For young women with anorexia nervosa (AN), oral contraceptives may limit bone loss, according to study results published in Fertility and Sterility.
The study included participants aged 14.5 to 34.9 years with AN (n = 305) and age-matched, normal-weight control participants (n = 121). The researchers used dual-energy X-ray absorptiometry and bone turnover markers to assess areal bone mineral density (BMD). They concomitantly evaluated leptin.
Of the participants with AN, 99 were using oral contraceptives. Of the control participants, 56% (n = 68) were using oral contraceptives. There were no significant differences in anthropometric characteristics between control participants receiving oral contraceptives and those who were not.
Compared with control participants, participants with AN taking oral contraceptives had lower areal BMD at all bone sites. However, participants with AN taking oral contraceptives had systematically higher areal BMD values for the whole body as well as the lumbar spine, femoral neck, hip, and radius compared with those with AN not taking oral contraceptives. Except for at the radius site, these differences remained significant after multiple adjustments.
The researchers found that participants with the lowest body mass index displayed the best bone tissue responses to oral contraceptives.
Compared with control participants, both groups of participants with AN had systematically lower values for bone formation markers (osteocalcin and procollagen type I N-terminal propeptide). However, the markers of bone resorption were normalized among participants with AN who were using oral contraceptives. Leptin levels were also significantly lower in patients with AN, with no difference based on status of oral contraceptive use.
The researchers did not find any significant differences between results for participants with AN using estrogen-progestin oral contraceptives compared with progestin alone.
“[A]s contraceptive use does not provide total protection of bone mass, our results should not be taken as an encouragement to clinicians to rely solely on this treatment to protect bone. Instead, they should encourage continued vigilance in monitoring these patients for variations in bone mass,” the researchers wrote. “New therapeutic approaches must be developed… to obtain a normalization of the bone mass in these patients.”
Maimoun L, Renard E, Lefebvre P, et al. Oral contraceptives partially protect from bone loss in young women with anorexia nervosa [published online March 25, 2019]. Fertil Steril. doi:10.1016/j.fertnstert.2019.01.008