Table 3.

OR*of breast cancer subgroups and 95% CI by quartile of adrenal hormone levels among predominantly premenopausal women in the Nurses' Health Study

No. of cases/No. of controlsQuartile categoriesP value for trend
Hormone level1234
DHEA, (ng/dL)<200200-307308-450≥451
    Invasive cancers only209/3981.0 (referent)1.01 (0.60-1.69)1.13 (0.66-1.94)0.94 (0.54-1.62)0.06
    ER positive cases only157/3041.0 (referent)0.80 (0.43-1.46)1.21 (0.66-2.23)0.82 (0.40-1.50)0.07
    Cases ≥2 years after blood242/4651.0 (referent)0.81 (0.51-1.29)0.90 (0.56-1.45)0.95 (0.58-1.57)0.15
    Premenopausal cases only‡,§101/1951.0 (referent)1.11 (0.52-2.37)1.26 (0.59-2.68)1.12 (0.53-2.40)0.61
    Postmenopausal cases only‡,§129/2521.0 (referent)0.82 (0.47-1.43)0.75 (0.41-1.39)0.74 (0.39-1.43)0.04
DHEA-S, (μg/dL)<9696-146147-218≥219
    Invasive cancers only211/4041.0 (referent)1.32 (0.80-2.20)1.39 (0.83-2.34)1.10 (0.63-1.91)0.79
    ER positive cases only†,e159/3091.0 (referent)1.22 (0.68-2.19)1.41 (0.78-2.54)1.08 (0.58-2.02)0.73
    Cases ≥2 years after blood244/4701.0 (referent)1.11 (0.69-1.76)1.37 (0.87-2.16)1.09 (0.66-1.78)0.67
    Premenopausal cases only‡,§101/1971.0 (referent)1.53 (0.69-3.41)1.49 (0.67-3.30)1.49 (0.67-3.29)0.62
    Postmenopausal cases only‡,§131/2541.0 (referent)0.89 (0.51-1.53)1.01 (0.57-1.80)0.86 (0.45-1.67)0.94
  • NOTE: To convert DHEA to nmol/l, multiply by 0.0347, and to convert DHEA to μmol/l, multiply by 0.0271.

  • Conditional logistic regression additionally controlling for age at first birth/parity, age at menarche, certainty of menopausal status (definite premenopausal versus dubious), first degree family history of breast cancer, age at blood draw (modeled as a linear continuous variable), mean alcohol intake, mean folate intake, and body mass index at age 18 (the latter three variables modeled as continuous variables with natural cubic splines).

  • ER positive is estrogen receptor positive.

  • Simple (unadjusted for other covariates) ORs from conditional logistic regression used due to sparse data.

  • § Case patients with breast cancer were either premenopausal or postmenopausal at diagnosis.

  • e Continuous covariate fitted as linear terms because of convergence problems with fitting the natural cubic splines.