Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA.
PLoS One. 2011;6(12):e28520. doi: 10.1371/journal.pone.0028520. Epub 2011 Dec 28.
Vitamin D status and levels of insulin-like growth factor (IGF)-1 and C-peptide have been implicated in colorectal carcinogenesis. However, in contrast to vitamin D IGF-1 is not an easily modifiable risk factor.
Combining data from the Health Professionals Follow up Study (HPFS) and the Nurses' Health Study cohort (NHS) additive and multiplicative interactions were examined between plasma 25-hydroxyvitamin D (25(OH)D) and IGF-1, IGFBP-3 as well as C-peptide levels in 499 cases and 992 matched controls. For the various analytes, being high or low was based on being either above (or equal) or below the medians, respectively.
Compared to participants with high 25(OH)D and low IGF-1/IGFBP-3 ratio (reference group), participants with a high IGF-1/IGFBP-3 ratio were at elevated risk of colorectal cancer when 25(OH)D was low (odds ratio (OR): 2.05 (95% CI: 1.43 to 2.92), but not when 25(OH)D was high (OR:1.20 (95% CI: 0.84 to 1.71, p(interaction): additive =0.06, multiplicative =0.25). Similarly, compared to participants with high 25(OH)D and low molar IGF-1/IGFBP-3 ratio and low C-peptide levels (reference group), participants with a combination of either high IGF-1/IGFBP-3 ratio or high C-peptide were at elevated risk for colorectal cancer when 25(OH)D was low (OR =1.90, 95% CI: 1.22 to 2.94) but not when 25(OH)D was high (OR=1.15, 95% CI: 0.74 to 1.77, p(interaction): additive=0.004; multiplicative=0.04).
The results from this study suggest that improving vitamin D status may help lower risk of colorectal cancer associated with higher IGF-1/IGFBP-3 ratio or C-peptide levels.
维生素 D 状况以及胰岛素样生长因子 1（IGF-1）和 C 肽的水平与结直肠癌的发生有关。然而，与维生素 D 不同的是，IGF-1 不是一个容易改变的风险因素。
结合健康专业人员随访研究（HPFS）和护士健康研究队列（NHS）的数据，在 499 例病例和 992 例匹配对照中，检查了血浆 25-羟维生素 D（25（OH）D）与 IGF-1、IGFBP-3 和 C 肽水平之间的相加和相乘交互作用。对于各种分析物，高或低是基于高于（或等于）或低于中位数。
与 25（OH）D 水平高和 IGF-1/IGFBP-3 比值低的参与者（参考组）相比，当 25（OH）D 水平低时，IGF-1/IGFBP-3 比值高的参与者结直肠癌的风险增加（比值比（OR）：2.05（95%置信区间（CI）：1.43 至 2.92），但 25（OH）D 水平高时（OR：1.20（95%CI：0.84 至 1.71，p（交互作用）：相加=0.06，相乘=0.25）。同样，与 25（OH）D 水平高和 IGF-1/IGFBP-3 比值低且 C 肽水平低的参与者（参考组）相比，当 25（OH）D 水平低时，IGF-1/IGFBP-3 比值高或 C 肽水平高的参与者结直肠癌的风险增加（OR=1.90，95%CI：1.22 至 2.94），但 25（OH）D 水平高时（OR=1.15，95%CI：0.74 至 1.77，p（交互作用）：相加=0.004；相乘=0.04）。
本研究结果表明，提高维生素 D 状况可能有助于降低与 IGF-1/IGFBP-3 比值或 C 肽水平升高相关的结直肠癌风险。
