Measurement error does not explain the persistence of a body mass index association with endometrial cancer after adjustment for endogenous hormones

Identified risk factors for endometrial cancer are accepted as operating th rough estrogen exposure. In a recent analysis, the effect of risk factors s uch as body mass index (BMI) was not explained by circulating estrogen conc entrations. In the present analysis, we correct for measurement error assoc iated with obtaining only one blood sample per subject. Applying regression calibration ideas, we found that error correction of log estrone had littl e impact on estimates of the BMI effect, suggesting that hormone measuremen t error does not account for the residual importance of BMI. The biologic m echanism for the increased risk associated with BMI remains to be explained .