MedicalResearch.com Interview with: Dr. Céline Vetter,  Dr.Phil. Instructor in Medicine Harvard Medical School Associate Epidemiologist Channing Division of Network Medicine Brigham and Women's Hospital Boston, MA, 02115 MedicalResearch.com: What is the background for this study? Response: Heart Disease is still the leading cause of death in the US, with 1 in every 4 deaths being attributed to heart disease. On the other hand, it is estimated that approximately 15 millions Americans work evening shifts, night shift, rotating shifts or any other kind of irregular schedule that is arranged by the employer. The link between shift work and coronary heart disease has been studied for decades now, but because shift work can take so many forms, results have not been consistent. Another contributing factor to this inconsistency might be that few studies could actually track individuals over long periods of time, so that some studies might have missed when participants did actually develop coronary heart disease. Our study was based on the Nurses' Health Studies I and II, where women about 189,000 registered female nurses completed every two years mailed questionnaires that comprise items about their health status, medical history, and known or suspected risk factors for cancer and heart disease. They also reported their lifetime history of rotating night shift work in 1988 and 1989, respectively. Across the 24 years of the study periods, we observed more than 10,000 cases of coronary heart disease (i.e. myocardial infarction, CHD death, angiogram-confirmed angina pectoris, and procedures related to coronary heart disease, i.e. angioplasty, coronary artery bypass graft surgery or stents). (more…)