Bone density and endometriosis

Relationship between bone mineral density and ovarian function and thyroid function in perimenopausal women with endometriosis: a prospective study

BACKGROUND

In women with endometriosis, the association between ovarian function, hormones, and bone mineral density (BMD) is unclear. Therefore, this study aimed to elucidate the association between changes in bone mineral density (BMD) and clinical data, such as ovarian reserves, in perimenopausal women with endometriosis.

METHODS

In this prospective study, we evaluated 207 female patients who visited the Department of Obstetrics and Gynecology at the University of Tokyo Hospital between December 2015 and December 2020. We included patients aged ≥ 40 years with a history of endometriosis or who presented with endometriosis lesions. Patients with a history of smoking, steroid administration, autoimmune diseases, dyslipidaemia, and heart disease were excluded. During the study period, patients who underwent two tests, an initial and a follow-up test (n = 142, average age: 45.02 years, average BMD: 1.16 g/cm2), were evaluated at regular intervals based on the annual rate of change in BMD.

RESULTS

There was a weak negative correlation between the follicle-stimulating hormone (FSH) and BMD and a weak positive correlation between the anti-Müllerian hormone (AMH) and BMD. The annual rate of change in BMD showed a very weak correlation with thyroid-stimulating hormone (TSH) levels. A large decline in BMD was associated with high TSH levels and higher average age at menopause. Patients with higher TSH exhibited a higher rate of decrease in BMD than those without.

CONCLUSIONS

High FSH or low AMH levels are associated with decreased BMD. Decreased ovarian reserve is associated with decreased BMD in perimenopausal women with endometriosis. High TSH levels increase the risk of BMD loss. This finding may suggest that women with endometriosis should undergo bone scanning to rule out the possibility of reduced bone mass and subsequent increased risk of fracture.

Bone mineral density in women with deep infiltrating endometriosis who have undergone early bilateral oophorectomy

OBJECTIVE

To study bone mineral density (BMD) in women with and without pelvic deep infiltrating endometriosis (DIE) who underwent early bilateral oophorectomy (BO).

METHODS

A case-control study was performed in 83 women who underwent early BO before the age of 45 years, 31 for DIE and 52 for another clinical condition. All the women answered a standardized computer-assisted questionnaire to record their clinical and historical data and were medically examined. Lumbar spine and femoral neck BMDs were measured by dual-energy X-ray absorptiometry after early BO. Simultaneously, serum calcium, intact parathyroid, 25-hydroxyvitamin D, and cross-linked C-telopeptide were also measured. Unadjusted and adjusted odds ratios (with 95% confidence intervals [CI]) for endometriosis were calculated using logistic regression.

RESULTS

The mean lumbar spine and femoral neck BMDs were significantly higher in women who underwent early BO for DIE than in those who underwent early BO for another clinical condition. After adjusting for age at BMD measurement, years since menopause, age at menarche and body mass index, odds ratio for endometriosis associated with a 1-SD increase in lumbar spine and femoral neck BMD was 2.59 (95% CI: 1.45-4.62) and 2.16 (95% CI: 1.23-3.81), respectively.

CONCLUSION

Higher lumbar spine and femoral neck BMDs are associated with an increase in the likelihood of pelvic DIE in women who underwent early BO. This might be expected to the extent that endometriosis is itself associated with enhanced estrogen status, although further studies are needed to confirm such a hypothesis. These findings suggest that BMD measurement could contribute to the hormonal management of surgical menopause in women with DIE.

Long-term fracture risk among women with proven endometriosis

OBJECTIVE

To determine whether women with pelvic endometriosis are at increased fracture risk.

DESIGN

Historical cohort study.

SETTING

Population-based investigation using the data resources of the Rochester Epidemiology Project.

PATIENT(S)

From Olmsted County, Minnesota, 987 women with endometriosis that was first surgically visualized or histologically proven in 1970-1989.

INTERVENTION(S)

None, observational study.

MAIN OUTCOME MEASURE(S)

Follow-up for fractures through complete inpatient and outpatient community medical records.

RESULT(S)

In 17,408 person-years of follow-up, 256 women experienced 449 different fractures. The cumulative incidence after 20 years (30.8%) was not elevated relative to that expected (30.6%). The independent predictors of any fracture included age (hazard ratio [HR] per 10 years: 1.61; 95% confidence interval [CI] 1.42-1.84]), corticosteroid use (HR: 2.78; 95% CI 1.48-5.24), prior hip, spine, or forearm fracture (HR: 1.82; 95% CI 1.10-3.02), and use of the selective estrogen receptor modulators, tamoxifen or raloxifene (HR: 4.34; 95% CI 2.14-8.81); physical activity was protective (HR: 0.40; 95% CI 0.18-0.88). There was no significant influence on fracture risk of surgery or other medical treatments for endometriosis.

CONCLUSION(S)

Despite reported adverse effects of treatment on bone density, there was no overall increase in long-term fracture risk in this unselected cohort of women with proven endometriosis.

Women of reproductive age with endometriosis are not osteopenic

OBJECTIVE

To determine whether women of reproductive age with endometriosis are osteopenic and whether bone density decreases with higher stages of endometriosis.

DESIGN

A multicenter cross-sectional study was performed.

SETTING

Thirty-nine gynecological clinics in the United States, Canada, and Puerto Rico.

PATIENT(S)

Two hundred forty-one women of reproductive age with laparoscopically proved endometriosis.

INTERVENTION(S)

Diagnostic laparoscopy, bone densitometry.

MAIN OUTCOME MEASURE(S)

Endometriosis stages according to the criteria of the American Society for Reproductive Medicine, lumbar spine bone mineral density (L2-L4) as measured by dual-energy x-ray absorptiometry.

RESULT(S)

The mean lumbar spine bone mineral density, as well as the distribution of bone mineral density, of the women with endometriosis was similar to that of a normal population. There were no significant differences between endometriosis stage groups I-IV regarding bone mineral density as well as body weight, body mass index, and height.

CONCLUSION(S)

Women of reproductive age with endometriosis are not osteopenic. More advanced stages of endometriosis are not associated with a decrease in lumbar spine bone mineral density.

Cortical remodeling following suppression of endogenous estrogen with analogs of gonadotrophin releasing hormone

The effects of estrogen suppression on osteonal remodeling in young women was investigated using transiliac biopsies (eight paired biopsies + four single pre; three single post biopsies) taken before and after treatment for endometriosis (6 months) with analogs of gonadotrophin releasing hormone (GnRH). Estrogen withdrawal increased the proportion of Haversian canals with an eroded surface (106%, p = 0.047), a double label (238%, p = 0.004), osteoid (71%, p = 0.002), and alkaline phosphatase (ALP) 116%, p = 0.043) but not those showing tartrate-resistant acid phosphatase (TRAP) activity (p = 0.25) or a single label (p = 0.30). Estrogen withdrawal increased TRAP activity in individual osteoclasts in canals with diameters greater than 50 microns (p = 0.0089) and also the number of osteons with diameters over 250 microns (p = 0.049). ALP activity in individual osteoblasts was increased but not significantly following treatment (p = 0.051). Wall thickness was significantly correlated with osteon diameter (p < 0.001). In a separate group of patients (four pairs + one post biopsy) on concurrent treatment with tibolone, there was no significant increase in the osteon density, cortical porosity, median canal diameter, or the markers of bone formation and resorption. Enzyme activities and numbers of active canals were also not increased with the concurrent treatment, but there was still an increase in the osteon diameter. As previously shown for cancellous bone, estrogen withdrawal increased cortical bone turnover. We have now shown that resorption depth within Haversian systems was also increased with treatment. The enhanced TRAP activity in individual osteoclasts supports the concept that osteoclasts are more active following estrogen withdrawal in agreement with theoretical arguments advanced previously. Understanding the cellular and biochemical mechanisms responsible for increased depth of osteoclast resorption when estrogen is withdrawn may allow the development of new strategies for preventing postmenopausal bone loss.

The impact of bone loss in women with endometriosis

Low peak adult bone mass in a premenopausal woman puts her at increased risk for osteoporosis postmenopausally. Episodes of hypo-estrogenism premenopausally are associated with loss of bone density. This is seen with gonadotropin-releasing hormone agonist therapy for endometriosis, and thus prolonged or repeated courses of such treatment may increase the future risk of osteoporosis. Danazol and related compounds do not result in any bone loss but may have certain metabolic disadvantages.