0518 GMT August 15, 2018
While researchers say it is not clear whether reproductive factors are driving the increased risks, they say that more frequent screening of women whose reproductive history suggested that they might be at higher risk of cardiovascular disease could help to prevent or delay its onset, theguardian.com reported.
Dr. Sanne Peters, an epidemiologist and coauthor of the latest study from the University of Oxford, said, “Further research into the underlying causes of these findings is really important because this helps us to come up with interventions, either population-based or individual-targeted.”
Writing in the journal Heart, Peters and coauthor Professor Mark Woodward, describe how they sought to scrutinize such links further by examining data from the UK Biobank — a database of genetic, medical and lifestyle information from more than half a million men and women aged between 40 and 69.
The team looked at more than 267,000 women and 215,000 men who were healthy and had no history of cardiovascular disease, and then looked at what happened to those participants in the seven years that followed.
The data showed 5,782 participants developed coronary heart disease and there were 3,489 cases of stroke.
Altogether, 9,054 participants developed one or both cardiovascular diseases, 34 percent of whom were women.
Once age and other factors including BMI, smoking status and blood pressure were taken into account, the team found that women who started menstruating before the age of 12 had a 10 percent higher risk of cardiovascular disease compared to those who began their periods aged 12 or older.
In particular, they had a 17 percent higher risk of stroke and a five percent higher risk of coronary heart disease.
But Peters said that it is not clear what is behind the link, pointing out that obesity in childhood could play a role, but that the study only considered BMI at the time of data collection.
Women undergoing natural menopause before the age of 47 were also found to have a greater risk of problems than those experiencing it later, being at a 33 percent higher risk of cardiovascular disease, with an increased risk of both coronary heart disease and stroke.
Again, said Peters, the reasons for the link are unclear. “It is really the chicken and the egg: is it sub-clinical cardiovascular disease causing early menopause, or is it early menopause causing cardiovascular disease?” she said.
While some have suggested that the link might be down to women with early menopause having a lower lifetime exposure to estrogen — a hormone thought to be protective against cardiovascular disease — Peters said the jury was still out.
Should we be worried about early puberty?
Peters added it would be helpful to analyze the genetics of participants to explore whether the associations for early puberty and early menopause with cardiovascular disease are direct links, or down to another common factor, such as environmental or lifestyle influences.
She said, “There’s quite a number of genes that have been identified to be associated with [female] reproductive lifespan.
“The question [is] whether those genes are also involved in the physiology of cardiovascular disease, or indeed also other conditions like cancers or diabetes.”
The risk of coronary heart disease was also increased in both men and women with children, the risk increasing with number of children.
That, said Peters, suggests that the link is not simply down to the effects of pregnancy but is likely complex, involving social, cultural and other factors.
In addition, miscarriage and hysterectomy were linked to a 14 percent and 20 percent higher risk of coronary heart disease respectively, while stillbirth was linked to a greater risk of stroke.
Dr. John Perry, co-leader of the growth and development program at the University of Cambridge’s MRC Epidemiology Unit, welcomed the research.
But, he added, it was not yet clear whether factors such as early puberty and early menopause were driving the higher risk of cardiovascular disease.
He said, “Further studies are however needed to ascertain if these represent causal, rather than correlative, associations.”