American College of Physicians: Internal Medicine — Doctors for Adults ®

Thursday, July 18, 2013

QD: News Every Day--Coffee is OK, or at least not harmful, for overall health

Two to three cups of coffee appears to be safe for most of health outcomes, according to a review of studies (albeit mostly observational ones).

On the plus side, coffee consumption may reduce the risks of type 2 diabetes and hypertension, as well as other conditions associated with cardiovascular risk such as obesity and depression. Drinking coffee is neutral when it comes to coronary heart disease, congestive heart failure, arrhythmias, and stroke. It may be related to anxiety, insomnia, tremulousness and palpitations, bone loss and possibly an increased risk of fractures.

Results appeared in the Journal of the American College of Cardiology.

In the evidence review, a meta-analysis of more than 400,000 patients in 21 independent prospective cohort studies from January 1966 to January 2008 suggested that moderate coffee consumption may decrease the long-term risk of coronary heart disease. Compared to light-to-absent coffee consumption (less than one cup a day in the U.S. less than two cups a day in Europe), moderate coffee consumption (more than one or two cups daily, respectively) was associated with significantly lower rates of coronary heart disease (relative risk [RR], 0.87; P=0.001).

Several studies suggested that it is safe for patients with established coronary heart disease to continue drinking coffee. A randomized, controlled trial of 103 patients with acute ST-segment elevation myocardial infarction found that drinking coffee was associated with an increase in parasympathetic tone, and coffee did not increase cardiac arrhythmia.

Coffee may reduce the risk of ischemic stroke. A recent meta-analysis of seven prospective studies with more than 440,000 participants, nearly 7,000 stroke events and follow-up of two to 24 years found that one to three cups of coffee were associated with a decreased risk of stroke (RR, 0.82; 95% CI, 0.74 to 0.90, P less than 0.001). There was a significant reduction of stroke risk in people drinking three to six cups of coffee per day (RR, 0.79; 95% CI, 0.68 to 0.92; P=0.003). Drinking more than six cups of coffee per day was not associated with any effect on stroke risk (RR, 1.00; 95% CI, 0.76 to 1.32; P=0.97).

Habitual coffee drinkers showed minimal impact on transient blood pressure in a meta-analysis of 10 randomized controlled trials and 5 cohort studies. Non-significant mean changes in systolic blood pressure of -0.55 mm Hg (95% CI, -2.46 to 1.36) and diastolic blood pressure of -0.45 mm Hg (95% CI, -1.52 to 0.61) were found in coffee drinkers when compared to the control group, with no clinically important effects. The Nurses' Health Study, with 1.4 million person-years of follow-up, demonstrated that daily intake of up to 6 cups of coffee was not associated with an increased risk of hypertension.

For diabetes, a systematic review of nine cohort studies compared coffee consumption of less than two cups a day to that of more than 6 six cups a day for risk of developing diabetes. The risk of developing diabetes was lowest in subjects who drank more than six cups daily (RR, 0.65; 95% CI, 0.54 to 0.78) and also significantly reduced for subjects who consumed four to six cups daily (RR, 0.72; 95% CI, 0.62 to 0.83). A prospective study of more than 88,000 women ages 26 to 46 years established a linear relationship between drinking coffee and lower rates of diabetes, whereby even small amounts of coffee on a daily basis conferred benefit, regardless of whether it was caffeinated or not.

Authors noted that coffee's possible advantages have to be weighed against potential risks (which are mostly related to its high caffeine content) including anxiety, insomnia, tremulousness and palpitations, as well as bone loss and possibly increased risk of fractures.

But, they added, "[S]ubstance abuse experts generally do not consider caffeine dependence a serious addiction. Indeed the tendency for coffee to promote habitual daily consumption may ultimately turn out to be advantageous if its myriad potential health benefits are confirmed. Caffeine, in moderate daily doses of about 300 milligrams, or about 3 cups of coffee, appears to be safe and harmless for healthy adults. ... Moderation, tending towards 2 or 3 with up to as much as 4 cups a day if tolerated, seems a reasonable suggestion."

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Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:

Albert Fuchs, MD
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.

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Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.

Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.

Zackary Berger
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.

Controversies in Hospital Infection Prevention
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Iowa City, IA, with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).

db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.

Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.

Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.

Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.

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Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.

Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.

Glass Hospital
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.

Gut Check
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.

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Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.

Informatics Professor
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.

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David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.

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Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.

Medical Lessons
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.

Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.

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Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.

The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.

Technology in (Medical) Education
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.

Peter A. Lipson, MD
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.

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Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.

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Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.

Other blogs of note:

American Journal of Medicine
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.

Clinical Correlations
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.

Interact MD
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PLoS Blog
The Public Library of Science's open access materials include a blog.

White Coat Rants
One of the most popular anonymous blogs written by an emergency room physician.

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