Thyroid Cancer in French Polynesia: A Population Based Case Control Study

Abstract

P-165 Abstract: A case-control study of thyroid cancer was conducted in FP, aiming to assess the potential role of atmospheric nuclear tests performed by France between 1966 and 1974. The study included 229 cases of differentiated thyroid carcinoma diagnosed between 1979 and 2004, aged up to 30 years old at start of nuclear weapons testing and born and living in FP. 371 controls matched on gender and birth date were randomly selected from the FP register of births. Face to face interviews were conducted from 2001 to 2004 by specialised investigators native from Polynesia who received a specific formation for this study. The addresses are then collected from the territorial medical insurance, which covers all the inhabitants, whatever their professional status. Interviews are monitored in face to face by specialised investigators native from Polynesia who received a specific formation for this study. Detailed information about nutrition at time of interview and at end of the adolescence was collected using a semi-quantitative method using pictures. Data concerning living places, hormonal and reproductive life, familial and personal background of thyroid pathologies and cancers, and professional and environmental exposition to carcinogens was also collected. The iodine intake was estimated from the diet questionnaire, as well as by measuring the stable iodine by spectrography of mass using clipping of nails, which are collected during the interviews. The assessment of individual thyroid doses took into account: residential history and dietary habits of the subjects and deposition densities of radionuclides reconstructed for each island where the subject resided during the testing period. Among these 229 cases born in FP, 89% were females, 54% declared themselves as of pure Maori origin and another 36% as of Maori-Asian or Maori-European origin. Ethnicity was well balanced between cases and controls. No difference was evidenced between archipelago of residence at time of birth of cases and controls: Leeward Islands for 52% vs 56%, Windward Islands for 22% vs 20%, Marquises for 7% vs 5%, Australs for 6% vs 7% and Tuamotu-Gambier for 14% vs 13%. Among the 26 male cases, 4 had worked at the Centre of Pacific Experimentation (CEP) during the atmospheric tests (15%), as compared to 5 of the 47 controls (11%); and 7 (27%) during the underground tests, as compared to 9 (19%) controls. This work was supported by ARC, DGS, EDF, AFSSET, and CHILD-THYR program of the EEC.