A Few Q and As from the January 15 CAP Meeting

These are a few of the Q&As from our CAP meeting at the CDC with Director Tom Frieden and new ATSDR Director Patrick Breysse.  These are a mix of requests and questions from both CAP members and the public. Thanks to Sheila at the ATSDR for compiling these:

QUESTION:  How will CDC/ATSDR communicate findings across all the exposure/health effects-related studies conducted thus far at Camp Lejeune? 

CDC/ATSDR will develop a summary of findings for the 4 health studies.  This summary will place our results in context of broader epidemiology and toxicology literature. This summary will be used to communicate an integrated assessment of our current findings to the CAP and other stakeholders.  Additionally, CDC/ATSDR plans to post a version targeted to potentially impacted Marines and their families on its website.  CDC/ATSDR technical staff will also prepare a version for publication in a peer-reviewed journal.

REQUEST:  A CAP member requested that we look into the association with auto-immune related health effects and research around immunotherapy.

Increased risk for a number of auto immune diseases have been associated, in other setting, with the chemicals present in Camp Lejeune water supply.  Investigating the impact of these chemical on auto immune diseases in the Camp Lejeune cohorts is an important component of our ongoing efforts.  Based on the CAP request, CDC/ATSDR will work with the CAP to invite an recognized expert on immunotoxicity of chemical exposure.  This expert will be invited to attend a CAP meeting (either on a monthly call or in person depending on availability).

QUESTION: Is CDC/ATSDR willing to follow the mortality cohorts?

CDC/ATSDR does plan to follow-up on mortality cohorts since the age of the cohort is relative young for this type of study, it is scientifically appropriate to follow up as they age.

QUESTION:  Why weren’t conotruncal heart defects included in the birth defects study?

CDC/ATSDR initially wanted to include conotruncal heart defects in the study of birth defects and childhood cancers among children born from 1968 through 1985 to mothers who resided on base at Camp Lejeune any time during their pregnancy. We chose these years because computerized birth certificates in North Carolina became available in 1968 and the contaminated wells on base were shut down in 1985.

Because there were no birth defects or cancer registries covering the time period of the study, CDC/ATSDR used a telephone survey to identify self-reported birth defects and childhood cancers. In an attempt to capture all potential conditions of interest, we were very liberal in what was included in the reported categories. Although a survey is a less accurate method for identifying cases because some cases will be missed, it was the only feasible option for conducting this study. CDC/ATSDR was able to interview the parents of 12,598 children. CDC/ATSDR made extensive efforts to confirm the self-reported birth defects and cancers.

Based on surveillance data from CDC’s Metropolitan Atlanta Congenital Defects Program, CDC/ATSDR expected approximately 8/10,000 live births during 1968–1985 to have a conotruncal heart defect. Survey participants reported three potential cases of conotruncal heart defects (2.4/10,000 live births) which is much lower than what was expected.

A sample size of a maximum of three cases severely limits the type of statistical analyses that can be performed (for example, we could not do categorical analyses using the water modeling) and makes it difficult to interpret the findings. Analyses based on this number of cases would have low power to detect an effect. Therefore, CDC/ATSDR cannot make any conclusions about whether exposure to the contaminated drinking water at Camp Lejeune is associated with conotruncal heart defects.