Combined hormonal contraceptives use and bone mineral density changes in  adolescent and young women in a prospective population-based Canada-wide  observational study

Tatjana S Brajic; Claudie Berger; Katharina Schlammerl; Heather Macdonald; Shirin Kalyan; David A Hanley; Jonathan D Adachi; Christopher S Kovacs; Jerilynn C Prior; CaMos Research Group

Combined hormonal contraceptives use and bone mineral density changes in adolescent and young women in a prospective population-based Canada-wide observational study

Brajic TS, Berger C, Schlammerl K, Macdonald H, Kalyan S, Hanley DA, Adachi JD, Kovacs CS, Prior JC, CaMos Research Group

Published June 2018 Journal of Musculoskeletal & Neuronal Interactions, 18(2), 227-236

PMID 29855445 PMC PMC6016495

RRM Academy Synopsis

Combined hormonal contraceptives linked to less teen hip bone gain

A 2018 study followed 307 Canadian women, ages 16 to 24, for two years. Teen girls who used combined hormonal contraceptives gained less hip bone, compared with girls who did not use them. After accounting for other factors, young women who used them gained more bone at the femoral neck than those who did not.

Key Findings

Among teen girls (16-19), before adjustment, non-users gained significantly more hip bone over two years than users: a gap of 0.012 g/cm2 (95% CI 0.001 to 0.023).
Among young women (20-24), after adjustment, non-users gained significantly less femoral neck bone than users: a gap of -0.021 g/cm2 (95% CI -0.036 to -0.006).
Of 307 women with full two-year data, 229 (74.6%) used combined hormonal contraceptives at some point; 78 (25.4%) did not use them during the study.
On average, women first used combined hormonal contraceptives at age 17.5; teen girls started younger (16.6) than young adults (18.4).
Bone density changes were not linked to how much estrogen the contraceptive contained, or to the age when a woman first started using it.

Interpretation

The study followed the same women for two years. Researchers recruited 527 women; the cohort's overall participation rate was 24.2%. Of those recruited, 307 had complete two-year data, and 220 did not complete follow-up. This was a population-based prospective cohort study. Results differed by age group and by bone site. The finding that young adult users gained more bone at the femoral neck was a surprise and has not been seen elsewhere. The authors call for randomized trials to confirm these results.

RRM Context

Combined hormonal contraceptives are common suppressive medications given to teen girls, often for period symptoms as well as birth control. Restorative reproductive medicine looks for the cause of cycle symptoms before treating them. This study adds new data on how that suppression affects bone, during the years when the body still builds its peak bone mass. Charting a woman's own cycle uses no added hormones.

Our editorial summary of this paper, not the article's abstract.

Abstract

Objectives

To assess combined hormonal contraceptives (CHC) use and adolescent women's peak areal bone mineral density (BMD) accrual.

Methods

We enrolled 527 randomly selected women across Canada (2004-6) divided by age into adolescents (16-19) and young adults (20-24) and by CHC use to ever (E-CHC)/never (N-CHC) users. At baseline and year 2 we measured height, weight, and BMD at lumbar spine (L1-4), femoral neck, and total hip sites. Interviewer-administered questionnaires addressed menarche age, cigarette and alcohol use, calcium/vitamin D intakes, physical activity and estrogen dose (≤30/>30 micrograms). Linear regression models examined associations of CHC use with 2-year BMD change adjusted for bone-related variables.

Results

Of 307 women with complete data, 229 (75%) used CHC. N-CHC adolescents gained significantly more unadjusted total hip BMD +0.012 g/cm2/2-y (95% C.I.: 0.001, 0.023) with similar trends at all sites. N-CHC adolescents tended to have greater adjusted femoral neck BMD gain: mean difference +0.009 g/cm2 (95% CI: -0.002; 0.021). In young women N-CHC, however, adjusted femoral neck BMD decreased significantly more -0.021 g/cm2 (95%CI: -0.006; -0.036) with similar trends at other sites. BMD changes were unrelated to estrogen dose and age at starting CHC.

Conclusions

Adolescent CHC users in a random population demonstrated less hip region peak BMD accrual than non-users. This requires randomized control trial confirmation.

Topics

Bone Health › Bone Mineral Density › Peak Bone Mass · Contraception › Oral Contraceptives › Metabolic Effects · Therapeutics › Hormonal Agents › Estrogen Preparations

Tatjana S Brajic, Claudie Berger, Katharina Schlammerl, Heather Macdonald, Shirin Kalyan, David A Hanley, Jonathan D Adachi, Christopher S Kovacs, Jerilynn C Prior

T Brajic, C Berger, K Schlammerl, H Macdonald, S Kalyan, Dave Hanley, D Hanley, Jon Adachi, J Adachi, Chris Kovacs, C Kovacs, J Prior

PMID 29855445 29855445 Brajic et al. 2018, Brajic 2018

Keywords

Contraceptives, Oral, Combined