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Older biological age may increase breast cancer risk
Biological age, estimated by measuring DNA methylation, appeared to be a predictor for breast cancer risk, according to study results.
“[When looking] at a group of people who are all the same age, some may be perfectly healthy while others are not,” Jacob K. Kresovich, PhD, MPH, a postdoctoral fellow in the molecular and genetic epidemiology group of the National Institute of Environmental Health Sciences, said in a press release. “That variability in health may be better captured by biologic age than chronologic age.”
Because chronological age is a leading risk factor for breast cancer, Kresovich and colleagues hypothesized that biological age acceleration may be associated with increased breast cancer risk.
They measured baseline blood DNA methylation in 2,764 women enrolled in the Sister Study, including 1,566 women who developed breast cancer within years after baseline blood draw.
Researchers used three established methylation-based biological “clocks” and defined biological age acceleration for each woman by comparing estimated biological age with chronological age.
Results showed a significant association between biological age acceleration and increased risk for breast cancer (HR = 1.15; 95% CI, 1.07-1.23).
HemOnc Today spoke with Kresovich about the study, the implications of the findings and what is next for research.
Question: What prompted this research?
Answer: People have tried to measure biological age. One way is by using epigenetic clocks. What we were interested in was examining how these epigenetic clocks work in relation to cancer outcomes.
Q: What is the rationale for why biologic al age is linked to breast cancer?
A: Age is the strongest risk factor for most cancers, including breast cancer. The incident rate of breast cancer during one’s lifespan reaches a maximum in the 70s to late 80s. There is a strong association between age and breast cancer risk.
Q: How did you conduct the study?
A: Our study included patients in the Sister Study population, which is a group of women who had been followed for about 10 to 15 years. At the time of study enrollment, all women had their blood drawn and were cancer-free. Some women went on to develop breast cancer, whereas other women remained cancer-free. We took the blood samples collected at the time they were enrolled and measured their biological age, and we looked at how that was associated with their risk for developing breast cancer.
Q: What did you find?
A: We found that for every 5 years that a woman’s biological age was higher than her chronological age, she experienced a 15% increase in risk for developing breast cancer. This works both ways. If a woman appears to be 5 years younger than her chronologic age, she experienced a 15% decreased risk for developing breast cancer.
Q: Did any of your findings surprise you?
A: We were surprised by the strength of the effect. We measured biological age using three different measures and they all showed the same thing — increased biological age, relative to chronological age, was associated with increased breast cancer risk. That consistency was surprising as well.
Q: What should clinicians do with this information?
A: At this point, the field of biological age is still new. Additional research is needed to determine whether it is useful as screening or prevention. However, these biologic clocks may improve our ability to identify women who are at increased risk for age-related disease.
Q: What is next for research?
A: We are curious in trying to understand what makes biologic age increase and decrease, whether it is reversible, and if we could intervene. We also want to know if it is associated with other diseases, not just breast cancer.
Q: Is there anything else that you would like to mention?
A: When talking about these ‘clocks,’ people often ask how they can have their biologic age measured and how it can be reversed. However, this is still a research tool. We do not yet know if biologic age can be changed and whether or not we can intervene. What we do know is that women can reduce their breast cancer risk with diet and exercise and by utilizing screening for breast cancer. – by Jennifer Southall
References:
Kresovich JK, et al. J Natl Cancer Inst. 2019;doi:10.1093/jnci/djz020.
For more information:
Jacob K. Kresovich, PhD, MPH, can be reached at the National Institute of Environmental Health Sciences, P.O. Box 12233, Durham, NC 27709; email: jacob.kresovich@nih.gov.
Disclosure : Kresovich reports no relevant financial disclosures.