Cancer Epidemiology Unit

About: Cancer Epidemiology Unit is a based out in . It is known for research contribution in the topics: Population & Cancer. The organization has 669 authors who have published 1725 publications receiving 93979 citations.

Applying the exposome concept in birth cohort research: a review of statistical approaches.

Abstract: The exposome represents the totality of life course environmental exposures (including lifestyle and other non-genetic factors), from the prenatal period onwards. This holistic concept of exposure provides a new framework to advance the understanding of complex and multifactorial diseases. Prospective pregnancy and birth cohort studies provide a unique opportunity for exposome research as they are able to capture, from prenatal life onwards, both the external (including lifestyle, chemical, social and wider community-level exposures) and the internal (including inflammation, metabolism, epigenetics, and gut microbiota) domains of the exposome. In this paper, we describe the steps required for applying an exposome approach, describe the main strengths and limitations of different statistical approaches and discuss their challenges, with the aim to provide guidance for methodological choices in the analysis of exposome data in birth cohort studies. An exposome approach implies selecting, pre-processing, describing and analyzing a large set of exposures. Several statistical methods are currently available to assess exposome-health associations, which differ in terms of research question that can be answered, of balance between sensitivity and false discovery proportion, and between computational complexity and simplicity (parsimony). Assessing the association between many exposures and health still raises many exposure assessment issues and statistical challenges. The exposome favors a holistic approach of environmental influences on health, which is likely to allow a more complete understanding of disease etiology.

Leukaemia and nuclear installations.

Abstract: The study of leukaemia and lymphoma in West Cumbria reported today (p 423) was commissioned by the Black inquiry into the raised incidence of childhood leukaemia in the village of Seascale near the nuclear plant Sellafield.' The risk of childhood leukaemia was found to be unrelated to various indices of environmental contamination from the Sellafield discharges, such as eating seafood or home grown vegetables or playing on the beach. But the risk was raised if the children's fathers had been employed at Sellafield, particularly if they had had relatively high exposures of radiation before the affected children were conceived. The numbers are small, but the effects are large. The fathers of nine (out of 46) cases and 41 (out of 277) local controls were working at Sellafield when the child was born; but four of the case fathers and three of the control fathers had accumulated exposures to 100 mSv or more of external radiation before the child was conceived. An exposure of 100 mSv or more was associated with a sixfold to eightfold increased risk of leukaemia in the offspring. There was evidence ofan increased risk at exposures lower than 100 mSv only when data for the six months before conception were considered, but the numbers were exceedingly small. When children with non-Hodgkin's lymphoma were included with those with leukaemia the results were similar to those for leukaemia alone. By contrast, Hodgkin's disease showed no association with paternal exposure to radiation. Two control groups were selected-area controls, chosen to permit analysis of the geographical relationship of leukaemia to residence near Sellafield, and local controls, chosen to permit analysis of the relationship to parental occupation. Although each control group served a specific and different purpose the findings are similar regardless of which control group was used. Information for the study was collected by painstaking searching through birth and medical records, by examination of Sellafield employment records, and from postal surveys ofparents ofthe children. Much effort has gone into checking the information collected and making it as accurate and complete as possible (p 429), but with diagnoses dating from as early as 1950 it is inevitable that some data are missing, especially those derived from postal surveys. There are few missing values for paternal employment, and details were obtained from birth certificates and Sellafield employment records, so the data relating to work at Sellafield are likely to be reliable and unbiased. This study by Gardner and his colleagues' is the first to examine the relation between paternal employment in the nuclear industry and the risk of leukaemia in the offspring. Some comments seem appropriate at this stage even though the children of other nuclear workers need to be studied before firm conclusions can be drawn. Three separate inquiries into alleged increases of childhood leukaemia near different nuclear installations each concluded that there was a real excess but that the increases were too large to be accounted for by radioactive discharges from the plants.'13 Each report emphasised that alternative-but as yet unknown-pathways of exposure and mechanisms of carcinogenesis needed to be considered. The results of this study by Gardner et al are remarkable not because they offer little support for environmental contamination by radioactive discharges being the cause of childhood leukaemia but because they point to possible alternatives. According to Gardner et al fathers' employment at Sellafield is sufficient to account for the raised incidence of childhood leukaemia in the vicinity. Could paternal employment account for the raised incidence of childhood leukaemia near other plants? The relative risk of childhood leukaemia ranges from 1-4 near Aldermaston and Burghfield to 5 near Dounreay and 10 near Sellafield.1-' This range is incompatible with the cause being environmental exposure to radiation: if that were the cause ofthe childhood leukaemia the relative risks would need to vary more than 1000-fold, since the estimated annual exposure of newborn infants from radioactive discharges ranges from 00000 1 mSv at Aldermaston to 0 005 mSv at Dounreay and 0-3 mSv at Sellafield.3 The variation in occupational exposure at the plants is much less: the average in radiation workers ranges from 7 8 mSv at Aldermaston to 47-0 mSv at Dounreay and 124-0 mSv at Sellafield.Y6 Thus the range of occupational exposure and the different mix of nuclear and other workers in the surrounding community is not inconsistent with the range of leukaemia risks observed. The explanation offered by Gardner et al is not, however, without its problems. The only other relevant human data available are on the 7400 children of Japanese men who survived the atomic bomb explosions, and these show no hint of an increased risk of leukaemia in the offspring.7 And the average exposure to external ionising radiation of the Japanese men was four times higher than that of the Sellafield workers. Some additional explanation will still be required for the children of Sellafield workers. For example, it could be argued that exposure to high levels of radiation at work is a surrogate for exposure to something other than radiation which itself is powerfully leukaemogenic in the next genera-

Ecological-Level Associations Between Highly Processed Food Intakes and Plasma Phospholipid Elaidic Acid Concentrations: Results From a Cross-Sectional Study Within the European Prospective Investigation Into Cancer and Nutrition (EPIC)

Abstract: Elaidic acid is the main unnatural trans fatty acid isomer occurring during partial hydrogenation of vegetable oils used as ingredients for the formulation of processed foods. The main objective is to assess associations between processed food intakes and plasma phospholipid elaidic acid concentrations within the European Prospective Investigation into Cancer and Nutrition study. A cross-sectional study was used to determine fatty acid profiles in 3,003 subjects from 16 centers. Single 24-h dietary recalls (24-HDR) were collected using a standardized computerized interview program. Food intakes were computed according to their degree of processing (moderately/nonprocessed foods, processed staple foods, highly processed foods). Adjusted ecological and individual correlations were calculated between processed food intakes and plasma elaidic acid levels. At the population level, mean intakes of highly processed foods were strongly correlated with mean levels of plasma elaidic acid in men (P = 0.0016) and in women (P = 0.0012). At the individual level, these associations remained but at a much lower level in men (r = 0.08, P = 0.006) and in women (r = 0.09, P = 0.0001). The use of an averaged 24-HDR measure of highly processed food intakes is adequate for predicting mean levels of plasma elaidic acid among European populations.