Biochemical Predictors of Low Bone Mineral Density and Fracture Susceptibility in Maltese Postmenopausal Women

Whole Genome Sequencing Unravels New Genetic Determinants of Early-Onset Familial Osteoporosis and Low BMD in Malta

Background: Osteoporosis is a skeletal disease with a strong genetic background. The study aimed to identify the genetic determinants of early-onset familial osteoporosis and low bone mineral density (BMD) in a two-generation Maltese family. Methods: Fifteen relatives aged between 28–74 years were recruited. Whole genome sequencing was conducted on 12 relatives and shortlisted variants were genotyped in the Malta Osteoporotic Fracture Study (MOFS) for replication. Results: Sequential variant filtering following a dominant inheritance pattern identified rare missense variants within SELP, TGF-β2 and ADAMTS20, all of which were predicted to be likely pathogenic and participate in osteoimmunology. TGF-β2 c.1136C>T was identified in five individuals from the MOFS in heterozygosity, four of whom had osteopenia/osteoporosis at the lumbar spine and hip, and/or had sustained a low-trauma fracture. Heterozygosity for the ADAMTS20 c.4090A>T was accompanied by lower total hip BMD (p = 0.018) and lower total serum calcium levels in MOFS (p < 0.01), recapitulating the findings from the family. Women carrying at least one copy of the alternative allele (TC/CC) for SELP c.2177T>C exhibited a tendency for lower lumbar spine BMD and/or wrist fracture history relative to women with TT genotype. Conclusions: Our findings suggest that the identified variants, alone or in combination, could be causal factors of familial osteoporosis and low BMD, requiring replication in larger collections.

Radiographic anatomy of the proximal femur: femoral neck fracture vs. transtrochanteric fracture

Objective

To evaluate the correlation between radiographic parameters of the proximal femur with femoral neck fractures or transtrochanteric fractures.

Methods

Cervicodiaphyseal angle (CDA), femoral neck width (FNW), hip axis length (HAL), and acetabular tear drop distance (ATD) were analyzed in 30 pelvis anteroposterior view X-rays of patients with femoral neck fractures (n = 15) and transtrochanteric fractures (n = 15). The analysis was performed by comparing the results of the X-rays with femoral neck fractures and with transtrochanteric fractures.

Results

No statistically significant differences between samples were observed.

Conclusion

There was no correlation between radiographic parameters evaluated and specific occurrence of femoral neck fractures or transtrochanteric fractures.

Lower serum P1NP/βCTX ratio and hypoalbuminemia are independently associated with osteoporotic nonvertebral fractures in older adults

Purpose

To estimate the discriminative value of serum P1NP/βCTX ratio and albumin levels in hospitalized orthogeriatric patients with and without nonvertebral fractures.

Methods

In 1,239 orthogeriatric patients (mean age 78.1±9.52 years, 69.1% women) including 854 (68.9%) with osteoporotic nonvertebral fractures (455 [36.7%] with hip fracture [HF]) and 385 (31.1%) without fractures, markers of bone formation (procollagen type 1 N-terminal propeptide [P1NP], osteocalcin [OC], and bone resorption (beta-C-terminal cross-linking telopeptide of type 1 collagen [βCTX]), indices of mineral metabolism, and parameters of liver and renal functions were assessed; data on clinical and laboratory characteristics were collected prospectively.

Results

Both lower serum P1NP/βCTX ratio and albumin concentration (as continuous or categorical variables) were independently associated with fracture presence in multivariate logistic regressions. Compared with the highest P1NP/βCTX tertile, the prevalence of HF, after adjustment for multiple covariates, was 3-fold higher in the lowest tertile and 1.5 times higher in the middle tertile; presence of any fracture was 2.3- and 1.6-fold higher, respectively; patients with albumin levels in the lowest tertile had multivariate odds ratio (OR) of 4.6 for HF and 2.8 for any fracture, in the middle tertile the ORs were 2.2 and 1.3, respectively. The P1NP/βCTX <100.0 (median) and hypoalbuminemia (<33 g/L) demonstrated area under the curve values for HF of 0.802 and 0.806, respectively, and for any fractures of 0.711 and 0.706, respectively. When both characteristics were combined, the ORs for HF or any fracture, compared with the nonfractured group, were 7.8 and 3.2, respectively, with an accuracy of 79.6% and 71.6%, respectively.

Conclusions

In orthogeriatric patients, both serum P1NP/βCTX ratio and albumin levels demonstrated an inverse dose–effect relationship with the prevalence of nonvertebral fractures and independently indicated fracture presence with acceptable discriminatory power. Lower P1NP/βCTX (<100) and hypoalbuminemia could be useful simple additive prognostic tools for fracture risk stratification in the elderly.

Evaluating Bone Health in Egyptian Children with Forearm Fractures: A Case Control Study

Objective. To determine the likelihood of vitamin D deficiency and low bone mineral density in Egyptian children with forearm fractures. Methods. A case control study of 46 children aged 3 to 10 years with or without forearm fractures. Validated questionnaires were used to assess calcium and vitamin D intake as well as sun exposure. Serum calcium, phosphorus, alkaline phosphatase, and 25-hydroxy-vitamin D were collected. Bone mineral density was evaluated using dual-energy X-ray absorptiometry. Results. Compared to the Control group, calcium and vitamin D intake was lower in the Cases group (p = 0.03). Cases had higher Body Mass Index than Controls, p = 0.01. Children in the Cases group had lower mean serum calcium values 8.3 ± 1.4 compared to 9.3 ± 1.1 in Controls (p = 0.01). Alkaline phosphatase was higher in Cases 265 ± 65.8 than Controls 226 ± 54.6 (p = 0.03). Vitamin D and bone mineral density scores were significantly lower in the Cases group (p < 0.05). Conclusion. Our data shows an increased rate of vitamin D deficiency and decreased bone mineral density in Egyptian children with forearm fractures.