NEW DELHI — Women who go through menopause later in life have healthier blood vessels which reduces their risk of heart disease, finds a study on Wednesday.
Women are less likely to die of a heart attack or stroke than men for most of their lives, but studies have shown that their risk spikes and overtakes male risk after menopause.
The study, published in the American Heart Association 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.
The findings by researchers at the University of Colorado Boulder in the US could help lead to new therapies, including dietary interventions, to reduce the risk of heart disease -- the number one killer of women
"Our study identifies that there's actually a physiological benefit to late-onset of menopause and is one of the first to identify the specific mechanisms driving these benefits," said Sanna Darvish, a PhD candidate in the Department of Integrative Physiology at the varsity.
The team assessed the vascular health of 92 women in the US, 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.
The results showed that all the postmenopausal women had significantly worse arterial function than their premenopausal counterparts.
The researchers explained that when menopause hits, the age-related decline in vascular health accelerates.
But the 10 per cent or so of women who experience late-onset menopause appear to be somewhat protected from this effect, said senior author Matthew Rossman.
In particular, the study found that vascular function was only 24 per cent worse in the late-onset menopause group. On the other hand, among women in the normal-onset group 51 per cent had worse vascular health.
Notably, such differences between the groups persisted five years or more after the women went through menopause, with the late-onset group still having 44 per cent better vascular function than the normal onset group.
This health benefit 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 favourable" levels of 15 different lipid or fat-related metabolites in their blood.
"Our data suggest that women who complete menopause at a later age have a kind of natural inherent protection from vascular dysfunction that can come from oxidative stress over time," said Rossman, an assistant research professor in the Department of Integrative Physiology.