Age at first oral contraceptive use as a major determinant of vertebral bone mass in female endurance athletes☆
Introduction
The achievement of peak bone mass during childhood and adolescence is predominantly influenced by genetic variability, physical activity, nutritional factors, and, after puberty, by sex steroid production [1]. The important role of sex hormones for the normal acquisition of peak bone mass is demonstrated by endocrine disorders such as delayed menarche [2], primary amenorrhea [3], or exercise-induced menstrual irregularities [4]. It is well known that systematic endurance training can negatively influence the pituitary–gonadal axis, and, as a consequence, bone turnover [5], [6]. Under systematic endurance training, an increased incidence of fatigue fractures and loss of bone mass has been reported [7], [8], [9], [10], [11].
Previous studies suggested that oral contraceptives (OCs) have positive effects on bone mass in women [12], [13], [14]. Therefore, OCs currently constitute a first line medication for exercise-induced menstrual irregularities [6], [15]. In addition, modern monophasic OCs are increasingly used for stabilization of the menstrual cycle and for the prevention of pregnancies in girls before the completion of puberty. However, OC use in pubertal girls suppresses endogenous sex hormone production long before skeletal maturity has been reached. At present, it is unclear whether endogenous production of estrogen during the normal cycle has different skeletal effects compared with exogenous administration of combinations of estrogen and progestins such as those used in modern monophasic OCs.
During recent years, many clinical trials have raised the concern that OC use may interfere with normal acquisition of peak bone mass in young women. In a prospective 5-year trial in 200 women aged 19–22 years, Polatti et al. [16] reported that a monophasic OC prevented the 7.8% increase in bone mineral density (BMD) of the lumbar vertebrae observed in the untreated control subjects within the study period. In a cross-sectional study in 524 Canadian women with a mean age of 36.3 years, BMD of the spine and of the proximal femur was significantly greater in women who had never used OCs (<3 months of OC use) relative to those who had used OCs (>3 months of OC use) [17]. In a randomized controlled clinical trial in 123 women 18–31 years of age, Burr et al. [18] found that OC use was associated with a suppression of the normal increase in bone mass and mechanical strength in the femoral neck in women within their third decade of life. Furthermore, we recently reported that long-term OC use prevented the beneficial effect of long-term exercise on bone mass in a cross-sectional study in 128 women aged 20–35 years [19]. In addition, two large epidemiological studies in Great Britain suggested an increased relative risk for fractures in premenopausal women who had ever used OCs compared with those who had never used OCs [20], [21].
Taken together, the available data on the skeletal effects of OCs in young women are controversial, and there is an important lack of data in this area. Therefore, it was the aim of the current retrospective analysis to examine the influence of low-dose monophasic OCs on BMD of the hip and of the spine in young female endurance athletes. Endurance athletes are at risk to develop exercise-induced amenorrhea and subsequent bone loss, and are, therefore, under close medical supervision. The data set provided by this supervision program allowed us to perform the current retrospective analysis in a well-controlled group of active, young women. Our results indicate that OC use is negatively associated with the accrual of peak bone mass in endurance athletes. Surprisingly, not the years of OC use, but the age at which OC use was initiated was found to be the major determinant of spine BMD in our study.
Section snippets
Subjects
This retrospective analysis is based upon data from a medical supervision program of regularly exercising women between 18 and 35 years of age, mostly professional triathletes and runners. The data on training intensity, menarche, OC use, medical history, menstrual cycle disorders, as well as alcohol and nicotine consumption were collected by a self-report questionnaire. Dietary intake was determined by a 7-day protocol developed by the Deutsche Gesellschaft für Ernährung (German Society for
Results
Six athletes had reported oligo-/amenorrhea in the self-report questionnaire. These women had low BMD values in the spine (0.962 ± 0.074 vs. 1.137 ± 0.023 g/cm2 in the controls), and in the femoral neck (0.878 ± 0.058 vs. 0.989 ± 0.021 g/cm2 in the controls), and were excluded from all subsequent data analyses. From the remaining 69 athletes, 38 were assigned to the control group, while 31 met the criteria for OC use. With the exception of slightly higher creatinine values in the OC group (P =
Discussion
In our retrospective analysis in 69 endurance athletes, OC use for more than 3 years in women younger than 22 years of age or OC use for more than 50% of the time after menarche in women aged 22–35 years was associated with a 7.9% lower spine BMD and a 8.8% lower proximal femur BMD, relative to control subjects characterized by short-term OC use. Based on a meta-analysis of current clinical data in osteoporotic patients treated with antiresorptive agents, it has been estimated that a 1%
Acknowledgements
The authors wish to thank Henrike Meincke, Patricia Haunsperger, Juergen Haindl, and Birge Herbst for collecting and coding the data. We would like to convey our special thanks to the clinical, nursing and technical staffs of all departments involved, particularly to Mrs. Henderkot, Mrs. Ermler, Mrs. Throll, Mrs. Besold, and Mrs. Habermeier for excellent technical assistance.
References (25)
- et al.
Bone loss in young hypoestrogenic women due to primary ovarian failure: spinal quantitative computed tomography
Fertil. Steril
(1989) - et al.
Bone densitometry: applications in sports-medicine
Eur. J. Radiol
(1998) - et al.
The effect of oral contraceptive use on vertebral bone mass in pre- and post-menopausal women
Contraception
(1986) - et al.
Bone mass and long-term monophasic oral contraceptive treatment in young women
Contraception
(1995) - et al.
Exercise and oral contraceptive use suppress the normal age-related increase in bone mass and strength of the femoral neck in women 18–31 years of age
Bone
(2000) - et al.
Effects on bone mineral density of low-dosed oral contraceptives compared to and combined with physical activity
Contraception
(1997) - et al.
Oral contraceptive pill use and fractures in women: a prospective study
Bone
(1993) - et al.
Oral contraception and other factors in relation to hospital referral for fracture. Findings in a large cohort study
Contraception
(1998) - et al.
Estrogen and bone-muscle strength and mass relationships
Bone
(1998) - et al.
Low-dose oral contraceptives and bone mineral density: an evidence-based analysis
Contraception
(2000)
Peak bone mass
Osteoporosis Int
Bone density in adolescents
N. Engl. J. Med
Cited by (41)
Woman olympic athlete
2019, Bulletin de l'Academie Nationale de MedecineNeuroendocrine mechanisms in athletes
2014, Handbook of Clinical NeurologyCitation Excerpt :Studies in adult amenorrheic women (exercisers or nonexercisers) are conflicting regarding the effect of hormone replacement on bone density. Some report no change (Gibson et al., 1999), others report an increase (Hergenroeder et al., 1997; Castelo-Branco et al., 2001) and some a decrease (Burr et al., 2000; Hartard et al., 2004) in bone density following estrogen administration. Additionally, the studies are usually small (Hergenroeder et al., 1997), often retrospective (Hartard et al., 2004), not randomized (Burr et al., 2000; Castelo-Branco et al., 2001), and do not control for weight changes (Hergenroeder et al., 1997; Castelo-Branco et al., 2001).
Impact of combined and progestogen-only contraceptives on bone mineral density
2009, Revue du Rhumatisme (Edition Francaise)Impact of combined and progestogen-only contraceptives on bone mineral density
2009, Joint Bone SpineCitation Excerpt :Two other studies in very small numbers of patients produced similar findings. These studies suggest a negative impact on bone of oral combination contraceptives in young women, most notably within 3 years after the menarche [18]. Several factors may be involved, with a decrease in androgen levels probably playing a key role.
Estrogen-progestin contraceptive use during adolescence prevents bone mass acquisition: a 4-year follow-up study
2008, ContraceptionCitation Excerpt :Low-dose EPCs suppress the normal estrogen production by modifying the circulating estrogen levels to be as low as those measured during early follicular phase [14]. Our results support the previous results, in which EPC use, especially the low-dose formulations, during adolescence and the age of peak bone mass acquisition, suppress the normal bone mass development [10,11,19,20]. Previous data suggest that long-term monophasic OC use will prevent the occurrence of physiologic peak bone mass in young women [10,21].
Oral Contraceptives and Female Rowers' Skeletal Health
2023, Journal of Strength and Conditioning Research
- ☆
Funding source: This retrospective analysis was supported in part by the Federal Institute of Sports Science of Federal Ministry of the Interior's, the “Bundesinstitut fuer Sportwissenschaften” Project Nr.: VF 0407/01/06/2000.