Kristal et al. Page 1494

Kristal and colleagues used data from the Selenium and Vitamin E Cancer Prevention Trial to test whether plasma vitamin D concentration was associated with the risk of prostate cancer. The authors found associations between both low and high vitamin D concentrations and total cancer risk. This study suggests that the optimal range of circulating vitamin D for prostate cancer prevention may be narrow, and supplementation of men with already adequate levels of vitamin D may be harmful.

Powell et al. Page 1505

A reduction in prostate cancer racial survival disparity between African American men (AAM) and European American men (EAM) during the PSA testing era compared to the pre-PSA era would strongly support the use of PSA testing in AAM. Powell and colleagues used SEER data to investigate this and report significantly shorter prostate cancer survival for AAM compared to EAM during the pre-PSA era. In addition, the authors found that during the PSA era there was no statistical difference in prostate cancer relative survival rates between AAM and EAM.

Prescott et al. Page 1512

Prescott and colleagues used the prospective Nurses' Health Study to examine the association of dietary insulin load and insulin index scores with endometrial cancer risk. The authors report that dietary insulin scores were not associated with overall risk of endometrial cancer. Findings did not vary substantially by alcohol consumption, total dietary fiber intake, BMI, or physical activity. The authors caution that dietary measures alone may not sufficiently capture absolute long-term insulin exposure.

Daskalakis et al. Page 1521

Colorectal cancer screening test preferences, test access, and navigation influence screening adherence in primary care. To examine this closely, Daskalakis and colleagues analyzed data from a randomized trial of primary care patients to assess the effects of screening test preference for fecal immunochemical test (FIT) or colonoscopy (CX), mailed access to FIT and CX, and telephone navigation for FIT and CX, on screening. Preference was not associated with overall screening but telephone navigation was associated with increased overall screening. The authors estimate that providing navigation for both screening tests could increase screening adherence.