Wald N, Boreham J, Bailey A
Br J Cancer. 1986 Dec;54(6):957-61. doi: 10.1038/bjc.1986.267.
In a prospective study of about 22,000 men attending a well person screening centre, serum samples were collected and stored. The concentration of retinol was measured in the stored serum samples from 227 men subsequently notified as having cancer and from 454 unaffected controls, matched for age, smoking history and duration of storage of the serum samples. The mean serum retinol concentration of the cancer subjects who developed cancer before the elapse of one year since the time blood was collected was significantly lower than the mean concentration of their matched controls (641 and 722 micrograms l-1 respectively, P less than 0.001). For subjects whose cancer developed one to two years after blood had been collected, the difference was less (650 and 701 micrograms l-1 respectively, P less than 0.01). For subjects whose cancer developed three or more years after blood was collected, the mean retinol level was higher than in their controls, although not statistically significantly so (694 and 663 micrograms l-1 respectively). These findings suggest that the inverse association between serum retinol and risk of cancer that was previously observed was due to low serum retinol being a metabolic consequence of cancer rather than a precursor of cancer.
在一项对约22000名前往健康体检中心的男性进行的前瞻性研究中，采集并储存了血清样本。对随后被通知患癌症的227名男性以及454名未受影响的对照者（根据年龄、吸烟史和血清样本储存时间进行匹配）的储存血清样本进行了视黄醇浓度测量。在采血后一年内患癌的癌症受试者的血清视黄醇平均浓度显著低于其匹配对照者的平均浓度（分别为641和722微克/升，P<0.001）。对于采血后一至两年患癌的受试者，差异较小（分别为650和701微克/升，P<0.01）。对于采血后三年或更长时间患癌的受试者，视黄醇平均水平高于其对照者，尽管在统计学上无显著差异（分别为694和663微克/升）。这些发现表明，先前观察到的血清视黄醇与癌症风险之间的负相关是由于血清视黄醇水平低是癌症的代谢结果而非癌症的前兆。
