Table 2.

Associations between statin use and breast cancer incidence in the NHS, 2000–2012

Cases, nAge-adjusted HR (95% CI)Multivariatea HR (95% CI)
All invasive cases (n = 3,055)
Never users1,9771.0 (ref)1.0 (ref)
Former users2020.93 (0.80–1.1)0.96 (0.82–1.1)
Current users
 Duration <4 y3301.1 (0.95–1.2)1.0 (0.92–1.2)
 4 y ≤ duration < 8 y3490.99 (0.88–1.1)0.95 (0.84–1.1)
 Duration ≥ 8 y1971.2 (1.0–1.4)1.1 (0.92–1.3)
Invasive ductal carcinoma (n = 1,952)
Never users1,3231.0 (ref)1.0 (ref)
Former users1130.91 (0.74–1.1)0.92 (0.75–1.1)
Current users
 Duration < 4 y2121.0 (0.87–1.2)0.95 (0.82–1.1)
 4 y ≤ duration < 8 y2140.94 (0.81–1.1)0.88 (0.75–1.0)
 Duration ≥ 8 y901.1 (0.88–1.4)1.0 (0.79–1.3)
Invasive lobular carcinoma (n = 313)
Never users2061.0 (ref)1.0 (ref)
Former users180.86 (0.52–1.4)0.87 (0.53–1.4)
Current users891.1 (0.82–1.4)0.98 (0.75–1.3)
ER-positive cases (n = 2,162)
Never users1,4301.0 (ref)1.0 (ref)
Former users1250.89 (0.74–1.1)0.90 (0.75–1.1)
Current users
 Duration < 4 y2451.1 (0.95–1.3)1.0 (0.91–1.2)
 4 y ≤ duration < 8 y2490.98 (0.85–1.1)0.91 (0.79–1.0)
 Duration ≥ 8 y1131.2 (0.94–1.4)1.0 (0.84–1.3)
ER-negative cases (n = 405)
Never users2521.0 (ref)1.0 (ref)
Former users301.2 (0.81–1.8)1.3 (0.85–1.9)
Current users
 Duration < 4 y411.1 (0.77–1.5)1.0 (0.74–1.5)
 4 y ≤ duration < 8 y561.2 (0.88–1.6)1.1 (0.82–1.5)
 Duration ≥ 8 y261.6 (1.0–2.5)1.5 (0.93–2.3)
In situ cases (n = 608)
Never users3851.0 (ref)1.0 (ref)
Former users341.1 (0.80–1.6)1.2 (0.83–1.7)
Current users
 Duration < 4 y821.4 (1.1–1.8)1.4 (1.1–1.7)b
 4 y ≤ duration < 8 y761.2 (0.95–1.6)1.1 (0.88–1.5)
 Duration ≥ 8 y311.7 (1.1–2.5)1.5 (0.99–2.2)
  • aAdjusted for body mass (continuous), first-degree family history of breast cancer (dichotomous), personal history of BBD (dichotomous), parity and age at first birth (design variables: see categories in Materials and Methods), age at menarche (<12, 12–13, or 14+), cumulative average ethanol consumption (design variables: see categories in Materials and Methods), MHT use (design variables: see categories in Materials and Methods), prevalent diabetes, and concomitant use of aspirin, ibuprofen, preventive tamoxifen, beta-blockers, calcium channel blockers, ACE inhibitors, and digoxin.

  • bThis association was near null in the subset of cohort members who had consistently undergone mammography screening (HRadj, 1.2; 95% CI, 0.96–1.6).