A new study led by a researcher at Milken Institute School of Public Health (Milken Institute SPH) at the George Washington University looks at the metal cadmium and finds that higher human exposure can lead to significantly shorter telomeres, bits of DNA at the ends of chromosomes that are associated with cardiovascular disease, diabetes and other diseases of old age. The study, which was published online today in the American Journal of Epidemiology, is the largest-ever to look at cadmium exposure and telomeres.
"We looked at heavy metals in this study and found a strong association between exposure to low levels of cadmium and telomere shortening," says Ami Zota, ScD, MS, an assistant professor of environmental and occupational health at Milken Institute SPH. "Our findings suggest that cadmium exposure can cause premature aging of cells. And they add to other evidence indicating this heavy metal can get into the bloodstream and trigger kidney disease and other health problems."
The World Health Organization calls environmental exposure to cadmium a "major public health concern," and notes this heavy metal has been associated with cardiovascular disease, respiratory problems, cancer and other serious diseases. People typically are exposed to small amounts of this toxic metal by inhaling tobacco smoke, eating fruits and vegetables grown in contaminated soil or living near an industrial site, according to Zota.
In this study, Zota and her colleagues looked at blood and urine samples taken from more than 6,700 adults who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2002, a nationally representative health survey of the U.S. population. The researchers obtained purified DNA from blood cells and then used a genetic technique known as polymerase chain reaction to measure the telomeres, the caps on the tips of chromosomes that help protect the genetic code.
Then the researchers measured the concentration of cadmium in the blood and urine samples. They divided the participants up into fourths based on the concentrations of cadmium found in their bloodstream, finding that people in the highest group had telomeres that were about six percent shorter than those in the lowest group.
"People with the highest cadmium exposure had cells that looked on average 11 years older than their chronological age," Zota said, adding that even people in the highest group of exposure still had very tiny amounts of metal in their bloodstream. "This study adds to evidence suggesting that no level of exposure to this metal is safe."
Normal wear and tear on the telomeres leads to shortening as people get older. But other factors, including cadmium, may speed up that process. When the telomeres get too short, the cell can no longer divide and chronic diseases can be the result.
The findings of this study suggest that cadmium can elicit harmful effects on the human body at levels well below the current safety standards set by environmental and occupational safety agencies. Such findings suggest that public health officials may need to accelerate the efforts to reduce the contamination of the environment--so that people are protected from even trace amounts of this metal, Zota notes.
The World Health Organization says global efforts to reduce exposure to this metal are urgently needed in order to protect the public health. Because tobacco smoke releases cadmium into the air WHO recommends a ban on smoking in public places. The group also suggests that governments worldwide promote better ways of disposing batteries and other measures to prevent contamination of the environment. Interventions should be aimed at protecting the most vulnerable, such as minority or low-income populations, who are often disproportionately exposed.
For non-smokers, food is generally the largest source of cadmium exposure, Zota says. Cadmium levels in some foods can be increased due to the application of phosphate fertilizers or sludge that is applied to farm fields.
Many other studies have linked exposure to cadmium to a host of health problems but this is one of the first to suggest it can shorten telomeres and set people up for premature aging, Zota says. This study also looked at human exposure to the heavy metal lead but found no link between blood levels of lead and shorter telomeres, Zota says.
Still, she says the new study's findings do not prove that exposure to cadmium actually causes telomeres to get shorter. Instead, this study finds an association between cadmium levels and shorter telomeres, a link that was strong and independent but must be proven with additional research.
Zota served as the lead author on the study. Other collaborators on the study included researchers from the University of California, San Francisco, the University of Michigan, Ann Arbor and the Stanford University School of Medicine. The study was funded by the National Institutes of Health
About Milken Institute School of Public Health at the George Washington University:
Established in July 1997 as the School of Public Health and Health Services, Milken Institute School of Public Health is the only school of public health in the nation's capital. Today, nearly 1,534 students from almost every U.S. state and more than 45 countries pursue undergraduate, graduate and doctoral-level degrees in public health. The school also offers an online Master of Public Health, MPH@GW, and an online Executive Master of Health Administration, MHA@GW, which allow students to pursue their degree from anywhere in the world.
Kathy Fackelmann | EurekAlert!
Atomic-level motion may drive bacteria's ability to evade immune system defenses
24.04.2017 | Indiana University
Two-dimensional melting of hard spheres experimentally unravelled after 60 years
24.04.2017 | University of Oxford
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences