Skip to Main Content

An official website of the United States government

Government Funding Lapse

Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted. The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit  cc.nih.gov. Updates regarding government operating status and resumption of normal operations can be found at OPM.gov.

Principal Investigator
Name
Kai Yu
Institution
NCI, DCEG, BB
Email
About this CDAS Project
Study
PLCO (Learn more about this study)
Project ID
2009-0006
Initial CDAS Request Approval
Nov 11, 2009
Title
New statistical approaches for adjusting seasonal variation in vitamin D concentration measurement, with application in the PLCO nested case-control study of serum vitamin D concentration and prostate cancer risk
Summary
Understanding the role of vitamin D in various diseases, including cancers, would have a tremendous public health impact. One of the major challenges in studying the relationship between vitamin D and a disease outcome is how to quantify a person's vitamin D level, as It is widely recognized that the vitamin D level like 25-hydroxyvitamin D [25(OH)D] in human body varies from season to season. The disease-vitamin D relationship can be obscure if such seasonal variation is not properly addressed. The locally weighted polynomial regression (LOESS) (LOESS), has been commonly used to estimate the seasonal trend. We propose two alternative statistical approaches for dealing with the seasonal variations, including one using the sine curve and the one using the penalized regression spline. To demonstrate the application of the proposed approaches, we plan to apply the new methods to reanalyze the recently published PLCO nested case-control study of serum vitamin D concentration and prostate cancer risk.
Aims

Use new proposed statistical approaches to reanalyze the recently published PLCO nested case-control study of serum vitamin D concentration and prostate cancer risk (Ahn et al . JNCI, 2008, 100: 796-804)

Collaborators

Jiyoung Ahn (New York University)