Paulsen Elise Marlen, Braaten Tonje Bjørndal, Urbarova Ilona, Brustad Magritt
Department of Community Medicine, University of Tromsø - The Arctic University of Norway, Tromsø, Norway.
The Public Dental Health Service Competence Centre of Northern Norway, Tromsø, Norway.
Br J Nutr. 2025 Jan 3;133(3):1-9. doi: 10.1017/S0007114524003350.
Colorectal cancer (CRC), the third most common cancer globally, causes over 900 000 deaths annually. Although vitamin D is observed to have potential anti-carcinogenic properties, research findings on its preventable effect against CRC remain inconclusive. Notably, different subsites within the colon and rectum may be associated with distinct risk factors. While some studies have explored this relationship with circulating 25-hydroxyvitamin D (25(OH)D), the results remain contradictory. Our study employed a nested case-control design, involving 775 CRC cases matched with 775 cancer-free controls based on age, region of living and the time of blood sampling. The study was conducted within the Norwegian Women and Cancer post-genome cohort, which comprises approximately 50 000 women. We measured pre-diagnostic circulating plasma 25(OH)D status 5-13 years before diagnosis. Adjustment variables were based on self-administered questionnaires and included BMI, physical activity level, smoking, intake of processed meat, calcium, alcohol and fibre. An increase of 5 nmol/l in 25(OH)D reduced the risk of proximal colon cancer by 6 % (OR = 0·94, 95 % CI 0·89, 0·99). Furthermore, a sensitivity analysis revealed a 62 % increased risk among the women with 25(OH)D levels below 50 nmol/l compared with sufficient levels, ≥ 50 to < 75 nmol/l (OR = 1·62, 95 % CI 1·01, 2·61). No association was found with CRC, colon or distal colon cancer. We observed a subsite-specific association between 25(OH)D and CRC, highlighting the need for further investigation to elucidate the potential underlying mechanisms and clinical implications.
结直肠癌（CRC）是全球第三大常见癌症，每年导致超过90万人死亡。尽管观察到维生素D具有潜在的抗癌特性，但其对结直肠癌预防作用的研究结果仍无定论。值得注意的是，结肠和直肠内的不同亚部位可能与不同的风险因素相关。虽然一些研究探讨了循环25-羟基维生素D（25(OH)D）与这种关系，但结果仍然相互矛盾。我们的研究采用巢式病例对照设计，纳入了775例结直肠癌病例，并根据年龄、居住地区和采血时间与775例无癌对照进行匹配。该研究在挪威女性与癌症基因组后队列中进行，该队列约有50000名女性。我们在诊断前5至13年测量了循环血浆25(OH)D的预诊断状态。调整变量基于自我填写的问卷，包括体重指数、身体活动水平、吸烟、加工肉类摄入量、钙、酒精和纤维摄入量。25(OH)D每增加5 nmol/l，近端结肠癌风险降低6%（OR = 0·94，95%CI 0·89，0·99）。此外，一项敏感性分析显示，与25(OH)D水平≥50至<75 nmol/l的充足水平相比，25(OH)D水平低于50 nmol/l的女性风险增加62%（OR = 1·62，95%CI 1·01，2·61）。未发现与结直肠癌、结肠癌或远端结肠癌有关联。我们观察到25(OH)D与结直肠癌之间存在亚部位特异性关联，这突出表明需要进一步研究以阐明潜在的机制和临床意义。
