July 19 (UPI) -- "Good cholesterol" may not be a good indicator an older woman has a lower risk of developing cardiovascular disease, according to a study.
Researchers in the University of Pittsburgh Graduate School of Public Health studied high-density lipoproteins -- or HDL -- as a factor on heart-protective situations in postmenopausal women. Their findings were published Thursday in Arteriosclerosis, Thrombosis, and Vascular Biology, a journal of the American Heart Association.
Traditionally, HDL reduces the build-up of plaque in the heart and lowers the potential for cardiovascular disease by carrying fat away from the organ.
HDL cholesterol levels greater than 60 milligrams per deciliter are good and HDL levels less than 40 mg/dL are not good, according to WebMD. Other measurements are low-density lipoproteins, or bad cholesterol, and triglycerides.
"The results of our study are particularly interesting to both the public and clinicians because total HDL cholesterol is still used to predict cardiovascular disease risk," lead author Dr. Samar R. El Khoudary, associate professor in Pitt Public Health's Department of Epidemiology, said in a press release. "This study confirms our previous work on a different group of women and suggests that clinicians need to take a closer look at the type of HDL in middle-aged and older women, because higher HDL cholesterol may not always be as protective in postmenopausal women as we once thought."
She noted that a high level of HDL cholesterol in postmenopausal women could not reveal "a significant heart disease risk that we still need to understand."
Women transitioning to menopause face physiological changes in their sex hormones, lipids, body fat deposition and vascular health. The decrease of estrogen, a cardio-protective sex hormone, and other metabolic changes can trigger chronic inflammation and alter the quality of HDL particles, according to the researchers.
"We have been seeing an unexpected relationship between HDL cholesterol and postmenopausal women in previous studies, but have never deeply explored it," El Khoudary said.
In the study, 1,138 women 45 through 84 in the United States were enrolled in the Multi-Ethnic Study of Atherosclerosis. MESA, which began in 1999, is sponsored by the National Heart, Lung and Blood Institute of the National Institutes of Health.
They examined the number and size of the HDL particles and total cholesterol carried by HDL particles. In addition, researchers looked at how their specific age and the amount of time since transitioning may impact the cardio-protective associations of HDL measures.
The researchers found older age at menopause and at least 10 years into postmenopause predicted the harmful association of higher HDL cholesterol with atherosclerosis risk.
But a higher concentration of total HDL particles was associated with lower risk of atherosclerosis. And a high number of small HDL particles benefited postmenopausal women. Age and how long it has been since women became postmenopausal weren't a factor in these instances.
The large HDL particles were linked to an increased risk of cardiovascular disease near menopause. As women move further away from transition, the good qualities of HDL may restore.
"Identifying the proper method to measure active 'good' HDL is critical to understanding the true cardiovascular health of these women," senior author Dr. Matthew Budoff, M.D., of Los Angeles Biomedical Research Institute, said.
A study published in 2016 found elevated levels of "good" cholesterol may not be good for everyone.
Researchers in the trial in the United States and Europe found a somewhat rare genetic mutation. Although HDL-C generally helps remove cholesterol from arteries, a mutation to SCARB1 prevents it from doing so.