Lipid-lowering drugs, dyslipidemia, and breast cancer risk in a Medicare population

• Published in: Breast cancer research and treatment 2018-06, Vol.169 (3), p.607-614
• Main Authors: Schairer, Catherine, Freedman, D. Michal, Gadalla, Shahinaz M., Pfeiffer, Ruth M.
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Breast cancer; Breast Neoplasms - epidemiology; Breast Neoplasms - etiology; Cancer prevention; Cancer research; Case-Control Studies; Diagnosis; Drugs; Dyslipidemia; Dyslipidemias - complications; Dyslipidemias - drug therapy; Epidemiology; Female; Health aspects; Health maintenance organizations; Health risk assessment; HMOs; Hormone replacement therapy; Humans; Hypolipidemic Agents - adverse effects; Hypolipidemic Agents - therapeutic use; Invasiveness; Lipids; Mammography; Medical diagnosis; Medicare; Medicine; Medicine & Public Health; Metabolic disorders; Odds Ratio; Oncology; Risk Assessment; Risk Factors; Statins; United States - epidemiology
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-018-4680-7

Purpose We sought to disentangle the effects of statins and other lipid-lowering drugs and the underlying dyslipidemia for which they are prescribed on breast cancer risk. Methods We conducted a case–control study within the linked Surveillance, Epidemiology, and End results (SEER)-Medicare data. Cases were women with invasive breast cancer aged 66 + years ( N  = 30,004) identified by SEER registries (years 2007–2011). Controls were women ( N  = 198,969) identified from a 5% random sample of Medicare recipients alive and breast cancer free in year of selection. Participants had a minimum of 13 months of Part A, Part B non-health maintenance organization Medicare and Part D Medicare coverage at least 13 months preceding cancer diagnosis/selection. Exposures were assessed until 12 months before diagnosis/control selection. Odds ratios (OR) and 99.9% confidence intervals (CI) were estimated using adjusted unconditional and multinomial logistic regression. Results ORs of invasive breast cancer associated with dyslipidemia, statins, and non-statin lipid-lowering drugs were 0.86 (99.9% CI 0.81–0.90), 1.07 (99.9% CI 1.03–1.13) and 1.03 (99.9% CI 0.95–1.11), respectively. Risk reductions with dyslipidemia were slightly greater when untreated than treated and did not vary much by time between dyslipidemia and breast cancer diagnosis. Whether treated or untreated, dyslipidemia was associated with greater reductions in risk for later stage than earlier stage breast cancer ( p -heterogeneity