Tuesday, September 26, 2017

Childhood experiences and PCBs relative to melanoma

This is a little weird and there is much to be considered when looking at an epidemiological study....was it strictly the point in question (here elevated PCBs), or the genetic make-up of the population, or something else they all happened to eat, drink, participate in, be exposed to????? - that makes the outcome what it is????  Nevertheless, this study caught B's eye because he knows that my grandparents and several aunts/uncles lived in this area while I was a child and young adult.  As such, I spent a fair amount of time visiting Anniston, Munford, Talledega, and Jacksonville, Alabama from early childhood until my granny passed in 1992.  I was born in 1964...so not sure what all this means or if it played any role in my condition.  For the record, no one else in my extended family who lived in that area, nor any of my siblings have melanoma, though my grandfather died of what was said to be "leukemia" though some of the information that has been passed on doesn't really line up with that, sounding more like lymphoma instead, but I was too young to understand much at the time and by the time I had a medical education there was really no way to extract more information.  However, an aunt in the area has dealt with non-Hodgkin lymphoma for about as long as I have been dealing with melanoma.  So...here you go:

Serum polychlorinated biphenyls and leukocyte telomere length in a highly-exposed population: The Anniston Community Health Survey. Callahan, Pavuk, Birnbaum et al.Environ Int. 2017 Sep 5.

Serum polychlorinated biphenyls (PCBs) have previously been associated with longer leukocyte telomere length (LTL) in most, but not all, of the few previous studies. PCBs were produced in Anniston, Alabama from 1929 to 1971 and participants of the Anniston Community Health Survey (ACHS) were highly exposed.

We evaluated serum levels of 35 PCBs and relative telomere length in 559 ACHS participants.

Relative LTL was measured in DNA extracted from blood clots. We assessed PCBs individually, grouped by chlorination, and summed PCBs. We used linear regression to assess the association between each PCB metric while adjusting for pertinent covariates.  

Serum PCBs were associated with longer LTL among white participants and the oldest age group of black participants. Among white participants, compared with those in the first quartile of sum PCBs those in the third quartile of sum PCBs had 8.09% longer relative LTL and those in the fourth had 7.58% longer relative LTL. Among African American participants, serum PCBs were associated with longer relative LTL among those over age 64 only. Tests for interaction were not statistically significant.  

We observed a non-linear positive association between serum PCBs and LTL among white participants. Serum PCBs were associated with longer LTL in the oldest age group of African Americans. This association may provide insight into the cancers previously associated with exposure to PCBs, melanoma and non-Hodgkin lymphoma, which have been associated with long LTL in previous studies.
So...if this is true, and the correlation is direct...there seems to be another need for limiting exposure to PCBs (not that we didn't already know that for numerous other reasons)!  For what it's worth. - c

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