Related Experiment Video
Updated: May 23, 2026
Estrogen-Like Effect of Bazi Bushen Capsule in Ovariectomized Rats
Published on: April 7, 2023
Low-dose estrogen combined oral contraceptives may negatively influence physiological bone mineral density
David Cibula1, Jana Skrenkova, Martin Hill
1Department of Obstetrics and Gynecology, Faculty of Medicine 1, Charles University, Prague, Czech Republic.
Background:
The aim was to evaluate changes of bone mineral density (BMD) and markers of bone turnover in healthy adolescents, and in adolescent users of combined oral contraceptives (COCs) with different ethinylestradiol (EE) contents.
Methods:
In this prospective crossover study, 56 healthy females (15-19.5 years) with desire to use hormonal contraception were randomized to COC with either 30 or 15 μg of EE in crossover design of 9-month intervention each in reverse order. Nonusers of the same age (n=28) served as controls. BMD at lumbar spine (LS), total femur, femoral neck, distal radius, and total body, and serum markers (N-propeptide of type I procollagen, and type I collagen C-telopeptide) were measured at baseline and after 9 and 18 months.
Results:
In COC nonusers, BMD significantly increased at LS and radius, while markers decreased. In COC users, BMD did not increase, with the exception of LS BMD in the 30 μg COC group (P<0.05). In the crossover design, a difference between the low- and very low-dose COC users was found in LS BMD changes (P<0.05), where increase in BMD was more impaired in the 15 μg COC users. The skeletal effects of COC remained significant after adjustments for age and smoking status. Markers declined faster in COC users during the first period, while they remained stable or even increased during the second 9 months.
Conclusion:
Physiological acquisition of LS BMD during adolescent age may be prevented by use of COC, especially those containing very low dose of EE.
Related Concept Videos
01:29Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
01:17Hormones and Bone Tissue
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
01:40Bone Remodeling
01:25Role of Vitamins in Maintaining Bone Health
Vitamin A
Vitamin A is involved in the process of bone remodeling. Retinoic acid, the active metabolite of Vitamin A, has nuclear receptors in osteoblasts and osteoclasts, which are involved in bone remodeling.
Vitamin B12
Vitamin B12 acts as a cofactor during the formation of osteoblast-related proteins, such as osteocalcin. Vitamin B12 plays a role...
01:30Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
01:31Essential Minerals for Bone Health
Calcium and Phosphorus
Calcium is a critical component of bones, especially in the form of calcium phosphate and calcium carbonate. Since the body cannot make calcium, it must be obtained from the diet. However, calcium cannot be absorbed from the small intestine without...