Wiseman R A, MacRae K D
Fertil Steril. 1981 Mar;35(3):277-83. doi: 10.1016/s0015-0282(16)45371-9.
Many publications have claimed that oral contraceptives (OCs) are associated with an increased risk of circulatory disease, yet between the years 1962 and 1976, when OCs became widely used in the United Kingdom, death rates from circulatory disease in women of reproductive age fell steadily. This decreased mortality was greater in young women than in men of comparable age, and did not occur in older women. These data tend strongly to refute the belief that OCs are causative of circulatory disease. The possibility that the decreased mortality rate is due to a protective effect of OCs was examined. It was concluded that they could not be completely responsible, although a partial effect could not be ruled out with certainty. It is suggested that, when mortality trends are opposed to the results of case-control or cohort studies, serious doubts are cast on the conclusions about causal relationships.
许多出版物声称口服避孕药（OCs）与循环系统疾病风险增加有关，但在1962年至1976年间，当口服避孕药在英国广泛使用时，育龄妇女的循环系统疾病死亡率却稳步下降。年轻女性的这种死亡率下降幅度比同龄男性更大，而老年女性则未出现这种情况。这些数据有力地反驳了口服避孕药会导致循环系统疾病的观点。研究了死亡率下降是否是由于口服避孕药的保护作用。结论是，虽然不能完全排除其有部分作用，但口服避孕药不可能是死亡率下降的完全原因。有人认为，当死亡率趋势与病例对照研究或队列研究结果相悖时，就会对因果关系的结论产生严重怀疑。
