Are your calcium supplements actually useless?

August 25, 2010 by  

Many of us swallow vitamin supplement pills each day, including calcium for bone health. Clinical guidelines on osteoporosis recommend supplementation with calcium especially for those who are at high risk for bone loss and fractures.

But the truth is, the benefits of calcium supplements are rather unclear, not to mention contradictory. Previous studies have shown that:

  • Calcium can protect against vascular disease.
  • Calcium can cause vascular disease by hastening vascular calcification.

So what now?

A group of researchers at the University of Auckland in New Zealand conducted a systematic search of electronic databases and conducted a meta-analysis of randomized clinical trials of calcium supplements compared to placebo. The results of the meta-analysis might have answered the calcium supplement question once and for all and can be summarized below:

  • Calcium supplements were associated with a significant increase (about 30%) in incidence of heart attacks.
  • Calcium supplements were also associated with trend of increased risk of stroke and mortality, although the increase is much smaller and not statistically significant.

These findings were consistent in all 5 trials included in the analysis and the increase of MI risk due to the supplements also increased with higher dietary calcium intake. Age, gender and type of supplement did not influence the results.

What is even more disappointing is the finding that calcium supplements have very little benefits when it comes to preventing fractures.

How reliable are the current results?

Some experts speculate that misdiagnosis of heart burns caused by the supplements as cardiac chest pains may have given erroneous results. This is based on the fact that many of the heart attack reported occurred within an average of 3.6 years after calcium supplementation was started. However, calcification of the blood vessels should take longer than that.

In addition, the studies analyzed were only those that did not include vitamin supplementation. It is common clinical practice, however, that calcium and vitamin D supplements are coadministered for osteoporosis. It is not clear whether vitamin D, which supposedly has cardiovascular protective properties, combined with calcium would give the same results.

However, the majority of experts agree is the fact that calcium supplements do not seem to prevent fracture indicates it is practically useless to take them even if the supplements as such are safe and do not cause heart problems.

According to senior author Dr Ian R Reid:

“Clinicians should tell their patients that, for most older people, the risks of calcium supplements outweigh the benefits. Changing to calcium-rich foods may be appropriate.”

According to independent expert Dr John Schindler (University of Pittsburgh Medical Center in Pennsylvania:

“I think the safest thing to tell your patients right now is if you can get your dietary calcium from good dietary sources, such as yogurt, sardines, and skim milk, that potentially might be all you need to ward off the risk of osteoporosis. Then we don’t have to deal with this increased cardiovascular risk.”

Your height and your heart

June 28, 2010 by  

What does your height have to do with your heart? Well, it seems that shorter people have higher risk for getting heart disease than tall people, according to a meta-analysis by Finnish researchers.

In a world wherein height is a well-prized attribute (think about fashion models and professional athletes), this is another additional blow to short people’s ego. Tell me about it, I’m a small girl living in a continent of giant Europeans.

But we cannot close our eyes to the scientific evidence in front of us. So let’s take a look.

The researchers at the University of Tampere in Finland conducted a systematic review and meta-analysis of 52 studies which involved more than 3 million people. The shortest group were under 160.5 cm and the tallest were more than 173.9. Genderwise, short women are under 153 cm and tall women above 166.4 whereas short and tall men are below 165.4 cm and 177.5 cm, respectively.

The analysis showed that those in the short group have almost 1.5 times higher likelihood of suffering and dying from cardiovascular or heart disease than the tall people. Again, according to gender, short men have 37% and short women 55% higher likelihood of mortality due to cardiovascular disease than their taller counterparts. However, the authors are quick to point out that they cannot give a “critical absolute height that demarcates between “short” and “tall.”

“Due to the heterogeneity of studies, we cannot reliably answer the question on the critical absolute height. The height cut-off points did not only differ between the articles but also between men and women and between ethnic groups. This is why we used the shortest-vs.-tallest group setting.”

One can only speculate the reasons why short people have this health disadvantage compared to tall people. Here are some ideas.

  • Short people may be easily affected by weight gain. Height is used to calculate body mass index (BMI), which is a widely used to quantify risk of coronary heart disease.
  • Shorter people may have smaller coronary arteries that can get occluded earlier.
  • Poor growth rate during childhood that leads to short height in adulthood has been associated with poor socioeconomic situation, poor nutrition, and more infections.
  • Genetic factors also play an important role in having short height, thus be further investigated.

The authors are quick to reassure us small people not to get too worried.

“Height is only one factor that may contribute to heart disease risk, and whereas people have no control over their height, they can control their weight, lifestyle habits such as smoking, drinking and exercise and all of these together affect their heart disease risk. In addition, because the average height of populations is constantly increasing, this may have beneficial effect of deaths and illness from cardiovascular disease.”

So do not take your rather short height to heart. Rather, let’s do something about it.

Does your blood pressure pill increase your cancer risk?

June 23, 2010 by  

If you have to choose between stroke and cancer, which would it be? Touch choice, eh?

Unfortunately, health professionals as well as patients might be forced to make the choice. A recent meta- analysis of studies on popular drugs used against hypertension brings some worrying news. These blood pressure pills actually increase the risk of developing cancer.

The five randomized controlled trials analyzed contained data of more than 60,000 patients who were taking the drugs called angiotensin-receptor blockers (ARBs) for hypertension, heart disease, and chronic kidney disease. The results of the analysis showed that patients on ARBs have about 1% higher risk for developing different types of cancers than those who are not taking the drugs. The cancers associated with this increased risk are prostate, breast and lung cancers.

Now, we may think that 1% is not much. But if we consider the number of people worldwide taking ARBs – estimated to be up to millions – then we can see how this 1% can actually translate to a large number of people who will be getting cancer.

According to study author Ilke Sipahi, associate director of heart failure and transplantation at University Hospitals Case Medical Center in Cleveland:

“The risk for the individual patient is modest. However, when you look at it from the population level, millions and millions of people are on these drugs and it can cause a lot of excess cancer worldwide.”

The authors estimate that for every 105 patients who take ARB for 4 years, one extra case of cancer will be diagnosed. However, the author cannot tell whether this increased risk is reversible after cessation. Also, there is no significant difference between cancer mortality between people on ARB and people who are not.

The bestselling drug in this class is telmisartan (Micardis), which was taken by about 85.7% of the patients in the studies. It is no wonder that its manufacturer Boehringer Ingelheim Corp is not too happy about the report which was published in Lancet Oncology.

Why do ARBs increase cancer risk? The experts do not know exactly why but it might have something to do with the drugs’ ability to enhance growth of new blood, the same enhancement that can promote tumor growth.

So what now?

Well, the study authors are cautious enough to tell patients on ARB not to stop their medications. In most cases, “their chances of dying from heart failure outweighed their chances of getting cancer”

The study conclusions are:

This meta-analysis of randomized controlled trials suggests that ARBs are associated with a modestly increased risk of new cancer diagnosis. Given the limited data, it is not possible to draw conclusions about the exact risk of cancer associated with each particular drug. These findings warrant further investigation.

Their ultimate advice: if in doubt, talk to your doctor about it.

Decaf coffee against diabetes

February 8, 2010 by  
Filed under DIABETES

So what did you drink for breakfast this morning? Coffee? Tea? How many cups? If you’ve had say, 3 or 4 cups of your favourite brew today, you may actually be protecting yourself from Type 2 diabetes. At least that’s what a team of researchers from University of Sydney in Australia is saying.

The researcher performed a so-called meta-analysis of data from 18 separate clinical studies that involved almost half a million participants. And the results of the analysis showed that people who drink lots of tea or coffee have lower risk for type 2 diabetes. A consumption of 3 to 4 cups of the drinks can reduce your risk by a fifth or even more. Each additional cup cuts the risk by 7%.

So what is in a cup of coffee or tea that gives us protection from diabetes? No, it is not the caffeine that provides the benefits because decaf coffee seems to work best. The researchers believe it might be other compounds that are responsible for the protection. Some of the possible compounds involved are the element magnesium and the antioxidants lignans or chlorogenic acids.

This isn’t the first time that decaf coffee gives positive health outcomes. A 2006 study of 28,000 women reported that consumption of 6 cups of decaf coffee a day translates into a 33% diabetes risk cut compared to no coffee consumption. In recent years, tea is also available in decaf form.

The authors concluded:

“The identification of the active components of these beverages would open up new therapeutic pathways for the primary prevention of diabetes mellitus. If such beneficial effects were observed in interventional trials to be real, the implications for the millions of individuals who have diabetes mellitus, or who are at future risk of developing it, would be substantial.”

Now, before you put your kettle to boil, let us slow down a bit. Previous studies on tea and coffee have been linked these beverages to health benefits against cardiovascular disease and cancer, although there are also evidence of harmful effects. More studies are needed to confirm these findings.

According to Dr Victoria King, of Diabetes UK, said:

“Without full information about what other factors may be influencing the type 2 diabetes risk of the studies’ participants – such as their physical activity levels and diet – as well as what the active ingredient in tea or coffee appears to be, we cannot be sure what, if anything, this observed effect is down to… What we can be sure of is that the development of type 2 diabetes is strongly linked to lifestyle, which means that many cases could be prevented by keeping active and eating a healthy balanced diet that is low in fat, salt and sugar with plenty of fruit and vegetables.”

Anti-hypertensive pills for everyone?

June 8, 2009 by  

pills_in_glasHow about anti-hypertensive drugs as part of your daily routine? British researchers recommend that hypertensive drugs (not one but a combination) be given to everybody starting at a certain age regardless of the fact whether they actually have high blood pressure or not. The logic behind this recommended generalized prophylactic treatment is to avoid cardiovascular events caused by hypertension.

According to Dr Malcolm  Law and Dr Nicholas Wald of the Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine, Queen Mary University of London,

“Guidelines on the use of blood-pressure-lowering drugs can be simplified so that drugs are offered to people with all levels of blood pressure. Our results indicate the importance of lowering blood pressure in everyone over a certain age, rather than measuring it in everyone and treating it in some.”

This means that we should swallow a daily cocktail of anti-hypertensive drugs just like we are swallowing vitamins or nutritional supplements.

The researchers based their recommendations on a meta-analysis of 147 randomized trials that included a total of 958,000 people. The same researchers also supported the so-called polypill which contains 5 different cardiovascular drugs that include:

  • a statin
  • three anti-hypertensive drugs
  • aspirin

The results of the meta-analysis showed that:

Currently, there are five main classes of blood-pressure-lowering drugs, namely:

  • beta blockers
  • thiazides
  • ACE inhibitors
  • angiotensin-receptor blockers
  • calcium-channel blockers

All drugs except calcium-channel blockers were similarly effective in preventing cardiac events and strokes. The calcium-channel blockers seem to have a greater preventive effect against stroke compared to the other drugs.

Other health experts, however, are not so convinced about the arguments and the results of the meta-analysis. They question a lot of assumptions and as well as analytical methods that may not be valid. According to Dr. Franz Messerli of St Luke’s-Roosevelt Hospital Center, New York City

“A meta-analysis is like a sausage; only God and the butcher know what goes in it, and neither would ever eat any.”

Indeed, the idea of prescribing anti-hypertensives for everybody is hard to sell. It is true that hypertension can lead to cardiac events and strokes but there are factors aside from blood pressure play a role as well. Besides, many of the risk factors for cardiovascular disease are lifestyle, and therefore, modifiable factors.

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NOTE: The contents in this blog are for informational purposes only, and should not be construed as medical advice, diagnosis, treatment or a substitute for professional care. Always seek the advice of your physician or other qualified health professional before making changes to any existing treatment or program. Some of the information presented in this blog may already be out of date.