This is a developing story. Policy Watch will run a full story, including interviews with scientists and community residents tomorrow.
Two areas near Lake Norman have reported statistically higher than expected incidences of thyroid cancer, according to a May 29 letter obtained Tuesday by Policy Watch from the state Department of Health and Human Services.
Most of the cases occurred in two Zip Codes: 28115 and 28117. The state undertook the analysis because of community reports of thyroid cancer, including several cases involving teenage girls.
Thyroid cancer is unusual in young people. It more commonly affects women in their 40s and 50s.
In preparing the assessment, the state’s Central Cancer Registry and the Division of Public Health concluded that from 1995 to 2016 the observed number of thyroid cancer cases in the 28115 Zip Code was two times the expected number.
In the 28117 Zip Code, the observed number was more than double over the same time period, and three times higher from 2012 to 2016.
Overall, Iredell County reported statistically higher rates of thyroid cancer: 1.5 times from 1995 to 2016, and more recently, 1.7 times from 2012 to 2016.
“This investigation cannot be used to determine the cause of the observed cancers or identify possible associations with any risk factors,” the letter read. “It is important to note that the data and statistical analysis conducted at this step cannot determine if cancers observed in the community are associated with specific environmental, lifestyle, or other risk factors.”
Genetics and/or environmental exposure can increase a person’s risk for thyroid cancer. Exposure to radiation, flame retardants and perfluorinated compounds, such as GenX and PFOAs, can also enhance the risk. These compounds have been found in the Cape Fear River, a result of discharges and emissions from the Chemours plant near Fayetteville.
However, they also been detected at low levels in Lake Michie, in northern Durham County; since no industry discharges into the lake, Durham water officials believe the compounds are entering the water from the air.
Duke Energy built Lake Norman in the late 1950s and early 1960s. The utility’s McGuire nuclear power plant sits on the southern end of the lake; the Marshall Steam Station, a coal-fired power plant is also located on the lake, directly west of Mooresville.
The Occupational and Environmental Epidemiology Branch will review the data and determine the next steps, which will include reviewing the literature for environmental exposures associated with thyroid cancer risk, a DHHS spokeswoman told Policy Watch. “These steps will be completed with input from the community and others who have been involved in bringing attention to this issue. Information gathered will help inform whether a study can be done to look for a common exposure or risk factor among thyroid cancer cases in this area of North Carolina.”