Khaw K T, Bingham S, Welch A, Luben R, Wareham N, Oakes S, Day N
Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge School of Clinical Medicine, UK.
Lancet. 2001 Mar 3;357(9257):657-63. doi: 10.1016/s0140-6736(00)04128-3.
Ascorbic acid (vitamin C) might be protective for several chronic diseases. However, findings from prospective studies that relate ascorbic acid to cardiovascular disease or cancer are not consistent. We aimed to assess the relation between plasma ascorbic acid and subsequent mortality due to all causes, cardiovascular disease, ischaemic heart disease, and cancer.
We prospectively examined for 4 years the relation between plasma ascorbic acid concentrations and mortality due to all causes, and to cardiovascular disease, ischaemic heart disease, and cancer in 19 496 men and women aged 45-79 years. We recruited individuals by post using age-sex registers of general practices. Participants completed a health and lifestyle questionnaire and were examined at a clinic visit. They were followed-up for causes of death for about 4 years. Individuals were divided into sex-specific quintiles of plasma ascorbic acid. We used the Cox proportional hazard model to determine the effect of ascorbic acid and other risk factors on mortality.
Plasma ascorbic acid concentration was inversely related to mortality from all-causes, and from cardiovascular disease, and ischaemic heart disease in men and women. Risk of mortality in the top ascorbic acid quintile was about half the risk in the lowest quintile (p<0.0001). The relation with mortality was continuous through the whole distribution of ascorbic acid concentrations. 20 micromol/L rise in plasma ascorbic acid concentration, equivalent to about 50 g per day increase in fruit and vegetable intake, was associated with about a 20% reduction in risk of all-cause mortality (p<0.0001), independent of age, systolic blood pressure, blood cholesterol, cigarette smoking habit, diabetes, and supplement use. Ascorbic acid was inversely related to cancer mortality in men but not women.
Small increases in fruit and vegetable intake of about one serving daily has encouraging prospects for possible prevention of disease.
抗坏血酸（维生素C）可能对多种慢性疾病具有保护作用。然而，前瞻性研究中关于抗坏血酸与心血管疾病或癌症之间关系的结果并不一致。我们旨在评估血浆抗坏血酸与随后因各种原因、心血管疾病、缺血性心脏病和癌症导致的死亡率之间的关系。
我们对19496名年龄在45 - 79岁的男性和女性进行了为期4年的前瞻性研究，以探讨血浆抗坏血酸浓度与各种原因、心血管疾病、缺血性心脏病和癌症导致的死亡率之间的关系。我们通过使用全科医疗的年龄 - 性别登记册邮寄招募个体。参与者完成了一份健康和生活方式问卷，并在诊所就诊时接受检查。他们被随访约4年以确定死亡原因。个体被分为血浆抗坏血酸的性别特异性五分位数。我们使用Cox比例风险模型来确定抗坏血酸和其他风险因素对死亡率的影响。
血浆抗坏血酸浓度与男性和女性因各种原因、心血管疾病和缺血性心脏病导致的死亡率呈负相关。抗坏血酸最高五分位数的死亡风险约为最低五分位数的一半（p<0.0001）。在抗坏血酸浓度的整个分布范围内，与死亡率的关系是连续的。血浆抗坏血酸浓度每升高20微摩尔/升，相当于每天水果和蔬菜摄入量增加约50克，与全因死亡率风险降低约20%相关（p<0.0001），且独立于年龄、收缩压、血胆固醇、吸烟习惯、糖尿病和补充剂使用情况。抗坏血酸与男性癌症死亡率呈负相关，但与女性无关。
每天增加约一份水果和蔬菜的摄入量，对于疾病预防可能具有令人鼓舞的前景。
