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Biological age affects the risk of breast cancer in women


How does increased biological age affect the risk of breast cancer?

The so-called biological age of people, a DNA-based estimate of a person's age, is associated with the risk of developing breast cancer. If women are five years older than their normal age, this increases their risk of breast cancer by 15 percent.

In their current study, scientists at the National Institute of Environmental Health Sciences (NIEHS) found that women with an increased biological age for their age were at greater risk of breast cancer. The doctors published the results of their study in the English-language journal "Journal of the National Cancer Institute".

How was biological age measured?

The biological age of the participants was determined by measuring DNA methylation, a chemical modification of DNA that is part of the normal aging process. The results show an increased risk of developing breast cancer by 15 percent for every five years, which is the biological age of a woman older than her chronological or actual age. The experts suspect that biological age may be linked to environmental exposures. The scientists used three different measures, the so-called epigenetic clocks, to estimate biological age. The clocks measure methylation at certain points in the DNA. The researchers used these clocks to determine biological age, which was then compared to chronological age. They used DNA from blood samples from more than 50,000 women in the US and Puerto Rico - from another NIEHS study. The study was specifically developed to identify ecological and genetic risk factors for breast cancer. Doctors measured methylation in a subgroup of 2,764 women who were all cancer-free at the time of blood collection.

What influences biological age?

The experts were thus able to determine that if the biological age of women was older than their chronological age, this contributed to an increase in the risk of breast cancer. Surprisingly, the opposite was also true, say the doctors. If the biological age was younger than the chronological age, this also increased the risk of breast cancer. It is still unknown how pollutant exposure and lifestyle factors can affect biological age or whether this process can be reversed.

Health variability better understood through biological age

The study's authors had looked at studies that used epigenetic clocks to predict age-related mortality. Because age is one of the main risk factors for breast cancer, the experts suspected that accelerating aging could be associated with a higher risk of breast cancer. People of the same age have different health, some may be perfectly healthy, while others may have different illnesses. This variability in health can be better captured by biological age than chronological age, the doctors explain. Using DNA methylation to measure biological age could help us better understand which people are at increased risk of developing cancer and other age-related diseases. (as)

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