Serum B6vitamers (pyridoxal 5'-phosphate, pyridoxal, and 4-pyridoxic acid) and pancreatic cancer risk: two nested case-control studies in Asian populations.
BACKGROUND
Vitamin B6is an important enzymatic cofactor in pathways relevant for the development of pancreatic cancer. In order to evaluate vitamin B6as a preventive factor for pancreatic cancer, a biomarker approach is needed to overcome the limitations inherent in self-reported dietary information.


METHODS
To determine whether levels of serum B6vitamers, including pyridoxal 5'-phosphate (PLP), pyridoxal (PL), 4-pyridoxic acid (PA), and the PA/(PLP + PL) ratio (PAr), were associated with risk of pancreatic cancer, two nested case-control studies of 187 incident pancreatic cancer cases and 258 individually matched controls were conducted within two prospective cohorts of 81,501 participants in Shanghai, China, and Singapore. PLP, PL, and PA were quantified in pre-diagnostic serum samples. Odds ratios and 95% confidence intervals (CIs) were calculated using conditional logistic regression with adjustment for potential confounders.


RESULTS
The median (5th-95th percentiles) concentrations of serum PLP among control subjects of the Shanghai and Singapore cohorts were 25.7 (10.0-91.7) nmol/L and 58.1 (20.8-563.0) nmol/L, respectively. In pooled analyses, high serum PLP was associated with a reduced risk of pancreatic cancer (P for trend = 0.048); the adjusted odds ratio for the highest category of PLP (>52.4 nmol/L) was 0.46 (95% CI 0.23, 0.92) compared to vitamin B6deficiency (<20 nmol/L). No associations were found for serum PL, PA, or PAr with pancreatic cancer risk.


CONCLUSIONS
Higher concentrations of PLP may protect against the development of pancreatic cancer. The protective effect may be more apparent in populations with low concentrations of circulating vitamin B6.
Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA.|Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
Joyce Y
JY
Huang
Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA. butlerl3@upmc.edu.|Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA. butlerl3@upmc.edu.
Lesley M
LM
Butler
Bevital A/S, Bergen, Norway.
Øivind
Ø
Midttun
Duke-NUS Medical School, National University of Singapore, Singapore, Singapore.|Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore.
Woon-Puay
WP
Koh
Department of Clinical Science, University of Bergen, Bergen, Norway.|Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway.
Per M
PM
Ueland
Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA.
Renwei
R
Wang
National Registry of Diseases Office, Health Promotion Board, Singapore, Singapore.
Aizhen
A
Jin
Shanghai Jiaotong University, Shanghai, China.
Yu-Tang
YT
Gao
Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA.|Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
Jian-Min
JM
Yuan
D000368:Aged; D044466:Asian People; D014408:Biomarkers, Tumor / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000097:blood* / Q000453:epidemiology; D011446:Prospective Studies; D011730:Pyridoxal / Q000097:blood*; D011732:Pyridoxal Phosphate / Q000097:blood*; D011735:Pyridoxic Acid / Q000097:blood*; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D025101:Vitamin B 6 / Q000097:blood; D014803:Vitamin B Complex / Q000097:blood
D014408:Biomarkers, Tumor; D014803:Vitamin B Complex; D011730:Pyridoxal; D011735:Pyridoxic Acid; D011732:Pyridoxal Phosphate; D025101:Vitamin B 6
Biomarker; Case–control studies; Cohort studies; Epidemiology; Pancreatic cancer; Pyridoxal 5′-phosphate; Risk factors; Vitamin B6