Healthy lifestyle cuts effect of genetic variants on breast cancer risk

  • Arthur RS & al.
  • J Natl Cancer Inst
  • 3 Jan 2020

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • Most invasive breast cancers are associated with having many low-penetrance single nucleotide polymorphisms (SNPs).
  • This UK Biobank study finds that a high score for these SNPs is linked to more than doubled likelihood of invasive breast cancer.
  • Risk is reduced by up to 31% among women with a highly healthy lifestyle, especially postmenopausal women.

Why this matters

  • Findings may empower women with high SNP-related risk to adopt a healthy lifestyle.

Study design

  • Prospective cohort of 146,326 women; median follow-up, 7.1 years.
  • Healthy lifestyle index (HLI) was derived at intake from diet, physical activity, smoking, alcohol intake, and anthropometry data and stratified by tertiles (high, medium, low).
  • A polygenic risk score (PRS) was derived from 304 breast cancer associated-genetic loci (SNPs) and stratified by tertiles.
  • Funding: Breast Cancer Research Foundation.

Key results

  • A high (vs low) PRS was associated with a more than doubled risk for invasive breast cancer:
    • HR, 2.64 for premenopausal women.
    • HR, 2.5 for postmenopausal women.
  • Compared with the lowest tertile, the highest tertile of HLI was linked to:
    • 22% reduction in breast cancer for premenopausal women (HR, 0.78; 95% CI, 0.64-0.94).
    • 31% for postmenopausal women (HR, 0.69; 95% CI, 0.63-0.77).

Limitations

  • Lifestyle was self-reported.
  • Observational.