An earlier first birth, a higher number of live births, and starting periods at a younger age are all linked to a higher risk of cardiovascular problems in women, according to new research. The study, led by Imperial College London researchers, provides evidence for a causal relationship between sex-specific factors and cardiovascular disease in women, and identifies potential ways to mediate this increased risk.
Researchers from Imperial’s National Heart & Lung Institute, University of Cambridge and Yale School of Public Health analyzed genetic data linked to women's age at first birth, their number of live births, their age at their first period (menarche), and their age at menopause. They looked at previous studies involving more than 100,000 women.
By using a statistical technique called Mendelian Randomization, the researchers were able to show a link between the genes that predict reproductive factors and the risk of multiple cardiovascular diseases. This type of analysis enables researchers to cut through the noise of factors such as diet, economic background and physical activity levels that can otherwise complicate the overall picture, and so it points to causal links.
The analysis showed that earlier first birth, a higher number of live births, and earlier menarche were associated with a higher risk of atrial fibrillation, coronary artery disease, heart failure, and stroke in women. However, it did not find an association between the age of menopause and cardiovascular disease.
The researchers also found that much of the increased risk for earlier menarche resulted from this factor being associated with women having a higher body mass index (BMI). This means that lowering a person’s BMI could help to reduce this risk. The increased risk for earlier first birth could be partly limited by acting on traditional cardiometabolic risk factors, such as BMI, high cholesterol and high blood pressure.
