Determinants of incidence of osteoporotic fractures in the female Spanish population older than 50

Hypogonadotropic Hypogonadism

Delayed puberty is defined as absent testicular enlargement in boys or breast development in girls at an age that is 2 to 2.5 SDS later than the mean age at which these events occur in the population (traditionally, 14 years in boys and 13 years in girls). One cause of delayed/absent puberty is hypogonadotropic hypogonadism (HH), which refers to inadequate hypothalamic/pituitary function leading to deficient production of sex steroids in males and females. Individuals with HH typically have normal gonads, and thus HH differs from hypergonadotropic hypogonadism, which is associated with primary gonadal insufficiency.

Association between age at menarche and bone mineral density in postmenopausal women

BACKGROUND

Age at menarche (AAM) directly affects female estrogen levels, which play a vital role in bone metabolism. The exact relationship between bone mineral density (BMD) and AAM remains controversial. Thus, this study aimed to determine the association between AAM and lumbar spine (LS) BMD in postmenopausal women.

METHODS

Our data were based on the National Health and Nutrition Examination Survey (NHANES) 2011-2018. AAM was divided into three categories including ≤ 12, 13-15, and ≥ 16 years, and the ≤ 12 years old category was used as the reference group. To examine the association between AAM and LS BMD, we used three weighted linear regression models, Model 1 (without adjustment), Model 2 (with adjustment for age, race, and body mass index [BMI]), and Model 3 (with adjustment for all covariates).

RESULTS

This study included 1195 postmenopausal women aged 40-59 years. In the unadjusted model, a menarche age of ≥ 16 years compared with a menarche age of ≤ 12 years was associated with lower LS BMD (β = - 0.083, 95% CI - 0.117, - 0.048, P < 0.001). After adjusting for potential confounding factors, there was still a negative correlation in model 2 (β = - 0.078, 95% CI - 0.113, - 0.042, P < 0.001) and model 3 (β = - 0.065, 95% CI - 0.096, - 0.033, P < 0.001). Moreover, this significant relationship persisted after excluding participants who used female hormones (β = - 0.053, 95% CI - 0.089, - 0.016, P = 0.006).

CONCLUSION

Our study found that postmenopausal women with a menarche age of ≥ 16 years had significantly lower LS BMD than that had by those with a menarche age of ≤ 12 years. As a result of this study, postmenopausal women with a late menarche age may have a higher risk of lumbar osteoporotic fractures and need better bone health care.

Heritability of Age at Menarche in Nigerian Adolescent Twins

Heritability of age at menarche (AAM) in African populations remains largely unknown. A question on AAM was given to 1803 [454 monozygotic (MZ), 823 same-sex dizygotic (DZ), and 526 female members of opposite sex] adolescent twins attending public schools in Lagos State, Nigeria. The age range of the sample was 12-18 years, with a mean (SD) of 14.57 (±1.70) years. The data included 905 missing cases consisting of those who had not experienced menarche and did not recall AAM. Missing values were imputed using the Expectation-Maximization algorithm. Kaplan-Meier analysis based on the imputed data yielded 13.23 years [95% CI [13.18, 13.28] for the mean and 13.00 years [95% CI [12.96, 13.04] for the median of AAM. Twin correlation and model-fitting analyses were performed on the basis of those who reported AAM (MZ = 82 complete pairs and 38 cotwin missing cases; DZ = 157 complete pairs and 99 cotwin missing cases). Maximum likelihood MZ and DZ twin correlations for AAM were .63 (95% CI [.48, .74]) and .33 (95% CI [.19, .45]) respectively. Model-fitting analyses indicated that 58% (95% CI [46, 67]) of the variance of AAM was associated with additive genetic influences with the remaining variance, 42% (33-54) being due to nonshared environmental influences including measurement error. The heritability estimate found in this study was within the range of those found in Asian and Western twin samples.

Heritability of Age at Menarche in South Korean Female Twins

Genetic and environmental influences on age at menarche (AAM) have rarely been examined in Asian females. This study aimed to investigate the heritability of AAM in South Korean female twins. The AAM data from 1370 female twins (933 monozygotic [MZ] twins, 294 dizygotic [DZ] twins and 160 female members of opposite-sex DZ twins) born between 1988 and 2001 were analyzed. The age of the sample at the time of the assessment ranged from 16 to 28 years with a mean of 19.3 (SD = 2.2) years. The mean AAM in the total sample was 12.49 (SD = 1.41) years. Although the mean AAM decreased with increasing birth years, it levelled off in birth years 2000-2001. Maximum likelihood MZ and DZ twin correlations were 0.72 [95% CI (0.67, 0.76)] and 0.35 [95% CI (0.19, 0.50)], respectively. The results of model-fitting analysis indicated that the additive genetic and individual-specific environmental effects were 72% [95% CI (67%, 76%)] and 28% [95% CI (24%, 33%)], respectively. Neither nonadditive genetic nor shared environmental effects were significant.

A meta-analysis of breastfeeding and osteoporotic fracture risk in the females

Our meta-analysis included 12 studies from PubMed, Embase, and Web of Science. Finding indicated breastfeeding may well reduce the risk of osteoporotic fracture.

INTRODUCTION

Several epidemiologic studies have investigated that breastfeeding is associated with short-term bone loss in the women, but the long-term effect on osteoporotic fracture risk remains unclear. Thus, we conducted this meta-analysis to explore the potential association between breastfeeding and osteoporotic fracture risk in the females and possible dose-response relationship between them.

METHODS

We searched PubMed, Embase, and Web of Science (ISI) up to April 2016 for relevant articles associated between breastfeeding and osteoporotic fracture. Pooled relative risks (RRs) with 95 % confidence intervals (CIs) were calculated with a random-effects model. Dose-response analysis was performed by restricted cubic spline.

RESULTS

Twelve articles including 14,954 participants were identified. The pooled RRs of osteoporotic hip and forearm fracture for the highest vs lowest duration of breastfeeding were 0.84 (95 % CI 0.67-1.05), 0.72 (95 % CI 0.52-0.99), and 0.82 (95 % CI 0.56-1.19), respectively. In subgroup analysis, breastfeeding was associated with a decreased risk of osteoporotic fracture in case-control study (RR = 0.70, 95 % CI 0.49-0.99) and postmenopausal women (RR = 0.66, 95 % CI 0.47-0.93). In dose-response analysis, osteoporotic and hip fracture risk decreased by 0.9 and 1.2 % for each month increment of breastfeeding, respectively.

CONCLUSIONS

Our meta-analysis revealed that breastfeeding may well reduce the risk of osteoporotic fracture. More cohort studies with large sample sizes are needed to confirm the conclusion.

Association between Age at Menarche and Cardiovascular Disease Risk Factors in China: A Large Population-Based Investigation

BACKGROUND

The association between age at menarche (AAM) and cardiovascular disease (CVD) has previously been investigated with controversial results. The relationship between the psychological characteristic of AAM and many cardiovascular risk factors remains unclear.

PURPOSE

To assess the association between AAM and CVD risk factors in a large population.

DESIGN AND SETTING

13,242 women aged 24-79 years were recruited from China mainland during 2009-2013 for a cross-sectional, population-based study to investigate the association between AAM and CVD risk factors. Information on AAM was obtained from self-report and information on CVD risk factors from physical examination.

RESULTS

In age-, body-mass-index- and height-adjusted analyses, AAM was positively associated with hypertension and 'college or above' educational level and incident CVD events. The adjusted odds ratios (ORs) and 95% confidence intervals for hypertension across AAM categories (≤12, 13-14, 15-16, and ≥17 years) were 0.820 (0.70-0.96), 0.82 (0.70-0.96), 0.88 (0.79-0.99) and 1 (referent), respectively; adjusted ORs for high educational level ('college or above') were 0.29 (0.24-0.34), 0.60 (0.41-0.51), 0.69 (0.62-0.76), and 1 (referent), respectively; adjusted ORs for incident CVD events were 0.18 (0.08-0.41), 0.18 (0.08-0.41), 0.62 (0.41-0.93), 1 (referent), respectively.

CONCLUSIONS

Earlier AAM were positively associated with incident CVD events, hypertension and 'college or above' educational level.

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

During pregnancy and lactation, female physiology adapts to meet the added nutritional demands of fetuses and neonates. An average full-term fetus contains ∼30 g calcium, 20 g phosphorus, and 0.8 g magnesium. About 80% of mineral is accreted during the third trimester; calcium transfers at 300-350 mg/day during the final 6 wk. The neonate requires 200 mg calcium daily from milk during the first 6 mo, and 120 mg calcium from milk during the second 6 mo (additional calcium comes from solid foods). Calcium transfers can be more than double and triple these values, respectively, in women who nurse twins and triplets. About 25% of dietary calcium is normally absorbed in healthy adults. Average maternal calcium intakes in American and Canadian women are insufficient to meet the fetal and neonatal calcium requirements if normal efficiency of intestinal calcium absorption is relied upon. However, several adaptations are invoked to meet the fetal and neonatal demands for mineral without requiring increased intakes by the mother. During pregnancy the efficiency of intestinal calcium absorption doubles, whereas during lactation the maternal skeleton is resorbed to provide calcium for milk. This review addresses our current knowledge regarding maternal adaptations in mineral and skeletal homeostasis that occur during pregnancy, lactation, and post-weaning recovery. Also considered are the impacts that these adaptations have on biochemical and hormonal parameters of mineral homeostasis, the consequences for long-term skeletal health, and the presentation and management of disorders of mineral and bone metabolism.

Duration of breastfeeding as a risk factor for vertebral fractures

PURPOSE

Among the risk factors for osteoporosis and fractures, gynecological history (fertile period, parity and breastfeeding) play an important part. Changes in calcium metabolism to enable an adequate mineral transfer to the milk have a prominent role in bone loss during breastfeeding. Data on the influence of breastfeeding in postmenopausal osteoporosis are inconsistent. The aim of the present study was to identify any association between duration of breastfeeding and vertebral fractures in postmenopausal women.

METHODS

All patients underwent the following tests: bone mineral density measurements of the lumbar spine (L1-L4) and the total and femoral neck using dual-energy X-ray absorptiometry and antero-posterior and lateral radiography of the thoracic and lumbar spine to identify vertebral fractures.

RESULTS

The study involved 752 women with a mean age of 64.5±9.3; 23% of them reported vertebral osteoporotic fractures. The women with vertebral fractures had breastfed for longer periods (11.8±12.9 vs. 9.3±11.2months, p=0.03) and had more pregnancies (2.6±2.2 vs. 2.2±1.3, p=0.002). Breastfeeding for more than 18months was associated with a two-fold risk of developing vertebral fractures (OR 2.12, 95% CI 1.14-5.38, p=0.04), particularly in those without current or past use of drugs positively affecting bone.

CONCLUSIONS

Our study showed an association between long periods of breastfeeding and vertebral fractures, supporting a role for lengthy lactation as a risk factor for osteoporotic fractures after menopause. Bearing in mind all the benefits of breastfeeding, this finding suggests the importance of an adequate calcium and vitamin D intake during pregnancy and breastfeeding, with the aid of dietary supplements if necessary.

Hip fracture in three elderly populations of central Spain: data from the NEDICES study

There is a paucity of data concerning the specific associations between hip fracture in the elderly and other age-related conditions, as well as its impact on long-term survival. This study was aimed to estimate the prevalence, risk factors, and outcome of self-reported hip fracture (srHF) in a cohort of Spanish elderly individuals. Neurological Disorders in Central Spain (NEDICES) is a census population-based survey of the prevalence and incidence of major age-associated conditions in three areas of central Spain. Data on health status and several chronic conditions were evaluated in the baseline questionnaire (1994-1995). Odds ratios for the association between srHF and other comorbidities and health-related variables were assessed by logistic regression. A Cox model estimated the impact of srHF on 13-year all-cause mortality. The final cohort comprised 5,278 community-living elderly subjects. A total of 166 participants (3.1%) had srHF. Prevalence was associated with higher age, female gender, degree of urbanisation of residence place, lower body mass index (BMI), higher number of chronic medications, higher Pfeffer FAQ score, being unmarried (P < 0.001 for all), and infantile living conditions (P = 0.007). Participants with srHF had a higher number of associated chronic conditions (P < 0.001). In the multivariate analysis, self-reported osteoporosis, lower BMI category, rural environment during childhood, and higher age were identified as independent risk factors for srHF. Adjusted hazard ratio for mortality in the srHF group was 1.40 (95% confidence interval 1.15-1.71; P = 0.001). srHF is a common condition among community-living elderly population in Spain, and has a significant impact upon long-term all-cause mortality.

2013 Up-date of the consensus statement of the Spanish Menopause Society on postmenopausal osteoporosis

Postmenopausal osteoporosis is a major female health problem that increases morbidity, mortality and healthcare system costs. Considering that gynecologists are the primary health practitioners involved in the treatment of women with osteoporosis in our country, a panel of experts from the Spanish Menopause Society met to establish a set of criteria and procedures for the diagnosis and treatment of this disease based on the best available evidence and according to the model proposed by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system to elaborate clinical practice guidelines and to classify the quality of the evidence and the strength of the recommendations. These recommendations should be a reference to gynecologist and other health professionals involved in the treatment of postmenopausal women.

Independent predictors of all osteoporosis-related fractures among healthy Saudi postmenopausal women: the CEOR Study

This study was designed to identify independent predictors of all osteoporosis-related fractures (ORFs) among healthy Saudi postmenopausal women. We prospectively followed a cohort of 707 healthy postmenopausal women (mean age, 61.3±7.2 years) for 5.2±1.3 years. Data were collected on demographic characteristics, medical history, personal and family history of fractures, lifestyle factors, daily calcium intake, vitamin D supplementation, and physical activity score. Anthropometric parameters, total fractures (30.01 per 1000 women/year), special physical performance tests, bone turnover markers, hormone levels, and bone mineral density (BMD) measurements were performed. The final model consisted of seven independent predictors of ORFs: [lowest quartile (Q(1)) vs highest quartile (Q(4))] physical activity score (Q(1) vs Q(4): ≤12.61 vs ≥15.38); relative risk estimate [RR], 2.87; (95% confidence interval [CI]: 1.88-4.38); age≥60 years vs age<60 years (RR=2.43; 95% CI: 1.49-3.95); hand grip strength (Q(1) vs Q(4): ≤13.88 vs ≥17.28 kg) (RR=1.88; 95% CI: 1.15-3.05); BMD total hip (Q(1) vs Q(4): ≤0.784 vs 0.973 g/cm(2)) (RR=1.86; 95% CI: 1.26-2.75); dietary calcium intake (Q(1) vs Q(4): ≤391 vs ≥648 mg/day) (RR=1.66; 95% CI: 1.08-2.53); serum 25(OH)D (Q(1) vs Q(4): ≤17.9 vs ≥45.1 nmol/L) (RR=1.63; 95% CI: 1.06-2.51); and past year history of falls (RR=1.61; 95% CI: 1.06-2.48). Compared with having none (41.9% of women), having three or more clinical risk factors (4.8% of women) increased fracture risk by more than 4-fold, independent of BMD. Having three or more risk factors and being in the lowest tertile of T-score of [total hip/lumbar spine (L1-L4)] was associated with a 14.2-fold greater risk than having no risk factors and being in the highest T-score tertile. Several clinical risk factors were independently associated with all ORFs in healthy Saudi postmenopausal women. The combination of multiple clinical risk factors and low BMD is a very powerful indicator of fracture risk.

[2011 Up-date of the consensus statement of the Spanish Society of Rheumatology on osteoporosis]

OBJECTIVE

Due to increasing improvement in the diagnosis, evaluation and management of osteoporosis and the development of new tools and drugs, the Spanish Society of Rheumatology (SER) has promoted the development of recommendations based on the best evidence available. These recommendations should be a reference to rheumatologists and other health professionals involved in the treatment of patients with osteoporosis.

METHODS

Recommendations were developed following a nominal group methodology and based on a systematic review. The level of evidence and degree of recommendation were classified according to the model proposed by the Center for Evidence Based Medicine at Oxford. The level of agreement was established through Delphi technique. Evidence from previous consensus and available clinical guidelines was used.

RESULTS

We have produced recommendations on diagnosis, evaluation and management of osteoporosis. These recommendations include the glucocorticoid-induced osteoporosis, premenopausal and male osteoporosis.

CONCLUSIONS

We present the SER recommendations related to the biologic therapy risk management.

Bone Loss Rate May Interact with Other Risk Factors for Fractures among Elderly Women: A 15-Year Population-Based Study

Aim was to investigate fracture risk (FR) according to bone loss (BL) rate. A random sample of 1652 women aged 53.5 years was measured with dual X-ray absorptiometry in femoral neck in 1989 and 1994 and divided into tertiles of annual BL rate: high >0.84%, moderate 0.13%-0.84%, and low <0.13%. Low trauma energy fractures during following 10 years were recorded. There were no differences in FR between BL tertiles in Cox regression model. Factors predicting lower FR in Cox model were in high tertile: high T-score (HR 0.71; 95% CI 0.54-0.93, P = .012), no sister's fracture (HR 0.35; 0.19-0.64, P = .001), no mother's fracture (HR 0.52; 0.31-0.88, P = .015), in moderate tertile: high T-score (HR 0.69;0.53-0.91, P = .008) and good grip strength (HR 0.98; 0.97-0.99, P = .022). In low tertile there were no predictors for FR. BL predicted FR in women with mother's fracture in univariate and multivariate model (OR 2.6; 1.15-5.7, P = .021) but with sister's fracture this was observed only in multivariate model (OR 2.66; 1.09-6.7, P = .039). Accordingly, the risk factors for postmenopausal fractures, especially mother's fracture, may interact with BL.

Sister's fracture history may be associated with perimenopausal bone fragility and modifies the predictability of fracture risk

SUMMARY

The present study investigated the effects of first degree relatives' fractures on fracture incidence after the menopause. Sister's, but not other relatives', wrist or hip fracture history was associated with increased risk of fragility fractures after the menopause. This suggests genetic predisposition to bone fragility among postmenopausal women.

OBJECTIVE

The aim of the present study was to investigate the association between first degree relatives' fractures and perimenopausal bone fragility.

MATERIALS AND METHODS

The study sample of 971 perimenopausal women was extracted from randomly selected Kuopio Osteoporosis Risk Factor and Prevention cohort and measured with dual X-ray absorptiometry in femoral neck (FN) in baseline (1989-1991), in 5 years (1994-97), and in 10 years (1999-2001). All low-trauma energy fractures during the 10-year follow-up were recorded based on self-reports and validated from medical records. First degree relatives' history of life-time hip and wrist fractures (exact classification or trauma energy not specified) was questioned by postal inquiries.

RESULTS

There was a significant correlation between fathers' vs. brothers' and mothers' vs. sisters' fractures (p < 0.01 in Pearson bivariate correlations). Sister's, but not mother's, father's, or brother's wrist and hip fractures were associated with significantly lowered 10-year fragility fracture-free survival rate (HR = 0.56, p = 0.006). Sisters' or other relatives' fractures were not associated with FN bone loss rate or bone mineral density (BMD) in the follow-up measurements (p = NS in ANCOVA). The predictive power of BMD for fragility fractures differed according to sisters' fracture history: Baseline FN T score predicted fracture-free survival only among women without sisters' fracture history (HR 0.62, p < 0.001 vs. women with sisters' fracture in Cox regression).

CONCLUSIONS

In conclusion, sisters' fracture history is associated with 10-year fracture-free survival in perimenopausal women but not with BMD or its changes. Predictability of fragility fracture risk with BMD may depend on sister's fracture history. This may indirectly suggest genetic predisposition to bone fragility independently of BMD.

[Evidence based comparative analysis for managing osteoporosis in a primary health care setting]

OBJECTIVE

To find out how physicians are managing osteoporosis in a primary care setting.

DESIGN

Cross-sectional study.

CONTEXT

Primary care setting with a target population of 276,000 inhabitants, grouped into 9 basic health areas, Spain.

PARTICIPANTS

Women older than 45 years old on treatments for osteoporosis.

INTERVENTIONS

Standardised questionnaire self-filled in by women and compared with clinical records.

MAIN MEASUREMENTS

Suitability of the indication of diagnostic tests, proportion of treatments supported by diagnostic tests and according to evidence.

RESULTS

The mean age of the sample was 65.3 (9.6) years. Of the women included, 73.2% (n=243) had an indication for densitometry and only 60.2% (n=200) of them had this performed. The results of the densitometries were: 14% (n=28) normal, 31% (n=62) osteopenia and 55% (n=110) osteoporosis. Based on risk factors, in those women with densitometry indication, 39.5% (n=96) did not have it performed. In those women with no risk factors to justify the indication of densitometry (n=89), 59.6% (n=53) did have it performed. The two-year follow densitometry was not carried out on 78.7% (n=261) of women. Statistically significant differences were observed in the percentages of adequacy of the indications of densitometry and in the percentages of adequacy of the treatments in the different medical specialities analyzed (P < .05). Of the women who had densitometry, 42.4% (n=81) were inadequately treated.

CONCLUSIONS

The indication of densitometry is clearly improvable and there is a high variability in its adequacy in all the medical specialities studied. To a great extent, the indication of treatments for osteoporosis is not based on densitometry and is against the recommendations of the evidence based studies recently published.

Management of osteoporosis with PTH: treatment and prescription patterns in Europe

BACKGROUND

PTH is an anabolic agent that promotes new bone formation and offers additional therapeutic options for the treatment of postmenopausal osteoporosis. Two forms of PTH are licensed for treatment of postmenopausal osteoporosis and are available in most European countries. Both demonstrate safety and efficacy in clinical trials with similar increases in bone mineral density (BMD) at the spine, total hip and femoral neck, and reductions in the number of vertebral fractures in postmenopausal women. The effect on the number of patients treated with PTH is analysed in terms of the total number of osteoporotic patients and total number of eligible patients, as defined by a literature review of vertebral fracture incidence in European populations.

AIMS

To analyse the management and treatment of postmenopausal osteoporosis with PTH in terms of the prescription patterns for PTH in five European countries and the underlying reasons for observed rates of prescription in each country.

FINDINGS

Osteoporosis patients with low vertebral BMD and two fractures are at appreciable risk of sustaining further fractures, particularly hip fractures. Hip fractures are associated with significant mortality and huge economic cost to society. These patients are approved for treatment with PTH but the availability of this therapy varies considerably across Europe. The number of patients receiving PTH varies from 0.24% of eligible patients in the UK to approximately 5% of eligible patients in Spain.

CONCLUSION

Large differences (up to 20-fold) exist in the number of patients receiving PTH across the five European countries. The reasons for the different accessibility to PTH arise from a combination of restrictive schedules of reimbursement, high cost and lack of knowledge of the potential benefits of PTH by physicians.

A genome-wide linkage scan for age at menarche in three populations of European descent

CONTEXT

Age at menarche (AAM) is an important trait both biologically and socially, a clearly defined event in female pubertal development, and has been associated with many clinically significant phenotypes.

OBJECTIVE

The objective of the study was to identify genetic loci influencing variation in AAM in large population-based samples from three countries.

DESIGN/PARTICIPANTS

Recalled AAM data were collected from 13,697 individuals and 4,899 pseudoindependent sister-pairs from three different populations (Australia, The Netherlands, and the United Kingdom) by mailed questionnaire or interview. Genome-wide variance components linkage analysis was implemented on each sample individually and in combination.

RESULTS

The mean, sd, and heritability of AAM across the three samples was 13.1 yr, 1.5 yr, and 0.69, respectively. No loci were detected that reached genome-wide significance in the combined analysis, but a suggestive locus was detected on chromosome 12 (logarithm of the odds = 2.0). Three loci of suggestive significance were seen in the U.K. sample on chromosomes 1, 4, and 18 (logarithm of the odds = 2.4, 2.2 and 3.2, respectively).

CONCLUSIONS

There was no evidence for common highly penetrant variants influencing AAM. Linkage and association suggest that one trait locus for AAM is located on chromosome 12, but further studies are required to replicate these results.

The physiological costs of reproduction in small mammals

Life-history trade-offs between components of fitness arise because reproduction entails both gains and costs. Costs of reproduction can be divided into ecological and physiological costs. The latter have been rarely studied yet are probably a dominant component of the effect. A deeper understanding of life-history evolution will only come about once these physiological costs are better understood. Physiological costs may be direct or indirect. Direct costs include the energy and nutrient demands of the reproductive event, and the morphological changes that are necessary to facilitate achieving these demands. Indirect costs may be optional 'compensatory costs' whereby the animal chooses to reduce investment in some other aspect of its physiology to maximize the input of resource to reproduction. Such costs may be distinguished from consequential costs that are an inescapable consequence of the reproductive event. In small mammals, the direct costs of reproduction involve increased energy, protein and calcium demands during pregnancy, but most particularly during lactation. Organ remodelling is necessary to achieve the high demands of lactation and involves growth of the alimentary tract and associated organs such as the liver and pancreas. Compensatory indirect costs include reductions in thermogenesis, immune function and physical activity. Obligatory consequential costs include hyperthermia, bone loss, disruption of sleep patterns and oxidative stress. This is unlikely to be a complete list. Our knowledge of these physiological costs is currently at best described as rudimentary. For some, we do not even know whether they are compensatory or obligatory. For almost all of them, we have no idea of exact mechanisms or how these costs translate into fitness trade-offs.

Searching for genes underlying susceptibility to osteoporotic fracture: current progress and future prospect

INTRODUCTION

Osteoporotic fracture (OF) is a public health problem. It is a common practice in the genetics of osteoporosis that bone mineral density (BMD) was studied as a major surrogate phenotype in gene search for risk of OF (ROF) because of their high phenotypic correlation. However, some studies indicate that the genetic correlation between BMD and ROF is very low. This implies that most genes found important for BMD may not be relevant to ROF. Ideally, employing OF per se as a direct study phenotype can directly find the relevant genes underlying ROF.

EVIDENCE

Here, we summarized some evidence supporting ROF under moderate genetic control, and the current progress of molecular genetic studies employing OF as the direct study phenotype, then give our consideration on the future prospects in the genetics of ROF.

Femoroplasty--augmentation of the proximal femur with a composite bone cement--feasibility, biomechanical properties and osteosynthesis potential

BACKGROUND

Analogous to vertebroplasty, cement-augmentation of the proximal femur ("femoroplasty") could reinforce osteoporotic bones. This study was to evaluate (i) the feasibility of femoroplasty with a composite cement (Cortoss), (ii) its influence on femoral strength by mechanical testing and (iii) the feasibility of stable osteosynthesis of the augmented fractured bones.

METHODS

Nine human cadaveric femora were augmented with a composite bone cement, the surface heat generation monitored, and then tested biomechanically against their native contralateral control to determine fracture strength. Subsequently, thirteen reinforced and fractured femora were osteosynthetized by different implants and tested against their osteosynthetisized, non-augmented contralateral control.

FINDINGS

Cement could be injected easily, with a moderate temperature rise. A positive correlation between BMD and fracture load and a significant increase in fracture load (+43%) of the augmented femora compared to their native controls (6324 N and 4430 N, respectively) as well as a significant increase in energy-to-failure (+187%, 86 N m and 30 N m, respectively) was found. Osteosynthesis was possible in cement-augmented femora. Osteosynthetisized femora showed equivalent strength to the intact controls.

INTERPRETATION

Augmentation of the proximal femur with composite bone cement could be of use in prophylaxis of fractures in osteoporotic femurs. Osteosynthesis of the fractured augmented bones is a challenging procedure but has a good chance to restore strength.