Inverse association between carotenoids, breast cancer more pronounced in high-risk women

Circulating carotenoids are inversely associated with the risk of breast cancer, and this is more evident in high-risk women, as defined by germline genetic makeup or mammographic density (MD), reports a recent study.

A total of 1,919 cases and 1,695 controls were included in a nested case-control study in the Nurses’ Health Study (NHS) and NHSII. The authors examined both multiplicative and additive interactions. Unconditional logistic regression was used to calculate relative risk reductions and 95 percent confidence intervals (CIs), adjusting for matching factors and breast cancer risk factors. Absolute risk reductions (ARRs) were calculated based on Surveillance, Epidemiology, and End Results incidence rates.

Women with higher genetic risk scores or high MD had greater ARRs for breast cancer as circulating carotenoid levels increase compared to those with low genetic risk or low MD (additive p_interaction=0.05).

Among women with a high polygenic risk score, those in the highest quartile of circulating carotenoids showed a significant ARR (28.6 percent, 95 percent CI, 14.8–42.1) than those in the lowest quartile. For women with a high percentage of MD (≥50 percent), circulating carotenoids correlated with a 37.1-percent ARR (95 percent CI, 21.7–52.1) when comparing women in the highest vs the lowest quartiles.

“Carotenoids represent one of few modifiable factors to reduce breast cancer risk,” the authors said. “Elucidation of interactions between circulating carotenoids and genetic predispositions or MD may help inform more effective primary preventive strategies in high-risk populations.”