Posts Tagged "heart disease"

Calcium, vitamin D and heart disease. What’s the 4-11?

Posted by Liz on May 2, 2011 in bone health, heart disease | 5 comments

“Calcium supplements cause heart attacks in postmenopausal women.”

Whoa! What?!

If you saw the headlines last week, you may be wondering what’s up with calcium supplementation. Afterall, don’t medical professionals advise the use of supplements to stave off bone loss associated with osteoporosis? And as a result, the Centers for Disease Control reports that over 50% of adults currently use calcium supplements and more than 60% of women over age 60.

It’s important to get away from the sensational headline and take a closer look at what the research shows and what you need to know.

Previous studies have suggested that there may be a link between use of calcium supplements (without vitamin D) and heart attack; in fact, as Reuters‘ reported last year, calcium supplements were shown to increase the risk of heart attack by as much as 31%, possibly as a result of plaque formation in blood vessels. However, is the risk the same if calcium is used alone versus if it is used in conjunction with vitamin D?  In the Women’s Health Initiative study, the use of calcium and vitamin D did not appear to influence heart disease risk at all.

However, researchers decided to take another look at the data because they say that in this trial, more than half of participants were taking ‘personal calcium’ (i.e. not regulated or standardized to all trial participants) and almost half were also adding Vitamin D.

In this reanalysis, published just last week in the British Medical Journal, the researchers discounted the women who were characterized as personal users of calcium supplements and instead, limited their evaluation to a group of women who were not using personal calcium supplements at the study’s start and previously unpublished data from the trial. The findings? The use of calcium with or without vitamin D appeared to cause a 25% to 30% increase in the risk for heart attack and a 15% to 20% increased risk for stroke. However, the researchers say that even small increases in the incidence in heart disease may manifest substantially, especially in the elderly. They add that if you take a look at the risk-benefit ratio, it is unfavourable, meaning that taking calcium with or without vitamin D for five years would cause twice as many heart attacks or strokes than then numbers of fractures that would be prevented.  Additionally, the data analysis suggests that dosing is not a factor, and that the total amount of calcium taken daily is less important than the abrupt changes in blood calcium levels immediately following supplementation.

Although this research answers a few questions about potential risks about calcium supplementation, it also leaves a key question unanswered:  how does the addition of magnesium and vitamin K, which are often included in commercially-available calcium supplements, affect these findings? Data suggest that these minerals and vitamins are added to keep calcium in the bones where it belongs and out the arteries where it does not.

The best guideline, as always, is to visit a physician to assess your bone health and come up with a plan that works specifically for you. Although calcium supplementation appears to be risky, more data are needed before leading organizations start to change their tune about calcium and bone health. Meanwhile, stay ahead of the headlines and try to focus on increasing the amount of calcium-rich foods in your diet:

* DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration to help consumers compare the nutrient contents among products within the context of a total daily diet. The DV for calcium is 1,000 mg for adults and children aged 4 years and older. Foods providing 20% of more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet. The U.S. Department of Agriculture’s Nutrient Database Web site lists the nutrient content of many foods. It also provides a comprehensive list of foods containing calcium.
** Calcium content varies slightly by fat content; the more fat, the less calcium the food contains.
*** Calcium content is for tofu processed with a calcium salt. Tofu processed with other salts does not provide significant amounts of calcium.

Estrogen: Worth the risk?

Posted by Liz on Apr 6, 2011 in breast cancer, estrogen, heart disease, osteoporosis | 9 comments

Any regular reader of this blog knows that I am not a fan of hormone replacement therapy (HRT) nor the health risks associated with it. Nevertheless, although I espouse alternative strategies for dealing with menopause, I do feel that sharing news about HRT is important; accurate information leads to informed and shared decisionmaking.

So, do they (i.e. hormones) or don’t they (cause harm)? Undoubtedly, important variables come into play, including current age, how close to menopause hormones are started, current health status, whether or not a woman has had a hysterectomy, smoking history, etc. Also important is whether estrogen is used alone or in combination with progesterone. And yet despite these factors, many medical organizations continue to recommend that HRT be used for the shortest time period possible if at all.

Still, researchers continue to delve into data from the now infamous Women’s Health Initiative Study to tease out the bad, ugly and even the good.

This week,  they are reporting on over 7,600 women who had taken estrogen alone for approximately 6 years, had had prior hysterectomies and were followed for an average of 10 years after the trial ended. If you recall, there has been some controversy as to whether or not estrogen alone is safer than combined HRT and actually lowers the risk for breast cancer in particular, which is why these data are particularly intriguing.

The researchers report that age at the time that hormone therapy (in this case, estrogen alone) is started is important. In fact, women who started estrogen therapy in their 50s, an increased risk for stroke and embolism, which appeared while taking estrogen, actually disappeared in the years that followed. Unfortunately, so did protection against hip fracture. Moreover, earlier reports of a decline in breast cancer risk were upheld despite body mass indices. However, the researchers say that this finding in particular, runs contrary to the preponderance of evidence from the majority of observational studies which show that estrogen use increases the risk of breast cancer, especially in lean women and after a long time period of use.

In an accompanying editorial, also in JAMA, the authors point out that more than 80% of women who took estrogen as directed only used it for an average of 3.5 years. Their point is that the results don’t directly address the “balance of risk and benefits associated with longer term estrogen use.” They also point to a larger review of data that show duration is an important factor when it comes to breast cancer risk, especially among lean women. Additionally, they say that tamoxifen, which actually antagonizes estrogen, has been shown to reduce breast cancer by 50%, which has led the International Agency for Research on Cancer to “conclude that unopposed estrogen therapy and combination HRT are carcinogenic.”

Are you confused yet?

Both set of researchers say that the decision to use estrogen or not is one that should be made between a woman and her doctor. Don’t forget: study findings continue to contradict. They add that while “there may still be a role for short-term use of unopposed estrogen for treating some women with menopausal symptoms, this role may be vanishing as existing and emerging data continue to be better understood in terms” of patients.

My thoughts? Err on the side of caution. Always.

Flaming the fires of HRT: what influences risk?

Posted by Liz on Mar 4, 2011 in heart disease, HRT | 6 comments

Let’s face it. Despite my doubts about hormone replacement therapy (HRT), just like the Energizer Bunny, it’s going to keep on going. So as any responsible journalist must do, I have to share the good along with the bad and ugly. The trouble is that data rarely agree, lending confusion to the growing controversy about health risks, appropriate timing, combination and use of HRT.

Last week, several of you sent me a link to a study in the current issue of Menopause that appears to further clarify use of HRT and heart disease risk. Quite honestly, I had seen the study but was hesitant to write about it for fear of simply fueling the fires. But you’ve asked so I’ve answered.

The investigators of this particular study note that experts suspect that timing of hormone replacement, i.e. age when it’s started or time since menopause has begun when it’s started, plays a role in some of the differences between previous reports on HRT and heart disease. For example, reanalysis of data from the Nurses Health Study demonstrates that any heart benefits of HRT rely on starting therapy within 10 years of menopause, while data from the Women’s Health Initiative show that younger age plays an important role as well.

In a quest to tease this out further, they examined information on deaths from ischemic heart disease, age at first and/or current use of HRT, prior use and duration of use in 71,237 postmenopausal women in the California Teachers Study over a period of approximately 9 years. The findings?

• Overall, current age while using HRT appears to influence risk of dying from any cause. This factor appears to be much more importan than age that HRT was started or years since menopause began. Indeed, women using HRT at the time of the study who were younger than 65 years were found to have a 45% reduced risk of death from any cause compared to women who had never used HRT.
• Similar findings were seen when the researchers examined death from heart disease, with HRT providing some protection in younger current users that virtually disappeared once they reached 75 years.

The upshot is that the health consequences and risks of HRT may be influenced most by age at current use, with younger women having the most benefits to gain. Any sort of protection starts to disappear as women grow older so the window of opportunity might be small.

Still, questions remain. These researchers were only trying to determine the most important influencer(s) of death from heart disease and not examining cancer or other risks that have been definitively demonstrated.  Do these data fan the controversial fires and serve to heat up the debate? I believe that they do.

As always, buyer beware. Nothing is ever as it seems. Especially when it comes to hormone replacement therapy.

Heart disease, flashes and sweats, oh my!

Posted by Liz on Feb 11, 2011 in heart disease | 1 comment

Heart disease is a major issue in women, especially as they age. In fact, more women die of heart disease than all forms of cancer, including breast cancer. During the time right before and up to five years after menopause starts, cholesterol and low-density lipoprotein (LDL) levels soar, placing women at even greater risk.

I’ve written previously about the link between waning estrogen levels and heart disease risk and steps you can take to address specific risk factors. But what about vasmotor symptoms like hot flashes and night sweats? Unfortunately, in addition to being linked to elevated cholesterol and LDL, researchers are discovering that vasomotor symptoms like hot flashes and night sweats actually cause calcium deposits to build up in the arteries and aorta, negatively blood pressure and increase body mass index compared to women without these symptoms.

In the latest bit of news from the research front (published in February issue of Menopause), it appears that night sweats might be the larger culprit. In fact, when researchers examined data culled from 10,787 Dutch women (mean age 53) participating in another study who were free of heart disease at the start, they discovered that over a period of approximately 10 years, women reporting night sweats had a 33% increased risk for heart disease compared to women who were asymptomatic. In comparison, hot flashes did not appear to increase risk in any significant way. What’s more, risk remained even after the researchers accounted for factors that might influence risk, such as BMI, blood pressure and total cholesterol. Additionally, elevated risk was even seen among women both who had used hormone replacement and had never used hormone therapy or oral contraceptives.

Before you become anxious about these findings, it is important to note that when the researchers did a second analysis that adjusted for sleep and mood (both of which have been linked to vasomotor symptoms and heart disease), and found that while risk was still elevated, it was no longer significant. This implies that factors other than night sweats might also be contributing to heart disease risk, and that the sympathetic nervous system, which is responsible for increases in nervous system activity and blood vessel abnormalities, may also play a role.

Meanwhile, prevention recommendations continue to be fairly straightforward:

• Don’t smoke or quit if you do.
• Exercise…at least an hour daily if you can.
• Eat a health diet, rich in whole grains, fruits and vegetables, healthy fats, fish oils and low fat proteins.
• Maintain a healthy weight.
• Drink in moderation.

Ladies, we are in control of our destinies when it comes to altering how we age in that we can influence certain factors. There are no guarantees. But you can bet that we can change the odds in our favour.

Please, please care for your heart. It matters. A lot.

In training? Make sure it’s resistance!

Posted by Liz on Jan 17, 2011 in exercise | 4 comments

For some time now, experts have advised that aerobic exercise is preferred over other forms of physical activity for reducing the risk of heart disease. One key reason is that it confers favorably changes in the arteries, making them pliant and able to assist with blood flow and maintenance of normal blood pressure. Although our arteries tend to stiffen naturally with age (losing their elasticity), other factors, including high cholesterol, an unhealthy diet, obesity and sedentary behavior also contribute. Unfortunately, the stiffer arteries become, the more difficult it is for blood to flow, meaning that the heart has to work harder to pump blood. This leads to high blood pressure, stroke and of course, death.

So, is the only physical option aerobic? Evidently not.

Historically, resistance training has been shown to increase the stiffness of the arteries. However, it also protects bone (thereby lowering the risk for osteoporosis), helps to maintain normal weight and promotes general health and wellbeing. These factors in particular, are essential to women as they age. However, for the first time, researchers are now saying that resistance training may confer heart benefits that are similar to aerobic exercise.

In a very small study published last year in the Journal of Strength and Conditioning Research, the effects of resistance training on the arteries and blood flow were thoroughly examined in young adult men, who, following a brief warm up, performed resistance exercises on weight machines; repetitions ranged from 3 to 15, and subsequent weight was added or reduced in increments to achieve the most optimal effort from each man. They found that 45 minutes moderate intensity resistance training, despite causing the arteries to stiffen, actually increased blood flow and as a result, lowered participant’s blood pressure by as much as 20%. What’s more, these benefits were greater than those seen with aerobic exercise, but, residual effects appeared to continue at least 30 to 60 minutes after resistance training stopped and recovery started. Among individuals who trained 30 to 45 minutes three times a week, these benefits continued for at least 24 hours.

The researchers point out that although it’s difficult to directly compare aerobic activity and resistance training, particularly with regards to exercise intensity, they believe that resistance training has an important role in lowering blood pressure and may be as “good as or better” than the benefit seen with antihypertensive medications.” They also say that for people who have orthopedic or weight limitations and can’t walk or run for long distances, these findings offer an important alternative: resistance training.

At the end of the day, any training is good, so long as it is supervised. Now it appears that adding resistance training to aerobic activity imparts a lot more benefits than previously thought. Aerobic AND resistance training = win/win for your heart and your health. Want to learn more? The American Council on Exercise has a great website on resistance and strength training. My friend Andrea Metcalf also provides some wonderful guidance in her new book, Naked Fitness.