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Institute for Women's Health Research   Putting Women's Health FirstFebruary 2012
In This Issue
Cholesterol and the Heart
Upcoming Events
Health Tip
Related Blogs
Sex differences in heart disease

Blood pressure changes at middle age raises risk for later heart attack or stroke

Broken heart syndrome higher in women and we are not talking about romance!

Statins and diabetes

Dear Friends,

 

Cardiovascular disease claims the lives of nearly 500,000 American women each year, yet for years it was thought of as a man's disease. In 2004, to dispel the myths and raise awareness of heart disease as the number one killer of women, the American Heart Association created Go Red For Women - an initiative designed to empower women to take charge of their heart health.

 

This campaign has not only bought needed awareness to women, it has ignited the research community to respond by conducting more sex based research on heart disease.   We now know that men and women have different symptoms, diagnostic profiles and treatment responses when it comes to the heart. However, a recently released report on the status of women's health research found that the number of women participating in clinical trials has increased over the last two decades but they are still underrepresented compared to men. Even when women are included in these trials, the results are often not analyzed separately by sex.

 

To celebrate American Heart Month, we have focused this e-newsletter on an important factor in heart disease: cholesterol. We hope you find it helpful!

 

Sincerely, 

IWHRpng

 

The Institute staff

 

 

   

 

 

CHOLESTEROL AND THE HEART  

   

What is cholesterol?

Cholesterol is a type of fat that travels in your bloodstream in the form of 'packages' called lipoproteins. We need small amounts of fat to help make tissues, hormones, vitamin D, and bile acid. The body makes all the cholesterol it needs. Cholesterol also comes from some of the foods we eat like meat, fried foods, and eggs. Too much can build up in your blood and cling to the walls of your arteries especially those that supply blood to the heart. This condition is often referred to as 'hardening of the arteries.'   The buildup, called plaque, narrows the arteries and eventually slows the amount of blood carrying oxygen that is necessary to feed the heart.   The lack of blood rich in oxygen can lead to a heart attack. 

 

There are several types of fats:

  • Low-density lipoprotein (LDL) or bad cholesterol that leads to blockages.
  • High-density lipoprotein (HDL) or 'good' cholesterol. High levels of this type of protein help lower the level of LDL.
  • Total cholesterol is the sum of LDL and HDL
  • Triglycerides are esters formed from glycerol and three fatty acid groups. They are produced in the liver. 

We can measure your values of fats (lipids) through blood tests. Lab results are reported in milligrams per deciliter of blood (mg/dL). An LDL level below 100 mg/dL is considered ideal. The higher the level of LDL, the greater your risk of heart disease. HDL levels indicate just the opposite: the lower your HDL level, the higher your risk for heart problems. See the table below to learn more:

 

Blood Level

Risk Category

Total Cholesterol Level

 

   Less than 200 mg/dL

Desirable

   200-239 mg/dL

Borderline high

   240 mg/dL and higher

High risk

LDL Cholesterol Level

 

   Less than 100 mg/dL

Desirable

   100-129 mg/dL

Near to above optimal

   130-159 mg/dL

Borderline High

   160-189 mg/dL

High

   190 mg/dL or above

Very high

HDL Cholesterol Level

 

   Less than 40 mg/dL

Major risk factor for heart disease

   60 mg/dL or higher

Somewhat protective for heart disease

 

What about Triglycerides?

Triglycerides, which are produced in the liver, are another type of fat found in the blood and in food. When you eat, your body converts any calories it does not need right away into triglycerides that are stored in your fat cells. High triglyceride levels may be the result of excessive weight, physical inactivity, smoking, excessive alcohol, and a diet very high in carbohydrates(60 percent of calories or higher). 

 

Recent research indicates that triglyceride levels that are borderline high (150-199 mg/dL) or high (200-499 mg/dL) may increase your risk for heart disease. Levels of 500 mg/dL or more need to be lowered with medication to prevent the pancreas from becoming inflamed. A triglyceride level of 150 mg/dL or higher also is one of the risk factors of the condition known as metabolic syndrome.

 

To reduce blood triglyceride levels:

  • control your weight,
  • be physically active,
  • don't smoke,
  • limit alcohol intake,
  • and limit simple sugars and sugar-sweetened beverages.
High triglycerides levels respond well to lifestyle intervention but sometimes medication is needed. (1)

 

Why is high cholesterol dangerous?

The higher your total blood cholesterol, the greater your risk for developing heart disease or having a heart attack. Other factors that could elevate your risk of heart problems are:

  • Cigarette smoking
  • High blood pressure
  • Family history especially (if male kin had heart disease before age 55 and women age 65)
  • Age (55 and older)
  • Metabolic syndrome

How can you lower your LDL?

Lifestyle changes:

If your lipid levels are slightly elevated or borderline, your doctor may first try lifestyle interventions including:

  • Staying active
  • Eating a heart healthy diet
  • Losing excessive weight
  • Moderating alcohol consumption
  • Keeping stress under control

See the Health Tip below for a link to an comprehensive guide to therapeutic lifestyle changes (TLC). 

 

Common medications to treat high cholesterol:

The following information from the Health Heart Handbook summaries the benefits and risk of the more available classes of cholesterol lowering drugs (2):

 

Statins (HMG-CoA Reductase Inhibitors):

These lower LDL levels about 20-55%, moderately lower triglycerides and raise HDL. Side effects are usually mild though liver and muscle problems may rarely occur. Recently, new concerns about statins in women have been raised and are discussed later in this publication.

 

Exetimibes:

This is a newer class of drugs that interferes with absorption of cholesterol in the intestine.  They lower LDL by 18-25%. They are sometimes combined with a statin. Joint or back pain have been reported.

 

Bile acid resins:

These lower LDL by 15-30% and are often prescribed with a statin.   Long term use is considered safe but side effects my include constipation, bloating , nausea and gas. Do not use these drugs if you have liver or gallbladder problems, bleeding issues, underactive thyroid, ulcers, or kidney disease.

 

Niacin:

Niacin lowers total cholesterol and LDL, lowers triglycerides while also raising HDL. It reduces LDL by 5-15% or more. Niacin is available over the counter but its side effect profile is high enough to warrant doctor oversight. Side effects include liver problems, gout, peptic ulcers and high blood sugar.

 

Fibrates:  

These reduce triglycerides by 20-50% while increasing HDL by 10-15%. They are not effective for lowering LDL cholesterol. Risks include the potential to develop gall stones and increase the effect of blood thinning drugs. They should not be used if you have kidney problems or liver disease.

 

Sex Differences that Affect Cholesterol Levels and Management

Low levels of HDL appear to be a stronger predictor of heart disease death in women than in men in the over-65 age group.   High blood levels of triglycerides may be a particularly important risk factor in women and the elderly. Studies show that women's cholesterol is higher than men's beginning at age 45 and older. As women go through menopause, their lipid profiles change and become more atherogenic.

 

NIH researchers have found that women's cholesterol levels correspond with monthly changes in estrogen. This variation could indicate a need to take a women's monthly cycle into consideration while evaluating her cholesterol measures. On average, the cholesterol level can vary by as much as 19% during a woman's menstrual cycle. While we know that taking medications that include estrogen (HRT and birth control pills) can affect cholesterol levels, we are just beginning to learn about the effects of naturally occurring hormone levels on women's cholesterol. (3)

 

Women who have extensive artherosclerosis (plaque) may have a greater risk of cardiovascular events than men with similar hardening of the arteries depending on the type of plaque. Calcified plaque is considered more advanced and possibly more stable, while mixed plaque may be a sign of intermediate progression and possibly more dangerous. Noncalcified plaque is believed to indicate early disease and can rupture, causing a heart attack or death. Plaque can be pictured using CT angiograpy but more research is needed to help clarify whether or not the type of plaque has gender implications. (4)

 

The location of plaque-closed arteries is also important. Dr. Noel Bairey Merz and colleagues from the Women's Heart Center in Los Angeles found that women's hearts were less likely than men's to lose their ability to pump blood after a heart attack, and that female heart patients were less likely to present with obstructive coronary heart disease. Instead, the oxygen deprivation and subsequent damage to the heart in women is more likely to occur when small blood vessels, not major arteries become dysfunctional due to plaque accumulation.(5)  This lack of identifying plaque in smaller vessels may be one reason women with heart disease are often misdiagnosed. A new type of cardiac magnetic resonance is being tested that is more capable of finding plaque in the smallest arteries. 

 

Statins and Diabetes Risk

Older women who take statins may be at increased risk for developing type 2 diabetes according to an observational analysis of more than 153,000 women in the Women's Health Initiative database.(6) The researchers found that statin therapy was associated with a moderate increased risk for diabetes. Dosage and type of statin did not seem to make a difference implying a "medication class" risk.   At this point in time, no changes have been made to clinical practice guidelines since benefits still seem to outweigh risks. Statins do a very good job in reducing risk for heart disease and stroke. However, the authors of the study suggest increasing vigilance for diabetic symptoms (thirst, frequent urination, blurred vision) and conducting more frequent blood sugar and liver function tests.  This finding is likely to create more research on the mechanism of statins.  

 

One of the interesting outcomes of this new study is the observation that obesity appeared to be protective against disease.  Statin use was associates with a higher risk of diabetes in women with body mass index (BMI) scores below 25 than in those with BMIs above 30. These results have some clinicians wondering if we are putting too many aging women on statins because we thought the risks so low. It has been suggested that there be more efforts to try lifestyle modifications to reduce cholesterol before putting postmenopausal women on statins.

 

Status of Sex-based Research in Cardiology

The findings reported in this newsletter are good examples of why sex is so important in cardiology and that it is a fertile area for future sex-based research. A new report by the Institute of Medicine, Sex-specific reporting of scientific research: A workshop summary (2012) noted that only 27% of the participants in 19 randomized cardiology clinical trials were female and only 13 of the studies reported results by sex. One of the report authors noted that this bias was not necessarily intentional.   Typical inclusion criteria may be the problem. For example, men have earlier onset of certain heart conditions that may favor their enrollment in clinical trials.   Also, endpoints in a particular study may be different for men and women and thus study results may be biased if the endpoints are more male centric.   In the future, researchers need to be more aware of reported sex differences in heart disease symptoms and physiology and consider them when designing future heart studies.
 

 

 Sources:

 

1)  www.nhlbi.nih.gov/health/public/heart/chol/chol_tlc.pdf

(2) Healthy Heart Handbook for Women 

(3) http://www.nih.gov/news/health/aug2010/nichd-10.htm

(4) Nance JW et al., RSNA 2011. Abstract MSVA51-17.

(5) Pauly DF et al. Am Heart J. (2011 Oct)

(6) Culver AL et al. Archives of Internal Medicine (2012 Jan 9)

UPCOMING EVENTS     

  

February 3, 2012, 8:00am-12:00pm

Heart Health: What Smart Women Need to Know 

Prentice Women's Hospital, Chicago, Illinois 

 

February 3, 2012, All Day

Fifth Annual Women's Cardiovascular Health Symposium 

Prentice Women's Hospital, Chicago, Illinois  

 

February 21, 2011, 12:00pm

 IWHR Monthly Research Forum--American Heart Association's 2020 Strategic Impact Goals: Implications for Women 

Prentice Women's Hospital, Chicago, Illinois

 

 

HEALTH TIP

If your cholesterol and triglycerides levels are slowly inching upwards but are still borderline, you may want to try some TLC (therapeutic lifestyle changes) before taking medication.  The National Institute of Health has created a booklet that focuses on health diet physical activity, and weight management that is available HERE.   

 

Illinois Women's Health Registry News      

The Institute for Women's Health Research is encouraging and helping researchers include more women in their studies through its Illinois Women's Health Registry.   Illinois researchers who are conducting an Institutional Review Board (IRB) approved study can utilize the Registry as long as it is looking at sex differences.  To learn more, contact the Registry Coordinator at [email protected] or by phone at (312) 503-1662.