Influence of weight and gonadal status on total and regional bone mineral content and on weight-bearing and non-weight-bearing bones, measured by dual-energy X-ray absosorptiometry

A review of menopause nomenclature

Menopause nomenclature varies in the scholarly literature making synthesis and interpretation of research findings difficult. Therefore, the present study aimed to review and discuss critical developments in menopause nomenclature; determine the level of heterogeneity amongst menopause definitions and compare them with the Stages of Reproductive Aging Workshop criteria. Definitions/criteria used to characterise premenopausal and postmenopausal status were extracted from 210 studies and 128 of these studies were included in the final analyses. The main findings were that 39.84% of included studies were consistent with STRAW classification of premenopause, whereas 70.31% were consistent with STRAW classification of postmenopause. Surprisingly, major inconsistencies relating to premenopause definition were due to a total lack of reporting of any definitions/criteria for premenopause (39.84% of studies). In contrast, only 20.31% did not report definitions/criteria for postmenopause. The present findings indicate that there is a significant amount of heterogeneity associated with the definition of premenopause, compared with postmenopause. We propose three key suggestions/recommendations, which can be distilled from these findings. Firstly, premenopause should be transparently operationalised and reported. Secondly, as a minimum requirement, regular menstruation should be defined as the number of menstrual cycles in a period of at least 3 months. Finally, the utility of introducing normative age-ranges as supplementary criterion for defining stages of reproductive ageing should be considered. The use of consistent terminology in research will enhance our capacity to compare results from different studies and more effectively investigate issues related to women's health and ageing.

Fat mass changes during menopause: a metaanalysis

OBJECTIVE

Data: Fat mass has been shown to increase in aging women; however, the extent to which menopausal status mediates these changes remains unclear. The purpose of this review was to determine (1) how fat mass differs in quantity and distribution between premenopausal and postmenopausal women, (2) whether and how age and/or menopausal status moderates any observed differences, and (3) which type of fat mass measure is best suited to the detection of differences in fat mass between groups.

STUDY

This review with metaanalyses is reported according to Metaanalysis of Observational Studies in Epidemiology guidelines.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies (published up to May 2018) were identified via PubMed to provide fat mass measures in premenopausal and postmenopausal women. We included 201 cross-sectional studies in the metaanalysis, which provided a combined sample size of 1,049,919 individuals and consisted of 478,734 premenopausal women and 571,185 postmenopausal women. Eleven longitudinal studies were included in the metaanalyses, which provided a combined sample size of 2472 women who were premenopausal at baseline and postmenopausal at follow up.

RESULTS

The main findings of this review were that fat mass significantly increased between premenopausal and postmenopausal women across most measures, which included body mass index (1.14 kg/m²; 95% confidence interval, 0.95-1.32 kg/m²), bodyweight (1 kg; 95% confidence interval, 0.44-1.57 kg), body fat percentage (2.88%; 95% confidence interval, 2.13-3.63%), waist circumference (4.63 cm; 95% confidence interval, 3.90-5.35 cm), hip circumference (2.01 cm; 95% confidence interval, 1.36-2.65 cm), waist-hip ratio (0.04; 95% confidence interval, 0.03-0.05), visceral fat (26.90 cm²; 95% confidence interval, 13.12-40.68), and trunk fat percentage (5.49%; 95% confidence interval, 3.91-7.06 cm²). The exception was total leg fat percentage, which significantly decreased (-3.19%; 95% confidence interval, -5.98 to -0.41%). No interactive effects were observed between menopausal status and age across all fat mass measures.

CONCLUSION

The change in fat mass quantity between premenopausal and postmenopausal women was attributable predominantly to increasing age; menopause had no significant additional influence. However, the decrease in total leg fat percentage and increase in measures of central fat are indicative of a possible change in fat mass distribution after menopause. These changes are likely to, at least in part, be due to hormonal shifts that occur during midlife when women have a higher androgen (ie, testosterone) to estradiol ratio after menopause, which has been linked to enhanced central adiposity deposition. Evidently, these findings suggest attention should be paid to the accumulation of central fat after menopause, whereas increases in total fat mass should be monitored consistently across the lifespan.

Bone Geometric Properties of the Femoral Neck in Underweight Eumenorrheic Women

The aim of this study was to describe femoral neck (FN) geometry among eumenorrheic underweight women around the age of peak bone mass. Proximal femur geometry and body composition were assessed in 12 underweight women and in 24 healthy controls using dual-energy X-ray absorptiometry. The Hip Structural Analysis program was used to determine bone geometry at the FN. The cross-sectional area (CSA) and the cross-sectional moment of inertia (CSMI) were significantly lower in underweight women than in controls (p < 0.05). There was a trend toward lower sectional modulus (Z) and strength index in underweight women (p < 0.15). Body weight, body mass index, and lean mass (LM) were positively correlated with CSA, CSMI, Z, and neck-shaft angle (r = 0.428-0.611, p < 0.05). After controlling for body weight, body mass index, and LM, the differences in CSA, CSMI, Z, and neck-shaft angle were no more statistically significant between the 2 groups. The multivariate analysis retained LM as the main predictor of CSA, CSMI, and Z in the whole population. The present study suggests that thinness is associated with low resistance to axial forces (CSA) and bending load (Z and CSMI) in adult eumenorrheic women. LM seems to be a key determinant of FN geometry in underweight women.

Ultrasonic value is not useful to detect bone changes following a biliopancreatic diversion

To study the evolution of the bone mass by ultrasonic transmission after biliopancreatic diversion. Forty eight morbid obese patients were prospectively studied during 36 months following the Larrad biliopancreatic diversion. The bone metabolism was studied by PTHi and the urinary pirydinolines. The bone mass by echography and bone densitometry, which correlate to the levels of PTHi and pyridinolines. After 3 years the bone mass decreased from 50.15 +/- 7.31 kg/m(2), preoperatively, to 34.03 +/- 4.53 kg/m2 (p < 0.001). There was an increase of the PTHi value (from 71.4 +/- 79.6 to 91.65 +/- 43.06 pg/ml) (p = 0.01), and the urinary pirydinolines (from 7.93 +/- 4.06 an 11.4 +/- 10.12 nM/mM) (p < 0.05). The ultrasonic transmission speed increased (from 1,990.93 +/- 62.38 to 2,035.25 +/- 53.98 m/s). However, the bone mineral content (BMC) did not show changes (from 3,016.5 +/- 562.8 to 2,909.6 +/- 304.2 g), as well as the Bone Mineral Density (BMD) (of 1,174.2 +/- 98.8 g/cm2). Neither correlation was found between the BMD (r = 0.212; p = 0.6), the BMC (r =-0.125; p = 0.768), and the T-score (r = 0.592, p = 0.093). The study of the bone mass through ultrasonic transmission speed revealed low sensitivity during the assessment of the morbid obese patients. A percentage of cases of osteopenia were observed despite the fact that they are not reflected in the bone content or in the bone mass. Ultrasonic evaluation of bone mass has no value in the morbidly obese, by the clear negative correlation between ultrasound velocity and thickness of soft tissue.

Natural history and risk factors for bone loss in postmenopausal Caucasian women: a 15-year follow-up population-based study

In this 15-year follow-up study, we found that the estimated rate of bone loss at the femoral neck (FN) for women aged 45-68 was linear at a rate of 1.67% per year, but quadratic for lumbar spine (LS) at a rate of 3.12% initially, and slowing down with age. We also confirmed the protective role of HRT, increasing weight, and lean mass in long-term bone loss.

INTRODUCTION

The objective was to describe the natural history of bone loss and explore the role of environmental factors in postmenopausal women over a 15-year period.

METHODS

Bone mineral density (BMD) at the FN and the LS were measured in postmenopausal women from the Chingford Study. Height, weight, HRT status, and calcium/vitamin D supplement were assessed at each visit. Osteoarthritis of hip and spine was assessed by X-ray at baseline and at year 8.

RESULTS

A total of 955 postmenopausal women with an average age of 54.7 at baseline were included. Both FN and LS BMD decreased significantly with age (p<0.0001). The decline was larger in the LS (-3.12% per year), which showed a quadratic relationship, than in the FN (-1.67% per year) with a linear relationship. The rate of bone loss was reduced by one third annually for the FN and LS respectively in current HRT users. Change in weight was positively associated with both DeltaFN and DeltaLS BMD (beta=0.16% and 0.09% change in DeltaFN and DeltaLS BMD per kilogramme change in weight respectively, p<0.0001 for both sites). Spine OA and progression were positively associated with DeltaLS BMD (beta=1.22% change in DeltaLS BMD per grade in spine OA and 0.45% change in DeltaLS BMD for patients who progressed, p<0.0001 for spine OA and p=0.002 for spine OA progression). Spine OA (beta=0.54% change in DeltaFN BMD per grade, p<0.0001), but not progression, and hip OA were positively associated with DeltaFN BMD. Furthermore, both age and body weight at baseline were positively associated with both DeltaFN and DeltaLS BMD (beta=0.02-0.04% change in DeltaFN and DeltaLS BMD per year increase in age at baseline and 0.004-0.007% change in DeltaFN and DeltaLS BMD per kilogramme increase in weight at baseline, all p<0.0001).

CONCLUSION

This large population-based longitudinal study demonstrated that the decline of BMD over 15 years is linear with age for the FN, but quadratic for the LS. The study confirmed the protective role of HRT, increased weight and lean mass in long-term bone loss.

Circulating leptin and osteoprotegerin levels affect insulin resistance in healthy premenopausal obese women

We investigated the relationship between circulating leptin and osteoprotegerin (OPG) levels and insulin resistance assessed by HOMA-IR in premenopausal obese and normal weight women. Thirty four obese women (age 31 +/- 8 years) (BMI 35 +/- 4 kg/m(2)) with 19 healthy controls (age 31 +/- 7 years) (BMI <25 kg/m(2)) (BMI 21 +/- 2 kg/m(2)) were included in the study. Women were healthy and had no osteoporosis. Circulating leptin levels were significantly higher in obese women (17.11 +/- 2.05 ng/mL vs. 8.38 +/- 4.71 ng/mL, p <0.0001) and decreased OPG levels were found (14.7 +/- 7.15 pg/mL vs. 19.17 +/- 6.37 pg/mL, p = 0.03). Leptin showed a positive correlation with BMI (r = 0.851, p <0.0001), waist-to-hip ratio (r = 0.692, p <0.0001), fasting insulin (r = 0.441, p <0.001), HOMA-IR (r = 0.412, p = 0.002), fibrinogen (r = 0.387, p = 0.004), uric acid (r = 0.293, p = 0.033), hematocrit (r = 0.394, p = 0.003), systolic (r = 0.504, p <0.0001), and diastolic blood pressure (r = 0.363, p = 0.008). OPG showed a negative correlation with insulin (r = -0.341, p = 0.013) and HOMA-IR (r = -0.324, p = 0.018). In obese women group, the regression equation of HOMA-IR was (HOMA-IR = [0.095 x leptin]-[0.051 x OPG] + 1.71). However, there was no relation between leptin and OPG levels. In conclusion, circulating leptin and OPG levels were related to insulin resistance in premenopausal obese women. However, leptin had no interference in OPG in premenopausal women.

Risk factors for low bone mineral density and the 6-year rate of bone loss among premenopausal and perimenopausal women

Risk factors that are associated with lower bone mineral density (BMD) may not necessarily be associated with increased bone loss among premenopausal and perimenopausal women. We determined risk factors for lower premenopausal and perimenopausal BMD while simultaneously determining risk factors for increased 6-year rate of bone loss among women aged 24-50 years within a population-based prospective cohort study. BMD of the lumbar spine and femoral neck, reported as t scores, were measured five times within the 6-year study among 614 women who were between the ages of 24 and 44 in 1992/1993. Rates of bone loss were calculated from the repeated BMD measurements. Risk factors for lower BMD over time at the lumbar spine included history of any fracture ( P=0.005). The major risk factor for lower BMD over time at the femoral neck was family history of osteoporosis ( P<0.002). The major protective factor for greater BMD over time at both skeletal sites was additional body weight ( P<0.0001). Other protective factors for greater BMD over time at the femoral neck were modest alcohol consumption ( P=0.0002) and high-school sports participation ( P=0.002). Risk factors for greater bone loss at either skeletal site included postmenopausal status ( P<0.0001 at the lumbar spine; P=0.01 at the femoral neck), and the reporting of a reproductive cancer ( P<0.0001 at the lumbar spine; P=0.0008 at the femoral neck). Body weight was protective against bone loss at both skeletal sites ( P<0.0001). Baseline age, calcium intake, smoking, and current physical activity were not associated with BMD or bone loss. The understanding of the relative importance of risk factors for both low BMD and bone loss may assist in the identification of women at greater risk for subsequent low postmenopausal BMD.

Serum leptin in dialysis renal osteodystrophy

BACKGROUND

The hormone leptin is considered to have a role in the prevention of osteoporosis and probably acts on bone tissue through inhibition of osteoclasia. Its action has been attributed to interference in osteoprotegerin (OPG)/OPG-ligand equilibrium. Contradictory data also have been reported, casting doubts on the positive effect on bone mass of the hormone, at least in males. To date, the relation between serum leptin levels of dialysis patients and renal osteodystrophy, defined by histomorphometric and histodynamic parameters of bone, has not been studied.

METHODS

The study included 46 hemodialysis patients (32 men, 14 women; age, 57.2 +/- 11.4 years). A transiliac bone biopsy after double-tetracycline labeling was performed for histological, histomorphometric, and histodynamic studies. Blood samples were drawn for leptin, intact parathyroid hormone (PTH), whole PTH (PTH1-84), OPG, bone alkaline phosphatase, calcium, phosphate, 25-hydroxycholecalciferol, and calcitriol. Serum leptin was measured by means of a radioimmunoassay.

RESULTS

Eighteen patients had mixed osteodystrophy (MO); 17 patients, hyperparathyroidism; 9 patients, adynamic bone disease (ABD); and 2 patients, osteomalacia. Aluminum histochemistry results were positive in 1 patient with ABD and 1 patient with MO. A sex difference was found in serum leptin levels (48.9 +/- 38 ng/mL in women and 12.2 +/- 13.2 ng/mL in men; P < 0.0002). In the entire population, lnleptin correlated significantly with body mass index (BMI; P < 0.01). SD score (SDS) leptin (adjusted for BMI, sex, and age) correlated inversely with PTH1-84 level and osteoclastic surface (OcS/BS; P < 0.05) and had a borderline correlation with bone formation rate. Correlations between leptin levels and other parameters were enhanced in men. SDS leptin correlated inversely with OcS/BS (P < 0.01), osteoclastic number (P < 0.01), and mineral apposition rate (P < 0.01). In addition, SDS leptin had a borderline inverse correlation with osteoblast surface (P < 0.06) and significant correlation with OPG level (P < 0.05). No difference was found in serum leptin levels between histological groups.

CONCLUSION

The reported data confirm the finding of a positive relation between serum leptin level and BMI and greater levels in women compared with men. Serum leptin level is connected to bone resorption and also bone formation, both inversely related to serum leptin levels. The decrease in osteoclasia that accompanies increasing serum leptin levels does not seem to be related to an enhanced OPG effect because it was accompanied by decreased OPG levels. Low-turnover bone disease does not appear to be caused by increased serum leptin levels. The nature of the interrelation between serum leptin and PTH1-84 levels requires further study.

Leptin reduces ovariectomy-induced bone loss in rats

Bone mineral density increases with fat body mass, and obesity has a protective effect against osteoporosis. However, the relationship between fat body mass and bone mineral density is only partially explained by a combination of hormonal and mechanical factors. Serum leptin levels are strongly and directly related to fat body mass. We report here the effects of leptin administration compared with estrogen therapy on ovariectomy-induced bone loss in rats. Leptin was effective at reducing trabecular bone loss, trabecular architectural changes, and periosteal bone formation. Interestingly, the combination of estrogen and leptin further decreased bone turnover compared with that in estrogen-treated ovariectomized rats. Leptin also significantly increased osteoprotegerin mRNA steady state levels and protein secretion and decreased RANK ligand mRNA levels in human marrow stromal cells in vitro. Our findings suggest that leptin could modulate bone remodeling in favor of a better bone balance in rats. This study is the first evidence that leptin therapy has a significant effect in preventing ovariectomy-induced bone loss, and this effect may at least in part be mediated by the osteoprotegerin/RANK ligand pathway.