Yin J, Yin LY, Freedman ND, et al. - This study with a nested case–control design was undertaken to assess the independent as well as joint links between prediagnostic concentrations of serum calcium and vitamin D and future risk of incident primary liver cancer. Individuals over 22 years of follow-up were examined. In multivariable adjusted models, an increased primary liver cancer risk was observed among participants with both low or high calcium, while an attenuated risk of primary liver cancer was noted in relation to high 25-hydroxy vitamin D [25(OH)D]. In joint analyses, increased odds of experiencing primary liver cancer were observed in participants with high calcium and medium 25(OH)D vs those with medium calcium and 25(OH)D; decreased odds of encountering primary liver cancer were evident in those with medium calcium and high 25(OH)D; and individuals in other classifications of calcium and serum 25(OH)D levels demonstrated no alteration in the odds of having primary liver cancer. Overall, experts concluded serum calcium and serum 25(OH)D as possible potentially modifiable risk or protective factors in a nutrient-deficient population.