Long-term variation in serum 25-hydroxyvitamin D concentration among participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.
Hofmann
Jonathan N
JN
Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 6120 Executive Boulevard, EPS 8109, Bethesda, MD 20892-7240, USA. hofmannjn@mail.nih.gov
Yu
Kai
K
Horst
Ronald L
RL
Hayes
Richard B
RB
Purdue
Mark P
MP