Department of Clinical Biochemistry and the Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Herlev, Denmark.
Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
Rheumatology (Oxford). 2018 Oct 1;57(10):1769-1776. doi: 10.1093/rheumatology/key171.
Gout is the most common form of inflammatory arthritis and is caused by hyperuricaemia. Some studies have found a reduction in plasma urate with vitamin C supplementation. We tested the hypothesis that high plasma vitamin C is causally associated with low plasma urate and low risk of hyperuricaemia, using a Mendelian randomization approach.
We measured plasma urate and genotyped for the SLC23A1 rs33972313 vitamin C variant in 106 147 individuals from the Copenhagen General Population Study, of which 24 099 had hyperuricaemia. We measured plasma vitamin C in 9234 individuals and genotyped for the SLC2A9 rs7442295 urate variant in 102 345 individuals.
Each 10 µmol/l higher plasma vitamin C was associated with a -2.3(95%CI: -0.69 to -3.9) µmol/l lower plasma urate after multivariable adjustments. The SLC23A1 rs33972313 GG genotype was associated with a 9% (5.6%, 11.9%) higher plasma vitamin C compared with AA and AG combined but was not associated with plasma urate (P = 0.31). Likewise, for each 10 µmol/l higher plasma vitamin C the odds ratios for hyperuricaemia were 0.92 (0.86, 0.98) observationally after multivariable adjustments, but 1.01 (0.84, 1.23) genetically.
High plasma vitamin C was associated with low plasma urate and with low risk of hyperuricaemia. However, the SLC23A1 genetic variant causing lifelong high plasma vitamin C was not associated with plasma urate levels or with risk of hyperuricaemia. Thus, our data do not support a causal relationship between high plasma vitamin C and low plasma urate.
痛风是最常见的炎症性关节炎，其病因是血尿酸过高。一些研究发现，补充维生素 C 可降低血浆尿酸水平。我们采用孟德尔随机化方法检验了这样一个假说，即高血浆维生素 C 与低血浆尿酸和低血尿酸风险相关。
我们在哥本哈根普通人群研究中测量了 106147 人的血浆尿酸水平，并对 SLC23A1 rs33972313 维生素 C 变异进行了基因分型，其中 24099 人患有高尿酸血症。我们在 9234 人的血浆维生素 C 水平进行了测量，并对 SLC2A9 rs7442295 尿酸变异进行了基因分型，在 102345 人的血浆维生素 C 水平进行了测量。
多变量调整后，血浆维生素 C 每增加 10 µmol/L，血浆尿酸降低 2.3（95%CI：-0.69 至-3.9）µmol/L。与 AA 和 AG 组合相比，SLC23A1 rs33972313 GG 基因型的血浆维生素 C 水平高 9%（5.6%，11.9%），但与血浆尿酸无关（P = 0.31）。同样，在多变量调整后，与高尿酸血症相关的每增加 10µmol/L 的血浆维生素 C 的比值比为 0.92（0.86，0.98），但在遗传上为 1.01（0.84，1.23）。
高血浆维生素 C 与低血浆尿酸和低血尿酸风险相关。然而，导致终生高血浆维生素 C 的 SLC23A1 遗传变异与血浆尿酸水平或高尿酸血症风险无关。因此，我们的数据不支持高血浆维生素 C 与低血浆尿酸之间存在因果关系。
