Bone Metabolism in Premenopausal Exercising Women

Not Applicable

• Conditions: Contraception; Bone Metabolism; Low Energy Availability; Eumenorrhea

• Registration Number: NCT06961773
• Lead Sponsor: Universidad Politecnica de Madrid

Brief Summary

The main goal of this study is to examine how sex hormones and low energy availability affect the concentrations of bone remodelling markers at rest and after a running protocol. The research questions to be addressed are:

1: Does the ovarian hormone profile influence serum bone marker concentrations in women exercising resting and in response to to exercise?

2. Are there differences in response to low energy availability in bone marker concentrations between eumenorrhoeic female athletes and oral contraceptive users?

3: Is the response of bone markers affected by different exercise stimuli: endurance or aerobic endurance?

4: Do bone markers return to baseline levels after 24 hours of high energy availability diet after 6 days of low energy availability?

Detailed Description

To achieve the aim of the study, there will be two experimental groups - e.g. eumenorrhoeic females and oral contraceptive users - who, after screening, will be randomly assigned to a low- or high-energy diet. After 6 days on this diet, the participant will undergo an intervallic running protocol and blood samples will be taken before and after the test. The following month the participant will do the other type of diet.

Study Timeline

• Study Start: 2024-12-05
• Study First Submitted: 2025-03-06
• Status Verified: 2025-05
• Study First Submitted QC: 2025-05-05
• Last Update Submitted: 2025-05-05
• Study First Posted: 2025-05-08
• Last Update Posted: 2025-05-08
• Primary Completion: 2025-12-20
• Study Completion: 2026-06-15

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: Female
• Target Recruitment: 22

Inclusion Criteria

• Be healthy and between 18 and 30 years old.
• Engage in endurance sports that involve running (such as athletics, running, triathlon, trail running, etc.) for 3 to 12 hours per week..
• Eumenorrheic females with regular menstruation at least 6 months prior to the study.
• Monophasic oral contraceptive users at least 6 months prior to the study.

Exclusion Criteria

• Amenorrheic females.
• Pregnant females.
• Affected by any disorder related to the hypothalamo-pituitary-ovarian axis.
• Having suffered a bone fracture in the year before the study.
• Taking any medication or supplements that affect bone metabolism.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Concentration of bone metabolism biomarkers	immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise	Concentration of procollagen type I N-propeptide (P1NP), cross-linking telopeptide of type I collagen (βCTX-1), paratyroid hormone, calcium, sclerostin, osteoprotegin, osteocalcin, bone alkaline phospatase, Receptor Activator for Nuclear Factor κ B Ligand (RANKL) measured in serum samples.
Concentrations of other biochemical biomarkers	Immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise	Concentrations of Triiodothyronine (T3), Albumin, Sex Hormone Binding Globulin (SHBG), etc. measured in serum
Concentrations of sex hormones	Immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise	Concentrations of 17β-Oestradiol and Progesterone measured in serum.
Bone mineral density	At the screening phase	Total, lumbar spine and femoral neck bone mineral density (g/cm\^2) measured by dual x-ray absorptiometry

Secondary Outcome Measures

Name	Time	Method
Training status variables	At the screening phase	Oxygen uptake at ventilatory threshold 1, ventilatory threshold 2, and maximal oxygen uptake (ml/kg/min) measured with a gas analyser.
Body composition variables	Immediately pre- and post-nutritional intervention (bioimpedance) and DXA at the screening	Fat mass (kg), fat free mass (kg), fat mass percentage, fat-free mass percentage (FFM), total mass (kg) measured by dual x-ray absorptiometry
Body metrics	Measured at the screening phase	Height (cm)

Trial Locations

Locations (1)

Faculty of physical activity and sport sciences; 🇪🇸 Madrid, Comunity of Madrid, Spain