February 7, 2005

Bone density returns when teens stop using popular contraceptive, Group Health study finds

Seattle—A new study of the popular injectable contraceptive Depo-Provera shows that teenagers' bone density recovers after they stop using the drug. Several previous studies have linked Depo-Provera to bone loss, raising concerns about its use among teens, a population in their peak bone-building years.

"These findings are reassuring for those concerned about future risk of fractures," said Delia Scholes, PhD, senior investigator at Group Health Center for Health Studies and the study's lead investigator. "This information can be useful in helping young women balance the need to avoid unintended pregnancies with the need to build strong bones."

Scholes' study, which appears in the February 2005 issue of Archives of Pediatric and Adolescent Medicine, is the first to show that teen-aged Depo-Provera users' bone loss appears to be reversed once young women stop taking the contraceptive. The findings come less than three months after a decision by the U.S. Food and Drug Administration to issue a black box warning on Depo-Provera. The warning states that the drug is associated with bone loss that "may not be completely reversible."

While Scholes and her colleagues found that Depo-Provera use in women aged 14 to 18 was associated with continuous bone density loss at the hip and spine, they also found that users experienced significant gains after they quit using the drug. This provides evidence "that the loss of bone mass is apparently reversed," Scholes concluded.

In 2002, Scholes reported similar results among women aged 18 to 39. However, the current study shows that teen women who discontinued using Depo-Provera appeared to regain their bone density faster than older women did.

Teens use Depo-Provera at higher rates than older women do. About 10 percent of American women aged 15 to 19 who are using birth control use Depo-Provera, compared to just 3 percent of women in the United States overall. Given once every three months, the method is effective, relatively low in cost, private, and easy-to-use, Scholes explained. It is also a popular choice among young women for whom other types of contraception have failed.

How the study was conducted

The researchers measured hip, spine, and whole-body bone densities in 170 healthy teen women, aged 14 to 18, who get their care at Group Health Cooperative. The bone densities of the 80 participants receiving Depo-Provera injections were compared to those of 90 similar women who were not using this method. Bone density measurements were taken at the start of the study, and at 6-month intervals over a span of 2 to 3 years. During that period, 61 of the Depo-Provera users stopped using the drug, allowing the scientists to see how their bone density changed once they discontinued.

What the researchers found

As with previous studies, the researchers found that, compared to non-users, Depo-Provera users had significant loss of bone density in the hip and spine.

  • Those who used Depo-Provera experienced an average loss of bone density at the hip of 1.81 percent per year compared with a loss of 0.19 percent per year among non-users.
  • At the spine, women who used Depo-Provera had a bone loss of 0.97 percent, while those not using the drug had an increase in bone density of 1.32 percent. These bone-loss rates are similar to that of women who are breastfeeding or going through menopause.
  • Women who were new Depo-Provera users lost bone density more rapidly than did longer-term users.

Once the Depo-Provera users stopped getting the injections, however, they gained a significant amount of bone density compared to non-users for the same period. For example:

  • The average amount of bone gained in a year for women who quit using Depo-Provera was 1.34 percent at the hip, compared to a slight loss of 0.19 for women who were not taking the drug.
  • Density at the spine increased 2.86 percent for women who quit the drug compared to an increase of 1.32 percent for women who were not taking the drug.

It's not clear from studies to date whether other hormonal methods of birth control might affect bone density, Scholes said. She and her colleagues are currently conducting a study of the effect of oral contraceptive use and discontinuation on women's bone density.

Scholes noted that a recent U.S. Surgeon General's report on bone health and osteoporosis provides a number of steps that teens and young women can take to improve or maintain bone density. The 2004 report recommends:

  • Eat foods high in calcium and vitamin D
  • Participate in regular weight-bearing exercise
  • Don't smoke
  • Limit consumption of alcoholic beverages

Scholes' study was funded by a grant from the National Institute of Child Health and Human Development, National Institutes of Health. The co-authors are Group Health investigators Andrea Z. LaCroix, PhD, Laura E. Ichikawa, MS, and William E. Barlow, PhD, and the University of Washington School of Medicine's Susan M. Ott, MD.

About Kaiser Permanente Washington Health Research Institute

Kaiser Permanente Washington Health Research Institute (KPWHRI), formerly Group Health Research Institute, improves the health and health care of Kaiser Permanente members and the public. The Institute has conducted nonproprietary public-interest research on preventing, diagnosing, and treating major health problems since 1983. Government and private research grants provide our main funding. Follow KPWHRI research on Twitter, Facebook, Pinterest, LinkedIn, or YouTube. For more information, go to: www.kpwashingtonresearch.org.

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Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, Kaiser Permanente has a mission to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 12.2 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal Permanente Medical Group physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: kp.org/share.

Andrea Z. LaCroix, PhD

Senior Investigator, KPWHRI; Professor and Chief of Epidemiology, Department of Family Medicine and Public Health, University of California, San Diego
Kaiser Permanente Washington Health Research Institute

Laura E. Ichikawa, MPH

Senior Biostatistician
Kaiser Permanente Washington Health Research Institute


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