Diabetes mellitus and osteoporosis

Association of overweight and obesity with vertebral fractures: a systematic review and meta-analysis

INTRODUCTION

Over the past decade, there has been increasing interest in exploring the relationship between overweight, obesity and vertebral fractures. Nonetheless, available data from studies on the relationship between overweight, obesity and vertebral fractures remains controversial.

EVIDENCE ACQUISITION

A systematic search was performed in the PubMed and Cochrane Library databases. We selected relevant literature by using these keywords: fracture, vertebral fracture, vertebral compression fracture, overweight, obese, obesity. The retrieval mainly collected publicly published observational studies on the correlation between overweight, obesity and vertebral fractures, excluding the literature that did not meet the inclusion criteria. Meta-analysis for the data extracted from all the included literatures was performed by STATA 12.0 (StataCorp LLC, College Station, TX, USA) to summarize test performance with forest plots and assess the heterogeneity.

EVIDENCE SYNTHESIS

Ten studies, including 1,024,181 subjects satisfied the predefined eligibility criteria. The results showed that the overweight (25.0≤ Body Mass Index [BMI] ≤29.9 kg/m2) and obesity (BMI≥30.0kg/m2) were associated with a decreased risk of vertebral fractures, respectively. The pooled RR is 0.86 (95% CI: 0.79, 0.95) and 0.81(95% CI:0.74-0.90) with no evidence of statistical heterogeneity. However, the relationship between overweight/obesity (BMI≥25 kg/m2) and vertebral fractures is not statistically significant.

CONCLUSIONS

This study showed that overweight and obesity might decrease the risk of vertebral fractures, respectively. However, we did not observe a significant association between overweight/obesity (BMI≥25 kg/m2) and vertebral fractures.

Coffee consumption, health benefits and side effects: a narrative review and update for dietitians and nutritionists

Coffee is one of the most popular beverages worldwide; however, its impact on health outcomes and adverse effects is not fully understood. The current review aims to establish an update about the benefits of coffee consumption on health outcomes highlighting its side effects, and finally coming up with an attempt to provide some recommendations on its doses. A literature review using the PubMed/Medline database was carried out and the data were summarized by applying a narrative approach using the available evidence based on the literature. The main findings were the following: first, coffee may contribute to the prevention of inflammatory and oxidative stress-related diseases, such as obesity, metabolic syndrome and type 2 diabetes; second, coffee consumption seems to be associated with a lower incidence of several types of cancer and with a reduction in the risk of all-cause mortality; finally, the consumption of up to 400 mg/day (1-4 cups per day) of caffeine is safe. However, the time gap between coffee consumption and some drugs should be taken into account in order to avoid interaction. However, most of the data were based on cross-sectional or/and observational studies highlighting an association of coffee intake and health outcomes; thus, randomized controlled studies are needed in order to identify a causality link.

Melatonin inhibits osteoclastogenesis via RANKL/OPG suppression mediated by Rev-Erbα in osteoblasts

Diabetic osteoporosis is secondary osteoporosis and a serious complication of diabetes with a high incidence rate and poor prognosis. The specific mechanism of diabetic osteoporosis is unclear, and prevention and treatment options are limited. Recently, melatonin has been found to prevent and treat diabetic osteoporosis. Herein, we investigated the mechanism whereby melatonin inhibits osteoclastogenesis and identified a new target for osteoporosis treatment. We established an in vitro osteoblast–osteoclast co‐culture system as a diabetic osteoporosis model. Osteoclastogenesis was determined using tartrate‐resistant acid phosphatase staining and cathepsin K expression. Real‐time PCR was used to ascertain expression of microRNA mir‐882, targeting Rev‐Erbα. Western blotting was performed to detect the expression of Rev‐Erbα, receptor activator of NF‐kB ligand (RANKL), and osteoprotegerin (OPG), and ELISA was utilized to analyse the secreted form of RANKL. High glucose promoted osteoclastogenesis and elevated the RANKL/OPG ratio in osteoblasts, while melatonin reversed these effects. High glucose inhibited Rev‐Erbα expression, while melatonin promoted its expression. Conversely, high glucose promoted mir‐882 expression, while melatonin inhibited it. We infer that melatonin inhibits RANKL expression in osteoblasts via the mir‐882/Rev‐Erbα axis, thus inhibiting osteoclastogenesis. Our findings provide insights into diabetic osteoporosis and identify a new therapeutic target for osteoporosis.