Hannaford P
RCGP Centre for Primary Care Research and Epidemiology, Department of General Practice and Primary Care, Foresterhill Health Centre, Aberdeen, Scotland.
Drug Saf. 2000 May;22(5):361-71. doi: 10.2165/00002018-200022050-00004.
Studies of combined oral contraceptive (COC) use and cardiovascular disease have been conducted against a background of low cardiovascular risk in young women, changing COC composition and changing user selection and monitoring. Studies of myocardial infarction have found inconsistent results, possibly because of differences in the prevalence of risk factors (particularly smoking and raised blood pressure) in the populations studied. In the absence of a history of smoking and other conventional risk factors, current users of modern COCs probably do not have an increased risk of myocardial infarction. Neither are former users at risk. Evidence for important differences in the risk of myocardial infarction between formulations is weak and contradictory. Current users of low estrogen dose COCs have a small increased risk of ischaemic stroke although most of the risk occurs in women with other risk factors (notably smoking, hypertension and probably a history of migraine). Former users of COCs do not have an increased risk of ischaemic stroke. There is insufficient information to determine whether major differences in the risk of ischaemic stroke exist between products. Current users appear to have a modestly elevated risk of haemorrhagic stroke, mainly in women older than 35 years; former users do not. Data examining the risk of haemorrhagic stroke in current COC users with other risk factors are very sparse, as are those relating to the haemorrhagic stroke risk associated with particular COCs. Numerous studies have found, with remarkable consistency, an elevated risk of venous thromboembolism among current users of low estrogen dose COCs. The risk is substantially elevated among women with various inherited clotting factor defects. The effects in COC users with other risk factors for venous thrombosis tend to be less pronounced and more inconsistent. A number of studies have found higher relative risks among current users of low estrogen dose COCs containing desogestrel or gestodene, than among users of similar products containing levonorgestrel. A number of explanations, in terms of bias or confounding, have been proposed for these clinically small differences. At best, empirical evidence for these explanations, is weak. The risk of cardiovascular disease of any description is low in COC users. Women can minimise, and possibly eliminate entirely, their arterial risks by not smoking and by having their blood pressure checked before using a COC (in order to avoid its use if raised blood pressure is discovered). Users may decrease their venous thromboembolic risk by their choice of COC preparation although the effects will be modest.
关于联合口服避孕药（COC）使用与心血管疾病的研究，是在年轻女性心血管风险较低、COC成分不断变化以及使用者选择和监测方式不断变化的背景下进行的。关于心肌梗死的研究结果并不一致，这可能是由于所研究人群中危险因素（尤其是吸烟和血压升高）的患病率存在差异。在没有吸烟史和其他传统危险因素的情况下，现代COC的当前使用者心肌梗死风险可能不会增加。既往使用者也不存在风险。不同剂型之间心肌梗死风险存在重要差异的证据薄弱且相互矛盾。低雌激素剂量COC的当前使用者缺血性中风风险略有增加，不过大部分风险发生在有其他危险因素（尤其是吸烟、高血压以及可能有偏头痛病史）的女性中。COC既往使用者缺血性中风风险并未增加。尚无足够信息来确定不同产品之间缺血性中风风险是否存在重大差异。当前使用者出血性中风风险似乎略有升高，主要发生在35岁以上女性中；既往使用者则不然。关于有其他危险因素的COC当前使用者出血性中风风险的数据非常稀少，与特定COC相关的出血性中风风险数据也是如此。众多研究都惊人一致地发现，低雌激素剂量COC的当前使用者静脉血栓栓塞风险升高。在患有各种遗传性凝血因子缺陷的女性中，该风险大幅升高。对于有其他静脉血栓形成危险因素的COC使用者，其影响往往不那么明显且更不一致。多项研究发现，与含左炔诺孕酮的类似产品使用者相比，含去氧孕烯或孕二烯酮的低雌激素剂量COC当前使用者的相对风险更高。针对这些临床上细微的差异，已提出了多种关于偏倚或混杂因素的解释。这些解释的实证证据充其量很薄弱。COC使用者患任何类型心血管疾病的风险都很低。女性可以通过不吸烟以及在使用COC之前检查血压（以便在发现血压升高时避免使用）来将其动脉风险降至最低，甚至可能完全消除。使用者可以通过选择COC制剂来降低静脉血栓栓塞风险，尽管效果会很有限。
