Waist circumference is an effect modifier of the association between bone mineral density and glucose metabolism

ABSTRACT Objective: The role of bone markers on insulin resistance (IR) remains controversial. The objective of this study is to evaluate the association between bone mineral density (BMD) and glucose metabolism and investigate if visceral hyperadiposity, evaluated by waist circumference (WC), is an effect modifier of this association. Subjects and methods: Cross-sectional analysis with 468 young adults from the fourth follow-up of the 1978/79 Ribeirão Preto prospective birth cohort, Brazil. BMD, total osteocalcin (OC), fasting plasma glucose and insulin concentrations were assessed. IR, sensitivity (S) and secretion (β) were estimated by homeostasis model assessment (HOMA) indexes. Multiple linear regression models were constructed to estimate the association between BMD and glucose metabolism. Beta coefficient, R2 and p-values were provided. WC was tested as an effect modifier and OC as a confounder. The covariates were selected based on Direct Acyclic Graph. Results: Significant interaction between BMD (femoral neck and proximal femur areas) and WC on glucose metabolism was observed in the adjusted models. Subjects with increased WC presented a positive association between BMD and log HOMA1-IR while an inverse association was found in those with normal WC (femoral neck R2 = 0.17, p = 0.036; proximal femur R2 = 0.16, p = 0.086). BMD was negatively associated with log HOMA2-S in individuals with increased WC and positively in those with normal WC (femoral neck R2 = 0.16, p = 0.042; proximal femur R2 = 0.15, p = 0.097). No significant associations between BMD, log HOMA2-β and OC and glucose metabolism markers were observed. Conclusions: BMD was associated with glucose metabolism, independently of OC, and WC modifies this association.

Bone turnover markers in sheep and goat: A review of the scientific literature

ABSTRACT Bone turnover markers (BTMs) are product of bone cell activity and are generally divided in bone formation and bone resorption markers. The purpose of this review was to structure the available information on the use of BTMs in studies on small ruminants, especially for monitoring their variations related to diet, exercise, gestation and metabolic lactation state, circadian and seasonal variations, and also during skeletal growth. Pre-clinical and translational studies using BTMs with sheep and goats as animal models in orthopaedic research studies to help in the evaluation of the fracture healing process and osteoporosis research are also described in this review. The available information from the reviewed studies was systematically organized in order to highlight the most promising BTMs in small ruminant research, as well as provide a wide view of the use of sheep and goat as animal models in orthopaedic research, type of markers and commercial assay kits with cross-reactivity in sheep and goat, method of sample and storage of serum and urine for bone turnover markers determination and the usefulness and limitations of bone turnover markers in the different studies, therefore an effective tool for researchers that seek answers to different questions while using BTMs in small ruminants.

Utilidad de los marcadores de remodelado óseo teniendo en cuenta el valor de referencia para el cambio / Clinical Utility of Bone Remodeling Markers Taking Into Account the Reference Value Change

La Modelación y el Remodelado de hueso son llevados a cabo a través del proceso de Recambio Óseo en sitios específicos llamados Unidades de Remodelación Ósea (URO). Este proceso puede evaluarse a través de marcadores bioquímicos de Formación y de Resorción que reflejan cambios globales del metabolismo esquelético. Estos marcadores de remodelado óseo son utilizados para investigación de enfermedades óseo-metabólicas, porque proveen información dinámica del metabolismo del hueso y pueden ser cuantificados en suero o en orina. La variación de estos marcadores se deben principalmente a variables preanalíticas, analíticas y biológicas y debe interpretarse teniendo en cuenta el Valor de Referencia para el Cambio significativo (VRC), que resulta de un cálculo en el que intervienen la variabilidad biológica (VB) del analito y el error aleatorio del método utilizado en el laboratorio.

The Modeling and Remodeling processes are conducted through the process of replacement bone at specific sites called Units Bone Remodeling (URO).These can be evaluated by biochemical markers of formation and resorption that reflect changes in skeletal metabolism. These markers of bone turnover are used for research óseo-metabolic diseases because they provide dynamic information of bone metabolism and can be quantified in serum or urine. The variation of these markers is mainly due to preanalytical, analytical and biological variables and should be interpreted taking into account the Reference Value Change (VRC), which results from a calculation in which the biological variability (VB) of the analyte and the random error of the method used in the laboratory are involved.