Linking Dioxins to Diabetes
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Linking Dioxins to Diabetes
Date:
Fri, 27 Sep 2002 10:28:51 -0400
From:
Stephen Tvedten <steve@getipm.com>
Organization: Get Set Inc. (www.getipm.com)
To: Paul Helliker <phelliker@cdpr.ca.gov>
Director, State of California, Department of Pesticide
Regulation
cc: Christine Whitman whitman.christine@epa.gov
http://ehpnet1.niehs.nih.gov/docs/2002/110p853-858remillard/abstract.html
...may give you the full paper, too: Remillard & Bunce, 'Linking Dioxins to Diabetes: epidemiology & biologic plausibility' _Env. Health Perspectives:110:853-8 (9/'02)
It's an excellent review of one of dioxin's most potent effects. Aside from thoroughly reviewing both the epidemiology and evidence for various mechanisms (revolving around metabolic pathways & signals), it crucially speculates on a critical reason that worker studies diverge from general population studies. The worker dioxin exposure studies, which unlike the general population studies showed no correlation w/ diabetes, were done on phenoxy herbicide manufacture workers. 2,4-D and 2,4,5-T, this paper says & cites, are known peroxisome proliferators (they bind to the p.p. activated receptor--PPAR). Apparently this is an anti-diabetic mechanism, which the authors speculate would mask the diabetic effect of TCDD. The paper says the Ah receptor may well antagonize PPAR functions, which promotes diabetes through various pathways discussed, rather densely (for me). The several general population/other studies all show a weak but consistent correlation of TCDD (low ppt levels typical in people) w/ diabetes. And of course diabetes incidence has exploded in recent decades, obviously for multifactorial reasons.
Anyway, the phenoxy herbicide confounder is a KEY, strong hypothesis to keep in mind in arguments about low dose effects of dioxin like compounds, and to pull out when people argue the epidemiological evidence is inconsistent. --
Tony Tweedale
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