The significance of this paper is that it summarizes a body of research that has spanned more than two decades and allows the synthesis of evidence from all available studies and the identification of patterns not discernible by looking at each study individually. This research is of broad interest to the general public since physical and sexual activity are common behaviors that affect a wide segment of the population. It’s particularly important to clinicians since the study supports current clinical guidelines regarding the initiation of physical activity programs.
The JAMA paper assesses the effect of episodic physical and sexual activity on acute cardiac events using data from fourteen previously published studies. Acute cardiac events are defined in this study as myocardial infarction or sudden cardiac death. Acute cardiac events are a major cause of morbidity and mortality, with as many as one million myocardial infarctions and 300,000 cardiac arrests occurring in the United States each year. Despite the well-established benefits of regular physical activity, anecdotal evidence has suggested that physical activity and psychological stress can act as triggers of acute cardiac events.
The authors conducted a meta-analysis of fourteen case-crossover studies published in thirteen articles; ten studies investigated physical activity, three studies investigated sexual activity, and one study investigated both exposures. Since many prior reports included a relatively small number of individuals who had had heart attacks, they used a statistical approach that combined the data from these previous studies. “This method can be a powerful way to arrive at a more confident answer about a particular clinical question when prior studies have been limited by small numbers,” writes Dr. Paulus.
Each author independently extracted descriptive and quantitative information from the studies identified through MEDLINE, EMBASE and Web of Science. Data collection was limited to case-crossover studies as this design was developed specifically to address the problem of identifying triggers of acute events. Case-control and cohort studies were not included as they are not particularly suitable for identifying triggers of acute events. The individual studies tended to include more males than females, and patients in their 50’s and 60’s.
This research concluded that episodic physical activity and sexual activity are associated with an increase in the risk of heart attacks for a short window of time during and shortly after the activity. This association was less pronounced among persons with high levels of habitual physical activity. The authors make particular note that this study should not de-emphasize the importance of regular physical activity. Dr. Dahabreh writes, “Our findings should not be misinterpreted as indicating a net harm of physical or sexual activity; instead they demonstrate that these exposures are associated with a temporary short-term increase in the risk of acute cardiac events.”
Dr. Paulus comments, “This project would not have been possible without the Tufts CTSI funded Clinical and Translational Science Graduate Program, as well as Tufts CTSI support for interaction between epidemiologists and meta-analysis experts. While our disciplines are not necessarily that far apart, our scientific approaches tend to keep us operating in different spheres. This work is an illustration of what is possible with Tufts CTSI encouragement and support for these types of interactions.”
About the Authors
Dr. Dahabreh, the corresponding author, is a research associate with the Center for Clinical Evidence Synthesis and Evidence-based Practice Center at Tufts Medical Center’s Institute for Clinical Research and Health Policy Studies. Dr. Paulus is an assistant professor at Tufts University School of Medicine and Tufts CTSI, associate director of the Research Design Center at Tufts CTSI, and adjunct assistant professor of epidemiology at the Harvard School of Public Health.
About Tufts Clinical and Translational Science Institute (CTSI)
Tufts CTSI was established in August 2008 with Grant Number UL1 RR025752 from the National Center for Research Resources (NCRR), National Institutes of Health (NIH). A collaboration of organizations, founded by Tufts Medical Center and Tufts University, Tufts CTSI accelerates the translation of laboratory research into clinical use, medical practice and health policy. It connects people to research resources, consultation, and education, and fosters collaboration with scholars of all disciplines and with community members, with the ultimate goal of improving the health of the public.
About Tufts Medical Center
Tufts Medical Center is an exceptional, not-for-profit, 415-bed academic medical center that is home to both a full-service hospital for adults and Floating Hospital for Children. Conveniently located in downtown Boston, the Medical Center is the principal teaching hospital for Tufts University School of Medicine. Floating Hospital for Children offers a comprehensive range of services from prevention and primary care to the most sophisticated treatment of rare and unusual conditions. The hospital’s focus and mission every day is to improve the lives of children and their families.
About Tufts University
Tufts University, located on three Massachusetts campuses in Boston, Medford/Somerville, and Grafton, and in Talloires, France, is recognized among the premier research universities in the United States. Tufts enjoys a global reputation for academic excellence and for the preparation of students as leaders in a wide range of professions. A growing number of innovative teaching and research initiatives span all Tufts campuses, and collaboration among the faculty and students in the undergraduate, graduate and professional programs across the university’s schools is widely encouraged.
Contact: Marc Belanger
Tufts University, Health Sciences