Table 1.

Population characteristics: EPIC nested case-control study

CasesControls
Full study population, n1976a1976a
Baseline characteristics, median (range), or n (%)
Age at blood collection, years56 (27–76)56 (27–77)
Age at menarche, years13 (8–20)13 (8–19)
Premenopausal460 (23%)460 (23%)
Postmenopausal1,516 (77%)1,516 (77%)
 PMH use at blood collectionb758 (50%)758 (50%)
 Age at menopause, yearsb50 (27–63)50 (21–63)
Completed term pregnancy1,675 (86%)1,709 (88%)
 Age at first term pregnancyc, years25 (16–44)24 (15–42)
BMI, kg/m224 (14–49)24 (16–46)
sRANKL concentrations, pmol/Ld0.11 (0.005, 1.67)0.11 (0.005, 0.85)
OPG concentrations, pmol/La9.81 (2.94, 31.81)9.84 (3.52, 32.86)
sRANKL/OPG ratioa0.01 (0.0002, 0.17)0.01 (0.0002, 0.20)
Case characteristics
ER+1,598 (81%)
ER−378 (19%)
ER+/PR+e920 (63%)
ER−/PR−e251 (17%)
Age at diagnosis, years61 (35–84)
Time between blood donation and diagnosis, years4.7 (0.02–11.7)
  • aAn additional nine case–control sets were missing OPG measurements. The total number of case–control sets for the sRANKL/OPG ratio is n = 1,967.

  • bAmong postmenopausal women.

  • cAmong women with completed term pregnancy.

  • dLowest measured value was 0.01 pmol/L; 327 observations (8.1%; 175 cases, 152 controls) had sRANKL concentrations below the LLOD of the assay, there were set to 50% the LLOD.

  • ePR status available for 74% of cases (sRANKL n = 1,461, sRANKL/OPG ratio n = 1,454); percentages represent percentage of total cases with ER and PR status available.