The Linear No-Threshold (LNT) dose response model: A comprehensive assessment of its historical and scientific foundations

An entire issue of Chemico-Biological Interactions (published 1 March 2019) is devoted to the topic of the Linear No-Threshold (LNT) Model. [Attached] is the contribution by Ed Calabrese, who says this “represents my most comprehensive assessment yet, of this topic.” [Chapters of all papers in the CBI issue are now available as free downloads from the journal website.]

The [attached] chapter provides a detailed historical assessment of the origin, and progressive development, of the LNT dose-response single-hit Model. The time period of this historical assessment began in 1927 β€” after Hermann Joseph Muller reported that he had produced transgenerational phenotypic changes (i.e. heritable mutations) in the fly (Drosophila melanogaster) by using very high doses of X-rays β€” to the present time, with discovery (over this past decade) of critical errors made by the U.S. NAS (National Academy of Sciences) BEIR (Biological Effects of Ionizing Radiation) I Genetics Subcommittee in 1972. This has led to acceptance of LNT, and perpetuation of these errors through subsequent BEIR committees, including BEIR VII [the 7th book (published 2oo6) in the series of titles from the National Research Council that addresses the effects of exposure to low-dose LET (linear energy transfer) ionizing radiation and human health].

Calabrese’s chapter not only details the peer-reviewed literature, but also makes extensive use of personal papers of numerous leading individuals that helped to determine the acceptance of LNT by scientific and regulatory communities β€” as well as the general public. Despite its standard toxicological analysis framework, this paper also has “elements of a scientific detective story” with its many unexpected historical twists and turns. This analysis is also different than the traditional scientific review in that it documents a disturbing effort by some leaders of the radiation genetics community (during the 1940s-1960s) to force acceptance of the LNT Model, at almost any cost.

Also discussed is the well-documented evidence of deceptions, obfuscations, and deliberate scientific misconduct β€” all of which has significantly impacted the broader scientific and medical communities, and regulatory agencies of the U.S. (e.g. the EPA) and worldwide. This, in turn, has affected cancer risk assessment policies, practices, and recommendations, and has had a major impact on environmental regulation, the public health, and medical practices throughout the world. Awesome reading. πŸ™‚

DwN

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