Cardiovascular events associated with different combined oral contraceptives: a review of current data

Oral contraceptives and stroke: Foes or friends

Incidents of strokes are increased in young women relative to young men, suggesting that oral contraceptive (OC) use is one of the causes of stroke among young women. Long-term exposures to the varying combinations of estrogen and progestogen found in OCs affect blood clotting, lipid and lipoprotein metabolism, endothelial function, and de novo synthesis of neurosteroids, especially brain-derived 17β-estradiol. The latter is essential for neuroprotection, memory, sexual differentiation, synaptic transmission, and behavior. Deleterious effects of OCs may be exacerbated due to comorbidities like polycystic ovary syndrome, sickle cell anemia, COVID-19, exposures to endocrine disrupting chemicals, and conventional or electronic cigarette smoking. The goal of the current review is to revisit the available literature regarding the impact of OC use on stroke, to explain possible underlying mechanisms, and to identify gaps in our understanding to promote future research to reduce and cure stroke in OC users.

Simultaneous nicotine and oral contraceptive exposure alters brain energy metabolism and exacerbates ischemic stroke injury in female rats

Smoking-derived nicotine (N) and oral contraceptives (OC) synergistically exacerbate ischemic brain damage in the females and underlying mechanisms remain elusive. Our published study showed that N toxicity is exacerbated by OC via altered mitochondrial function owing to a defect in the activity of cytochrome c oxidase. Here, we investigated the global metabolomic profile of brains of adolescent female Sprague-Dawley rats exposed to N ± OC. Rats were randomly exposed to saline or N + /-OC for 16-21 days followed by random allocation into two cohorts. One cohort underwent transient middle cerebral artery occlusion and histopathology was performed 30 days later. From the second cohort, cortical tissues were collected for an unbiased global metabolomic profile. Pathway enrichment analysis showed significant decrease in glucose, glucose 6-phosphate and fructose-6-phosphate, along with a significant increase in pyruvate in the N + /-OC exposed groups when compared to saline (p < 0.05), suggesting alterations in the glycolytic pathway which were confirmed by Western blot analyses of glycolytic enzymes. Infarct volume quantification showed a significant increase following N alone or N + OC as compared to saline control. Because glucose metabolism is critical for brain physiology, altered glycolysis deteriorates neural function, thus exacerbating ischemic brain damage.

Cigarette smoking women of reproductive age who use oral contraceptives: results from the 2002 and 2004 behavioral risk factor surveillance systems

BACKGROUND

Despite health warnings about the increased risk of cerebrovascular disease among women who smoke while using oral contraceptives (OCs), prior research suggests that OC use is still prevalent among women who smoke cigarettes. Our objective was to investigate the prevalence of OC use among cigarette smoking women of reproductive age in the United States.

STUDY DESIGN

We extracted data from the 2002 and 2004 Behavioral Risk Factor Surveillance System surveys of 76,544 women between 18 and 44 years of age who reported using some form of contraception. OC use, or self-reported use of "the pill," was examined among those who currently smoke, either everyday or some days. Multivariable logistic regression models were used to compare OC use between smoking and nonsmoking women.

RESULTS

One fourth (26.9%) of U.S. women who smoke compared with 34.6% of nonsmoking women reported currently using OCs. After adjusting for age, race/ethnicity, marital status, education level, binge drinking, and health care coverage, women who smoke were 0.6 (95% confidence interval [CI], 0.6-0.7) times as likely to use OCs as nonsmoking women. Among women aged 35 to 44 years, the odds of OC use among smokers was even further reduced (odds ratio [OR], 0.3; 95% CI, 0.3-0.4) compared with nonsmokers.

CONCLUSION

Among U.S. women of reproductive age who use contraception, particularly among women aged 35 to 44 years, those who smoke cigarettes are significantly less likely to use OCs than those who do not.

Interleukin-6 and Antiphospholipid Antibodies in Women With Contraceptive-Related Thromboembolic Disease

OBJECTIVE

The aim of this study was to explore the possible (joint) contributing role of interleukin-6 (IL-6) and antiphospholipid antibodies to the occurrence of the venous thromboembolism in women using oral contraceptives.

METHODS

Interleukin-6 and antiphospholipid antibodies (anti-beta2-glycoprotein I antibody-immunoglobulin M [IgM], G [IgG], and A [IgA]; anticardiolipin-IgM and IgG; antiphosphatidylserine-IgM and IgG) were measured in 30 women (median age 41, range 28-49 years) in the stable period (on average 3.5 years) after first venous thromboembolism. Sixteen patients used oral contraceptives during the episode of venous thromboembolism (oral contraceptives group), whereas 14 patients did not (non-oral contraceptives group). Thirty-seven age-matched, healthy women served as controls

RESULTS

Compared with controls, the oral contraceptives group had elevated IL-6 (median interquartile range 2.3 [1.1-4.3] versus 1.4 [0-2.0] pg/mL, P <.05). The oral contraceptives group had elevated anti-beta2-glycoprotein I antibody-IgM in comparison with both the non-oral contraceptives group (median interquartile range 47.5 [2.0-77.0] versus 29.50 [11.00-45.50] OD(450), P <.06) and controls (47.5 [2.0-77.0] versus 17.5 [3.5-30.0] OD(450), P <.001). Interleukin-6 level in the non-oral contraceptives group was related to obesity, whereas such a relation was not found in the oral contraceptives group, suggesting the presence of another factor (oral contraceptive use), which stimulates IL-6 production. Of particular interest is our finding that elevated IL-6 levels correlated significantly positively with elevated anti-beta2-glycoprotein I antibody-IgG in patients who were users of oral contraceptives (but not overweight, n = 10) (r = 0.56, P <.05)

CONCLUSION

The results suggest a new hypothesis that, in susceptible women, use of oral contraceptives induces production of IL-6, which stimulates production of anti-beta2-glycoprotein I. Thus, the prothrombotic profile is aggravated and could facilitate occurrence of venous thromboembolism. This remains to be elucidated in further studies.

Causal association in pharmacovigilance and pharmacoepidemiology: thoughts on the application of the Austin Bradford-Hill criteria

The methods used for the evaluation of drug safety signals (including major signals leading to withdrawal of products from the market) are inconsistent and sometimes of poor quality. While the assessment of the safety of medicines needs to consider specific issues such as drug interactions and variation in compliance, the general principles, which are used to study environmental hazards, can be applied for this purpose. The criteria proposed by Sir Austin Bradford-Hill more than 35 years ago for attributing disease causation to environmental factors have been used widely in epidemiology, are applicable to pharmacovigilance and pharmacoepidemiology. The Austin Bradford-Hill criteria include strength, consistency, specificity, temporality, biological gradient, plausibility, coherence, experimental evidence and analogy. The paper reviews each of these criteria with emphasis on pharmacovigilance and pharmacoepidemiology and with some examples. The application of the Austin Bradford-Hill criteria to the evaluation of causal association in pharmacovigilance and pharmacoepidemiology is very useful. However, it requires understanding of the limitations of the data, such as, under-reporting, poor quality of information from third parties and misclassification. Further work is required to develop strategies to handle these limitations.

Drug-Induced lipid changes: a review of the unintended effects of some commonly used drugs on serum lipid levels

Many drugs besides lipid-lowering drugs affect serum lipid levels in either a potentially harmful or beneficial way, and may therefore increase or decrease the risk of cardiovascular disease. Diuretics, beta-blocking agents, progestogens, combined oral contraceptives containing 'second generation' progestogens, danazol, immunosuppressive agents, protease inhibitors and enzyme-inducing anticonvulsants adversely affect the lipid profile. They increase total cholesterol, low density lipoprotein cholesterol and triglycerides by up to 40, 50 and 300%, respectively, and decrease high density lipoprotein cholesterol by a maximum of 50%. Conversely, alpha-blocking agents, estrogens, hormone replacement therapy, combined oral contraceptives containing 'third generation' progestogens, selective estrogen receptor modulators, growth hormone and valproic acid show mostly beneficial effects on the lipd profile. Some drugs, for example, isotretinoin, acitretin and antipsychotics, mainly elevate triglyceride levels. Adverse or beneficial effects on serum cholesterol levels do not always translate into a higher or lower, respectively, incidence of cardiovascular disease. because these drugs may influence cardiovascular risk through multiple pathways. In some cases, excessive cholesterol levels occur, for example, with protease inhibitor therapy, and several cases of pancreatitis attributable to drug-induced hypertriglyceridaemia have been reported. Some general guidelines on the management of drug-induced dyslipidaemia can be given. Replacement of the dyslipidaemia-inducing drug by an equivalent alternative therapy is preferred. However, such alternatives are often difficult to find. If there is no equivalent alternative and treatment with the dyslipidaemia-inducing drug must be initiated, monitoring of serum lipid levels is important. If drug use is expected to be long term, the existing guidelines for the management of dyslipidaemia in the general population can be applied to drug-induced dyslipidaemia. In cases of extreme hyperlipidaemia, medication use should be reassessed.