combined treatment was higher. An evaluation of cumulative incidence and relative risk established an indirect but positive correlation between SN dose, on the one hand, and spontaneous and induced carcinogenesis, on the other. The strongest carcinogenic effect was reported when DMH was used in combination with SN 500 mg/l. Our data confirmed the carcinogenic hazard of chronic exposure to SN which increased when in combination with that to a specific carcinogenic substance.

Topics: 1,2-Dimethylhydrazine; Animals; Carcinogens; Cocarcinogenesis; Drug Synergism; Leukemia; Lung Neoplasms; Male; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Sodium Nitrite

The carcinogenicity of sodium and of sodium nitrate was examined in F-344 rats. Sodium nitrite was administered in the drinking-water for 2 yr at levels of 0.125 or 0.25%. Sodium nitrate was given in the diet at levels 2.5 or 5%. A variety of tumours occurred in all groups including the controls. The only significant difference between treated and control groups in the total number of tumours detected in either of the studies was a significant decrease in tumour incidence in the high-dose females given nitrite compared with controls. There was no positive dose-response relationship either in the incidence or in the induction time of tumours in either of the studies. The only significant result was a reduction in the incidence of mononuclear cell leukaemias in the experimental groups in both studies. It is concluded that sodium nitrite and sodium nitrate did not exert a carcinogenic effect that could be detected under the conditions of this study in which the animals showed a high incidence of spontaneous tumours.

Topics: Animals; Female; Leukemia; Liver Neoplasms; Male; Mammary Neoplasms, Experimental; Neoplasms; Nitrates; Nitrites; Nitroso Compounds; Rats; Rats, Inbred F344; Sodium Nitrite; Stomach

Sodium nitrite has been widely used as one of the most effective food additives to tinge color on cured meat. However, it has been elucidated that this chemical is not merely a precursor of N-nitroso compounds, many of which are strongly carcinogenic, but also a mutagenic substance in biological tests. In order to ascertain the possible tumorigenicity of sodium nitrite itself, chronic toxicity of the agent in mice, by means of daily oral administration as drinking water for more than 18 months, in the concentration of 0.5 (maximum tolerated dose), 0.25, and 0.125%, was tested. As a result, development of various tumors, including thymic lymphoma, nonthymic lymphoid leukemia, pulmonary adenoma and carcinoma, and benign and malignant tumors in soft tissue, was seen in these mice. However, as to the incidence of tumors as well as the developmental time of each histologically classified tumor, no apparent difference was detected between those in the experimental groups and the control group.

Topics: Animals; Carcinogens; Female; Leukemia; Liver Neoplasms; Lung Neoplasms; Male; Mammary Neoplasms, Experimental; Mice; Mice, Inbred ICR; Nitrites; Sodium Nitrite; Soft Tissue Neoplasms; Thymus Neoplasms; Time Factors; Uterine Neoplasms