Sleep and Circadian Rhythm Disturbance and Cancer

Dr. Burch's research focuses primarily on linkages between sleep disturbances, circadian rhythm disruption, and cancer incidence or survival. This area of scholarship offers promise not only for ameliorating health and safety impacts among shiftworkers, but also for the development of innovative cancer prevention and survivorship strategies. His recently awarded R01 grant (1R01CA231321-01A1) targets one of the National Cancer Institute’s research priorities (Provocative Question 6: ‘How do circadian processes affect tumor development, progression, and response to therapy?’, RFA-CA-17-017). This case-control study will determine whether the disruption of circadian rhythms and sleep, including their genetic and epigenetic correlates, is associated with gastrointestinal inflammation or colorectal adenoma formation among African- and European-American patients receiving a screening colonoscopy for colorectal cancer. This project was derived in part from research Dr. Burch performed to help document some of the significant and incompletely explained racial cancer disparities in South Carolina,1-4  as well as the role of ‘circadian disruption’ in cancer susceptibility.5-9  His case-control study in India was the first among non-shiftworking women to suggest that extremes in chronotype (morning or evening preference) may confer an increase in breast cancer susceptibility.6 This research is innovative and significant because ‘circadian hygiene’ may serve as a novel strategy for the cancer prevention.

Another aspect of Dr. Burch's research focuses on military personnel and police, who are impacted by myriad occupational hazards associated with increased disease risk (e.g., irregular sleep/wake schedules, extreme stress, physical and psychological injury, and exposure to chemical and biological agents). His National Veteran Sleep Disorder Study found a ~6-fold increase in sleep disorder prevalence among Veterans in the USA from 2000 to 2010.10 The largest increases were observed among those with post-traumatic stress disorder (PTSD), or combat experience. Dr. Burch is a Multi-Principal Investigator (M-PI) for a recently awarded National Institute of Justice grant (2019-R2-CX-0021) that includes collaborators at National Institute for Occupational Safety and Health (NIOSH) and the State University of New York at Buffalo. They will utilize data from one of the most comprehensive shiftwork cohorts in existence, the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) study, from which they have previously published multiple papers.11-16  The team's manuscript on shiftwork and cortisol secretion received honorable mention from NIOSH for the national Alice Hamilton Award for Excellence in Occupational Safety and Health (in the epidemiology and surveillance category).14 This new study will examine the role of shiftwork, overtime hours, and secondary jobs on adverse trends in health risk indicators over time (chronic inflammation, metabolic dysregulation, DNA hypomethylation, reduced heart rate variability [HRV]). The goal is to identify evidence-based shiftwork adaptation strategies that foster beneficial trajectories of immune, neurological, and metabolic health. This investigation was informed by Dr. Burch's research on shiftwork adaptation,17-19 his recent publications using longitudinal latent class analysis to examine sleep disturbances and PTSD,20-22 and his recently completed BCOPS study that identified biomarkers of inflammation and metabolic disturbance associated with shiftwork maladaptation (submitted, in review). There are surprisingly few studies of health risks among adapted versus maladapted shiftworkers. In future research, Dr. Burch intends to examine the potential role of shiftwork maladaptation in carcinogenesis.

Dr. Burch also served as M-PI of a Merit Award from the Veterans Affairs’ Office of Research and Development (I01CX001182) that is examining HRV biofeedback as an intervention to alleviate symptoms of chronic pain, stress, fatigue, depression, cognitive disturbances, and insomnia among Veterans. He also served as M-PI for a recently completed pilot intervention examining HRV biofeedback for the treatment of symptom clusters among cancer survivors.23  Improved sleep is among the most potent effects of this treatment. This research builds upon Dr. Burch's previous studies that used wrist actigraphy to characterize sleep.18,21,22,24,25  Through the submission of several recent grants, Dr. Burch intends to expand this research to evaluate whether HRV biofeedback can improve sleep, cognitive performance and other symptoms among Veterans with concussion (mild traumatic brain injury or mTBI), and among firefighters. His recent Dorn Research Institute Seed Grant facilitated development of a telemedicine-based protocol for delivering HRV biofeedback, which will increase its potential for broader dissemination, for example among health care providers working irregular shifts, or for rural or homebound chronically ill patients.