Later-onset menopause linked to lower heart disease risk

Women who go through menopause later in life have healthier blood vessels for years to come than those who go through it earlier, a study by the University of Colorado Boulder researchers found. The study published in the journal Circulation Research, offers new insight into why females who stop menstruating at age 55 or later are significantly less likely to have heart attacks and strokes in their postmenopausal years. 

Previous studies show that women who hit menopause — defined as going one year without a period — at age 55 or later are as much as 20% less likely to develop heart disease than those who cease menstruation at the usual 45 to 54 years old. University of Colorado researchers set out to determine the reason by assessing the vascular health of 92 women, looking specifically at a measure called brachial artery flow-mediated dilation (FMD), or how well their brachial artery — the main blood vessel in the upper arm — dilates with increased blood flow. 

They found all the postmenopausal women had significantly worse arterial function than their premenopausal counterparts. The reason: as people age, they produce less nitric oxide, a compound that helps blood vessels dilate and keeps them from getting stiff and developing plaque. Mitochondria in cells lining the blood vessels also become dysfunctional with age and generate more damaging molecules called free radicals.

When menopause hits, the age-related decline in vascular health accelerates. But the 10% or so of women who experience late-onset menopause appear to be somewhat protected from this effect, senior author Dr. Matthew Rossman said in a release.

For instance, the study found that vascular function was only 24% worse in the late-onset menopause group compared to the premenopausal group, while those in the normal-onset group had 51% worse vascular health. 

Remarkably, such differences between the groups persisted five years or more after the women went through menopause, with the late-onset group still having 44% better vascular function than the normal onset group.

Preserved vascular health in the late-onset group was related to better functioning of mitochondria which produced fewer free radicals, the study found. The circulating blood of the two groups also looked different, with the late-onset group showing “more favorable” levels of 15 different lipid or fat-related metabolites in their blood.