Posted on October 22, 2018
In October 2018, Dale Sandler, Ph.D., head of the Chronic Disease Epidemiology group and chief of the Epidemiology Branch of the National Institute of Environmental Health Sciences (NIEHS), spent two days with DCEG staff and fellows as a Visiting Scholar.
The highlight of her visit was the well-attended seminar, “Prospective Studies of Environment and Health,” hosted by senior investigator, Laura Beane-Freeman, Ph.D., Dr. Sandler began by briefly summarizing The Sister Study and the NIEHS-led research within the Agricultural Health Study (AHS), a joint initiative with NCI, and extending an invitation for future collaborations. She focused the remainder of her talk on the design, execution, and results of the Gulf Long-term Follow-up Study (GuLF), a massive undertaking she coordinated to investigate health effects among workers involved in the clean up of the 2010 Deepwater Horizon oil rig disaster in the Gulf of Mexcio.
“It was a whirlwind experience that was exciting and high-stakes from the beginning,” Dr. Sandler explained, “Within just a week after I submitted a rough proposal to NIH Director Dr. Francis Collins, he announced to Congress that he would fund the study with $10 million from his Director’s Fund, and appointed me to lead it.”
Dr. Sandler went on to describe the numerous challenges she and her team faced in standing-up such a complex investigation. The protocol needed accelerated review in order to get into the field as soon after the disaster as possible. As a result of GuLF study, there are now procedures in place to fast-track IRB approval for disaster response.
Dr. Sandler and her team focused on clean-up workers with the greatest exposure to oil and chemical dispersants. From 2011- 2013, starting less than a year after the oil spill, they enrolled over 32,000 adults. They conducted home visits, telephone follow-ups and clinical exams. Despite the accelerated timeline, many of the individuals involved in clean-up were already gone by the team arrived in the Gulf. The study population was not typical by any means—it was not solely occupational, nor was it a distinctive community, but a mix of the two. Nevertheless, they designed the study with limited information and committed to modifying it along the way as they gained more knowledge.
“Characterizing exposures, determining which to measure and how to adequately measure them were and are some of the most significant challenges,” Dr. Sandler said, “because of how varied each individual’s experience was in the clean-up. It was hard to really know what people did.” The study team decided to look at exposure to hydrocarbons, burning oil, chemical dispersants, heat stress, and psychological stress, among others, and the correlation of these exposures with about 25 symptoms.
Most notable was the observation of a dramatic decrease in lung function with exposure to burning oil and gas, especially among decontamination workers. At the initial home visit, these workers experienced an average 183 mL reduction in FEV1, a measure of lung function, but those numbers appeared to improve in the follow-up clinical exam.
There was some correlation with chemical dispersants and eye and respiratory symptoms in individuals that lived near the areas where these were used. Mental health was also a consideration. There was an increased risk of post-traumatic stress disorder and depression among people who worked on the clean-up, but it was unclear whether these originatied from exposure to chemical or psychological stress. Heat stress may have been a considerable but not permanent factor in cardiac events, but the data also show an association between hydrocarbon exposure and heart attack that continues to increase over time. Finally, despite reports of increased deaths due to the effects of the oil spill, they found no evidence of increased mortality rates or cancer incidence rates.
In closing her talk, Dr. Sandler encouraged senior staff and postdoctoral fellows to pursue and engage in multi-disciplinary research collaboration, highlighting the ample opportunities for growth and improved science.
During her visit, Dr. Sandler met with several investigators and fellows to discuss research and collaborations. She participated in a roundtable discussion with DCEG staff and fellows, entitled “Epidemiology of Female Cancers: Opportunities for Collaboration,” hosted by Britton Trabert, Ph.D., M.S., Earl Stadtman Investigator, and staff scientist, Clara Bodelon, Ph.D., M.S. Dr. Sandler shared her insights from the NIEHS Sister Study, and answered questions about the creation of cohort studies, collaborative opportunities in research on cancer survivors, intermediate endpoints, and cancer precursor conditions. She also shared career advice at a brown bag lunch with fellows, organized by Catherine Lerro, Ph.D., M.P.H. Dr. Sandler emphasized the need to focus on one's unique strengths and interests, and gave helpful tips on how to develop skills in primary data collection, solicit strong references, and foster collaborations.