Saturday August 16, 2008 (foodconsumer.org) -- A new study in the journal Diabetes Care shows people who have been exposed to high levels of polychlorinated biphenyls or PCBs may be at a higher risk of type 2 diabetes than those who have not.

The toxic effect of PCBs was found in Taiwanese adults who were poisoned in the 1970s by cooking oil contaminated with the pollutants.

For the study, Dr. Yueliang Leon Guo at the National Taiwan University and colleagues compared 378 adults who were exposed to PCBs with 370 of their neighbors who were not for their incidences of type 2 diabetes.

Women who used cooking oil tainted with PCBs were found twice as likely as others to develop type 2 diabetes during a period of 24 years.   Those who were severely affected by PCB exposure were four times as likely to develop the condition.

But no association was found in men.

PCBs were used as coolants and insulating fluids for transformers and capacitors, pesticide extenders, cutting oils, flame retardants, hydraulic fluids, sealants, adhesives, wood floor finishes, paints, de-dusting agents, and in carbonless copy paper, according to wikipedia.

Due to their high toxicity, PCBs were banned in 1970s.   But they are persistent in the environment decades later causing concerns about their impact on the environmental health.

Another similar group of chemicals known as polybrominated biphenyls or PBBs replace PCBs in many applications such as in flame retardants.   These chemicals also cause concerns because they are chemically very similar to PCBs.