Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Oral contraceptives increase C-reactive protein, an infIammatory biomarker

10.04.2003


New study results offer potential explanation of complications from birth control pills



When women think about birth control, estrogen, and cardiovascular risk, they often assume that there are no answers. They would appear to be correct.

On the one hand, new pharmacological advancements have provided combination oral contraceptive (OC) formulations with lower-dose estrogen. These formulations have significantly less risk of cardiovascular adverse events compared to the older combined formulations with higher doses. They also provide excellent cycle control, a low incidence of breakthrough bleeding and spotting, and increased patient satisfaction.


On the other hand, the current generation progestins appear less safe than earlier formulations with respect to the risk of blood clotting. Moreover, recent studies have associated current oral contraceptive use with risks for ischemic stroke and myocardial infarction, impaired blood anticoagulant pathways, and increased cardiovascular reactivity. Thus, cardiovascular risk relating to consumption of oral contraceptives still remains.

C-reactive protein (CRP) is a protein in the body whose level increases when blood vessels become inflamed. Measuring cardiovascular risk is thought to be possible by assessing CRP levels. Previously published data has shown that blood levels of CRP are elevated many years before a first heart attack or stroke occurs. Accordingly, a team of researchers set out to investigate the association between current low-dose oral contraceptives and levels of plasma CRP.

A New Study

The authors of "Oral Contraceptive Use and Increased Plasma Concentration of C-reactive Protein" are Darlene M Dreon, DrPH; Joanne L Slavin, PhD; and Stephen D Phinney, MD, PhD, from Galileo Pharmaceuticals, Inc, Santa Clara, CA and the University of Minnesota, St. Paul, MN. They will present their findings at the American Physiological Society’s upcoming conference, Experimental Biology 2003, being held April 11-15, 2003, at the San Diego Convention Center, San Diego, CA.

Background

In a previously published study, investigators used an insensitive, non-quantitative immunoprecipitation technique capable of identifying CRP levels above the current normal range. That study reported the presence of CRP in more than half of women using first generation combined or sequential oral contraceptives of the 1960s. Among women using the then "low dosage" progestin oral contraceptives, the study found no difference in the prevalence of positive serum CRP between this class of OC users versus nonusers.

Given the current availability of the high sensitivity CRP test, it is possible to assess the effects of current low dose oral contraceptives on this biomarker for cardiovascular disease risk. The research team involved in the current study measured the levels of CRP in otherwise healthy, young adult women according to the following methodology.

Methodology

CRP levels were measured using stored samples from 30 healthy, premenopausal women who had previously participated in a randomized, crossover study of the effects of soy intake on sex hormone metabolism in women using OCs and non-users. The study was sited at a university outpatient general clinical research center.

Participants (women aged 18-40 years of age) consumed their habitual diet or a soy-enriched diet for two menstrual cycles each. (Soy consumption had no effect on sex hormone metabolism in OC or non-OC users.) Non-OC users were trained in basal body temperature charting and ovulation testing for verification of follicular and luteal phases. Serum progesterone concentrations were used to confirm ovulation. Four fasting blood samples and 24-hour urine (two mid-follicular and two mid-luteal) were collected from each participant over two menstrual cycles and were stored at –700C until laboratory analysis. OC users provided fasting blood samples on days 8 and 22 after menses. Plasma samples were later thawed and assayed for CRP by use of a high-sensitivity assay.

Results

There were no significant differences in baseline demographic characteristics between oral contraceptive users and nonusers. Plasma CRP levels were two times higher among OC users than among non-users independent of diet assignment, diet treatment order, and phase of the menstrual cycle. In a multivariate model, OC use predicted 32 percent of the variance in CRP levels. As all CRP levels were within a previously established normal range, further study is indicated to establish the clinical significance of the observed elevated CRP levels in OC users.

Conclusions

The results from this research and past studies suggest that estrogenic hormones significantly affect pro-inflammatory pathways. Whether these changes have clinical significance remains to be determined. The present data also showed that CRP levels are higher in the luteal, or post-ovulatory phase, versus the follicular phase. This association was more pronounced in OC users than non-users.

This cross-sectional survey demonstrates that CRP levels are significantly increased among OC users versus non-users. The possibility that these results are due to chance or confounding variables cannot be excluded entirely, and the results need to be confirmed by larger independent studies. The researchers suggest that the impact of OC use on CRP and inflammatory parameters should be investigated in prospective trials.


The American Physiological Society (APS) is one of the world’s most prestigious organizations for physiological scientists. These researchers specialize in understanding the processes and functions underlying human health and disease. Founded in 1887 the Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals each year.

Donna J. Krupa | EurekAlert!
Further information:
http://www.faseb.org/aps/

More articles from Health and Medicine:

nachricht Penn vet research identifies new target for taming Ebola
12.01.2017 | University of Pennsylvania

nachricht The strange double life of Dab2
10.01.2017 | University of Miami Miller School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>