Researchers with the Navajo Birth Cohort Study aren’t looking for simple answers about how uranium exposure affects health. We already know—and have known for decades—that contact with uranium can cause kidney disease and lung cancer.
This study is the first to look at what chronic, long-term exposure from all possible sources of uranium contamination—air, water, plants, wildlife, livestock and land—does down through the generations in a Native American community.
Since the study began in 2012, over 750 families have enrolled and 600 babies have been born to those families, said Dr. Johnnye Lewis, director of the Community Environmental Health Program & Center for Native Environmental Health Equity Research at the University of New Mexico Health Sciences Center and NBCS principal investigator.
“We’re collecting a huge amount of data,” Lewis said. “At this point … all of our results are preliminary, [but] what we do know is that if we look at uranium in urine in the Navajo participants we see higher concentrations than we would expect based on the U.S. population as a whole… [In babies,] we are seeing a trend that uranium levels in urine increase over the first year.”
The Navajo Nation overlies some of the largest uranium deposits in the U.S. Between 1944 and 1986, miners extracted nearly 30 million tons of uranium from Navajo Nation lands. Navajo miners did not have protective suits or masks; they took their work clothes home for laundering; they and other community members used rocks from the mines to build their homes.
When the Cold War ended, most of the uranium mines on Navajo were abandoned—not covered, or sealed, or remediated, just left as they were with waste piles exposed to wind and rain and accessible to anyone, including children.
Today, more than 500 open abandoned uranium mines are spread across the Navajo Nation and uranium dust, particles and radiation continue to be released into the environment.
The questions the NBCS seeks to answer are complex. Uranium does not exist in isolation at the mine sites, so the study is looking at 36 different metals associated with uranium. “We do that because when you look at uranium waste, it’s not just uranium that’s in the waste,” said Lewis. “None of the variables that we look at, none of the causes or the outcomes that we look at are on-off binary sort of things. What we look at is as concentrations of uranium or other metals changes, can we see changes in responses?”
Researchers have also been alarmed by the findings that levels of iodine and zinc are lower than they should be in the study group. Iodine levels are about 40 percent below the World Health Organization sufficiency level, and 61 percent of the mothers in the study have zinc levels below the WHO sufficiency level. “Iodine deficiencies [are] very, very important because iodine is really critical for normal organ development and neurodevelopment,” said Lewis. “And we worry about zinc because we have some evidence that it may be involved in the repair process when you have exposure to some of the metals that we look at. [A lack of zinc] actually inhibits the body’s ability to fix damage to DNA.”
Documenting these deficiencies would make the NBCS worthwhile “even if we learn there are absolutely no [long-term health] effects from uranium,” Lewis said. “Whatever we find out is going to be important.”
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Two other endeavors resulting from the study are already in the works, and both will be hugely important to the well-being of Navajo families in the future.
The project has just won Environmental Influences on Child Health Outcomes (ECHO) Program funding from the National Institutes of Health. The project is looking at kids all across the U.S. to try to understand how their environment influences their health. It will eventually include 50,000 children and at least two cohorts will be from Native American communities, Lewis said. “We’re just really pleased that they’re including Native Americans.”
The Centers for Disease Control funding for the NBCS only allows families to be followed for up to one year. This new funding, which extends over 5 years after a 2-year initial period, will allow the researchers to go back and look again at each child on an annual basis and do much more detailed developmental assessments. In the process, they will be able to develop an assessment that takes into account Navajo parenting styles and create an instrument that is valid specifically for Navajo children, unlike standardized developmental assessments that are devised based primarily on the dominant culture’s parenting practices.
To accomplish that, “we put together a clinical team that is going to be training our Navajo staff to deliver these developmental assessments. It will be a long process of working together. They’ll be trained and then they will shadow the clinical team so that they get a lot more experience off Navajo before ever coming back here and then when they come back they’ll each be partnered with either a neurodevelopmental expert or psychometrician … who will be hired through the program. They will initially shadow them and then be shadowed by them to ensure that we have consistency.
“So at the end of seven years what we’re going to have is a really great team of professional evaluators who will be staying on Navajo and who will provide that new service” to Navajo families, Lewis said.
The NBCS is a collaborative effort of the University of New Mexico’s DiNEH Project, Center for Disease Control/Agency for Toxic Substances and Disease Registry (CDC/ATSDR), Navajo Area Indian Health Service, and the Navajo Nation Division of Health, and the Southwest Research and Information Center.
Women between the ages of 14 and 45 who have lived on the Navajo Nation for five years, are pregnant and will deliver their babies at hospitals in Chinle, Gallup, Shiprock, Ft. Defiance and Tuba City are eligible to participate in the study. Call 1-877-545-6775 for information.