Drink coffee moderately and regularly; it may reduce heart failure risk

I did not know that coffee drinking can have some benefits. I drink two cups a day one in the morning and one in the evening. I was pleased to read that  researchers from the Cardiovascular Epidemiology Research Unit at Beth Israel Deaconess Medical Center in Boston, Harvard School of Public Health, Boston, Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Boston,  Department of Epidemiology, University of Alabama at Birmingham, Birmingham, showed that  by drinking coffee regularly and in moderation, you could reduce your risk of heart failure; the new study was published in the American Heart Association's journal Circulation: Heart Failure.

They did not do any study themselves; but searched electronic databases (MEDLINE, EMBASE, and Cinahl) from January 1966 through December 2011 with the use of a standardized protocol to analyze previous studies on the link between coffee consumption and heart failure.

Why did they do this research? They learnt that the studies so far to find linkage between coffee consumption and heart failure gave conflicting results.

They used "coffee" and "heart failure" as the key words and reviewed the reference lists of retrieved articles. They analyzed all articles with an abstract suggesting that it was relevant.

The search identified 116 publications. They excluded 27 duplicates. An additional 84 articles were excluded after review of the title or abstract. Finally, the meta-analysis included five independent prospective studies of coffee consumption and heart failure risk. Combined, these studies included 6,522heart failure events among 140,220 participants. Four of the studies were done in Sweden and one in Finland. Three studies consisted of participants with no history of myocardial infarction (MI); one consisted of participants with a history of MI, and one included separate analyses for people with and without a history of diabetes or MI.Two

studies included men one included women and two included both men and women.

The researchers found that moderate coffee drinking as part of a daily routine may be linked with a significantly lower risk of heart failure. In contrast, excessive drinking may be linked with an increased chance of developing serious heart problems.

"While there is a commonly held belief that regular coffee consumption may be dangerous to heart health, our research suggests that the opposite may be true," said Dr Murray Mittleman, senior study author.

"We found that moderate consumption — which we define as the equivalent of about two typical American coffee shop beverages — may actually protect against heart failure by as much as 11 percent," he said. "On the other hand, excessive coffee drinking — five to six commercial coffee house cups per day has no benefit and may even be dangerous. As with so many things, moderation appears to be the key here, too."

The study defines moderate consumption as four Northern European servings per day, the equivalent to about two typical 8-ounce American servings. Excessive coffee consumption is 10 Northern European servings per day, the equivalent to four or five coffees from popular American coffee restaurant chains (servings sizes vary from 9 to 20 fluid ounces per serving).

Researchers didn't account for brew strength. Coffee is typically weaker in the United States than it is in Europe. Also they also didn't differentiate between caffeinated and decaffeinated coffee, but most of the coffee consumed in Sweden and Finland is caffeinated.

"There are many factors that play into a person's risk of heart failure, but moderate coffee consumption doesn't appear to be one of them," said Elizabeth Mostofsky, lead study author and research fellow at Beth Israel.

This is good news for coffee drinkers. Ms Mostofsky boldly proposed that their study warrants changes to the current heart failure prevention guidelines, which suggest that coffee drinking may be risky for heart patients.The American Heart Association recommends that heart failure patients consume only a moderate amount of caffeine — no more than a cup or two of coffee or other caffeinated beverage a day.

Researchers didn't definitively say why coffee offers a heart-health benefit. But evidence suggests that frequent coffee drinkers develop a tolerance to the beverage's caffeine, which may put them at a decreased risk of developing high blood pressure.

Habitual coffee consumption is also associated with a lower risk of type 2 diabetes, with most studies showing the greatest reduction in risk with higher levels of coffee consumption.

"Diabetes and hypertension are among the most important risk factors for heart failure, so it stands to reason that reducing one's odds of developing either of them, in turn, reduces one's chance of heart failure," Mittleman said.

Lead glass from TV Tubes could help contain Fukushima radiation

I thought that the headline "TV tubes could help contain Fukushima radiation" in The Asahi Shimbun( June 22, 2012) referred to containing radiophobia rather than radiation.

It was actually more mundane. The  reporter was referring to the use of lead glass from obsolete TV tubes to fortify concrete. It seems that Japan accumulated over 100,000 tons of lead glass from TV tubes.TV tube glass contains 25 % lead.Lead glass is used in TV tubes to shield viewers from x-rays emitted by such tubes. Disposing old TV tubes is a serious solid waste management issue in many countries.

Researchers at Miyagi University have made a container capable of effectively blocking radiation made from concrete blended with lead-laced glass from the TV tubes. Such a practice is not new. Structural engineers  mix  ordinary concrete with iron ore (hematite) to increase its effective density. Denser concrete is more effective as a shielding material.

SHUNSUKE KIMURA, a Staff Writer of  The Asahi Shimbun reported thjat the researchers made a  a prototype container that is 10 centimeters thick and capable of holding 1 cubic meter of soil at a concrete factory in Sukagawa, Fukushima Prefecture, in late May.

The container is almost the same strength as a similarly sized one made of normal concrete and looks similar  but was more effective as a radiation shield. Ordinary concrete has a density of about 2.5 gm per cc. 

A 44-cm-thick slab of the lead-glass concrete is found to be as effective as a shield as a 50 cm ordinary concrete. May be if more lead glass is added, the mix may become weaker. Over all it does not seem to be a big deal, though for those who stored the obsolete TV tubes, the development will be a blessing in disguise. 

Radiation from CT scan from childhood could tripple the risk of leukemia or brain cancer

The Lancet Journal published a paper stating that the radiation exposure received from 2 to 3 computed tomography (CT) scans of the head in childhood (aged under 15 years)—giving a cumulative dose of around 60 mGy— can triple the risk of later developing brain cancer, while around 5 to 10 such scans (cumulative dose around 50 mGy) could triple the risk of developing leukaemia (with the differing number of scans related to different absorption rates of the brain versus the bone marrow and age at time of scanning).
There is some thing unique about this study. The risk estimate in this instance is directly derived. Dozens of such studies are going on all over the world. Normally, the researchers estimated the cancer risks from CT on the basis of risk estimates derived from A-bomb survivors. There were justifiable criticism against this approach.

You can access the paper at:

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2812%2960815-0/fulltext

This paper is published Online First by The Lancet on 7 June 2012.

The absolute risk of these cancers occurring after CT is small but there is sufficient reason to keep the radiation doses from CT scans  as low as possible.Dr Mark Pearce and Professor Sir Alan Craft, Newcastle University, UK; Professor Louise Parker, Dalhousie University, Halifax, NS, Canada; Dr Amy Berrington de González, National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD, USA, and colleagues conlude that if appropriate, alternative procedures, that do not use ionising radiation, should be considered.  The study represents the culmination of almost two decades of research in this area, and is jointly funded by the UK Department of Health and NCI/NIH.

CT imaging is a unique medical radiation procedure. Use of this technology has increased rapidly in the USA and elsewhere, especially in the past decade. However, potential cancer risks exist due to the ionising radiation used in CT scans, especially in children who are more radiosensitive than adults.

In this retrospective study, the authors examined the records of close to 180,000 patients who underwent a CT scan between 1985 and 2002. It includes the records from the radiology departments of some 70% of the UK's hospitals. They extracted the number and types of CT scan from the records and estimated the dose absorbed in milli-Grays (mGy) by the brain and bone marrow in patients for each scan.

Then they linked the data to cancer incidence and mortality reports in the UK National Health Service Registry between 1985 and 2008. From this, they calculated excess incidence of leukaemia and brain tumours. The dose of radiation received by the brain and bone marrow varies by age, and body part scanned.

A total of 74 from 178 604 patients were diagnosed with leukaemia and 135 of 176 587 were diagnosed with brain cancer. The authors calculated that the relative risk of leukaemia increased by 0.036 per extra mGy received, whilst for brain tumours this increased risk was 0.023. Compared with patients who received a dose of less than 5 mGy, patients who received a cumulative dose of at least 30 mGy (mean 50 mGy) had around three times the risk of leukaemia.

The  patients receiving a cumulative dose of 50-74 mGy (mean 60 mGy) had triple the risk of developing primary brain tumours. The authors say that, of every 10 000 people between the ages of 0-20 years receiving 10 mGy from a CT scan, there would be about one expected excess leukaemia case, whereas there were would be one excess case of brain cancer for every 30,000 people.

Applying the dose estimates for one head CT scan before the age of 10 years, this would translate into approximately one excess case of leukaemia and one excess brain tumour per 10 000 patients in the decade after first exposure. The authors note that increased follow-up and analysis of other cancer types is needed to identify the total excess risk for all cancers associated with CT scans.

The authors note that, in the UK, the Ionising Radiation (Medical Exposure) Regulations mean that a CT scan should only be done when clinically justified. This might explain the relatively low levels of CT use in the UK compared with other countries that do not have such regulations.

According to the lead author Dr Pearce the immediate benefits of CT outweigh the potential long¬term risks in many settings and because of CT's diagnostic accuracy and speed of scanning, notably removing the need for anaesthesia and sedation in young patients, it will, and should, remain in widespread practice for the foreseeable future.

He argued that further refinements to allow reduction in CT doses should be a priority, not only for the radiology community, but also for manufacturers. Alternative diagnostic procedures that do not involve ionising radiation exposure, such as ultrasound and MRI [magnetic resonance imaging] might be appropriate in some clinical settings. Of utmost importance is that where CT is used, it is only used where fully justified from a clinical perspective.

"It's well known that radiation can cause cancer but there is an ongoing scientific debate about whether relatively low doses of radiation like those received from CT scans do increase cancer risks, and if so the magnitude of those risks. Ours is the first study to provide direct evidence of a link between exposure to radiation from CT in childhood and cancer risk and we were also able to quantify that risk." Dr Berrington de González a co-author added

In a linked comment, Dr Andrew J Einstein, New York Presbyterian Hospital and Columbia University Medical Center, New York, NY, USA, says: "This study should reduce the debates about whether risks from CT are real, but the specialty has anyway changed strikingly in the past decade, even while the risk debate continued. New CT scanners all now have dose-reductions options, and there is far more awareness among practitioners about the need to justify and optimise CT doses—an awareness that will surely be bolstered by Pearce and colleagues' study."

I am not sure that this comment applies to countries such as India.An AERB funded project on CT scan practices in Tamil Nadu revealed that 32 out of the 71 centres do not follow paediatric protocols. Evidently the children undergoing CT exams in these clinics are receiving more doses.

The risk from this practice may be small. But there is no reason why those children should receive unwanted doses. Parents may ask the technologist whether the x-ray centre is following pediatric protocols or not . If they are not ,parents may insist on getting reference to centres where the protocols are followed.