Risk prediction of second hip fracture by bone and muscle density of the hip varies with time after first hip fracture: a prospective cohort study

Purpose: Predictors of 'imminent' risk of second hip fracture are unknown. The aims of the study were to explore strength of hip areal bone mineral density (aBMD), and muscle area and density for predicting second hip fracture at different time intervals.Methods: Data of the Chinese Second Hip Fracture Evaluation were analyzed, a longitudinal study to evaluate the risk of second hip fracture (of the contralateral hip) by using CT images obtained immediately after first hip fracture. Muscle cross-sectional area and density were measured of the gluteus maximus (G.MaxM) and gluteus medius and minimus (G.Med/MinM) and aBMD of the proximal femur at the contralateral unfractured side. Patients were followed up for a median time of 4.5 years. Separate Cox models were used to predict second hip fracture risk at different time intervals after first event adjusted for age, sex, BMI and diabetes. Results: The mean age of subjects with imminent (within 1st or 2nd year) second hip fracture was 79.80 +/- 5.16 and 81.56 +/- 3.64 years. In the 1st year after the first hip fracture, femoral neck (FN) aBMD predicted second hip fracture (HR 5.88; 95 % CI, 1.32-26.09). In the remaining years of follow-up after 2nd year, muscle density predicted second hip fracture (G.MaxM HR 2.13; 95 % CI, 1.25-3.65,G.Med/MinM HR 2.10; 95 % CI, 1.32-3.34).Conclusions: Our results show that femoral neck aBMD is an important predictor for second hip fracture within the first year and therefore suggest supports the importance concept of early and rapid-acting bone-active drugs to increase hip BMD. In addition, the importance of muscle density predicting second hip fracture after the second year suggest post hip fracture rehabilitation and exercise programs could also be important to reduce muscle fatty infiltration.Metabolic health: pathophysiological trajectories and therap

Literacy Skill Development of Children With Familial Risk for Dyslexia Through Grades 2, 3, and 8

This study followed the development of reading speed, reading accuracy, and spelling in transparent Finnish orthography through Grades 2, 3, and 8. We compared two groups of children with familial risk for dyslexia, with or without dyslexia in Grade 2 (Dys_FR, n = 35 and NoDys_FR, n = 66) to a group of children without familial risk and dyslexia (Controls, n = 72). The Dys_FR group showed persisting deficiency especially in reading speed, and, to a minor extent, in reading and spelling accuracy. The Dys_FR children, contrary to the other two groups, relied heavily on letter-by-letter decoding in Grades 2 and 3. In children not fulfilling the criteria for dyslexia in Grade 2, the familial risk did not substantially affect the subsequent development of literacy skills.peerReviewe

Literacy Skills and Online Research and Comprehension : Struggling Readers Face Difficulties

The present study evaluated the extent to which literacy skills (reading fluency, written spelling, and reading comprehension), together with nonverbal reasoning, prior knowledge, and gender, are related to students’ online research and comprehension (ORC) performance. The ORC skills of 426 sixth graders were measured using a Finnish adaptation of the Online Research and Comprehension Assessment. Results of a structural equation model showed that these ORC skills were divided into six highly correlated factors, and that they formed a common factor in ORC. Altogether, these predictor variables explained 57% of the variance in ORC. Reading comprehension, along with gender, was the strongest predictor for ORC performance. In addition, reading fluency and written spelling explained ORC variance over and above reading comprehension. These findings suggest that struggling readers probably face difficulties online.peerReviewe

Assessing reading and online research comprehension : Do difficulties in attention and executive function matter?

This study evaluated the relation between sixth graders' (N = 426) teacher-rated difficulties in attention and executive function (EF) and their comprehension skills. Reading comprehension was assessed with a multiple-choice task and online research and comprehension (ORC) with a problem-solving task. The analyses were controlled for gender, reading fluency and nonverbal reasoning. To investigate differences in students' performance between the tasks, comprehension skills in the multiple-choice task were also controlled for in the ORC task. Structural equation models showed that teacher-rated attention and EF difficulties were related to students' performance more in the problem-solving task than in the multiple-choice task. After controlling for all the background variables, these difficulties explained 9% of the variance of ORC performance in girls and 4% in boys. These results indicate that for students with attention and EF difficulties the ORC task was more challenging than the reading comprehension task.peerReviewe

Polysaccharide-Coated Thermosets for Orthopedic Applications: From Material Characterization to In Vivo Tests

The long-term stability and success of orthopedic implants depend on the osseointegration process, which is strongly influenced by the biomaterial surface. A promising approach to enhance implant integration involves the modification of the surface of the implant by means of polymers that mimic the natural components of the extracellular matrix, for example, polysaccharides. In this study, methacrylate thermosets (bisphenol A glycidylmethacrylate/triethyleneglycol dimethacrylate), a widely used composition for orthopedic and dental applications, have been coated by electrostatic deposition of a bioactive chitosan-derivative. This polysaccharide was shown to induce osteoblasts aggregation in vitro, to stimulate cell proliferation and to enhance alkaline phosphatase activity. The coating deposition was studied by analyzing the effect of pH and ionic strength on the grafting of the polysaccharide. Contact angle studies show that the functionalized material displays a higher hydrophilic character owing to the increase of surface polar groups. The mechanical properties of the coating were evaluated by nanoindentation studies which point to higher values of indentation hardness and modulus (E) of the polysaccharide surface layer, while the influence of cyclic stress on the construct was assessed by fatigue tests. Finally, in vivo tests in minipigs showed that the polysaccharide-based implant showed a good biocompatibility and an ability for osseointegration at least similar to that of the titanium Ti6Al4V alloy with roughened surface

Biological responses of silver-coated thermosets: An in vitro and in vivo study

Bisphenol A glycidylmethacrylate (BisGMA)/triethyleneglycol dimethacrylate (TEGDMA) thermosets are biomaterials commonly employed for orthopedic and dental applications; for both these fields, bacterial adhesion to the surface of the implant represents a major issue for the outcome of the surgical procedures. In this study, the antimicrobial properties of a nanocomposite coating formed by polysaccharide 1-deoxylactit-1-yl chitosan (Chitlac) and silver nanoparticles (nAg) on methacrylate thermosets were studied. The Chitlac\u2013nAg system showed good anti-bacterial and anti-biofilm activity although its biocidal properties can be moderately, albeit significantly, inhibited by serum proteins. In vitro studies on the silver release kinetic in physiological conditions showed a steady metal release associated with a gradual loss of antimicrobial activity. However, after 3 weeks there was still effective protection against bacterial colonization which could be accounted for by the residual silver. This time-span could be considered adequate to confer short-term protection from early peri-implant infections. Preliminary in vivo tests in a mini-pig animal model showed good biological compatibility of Chitlac\u2013nAg-coated materials when implanted in bony tissue. The comparison was made with implants of titanium Ti6Al4V alloy and with a Chitlac-coated thermoset. Bone healing patterns and biocompatibility parameters observed for nAg-treated material were comparable with those observed for control implants