Reconstruction of the radiological component of the exposome in the CONSTANCES cohort

As an innovative approach to contribute to the study of the health effects of ionizing radiation (IR) exposure, we developed a method to characterize the radiological component of the exposome as exhaustively as possible. We estimated annual equivalent IR doses in millisieverts (mSv) received by six target organs (brain, breast, lung, colon, prostate and thyroid) from the largest possible set of sources, for 21,720 adult participants in the French general population cohort CONSTANCES from birth (age 0 year) until the age they reached in 2020. We considered the following environmental sources of IR: indoor radon, telluric and cosmic radiation (at ground level and from air travel), ingestion of natural radionuclides, fallout from the Chernobyl accident and atmospheric nuclear tests, emissions from normally operating nuclear plants. In addition, we included doses from frequent medical procedures, namely diagnostic nuclear medicine, computed tomography, mammograms, panoramic dental radiographs and repeated chest X-rays from occupational medicine check-ups. We estimated organ equivalent doses considering year, age at exposure and sex where appropriate, based on CONSTANCES data, supplemented with responses from a specific questionnaire related to IR exposures. At the end of follow-up in 2020, the mean attained age was 53 years (standard deviation: 13 years) and the average doses from all sources cumulated up to this age from age 0 (with 25th and 75th percentiles) are for colon: 98 mSv (61-107); brain: 79 mSv (55-92); breast: 98 mSv (60-115); thyroid: 89 mSv (54-97); lung: 1712 mSv (1110-2133) and prostate 74 mSv (52-87). This first reconstruction of the radiological exposome will be used for analyses of the health effects of low-dose IR integrated over lifetime.