Exposure to metallic cadmium produces a shortening of the ends of human DNA called telomers that are equivalent to an 11 year reduction in cell’s lifespan. The equivalent loss of lifespan in the body is considered to be valid as well. These are the results of the largest study of the effects of heavy metals on human genetics ever undertaken.
The study examined the DNA of 6,700 adults that were part of the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2002. The length of each individual’s telomers was measured from DNA extracted from blood cells. The levels of cadmium were found from urine and blood samples.
The results indicate that the people that were exposed to the highest levels of cadmium had a six percent reduction in telomer length versus people that had no exposure. The shortening of the telomers is the equivalent of losing 11 years of cell life. Telomer length has been shown to directly correlate with chronological age.
The majority of exposure to cadmium comes from smoking tobacco. Improper battery disposal and the uptake of cadmium into food from contaminated soil were the major causes of telomer shortening in people that did not smoke. The study indicates that present levels of exposure to cadmium that are considered safe by all of the world’s health organizations are too high to prevent changes in cellular DNA.
