A woman’s biologic age is an estimate of age based on their DNA and the older it is the higher her risk is for developing breast cancer later in life, according to National Institutes of Health researchers.
To determine biologic age, the scientists measured DNA methylation, a chemical modification to DNA that occurs normally when people age. Using three different measures, called epigenetic clocks, they were able to measure the DNA methylation in precise locations to estimate biologic age, which was then compared to chronologic age.
They found that when a woman’s biologic age was five years older than her real age, the risk of developing breast cancer increased 15 percent. For every five years her biologic age increased, so did her risk. Scientists from the National Institute of Environmental Health Sciences (NIEHS) have suggested that environmental exposures have an impact on this process, which could prove useful for identifying disease risk.
The researchers used DNA from blood samples provided by women enrolled in the NIEHS-led Sister Study, a group of more than 50,000 women in the U.S. and Puerto Rico. The study was specifically designed to identify environmental and genetic risk factors for breast cancer. The research team measured methylation in a subset of 2,764 women, all of whom were cancer-free at the time of blood collection.
