Cottingham J, Hunter D
Department of Population Sciences, Harvard School of Public Health, Boston.
Genitourin Med. 1992 Aug;68(4):209-16. doi: 10.1136/sti.68.4.209.
Chlamydia trachomatis is now recognised as a major sexually transmitted disease; oral contraceptive use is rapidly increasing particularly in developing countries. There are thus important public health implications of the many reports that isolation of C trachomatis is more frequent among users of oral contraceptives. The aim of this analysis was to assess the strength and consistency of this association by summarising published studies between 1972 and 1990.
Studies identified were grouped according to whether they were prospective or case-control studies. Data were extracted and pooled estimates of the unadjusted odds ratios were made for all studies, as well as for sub-groups defined by an index of study quality, background prevalence of C trachomatis, and the contraceptive comparison being made.
Studies in the analysis were mainly conducted in Europe and North America; the meta-analysis was done at the Harvard School of Public Health, Boston, MA, USA.
The pooled estimated unadjusted odds ratio for 29 case-control studies examined was 1.93 (95% CI, 1.77-2.11), indicating an almost twofold increased risk of chlamydial infection for oral contraceptive users. Neither study quality nor prevalence of C trachomatis modified this risk. When compared to the use of barrier contraceptives, however, the risk of infection for women using oral contraceptives increased to 2.91 (95% CI, 1.86-4.55). The pooled estimated protective effect of barrier methods in these studies was 0.34 (95% CI, 0.22-0.54).
Cross-study comparisons of the relationship between oral contraceptive use and chlamydial infection are limited by the design and analysis of many component studies which did not control for confounding factors such as sexual behaviour and age. The almost twofold risk of increased chlamydial infection for oral contraceptive users, supported by the findings of two prospective studies, however, points to the importance of considering the risks and benefits of oral contraceptive use in women who are likely to be exposed to C trachomatis and other STDs. The protective effect of barrier methods emphasizes the continued need for promoting barrier methods of contraception.
沙眼衣原体现已被公认为一种主要的性传播疾病；口服避孕药的使用正在迅速增加，尤其是在发展中国家。因此，许多报告称口服避孕药使用者中沙眼衣原体的分离更为频繁，这具有重要的公共卫生意义。本分析的目的是通过总结1972年至1990年发表的研究来评估这种关联的强度和一致性。
根据研究是前瞻性研究还是病例对照研究进行分组。提取数据并对所有研究以及按研究质量指数、沙眼衣原体背景患病率和所做的避孕药具比较定义的亚组进行未调整比值比的合并估计。
分析中的研究主要在欧洲和北美进行；荟萃分析在美国马萨诸塞州波士顿的哈佛公共卫生学院进行。
对29项病例对照研究进行合并估计的未调整比值比为1.93（95%可信区间，1.77 - 2.11），表明口服避孕药使用者感染衣原体的风险几乎增加了一倍。研究质量和沙眼衣原体患病率均未改变这种风险。然而，与使用屏障避孕法相比，口服避孕药使用者的感染风险增加到2.91（95%可信区间，1.86 - 4.55）。这些研究中屏障方法的合并估计保护作用为0.34（95%可信区间，0.22 - 0.54）。
许多组成研究的设计和分析未控制性行为和年龄等混杂因素，这限制了对口服避孕药使用与衣原体感染之间关系的跨研究比较。然而，两项前瞻性研究的结果支持口服避孕药使用者衣原体感染风险几乎增加一倍，这表明在可能接触沙眼衣原体和其他性传播疾病的女性中考虑口服避孕药使用的风险和益处具有重要意义。屏障方法的保护作用强调了持续推广屏障避孕方法的必要性。
