The cholesterol numbers you get from your doctor are the sum of three scores: LDL, or low-density lipoproteins, the “bad” cholesterol; triglycerides, which you want to be as low as possible; and HDL, high-density lipoproteins, generally considered the “good” cholesterol.

High-density lipoproteins (HDL) in the blood vary in size and the amount of cholesterol they carry. HDL carries fats away from the heart, reducing the buildup of plaque and lowering the risk of cardiovascular disease (CVD). These cardio-protective effects are why HDL is known as the “good cholesterol.”

But HDL may not always be so good, at least not for women of a certain age.

“High total HDL cholesterol in postmenopausal women may mask significant heart disease risk, which we still need to understand.”

HDL has usually been measured as the cholesterol carried by all types of HDL particles, and called simply HDL cholesterol (HDL-C). However, HDL-C may not accurately reflect the concentration, distribution, content or function of all HDL particles, and that makes women's overall cholesterol picture fuzzier.

The hormonal changes associated with menopause and post-menopause can decrease the heart protective effects of high density lipoproteins, a new study reveals. Because total HDL-C is still used to predict CVD risk, these findings should interest women and their doctors, Samar El Khoudary, lead author of the study, told TheDoctor.

Their findings show that HDL-C may not be as cardio-protective as was once thought, she said, so doctors may want to take a closer look at the type of HDL particles in middle-aged and postmenopausal patients. “High total HDL cholesterol in postmenopausal women may mask significant heart disease risk, which we still need to understand,” said El Khoudary.

The study reviewed data from over 1100 women between the ages of 45 and 84. Participants from around the U.S. were enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA), which is still ongoing. The researchers wanted to see if the decrease in levels of estrogen, a cardio-protective hormone, along with other metabolic changes associated with menopause, might trigger chronic inflammation that could affect the quality of HDL particles over time.

HDL Particles Come in Two Sizes

Researchers at the University of Pittsburgh Graduate School of Public Health examined the number and size of HDL particles, and the amount of cholesterol these particles carried. They also looked at how age at menopause and the amount of time since menopause affected the cardio-protective properties of HDL.

As a woman transitions to menopause, large HDL particles were linked to an increased risk of cardiovascular disease. During that time the quality of HDL may deteriorate, putting women at risk for CVD and atherosclerosis.

Women who were older at menopause and those who were 10 or more years post-menopause showed a harmful association between high HDL-C levels and atherosclerosis. On the other hand, a higher concentration of total HDL particles — not just HDL-C — was associated with a lower risk of atherosclerosis, regardless of age or age at menopause.

It appears the reason for this is that having a greater number of small HDL particles was beneficial for postmenopausal women, no matter their age or age at menopause. But as a woman transitions to menopause, large HDL particles were linked to an increased risk of CVD. The researchers believe during this transition, the quality of HDL may deteriorate, putting women at risk for CVD and atherosclerosis. As women move further away from menopause, the quality of HDL may once again improve, making HDL cardio-protective.

“Identifying the proper method to measure active ‘good’ cholesterol is critical to understanding cardiovascular health in these women,” Matthew Budoff, senior author on the study, said in a statement.

Measuring HDL-C in postmenopausal women may not be accurate enough, warned El Khoudary. The researchers did not have an opportunity to follow women in the MESA study for several years. El Khoudary said that, in the future, she and her team would like to see if their findings could be replicated in a long-term, or longitudinal, study.

The study is published in Arteriosclerosis, Thrombosis, and Vascular Biology.