title: Epidemiological assessment of risk to humans from exposure to nitrosamines.
abstract: In order for epidemiologists to evaluate the 'nitrosamine hypothesis' it is necessary to develop measures of human exposure to N-nitrosamines - both exogenous and when formed internally through consumption precursors. Dissatisfied with indefinite findings using indirect indices of N-nitrosamine exposure, we have attempted to derive an index based on the known kinetics of N-nitrosamine formation. This has been applied in a case-control study of cerebral tumours and resulted in a suggestive finding of increased risk for exogenous but not total N-nitrosamine exposure. A potential difficulty with our index is doubt as to whether vegetable sources of nitrates and consequent endogenous formation of nitrites indeed result in N-nitrosamine exposure, in view of the possible presence of blocking agents or of vitamin C consumed at the same time as vegetables. Further work is necessary, but we hope to apply the index in a case-control study of gastric cancer currently under analysis.
mesh_terms: D004128:Dimethylnitrosamine / Q000032:analysis; D004781:Environmental Exposure; D005260:Female; D005504:Food Analysis; D006801:Humans; D008297:Male; D008460:Meat / Q000032:analysis; D009369:Neoplasms / Q000139:chemically induced*; D009566:Nitrates / Q000032:analysis*; D009573:Nitrites / Q000032:analysis*; D009602:Nitrosamines / Q000009:adverse effects* / Q000032:analysis; D010947:Plants, Toxic; D012306:Risk; D014026:Nicotiana / Q000032:analysis
chemical_list: D009566:Nitrates; D009573:Nitrites; D009602:Nitrosamines; D004128:Dimethylnitrosamine