While high levels of "good" cholesterol are associated with heart health benefits, they may not always be as protective in the case of postmenopausal women.

The study titled "HDL (High-Density Lipoprotein) Metrics and Atherosclerotic Risk in Women" was published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology on July 19.

Unlike LDL (referred to as the "bad" type) cholesterol, HDL cholesterol is good for the body as it reduces the risk for heart disease. To do so, it clears up the bloodstream by removing the bad cholesterol and cleaning the inner walls of the vessels.

Damaged inner walls and the build-up of plaque can both affect the transportation of blood and oxygen, increasing the risk of heart attacks and strokes. 

But past studies have found HDL shared an unexpected relationship with postmenopausal women — a link that was never explored in depth according to lead author Dr. Samar R. El Khoudary, associate professor in the Department of Epidemiology at the university.

"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 said.

The research team examined over 1,100 women across the United States who were aged between 45 and 84. Their findings revealed the size of HDL particles was an important factor. 

The higher concentration of total HDL particles as well as a high number of small HDL particles were found to be beneficial for the heart health of the postmenopausal women. This was regardless of a woman's age or how much time had passed since she had become postmenopausal.

But a high number of large HDL particles was linked to an increased risk of heart disease when a woman was close to menopause. While standard tests do not measure the size of particles, experts believe that this may not be required for everyone. 

"People on the borderline or people who have a family history of early heart disease — those people might need specialized cholesterol testing," said Dr. Nieca Goldberg, medical director of the Tisch Center for Women’s Health at New York University.

A healthy diet of fruits, vegetables, and whole grains is recommended by the American Heart Association. Goldberg, who was not involved in the study, also encouraged regular exercise as an effective way to improve cholesterol levels, especially in older women. 

"I don’t want people to think that all of a sudden when it comes to menopause, you have a whole lot of health problems, because menopause is a natural part of the life cycle," she said.