Vitamin D receptor (VDR) is an important candidate gene in muscle function. Scientific reports on the effect of its genetic variants on muscle strength are contradictory likely due to the inconsistent study designs. Hand grip strength (HGS) is a highly heritable phenotype of muscle strength but only limited studies are available on its genetic background. Association between VDR polymorphisms and HGS has been poorly investigated and previous reports are conflicting. We studied the effect of VDR gene variants on HGS in a sample of 706 schoolchildren. Genomic DNA was extracted from saliva samples and six candidate single nucleotide polymorphisms (SNPs) across the VDR gene were genotyped with Sequenom MassARRAY technique. HGS was measured with a digital dynamometer in both hands. Single marker and haplotype associations were adjusted for demographic parameters. Three SNPs, rs4516035 (A1012G; p = 0.009), rs1544410 (BsmI; p = 0.010), and rs731236 (TaqI; p = 0.038) and a 3′ UTR haploblock constructed by three SNPs (Bsml‐Taq1‐rs10783215; p < 0.005) showed significantly associations with HGS of the dominant hand. In the non‐dominant hand, the effects of the A1012G (p = 0.034) and the 3′ UTR haploblock (p < 0.01) on HGS were also significant. Since the promoter SNP (A10112G) and the 3′ UTR haplotype were proved to be associated with the expression and the stability of the VDR mRNA in earlier studies, VDR variants can be supposed to have a direct effect on muscle strength. The individual genetic patterns can also explain the inconsistency of the previously published clinical results on the association between vitamin D and muscle function. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2031–2037, 2016.

Epidemiological studies suggested the chemopreventive role of higher calcium intake in colorectal carcinogenesis. We examined genetic polymorphisms that might influence calcium metabolism: lactase (LCT) gene 13910 C/T polymorphism causing lactose intolerance and calcium-sensing receptor (CaSR) gene A986S polymorphism as a responsible factor for the altered cellular calcium sensation.

Purpose: The objective of this systematic review is to present a comprehensive summary of existing research on the use of 3D printing in spinal surgery. Methods: The researchers conducted a thorough search of four digital databases (PubMed, Web of Science, Scopus, and Embase) to identify relevant studies published between January 1999 and December 2022. The review focused on various aspects, including the types of objects printed, clinical applications, clinical outcomes, time and cost considerations, 3D printing materials, location of 3D printing, and technologies utilized. Out of the 1620 studies initially identified and the 17 added by manual search, 105 met the inclusion criteria for this review, collectively involving 2088 patients whose surgeries involved 3D printed objects. Results: The studies presented a variety of 3D printed devices, such as anatomical models, intraoperative navigational templates, and customized implants. The most widely used type of objects are drill guides (53%) and anatomical models (25%) which can also be used for simulating the surgery. Custom made implants are much less frequently used (16% of papers). These devices significantly improved clinical outcomes, particularly enhancing the accuracy of pedicle screw placement. Most studies (88%) reported reduced operation times, although two noted longer times due to procedural complexities. A variety of 3DP technologies and materials were used, with STL, FDM, and SLS common for models and guides, and titanium for implants via EBM, SLM, and DMLS. Materialise software (Mimics, 3-Matic, Magics) was frequently utilized. While most studies mentioned outsourced production, in-house printing was implied in several cases, indicating a trend towards localized 3D printing in spine surgery. Conclusions: 3D printing in spine surgery, a rapidly growing area of research, is predominantly used for creating drill guides for screw insertion, anatomical models, and innovative implants, enhancing clinical outcomes and reducing operative time. While cost-efficiency remains uncertain due to insufficient data, some 3D printing applications, like pedicle screw drill guides, are already widely accepted and routinely used in hospitals.