Volatile N-nitrosamines and their precursors in chinese salted fish—a possible etological factor for NPC in China

Authors

  • Xiao Nong Zou,

    Corresponding author
    1. Departments of Epidemiology, Cancer Institute, Chinese Academy of Medical Sciences, Beijing, China
    • Department of Epidemiology, Cancer Institute, Chinese Academy of Medical Sciences, P.O. Box 2258, Beijing, 100021, China. Fax: 01 771 3648.
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  • Shih Hsin Lu,

    1. Etiology and Chemical Carcinogenesis, Cancer Institute, Chinese Academy of Medical Sciences, Beijing, China
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  • Bin Liu

    1. Departments of Epidemiology, Cancer Institute, Chinese Academy of Medical Sciences, Beijing, China
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Abstract

Epidemiological studies show that the consumption of Chinese salted fish is a causative factor for nasopharyngeal carcinoma (NPC) in southern China. In the present study, N-nitrosamines and their precursors were analyzed in 145 samples of cooked, salted fish collected from various areas in China. The results show that N-dimethylnitrosamine (NDMA), N-diethylnitrosamine (NDEA), N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP) were present in the salted fish. Total volatile N-nitrosamines (TVN) in the salted fish were 0.028 to 4.54 mg/kg. The samples from areas with higher NPC risk showed a higher average level of TVN than those from areas of lower NPC risk. Positive correlations were found between the levels of NDMA, NDEA and TVN and mortality from NPC. Although neither the nitrates nor the nitrites in the salted fish were present at significantly high levels, in vitro data regarding nitrosation of salted fish showed that the N-nitrosamine content had increased substantially. The results support the conclusion that the high NPC risk in southern Chinese may be attributed to consumption of salted fish containing high levels of N-nitrosamines.

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