Sunday, September 20, 2009

Low dose birth control pills and bone growth

High BMD is a must for ballet dancers

Low-Dose Birth Control Pills Retard Bone Growth

By John Gever, Senior Editor, MedPage TodayPublished: September 14, 2009
Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston and Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner

DENVER -- Teenage girls taking low-dose, oral contraceptives with 15 mcg of ethinyl estradiol showed abnormally low levels of bone growth, or even lost bone density, compared with teens who took a product with a higher dose of estrogen, researchers said.In a randomized crossover trial, bone mineral density (BMD) in girls 15 to 19 years old who took the lower-dose oral contraceptive for nine months failed to increase or dropped, while BMD increased at normal rates in participants taking pills with a 30-mcg ethinyl estradiol content, according to Jan Stepan, MD, of Charles University in Prague.In a poster presentation here at the American Society for Bone and Mineral Research (ASBMR), Stepan said the findings suggested girls needing oral contraceptives "could be counseled toward preparations with higher estrogen levels."

The study involved 82 girls in their middle to late teens, a period during which they should be accumulating bone density.

Twenty-eight were given no medications and served as controls. The other 54 were randomly assigned to nine months of treatment with oral contraceptives containing 60 mcg of gestodene (a progestin, not FDA-approved but common in European contraceptives) and either 15 or 30 mcg of ethinyl estradiol. After this initial treatment period, those in the treatment group were switched to the other contraceptive dosage for another nine months.

Lumbar spine BMD and whole body bone mineral content were measured at baseline and after each nine-month period. In the control participants, spinal BMD increased by 1% during each treatment period, and whole body bone mineral content rose 2% in each period.

Those initially assigned to the 30-mcg ethinyl estradiol dosage also showed a 1% increase in spinal BMD, but it returned to baseline levels when they switched to the 15-mcg dosage.

Participants first receiving the 15-mcg dose showed virtually no increase in spinal BMD. After switching to the higher dosage, spinal BMD accumulation paralleled that of control participants.

With the 15-mcg formulation, "physiological BMD increase in lumbar spine was interrupted and, after nine months, its users had 2% lower lumbar spine BMD compared with controls," the poster summarized.

Whole body bone mineral content did not accumulate as quickly in the girls taking the oral contraceptives as in the control group.

Those starting at 15 mcg and switching to 30 mcg ended up with about half the level of increase seen in the control group (1.7% versus 3.7%, P<0.05), while girls taking the drugs in the reverse order had even less increase in whole body bone mineral content (0.4%, P<0.05 versus both of the other groups).

During the first nine months of the study, serum PINP -- a marker of bone turnover -- declined in all three groups, somewhat faster in those taking oral contraceptives. However, those switching from the high- to low-dose product then showed a 30% increase in PINP levels.

The final treatment period saw no change in mean PINP among controls or those switching from the low- to high-dose ethinyl estradiol.

Stepan explained that the lower dose of ethinyl estradiol suppresses endogenous estrogen release without fully replacing it. Those on the higher dose end up with a more normal level of estrogens, he said.

He said no untoward side effects were seen with the higher-dose product.
Commenting on the study, Craig Langman, MD, a pediatric endocrinologist at Children's Memorial Hospital in Chicago, said the findings were plausible and clinically relevant.
But he cautioned that the findings may not apply to many U.S. teens, who often take these drugs to correct endocrine dysfunctions rather than to prevent pregnancy.

Langman said such use is increasingly common in American adolescents as a treatment for the so-called female triad -- eating disorders, amenorrhea, and osteoporosis. In contrast, the Czech study enrolled healthy girls, reflecting the population using the medications as contraceptives.

Primary source: American Society for Bone and Mineral ResearchSource reference: Stepan J, et al., "A cross-over study of BMD and markers in adolescent users of combined oral contraceptives with different estrogen content" ASBMR 2009; Abstract FR0005.

Action Points
Explain to interested patients that estrogen hormones are important for building bone mass during adolescence.

Explain that this study was a randomized, controlled trial, a relatively strong form of evidence. But caution that each treatment period was only nine months and the study included relatively small numbers of participants.

Explain that the findings may not be relevant to adolescents prescribed oral contraceptives to correct endocrine abnormalities rather than to prevent pregnancy.

Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.”

Personal comment: While preliminary this study reinforces Our Clinic’s efforts to switch girls to forms of birth control other than hormones. Hormonal methods are an option for girls who need to control heavy bleeding or menstrual pain and for alleviation of the symptoms of endometrioses and polycystic ovary disease (PCOS) but for otherwise healthy girls to fill their bodies with artificial hormones just to avoid pregnancy when other methods of contraception are as effective and healthier is a shame. Some of the hormonal methods that have 15 mcg of estrogen in them which slow or decrease bone density are: Mirelle (60mcg gestodene, 15mcg EE) not available in the U.S.) and the vaginal ring, NuvaRing, which releases 0.12mg etonogestrel, 15mcg EE per day. Fortunately, only NuvaRing is available in the U.S. at the moment and the ick-factor of having to insert and remove the ring has minimized its use so far.

Our clinic and Student Health at St Lucy’s are encouraging girls to increase bone mineral density now – by weight-bearing and resistance exercises (pointe class, Pilates and light weights are great for this), and by eating a diet rich in calcium and vitamin D via salmon, dairy, and spinach. We also require our casino dancers and St Lucy’s ballet students to have bone density measurements every 6 months to make sure they are healthy enough to handle the physically intense schedule of a ballet dancer.

No comments:

Post a Comment

Blog Archive

Lijit Search



About Me

My photo
Powys , Wales, United Kingdom
I'm a classically trained dancer and SAB grad. A Dance Captain and go-to girl overseeing high-roller entertainment for a major casino/resort