Cholesterol Archive

Chronic stress is associated with an increased risk of heart disease, heart attacks, and strokes. These strategies can help you manage it.

People often complain about stress, but it's actually a natural reaction with an essential purpose.

When the body senses danger, it starts its fight-or-flight response. Your nervous system releases hormones like adrenaline and cortisol, which jolt the body into a protective mode. Your heart pounds faster, muscles tighten, blood pressure rises, breathing quickens, and your senses sharpen.

Several new technologies and medications that may benefit the heart are moving into cardiology care.

As regular readers of the Heart Letter know, our features tend to focus on lifestyle advice and currently available therapies for heart disease. As the new decade begins, we're also looking to the future. Editor in Chief Dr. Deepak L. Bhatt selected five promising new developments in cardiovascular research that you may be hearing more about in the coming years.

1. Digital stethoscopes

First developed more than 200 years ago, the instrument doctors use to listen to the heart and lungs has undergone some high-tech improvements in recent years. The latest digital stethoscopes feature specialized microphones and sensors that filter, buffer, and amplify sounds from the heart. The sounds are then converted to a digital signal and sent wirelessly to a smartphone, where the patterns can be visualized and further analyzed. Some models are so sensitive they can detect turbulent blood flow in the arteries of the heart, possibly enabling doctors to detect coronary artery disease. Studies assessing that potential use are currently under way.

A higher-than-normal blood sugar level puts you at risk for developing diabetes and heart disease.

If you're hoping to avoid heart disease, you probably pay close attention to your blood cholesterol levels. But you also should keep an eye on your blood sugar, because an elevated blood sugar level is an early warning sign of diabetes, one of the main risk factors for cardiovascular disease.

A fasting blood sugar level of 100 to 125 milligrams per deciliter (mg/dL) means you may have a common precursor to diabetes, called prediabetes. (Normal blood sugar values range from 70 to 99 mg/dL.) An estimated one in three American adults has prediabetes, although most of them don't know it.

What is the test?

People who have leg pain when exercising may need an evaluation to make sure they have normal blood flow through their leg arteries. Normally blood pressure is similar whether it is measured in the legs or in the arms. If blood pressure is lower in the legs, it usually means that cholesterol buildup inside the leg arteries is interfering with circulation. By taking accurate blood pressure measurements at different locations along your legs, your doctors can determine if you have any arterial narrowing and, if so, where.

In order to get accurate blood pressure measurements, your doctor uses a technique called Doppler ultrasound. Doppler ultrasound is a painless way to detect blood flowing through a small artery. It uses sound waves and a type of sonar detection system to make noise when blood flow is detected. For arterial studies of the legs (called segmental Doppler pressures), Doppler ultrasound is used in place of the stethoscope that doctors usually use when taking blood pressures.

Ongoing efforts seek to better identify and treat familial hypercholesterolemia, a leading cause of early heart attacks.

Some 35 million Americans have cholesterol values that put them at high risk for heart disease. The vast majority likely have dozens of different genetic mutations, each of which raises cholesterol by a little bit. Coupled with an unhealthy diet and not enough exercise, cholesterol creeps up slowly over time in these people.

But a small minority — about one of every 250 adults — have a genetic condition called familial hypercholesterolemia (FH). Most have a mutation in one of three key genes that provide instructions that help remove excess "bad" LDL cholesterol from the bloodstream. When one of these genes doesn't operate properly, LDL cholesterol levels can skyrocket as high as 350 milligrams per deciliter (mg/dL) — more than three times higher than the desirable level of less than 100 mg/dL. Their total cholesterol levels (which includes LDL cholesterol plus other lipids) may reach 500 mg/dL or higher.

Research we're watching

Don't want to skip breakfast before your cholesterol test? You probably don't need to. A study published online May 28 by JAMA Internal Medicine adds to the evidence that fasting isn't necessary before this common blood test, often referred to as a lipid profile.

For the study, nearly 8,300 people at risk for heart disease had fasting and nonfasting lipid profile tests done at least four weeks apart. (Fasting means they had nothing to eat or drink except water for at least eight hours before the test.) The differences in their total, LDL, and HDL cholesterol values were negligible. Triglyceride levels were modestly higher in the nonfasting samples.

In the journals

Eating large amounts of red meat can raise LDL (bad) cholesterol levels, but new research suggests you should curb your intake of white meat, too. The findings were published online June 4, 2019, by The American Journal of Clinical Nutrition.

Researchers randomly assigned 113 healthy adults, ages 21 to 65, to follow a four-week diet with high levels of either red meat, white meat (chicken and turkey), or plant-based protein (such as nuts, whole grains, soy products, and legumes). Afterward, LDL levels in the high-red-meat diet group rose, as predicted, but the researchers found that high levels of poultry had the same effect on LDL levels as red meat.

There are several things you can do to prevent or minimize the aches and pains that might accompany statin use.

If you're not taking a statin now, you may well be soon. These medications are commonly prescribed to lower "bad" LDL cholesterol and have been shown to reduce the risk of heart attack, stroke, and death. They are routinely recommended for people who have cardiovascular disease and for many people ages 40 to 75 who don't have cardiovascular disease but have at least one risk factor (high blood pressure, high cholesterol, diabetes, or smoking) and a 7.5% or greater risk of a stroke or heart attack in the next decade. Moreover, recent research indicates that they may benefit high risk individuals over age 75 as well.

Muscle pain and other statin side effects

Taking a statin may give you some assurance that you're doing all you can to avoid heart attack and stroke, but you may also experience side effects. Reported side effects include an increased chance of developing diabetes — which is largely restricted to people who are already at risk for diabetes, and who can be monitored with glucose or hemoglobin A1c tests. Statin use has also been associated with difficulties with memory and reasoning, although there is no clear evidence that the drugs were responsible. In very rare cases, statins may cause liver problems or a potentially life-threatening breakdown in muscle cells.

Research we're watching

Got a high cholesterol reading? You may have a higher risk for a dangerous eye condition called glaucoma, according to a recent study published online May 2 by JAMA Ophthalmology. The condition, characterized by pressure in the eye that can damage the optic nerve, can lead to vision loss.

The study looked at 866 cases of primary open-angle glaucoma, the most common type of glaucoma, among more than 136,000 study participants who were followed for 15 or more years. Participants provided researchers with updates on statin use and cholesterol levels every other year throughout the study period. After analyzing the information, study authors found that for every 20-point increase in total cholesterol there was a 7% increase in glaucoma risk. But the use of cholesterol-lowering statin drugs seemed to reduce risk. People who used statins for five years or longer had a 21% lower risk of developing glaucoma.

News briefs

Vitamins and supplements won't help stave off dementia, but a healthy lifestyle might, suggest new guidelines released May 19, 2019, by the World Health Organization (WHO). The WHO warns that the number of new dementia cases around the world — currently 10 million per year — is set to triple by 2050. While there's no cure for any kind of dementia (such as Alzheimer's disease and vascular dementia), the WHO says it may be possible to delay the onset of the disease or slow its progression. The key: managing modifiable risks, such as chronic disease and unhealthy habits. The guidelines recommend that you keep your weight, cholesterol, blood pressure, and blood sugar under control; get lots of exercise; and eat a Mediterranean-style diet (which emphasizes olive oil, fruits, vegetables, nuts, and fish; minimizes red meats and processed meats; and includes a moderate amount of cheese and wine). The WHO also advises that you don't smoke and you avoid harmful use of alcohol (no more than one drink per day for women, no more than two drinks for men). But don't count on supplements to help you stave off dementia. The WHO says there's no evidence that vitamin B, vitamin E, multivitamins, or fish oil supplements help reduce the risk for dementia. The agency recommends against using supplements as a means to ward off cognitive decline.

Image: © kali9/Getty Images