Vitamin D and Pancreatic Cancer Risk - No U-Shaped Curve

In a recent paper entitled "Circulating 25-Hydroxyvitamin D and the Risk of Pancreatic Cancer," Stolzenberg-Solomon et al. reported that the odds ratio for diagnosis of pancreatic cancer shows a "statistically significant" precipitous jump of more than a factor of 2 at the highest presented concentrations of >100 nmol/l. This was one of six related studies of the relation of 25-hydroxyvitamin D and six types of rarer cancers, collected by the Vitamin D Pooling Project (VDPP). An alternative analysis of the presented data suggests that the reported two-fold higher risk at the highest serum 25(OH)D level in the pancreatic cancer study is most likely a statistical artifact associated with the chosen cut-off point groupings and there is no U-shaped curve to be explained.