Mant J, Painter R, Vessey M
Division of Public Health and Primary Health Care, University of Oxford, Institute of Health Sciences, UK.
Br J Obstet Gynaecol. 1998 Aug;105(8):890-6. doi: 10.1111/j.1471-0528.1998.tb10235.x.
To investigate risk of myocardial infarction, angina and stroke in users of contraceptive pills compared with users of other methods of contraception.
Prospective cohort study, with recruitment between 1968 and 1974 and annual follow up until the age of 45 years. After this age, only women who had never used oral contraception or those who had used it for eight or more years continued to be followed up annually until July 1994.
Seventeen family planning clinics in England and Scotland.
17,032 women aged between 25 and 39 years at entry to the study.
Occurrence of angina, myocardial infarction or stroke that was associated with either hospital admission or outpatient referral to hospital or death.
Increased risk of myocardial infarction in oral contraceptive users was observed only in women who were heavy smokers at entry to the study. In this subgroup the relative risk of a myocardial infarction was 4.2 (95% CI 1.4-16.6) in ever users of oral contraception compared with non-users, 4.9 (1.2-23.6) in current users, and 4.0 (1.3-16.2) in ex-users. In all current users the relative risk of angina was 0.5 (0.1-1.4), and the relative risk of ischaemic stroke was 2.9 (1.3-6.7). The increased risk of ischaemic stroke did not persist in ex-users.
Use of oral contraception is associated with increased risk of ischaemic stroke and increased risk of myocardial infarction (only in heavy smokers), but no increased risk of angina. These increased risks need to be considered within the context of the very low absolute risks of cardiovascular disease in this population. 5880 women need to take oral contraception for one year to cause one extra stroke, and 1060 women who are heavy smokers need to take it for one year to cause one extra myocardial infarction.
比较服用避孕药的女性与采用其他避孕方法的女性发生心肌梗死、心绞痛和中风的风险。
前瞻性队列研究，于1968年至1974年招募研究对象，每年进行随访直至45岁。45岁之后，仅对从未使用过口服避孕药或使用过八年及以上口服避孕药的女性继续每年随访，直至1994年7月。
英格兰和苏格兰的17家计划生育诊所。
17032名年龄在25至39岁之间的女性，她们在研究开始时进入研究。
因心绞痛、心肌梗死或中风而住院、门诊转诊至医院或死亡的情况。
仅在研究开始时为重度吸烟者的女性中观察到口服避孕药使用者发生心肌梗死的风险增加。在该亚组中，曾经使用过口服避孕药的女性发生心肌梗死的相对风险为4.2（95%可信区间1.4 - 16.6），与未使用者相比，当前使用者为4.9（1.2 - 23.6），既往使用者为4.0（1.3 - 16.2）。在所有当前使用者中，心绞痛的相对风险为0.5（0.1 - 1.4），缺血性中风的相对风险为2.9（1.3 - 6.7）。缺血性中风风险增加在既往使用者中并未持续存在。
使用口服避孕药与缺血性中风风险增加以及心肌梗死风险增加（仅在重度吸烟者中）相关，但心绞痛风险未增加。这些风险增加需要在该人群心血管疾病绝对风险非常低的背景下加以考虑。5880名女性需要服用口服避孕药一年才会多发生一例中风，1060名重度吸烟女性需要服用一年才会多发生一例心肌梗死。
